Will ASECNA meet the needs of african air navigation for the 21st century? an analysis of asecna strategy for adopting CNS/ATM

Department of Air
Transport Management

Will ASECNA meet the needs of African

air navigation for the 21^st century?

An analysis of ASECNA strategy for adopting advanced CNS/ATM

MSc THESIS

Academic year 2004-2005 Francis Fabien Ntongo Ekani Supervisor: Rodney Fewings

CRANFIELD UNIVERSITY

SCHOOL OF ENGINEERING
DEPARTMENT OF AIR TRANSPORT

MSc THESIS
Academic year 2004 - 2005

Will ASECNA meet the needs of African
air navigation for the 21^st century?

An analysis of ASECNA strategy for adopting advanced CNS/ATM

By Francis Ntongo
Supervisor: Rodney Fewings

This thesis is submitted in partial fulfilment of the requirements for the degree of Master of Science

To My Parents

Abstract

This MSc thesis aims at investigating the rationale of implementing CNS/ATM¹ systems in ASECNA area, a region of the African continent. The question of whether ASECNA's modernisation strategy will respond to African air navigation's future needs is essential to the region, as a performing system is a prerequisite for the viability of air transport activities.

The study analyses the situation of service provision in the region and highlights the needs and the priorities. It also assesses the suitability of future air navigation systems, their ability to respond to these needs, and it provides an analysis of ASECNA's strategy.

The region is characterised by an insignificant level of traffic at a global scale. Local air transport industry needs help to reduce its costs, as the majority of carriers are struggling to survive in a context of combined low demand, and very high fuel prices. There are a high number of air navigation incidents relatively to the level of traffic. That is due to an inefficient system based essentially on conventional navigation systems, which are very often unreliable and underperforming. The research reveals the predominance of Safety, Efficiency and airspace Fragmentation as the primary performance drivers for evolving the system. ASECNA is responding to its users' needs by implementing future air navigation systems. CNS/ATM trials suggest that the technology can respond to regional priorities as they bring greater efficiency, increased capacity and safety, and enhanced cross border cooperation and cost effectiveness. They are also suitable for inhospitable areas like in ASECNA.

Local airlines have limited means to upgrade their old fleets. Foreign carriers operate high yield routes and generate 80 per cent of ASECNA's revenues and operate young well equipped aircraft. Therefore, the agency has developed a dual strategy, by maintaining ground-based systems for small local carriers on domestic routes, while introducing CNS/ATM systems on main areas of routing.

ASECNA will make the new systems available to its users, but it will not necessarily be cost effective. However, the success of the implementation process also depends on the ability of member states to upgrade and harmonise their legislations on time. The slowness of legislative procedures and the lack of harmonisation in Africa will delay the benefits, which is damaging to the industry.

¹ Air Traffic Management supported by three components: Control, Navigation and Surveillance

Acknowledgement

I'd like to thank Rodney, my supervisor, for his constant support, his wise and constructive critics and all the advices he gave me and that contributed to the success of this thesis. Andy Foster and Simon Place also gave me a decisive support.

I'll also like to thank Professor Fariba Alamdari, the Head of Air Transport Group, for having made me to understand what management is about: Always being Positive and getting the best from People.

Special thank to ASECNA for their precious and invaluable support throughout the project, and for welcoming me during one week at their Head Quarter in Dakar, Senegal:

Youssouf Mahamat, Director General Amadou Guitteye, Director of Operations Wodiaba Samake, Head of training office

And

Marafa Sadou, Special adviser to the director of operations Diallo amadou Yoro, Head of Normalization office

Hilaire Tchicaya, Head of Aeronautical Telecommunication office

Ngoue Celestin, Head of Air Navigation

Sacramento Martin, Engineer, office of Statistics

Edmond Hocke Nguema-Biteghe, Head of Network Operations

Armand Boukono, Engineer, Normalization office Ndobian Kitagoto, Engineer, Meteorology office

Aviation companies Air Benin, Air France KLM Air Inter Cameroon Air Madgascar Air Senegal international Bellview Airlines, Cameroon Airlines

Aéroport Du Cameroun (ADC) Etablissement National de la Navigation Aérienne (ENNA, Algeria)

Table of content

Abstract i

Acknowledgement ii

Table of Content iii

List of figures v

List of tables viii

Glossary ix

Chapter 1 Introduction to thesis page 1

1.1 Background 1

1.2 Research questions 3

1.3 Objectives 4

1.4 Methodology 4

1.5 Structure of thesis 7

1.6 Data sources 7

1.7 Key assumption 7

1.8 Choice of performance measures 8

1.9 Summary 9

Chapter 2 ASECNA's region Air Transport Industry 10

2.1 Economic characteristics 11

2.2 Transport infrastructure 13

2.2.1 Roads 13

2.2.2 Railways 13

2.2.3 Ports 14

2.3 Air Transport Industry 14

2.3.1 Airport Infrastructure 15

2.3.2 Airlines 16

2.3.3 Fleet 17

2.4 Regulatory 25

2.5 Air Travel Demand 26

2.6 Conclusion 32

Chapter 3 Air navigation Performance Review 34

3.1 Introduction 34

3.2 Airspace organization 34

3.2.1 Description of ASECNA's strategy 34

3.2.2 Fragmentation 36

3.3 Traffic 38

3.3.1 Airport activity 38

3.3.2 En-route traffic 40

3.4 Delays 44

3.5 Impact of future trends 44

3.5.1 Prospects 44

3.5.2 Impact on runway capacity 45

3.5.3 Impact on en-route capacity 46

3.6 Traffic complexity 47

3.7 Safety 48

3.7.1 Air Proximities 48

3.7.2 Users' claims 49

3.7.3 Birdstrikes 49

3.7.4 Safety Review System 50

3.8 Efficiency 50

3.8.1 Flight efficiency 50

3.8.2 Fuel efficiency 51

3.9 Cost effectiveness 54

3.9.1 Navigation charges 54

3.9.2 Air Navigation Costs 55

3.10 Cooperation 57

3.11 Training 59

3.12 Financing 59

3.13 CNS and Aviation weather management issues 60

3.13.1 Shortcomings of conventional systems 60

3.13.2 ASECNA's systems' performance 64

3.15 Conclusion 69

Chapter 4 CNS/ATM systems and concepts 70

4.1 Introduction 70

4.2 Suitable CNS/ATM systems for ASECNA 72

4.2.1 Geographic characteristics 72

4.2.2 Efficiency 72

4.2.3 Capacity for Safety 73

4.2.4 Surveillance 73

4.3 Study of selected systems 73

4.3.1 Communications 73

4.3.2 Navigation 83

4.3.3 Surveillance 92

4.3.4 Air Traffic Management 97

4.4 Transition phase 98

4.6 Affordability 99

4.7 Conclusion 100

Chapter 5 Analysis of ASECNA's modernization strategy 102

5.1 Description of the strategy 102

5.1.1 Communications 102

5.1.2 Navigation 103

5.1.3 Surveillance 103

5.1.4 Systems on board the aircraft 105

5.1.5 Aviation weather 105

5.1.6 Air Traffic Management 106

5.1.7 Cooperation 107

5.1.8 Training 110

5.1.9 Financing 110

5.1.10 Implementation schedule up to 2015 112

5.2 Analysis 113

5.3 Conclusion 115

Chapter 6 Recommendations and Conclusion 117

References 122

Appendix 1 Presentation of ASECNA 126

Appendix 2: Ground Based Navigation Systems Principles 130

1 How the VOR works 130

2 How DME works 132

3 How ILS works 133

4 Multilateration 134

Appendix 3 WGS-1984 136

Appendix 4 ASECNA'S Telecommunications Network 137

Appendix 5 Air Traffic Projected Growth by world region 138

Appendix 6 ICAO's Navigation SARPs 139

Appendix 7 ASECNA's Satellite Navigation Circuits 140

Appendix 8 ASECNA'S ATS/Direct Speech Network 141

Appendix 9 CNS/ATM: Drivers and Origins 142

List of Figures

Chapter 1

Figure 1.1 Short term evolution of crude oil 2

Figure 1.2 Analytical Framework of ASECNA's performance analysis 5

Chapter 2

Figure 2.1 ASECNA area in this report 10

Figure 2.2 Share of population and GDP by country 12

Figure 2.3 Stakeholders 15

Figure 2.1 Repartition of Aircraft types in Africa 18

Figure 2.2 Intra African market Fleet (Jets + Turbo Propellers) 19

Figure 2.3 African fleet annual utilization 20

Figure 2.4 African fleet Evolution from 2003 to 2023 21

Figure 2.5 RPK, ASK (Billion) and Passengers load factors in Africa 21

Figure 2.6 Trend in Aviation fuel cost 23

Figure 2.7 Yields and Unit costs in Key markets 23

Figure 2.8 African Airlines ¹ Operating costs (Unit cost $ per tonne per Km) 24

Figure 2.9 Regional share of global international air passenger traffic 26

Figure 2.10 Evolution of passenger traffic (1994-2003) 27

Figure 2.11 Average Airport Passenger Traffic (2000-2004) 28

Figure 2.12 Evolution of Cargo traffic (1994-2003) 31

Chapter 3

Figure 3.1 ASECNA's Flight Information Regions 37

Figure 3.2 Number of flights from 1993 to 2003 38

Figure 3.3 Number of aircraft movements at 15 key airports 39

Figure 3.4 Areas of Routing 41

Figure 3.5 Average number of flights controlled per hour and per controller 43

Figure 3.6 Projected growth over the next decade 45

Figure 3.7 Projected runway occupancy in ASECNA's main airports 46

Figure 3.8 Projected controllers' productivity in 2015 47

Figure 3.9 Evolution of Air Proximities 48

¹ Flight Equipment comprises maintenance, insurance, and rental. The others operating expenses are not mentioned here. But it's interesting to note that administration unit costs for non efficient airlines are extremely high, almost twenty times higher than an efficient airline' unit costs.

Figure 3.10 Evolution of incidents during the last six years 49

Figure 3.11 Flight paths between Douala and Dakar 51

Figure 3.12 The different phases of a flight 52

Figure 3.13 Evolution of air navigation charges 54

Figure 3.14 Personnel, ANS and transport costs from 1996 to 2003 55

Figure 3.15 Evolution of the average cost per flight from 1996 to 2003 56

Figure 3.16 Evolution of en route revenues from 1996 to 2003 57

Figure 3.17 Regional fragmentation of ATM sectors 58

Figure 3.18 Financial results from 1994 to 2003 59

Figure 3.19 OPMET availability rate 68

Chapter 4

Figure 4.1 Communication links in ASECNA 74

Figure 4.2 CPDLC test message 75

Figure 4.3 Estimated capacity gained as a function of % of CPDLC equipage 76

Figure 4.4 Aeronautical telecommunications network concept 82

Figure 4.5 Comparison between EGNOS and GPS 85

Figure 4.6 Lateral and Vertical Total System Error 87

Figure 4.7 Comparison between RNAV, RNP and conventional navigation 89

Figure 4.8 Atlanta SID trials: Non RNAV tracks 90

Figure 4.9 Atlanta SID trials: RNAV tracks 90

Figure 4.10 Projected RNP-RNAV capable aircraft 91

Figure 4.11 ADS-B operational capabilities 94

Figure 4.12 ADS-B performances Vs Radar 96

Chapter 5

Figure 5.1 Classification of CNS/ATM expenditure 112

Figure 5.2 Possible Airspace redesign by 2030 115

Appendices

Statutory structure 128

External representations' organisation chart 129

VOR station 131

World Geodetic System 136

ASECNA's Telecommunication Network 137

ASECNA's Satellite connectivity 140

ASECNA's ATS/DS network 141

Evolution of CNS/ATM implementation 145

List of Tables

Table 2.1 Comparative GDP and Population 11

Table 2.2 Situation of aircraft operated in the world 19

Table 2.3 Daily passenger traffic between city pairs 29

Table 2.4 International traffic at major regional airports 30

Table 3.1 The main airstream in ASECNA 40

Table 3.2 Traffic by FIR 40

Table 3.3 Average traffic density from 2001 to 2003 42

Table 3.4 Average traffic density by 2015 46

Table 3.5 Average ANS cost per flight in Europe, ASECNA and the USA 56

Table 3.6 Equipments availability 65

Table 3.7 Air circulation control: controlled routes 67

Table 4.1 Workload reduction as a function of aircraft equipage 77

Table 4.2 Delays reduction as function of aircraft equipage 77

Table 4.3 Results for lateral and vertical accuracy with EGNOS 87

Table 4.4 Results for availability during trials Vs ICAO's SARPs 87

Table 4.5 ICAO's SARPs for lateral and vertical accuracy 87

Glossary A

ACC Area Control Centre

ADS Automatic Dependent Surveillance

ADS-B Automatic Dependent Surveillance Broadcast mode

ADS-C Automatic Dependent Surveillance Contract mode

AFI Africa Indian ocean area

AFS Aeronautical Fixed Service

AFTN Aeronautical Fixed Telecommunication Network

AIS Aeronautical Information Service

AMS(R) S Aeronautical Mobile-Satellite (R) Service

AMHS Aeronautical Mobile Handling System

AMSS Aeronautical Mobile-Satellite Service

ANSP Air Navigation Service Provider

AOC Airline Operation Centre

APIRG AFI Planning and Implementation Regional Group

APV Approach with vertical guidance

AR Area of routing

ASECNA Agency for Security, Aerial Navigation in Africa and Madagascar

ASM Airspace Management

ASK Available Seat Kilometre

ATC Air Traffic Control

ATFM Air Traffic Flow Management

ATM Air Traffic Management

ATN Aeronautical Telecommunication Network

ATS Air Traffic Services

ATS/DS Air Traffic Services Direct Speech

C

CDM Collaborative Decision Making

CDMA Code Division Multiple Access

CFIT Controlled Flight Into Terrain

CNS/ATM Communications, Navigation, Surveillance / Air Traffic Management CPDLC Controller pilot data link communications

D

DECCA A low frequency hyperbolic radio navigation system

DFIS Data Link Flight Information Services

DME Distance Measuring Equipment

E

EGNOS Eurpean Geostationary Navigation Overlay Service

EUR European Region

EUROCAT Thales ATM (Commercial organisation) air traffic management automation product

F

FAF Final Approach Fix

FANS Future Air Navigation Systems

FIR Flight Information Region

FDPS Flight Data Processing System

FL Flight Level

FMS Flight Management System

G

GLONASS Global Orbiting Navigation Satellite System (Russian Federation)

GNSS Global Navigation Satellite System

GPS Global Positioning System (United States)

H

HF High Frequency

HFDL High Frequency Data Link

I

IATA International Air Transport Association

ICAO International Civil Aviation Organization

IFR Instrument Flight Rules

ILS Instrument Landing System

INS Inertial navigation system

ITU International Telecommunication Union

L

LORAN Long Range Air Navigation

M

MET Meteorological services for air navigation

METAR Aviation routine weather report

MLS Microwave Landing System

MODE S Mode Select

N

NDB Non-directional beacon

NOTAM Notice To Airmen

NPA Non-precision approach

NSE Navigation System Error

O

OPMET Operational Meteorology

P

PDN Paquet data Network

PIRG Planning and Implementation Regional Group

R

RIMS Ranging Integrity Monitoring Station

RNAV Area Navigation

RNP Required Navigation Performance

RPK Revenue Passenger Kilometre

RTK Revenue Tonne Kilometre

RVSM Reduced Vertical Separation Minimum

S

SAM South American Region

SARPs Standards and Recommended Practices

SAS Scandinavian Airways

SAT South Atlantic

SATCOM Satellite Communication

SBAS Satellite-based augmentation system

SID Standard Instrument Departure

SIGMET Significant Meteorological event

SIGWX Significant Weather

SITA Société Internationale de Télécommunications Aéronautiques

SSR Secondary Surveillance Radar

T

TACAS Terminal Access Controller Access Control System

TACAN Tactical Air Navigation

TAF Terminal area forecast

TDMA Time Division Multiple Access

TMA Terminal Manoeuvring Area

TSE Total System Error

V

VDL VHF Data Link

VFR Visual flight rules

VHF Very High Frequency

VOR VHF Omnidirectional Radio Range

W

WGS-84 World Geodetic Reference System 1984

Chapter 1 : Introduction to Thesis

The aim of this chapter is to introduce the research topic and to present the objectives and the methodology used to respond to the research question.

1.1. Background

Agency for Air Navigation Safety in Africa (ASECNA¹) is a regional publicly held establishment that provides navigation services to 15 West and Central African Countries², plus Madagascar and the Comoro islands in the Indian ocean.

The region is relatively poor. Economic characteristics are those of developing countries. Some of the less advanced countries are located there.

ASECNA covers an area of 16 million square kilometres³, most of which is unoccupied and dominated by the Sahara desert, oceans and forests.

The Air Transport Industry has changed significantly over the past decade. These changes were dictated by a combination of factors, mainly operational and financial, following a succession of crisis⁴. The airline industry is increasingly sensitive to the cost of doing business.

Efficiency

Air carriers demand direct routes, flight level optimization, efficient in-flight and improved en-route fuel⁵ consumption. Figure 1.1 below shows the projected upwards evolution of crude oil prices. That means airlines' fuel bill will significantly increase. Cost reduction is one aspect of mitigating the effects of fuel high price. It explains why airspace users want more efficiency. It is one of the factors that led them to incite suppliers, such as air navigation service providers (ANSP) to improve their effectiveness and the quality of service provision.

¹ In the present study designates both the agency or the geographic region

² Benin, Burkina Faso, Cameroon, Central African Republic, Chad, Congo Brazzaville, Equatorial Guinea, Gabon, Ivory Cost, Mali, Mauritania, Niger, Senegal, Togo. France is also an observer member.

³ Equivalent to almost 66 times Great Britain size.

⁴ September Eleven, SARS, Bird Flu, Second Golf War...

⁵ Crude oil price was around 50 dollars per barrel in 2005

Figure 1.1: Short-term evolution of crude oil prices

Source: IATA, 2006

Capacity

Air travel and air traffic are continuously growing. The number of aircraft movements has increased by 5.3 per cent per year on average over the past 15 years in ASECNA region, which is in line with worldwide trends. The growth is forecast to continue at an estimated yearly pace of 5 per cent. That activity means an increasing pressure will be put on airports and air navigation systems, which may raise airspace and airport capacity concerns.

Safety

Safety records are worrying in Africa. The continent represents only about 3 per cent of global traffic. Nevertheless, statistics show that almost one third of fatal accidents over the past ten years occurred in Africa according to IATA.

Air Transport is a catalyst for development and trade. Efficiency, Capacity and Safety of air navigation systems are therefore strategic components for a viable regional⁶ air transport industry and growing national economies.

The important question is whether ASECNA will manage to overcome the current and future challenges. Will they respond to users' requirements while delivering a safer service, in the interest of regional air transport?

The agency has embarked on a modernisation programme since 1994. It is implementing modern air navigation systems, known as Future Air Navigation Systems (FANS) or CNS/ATM (Control, Navigation, Surveillance and Air Traffic Management).

CNS/ATM systems are a complex and interrelated set of technologies and concepts largely based on satellite communication. They are the response brought forward by the aviation community, under the aegis of the International Civil Aviation Organisation (ICAO), in response to the challenges described above. Regional work groups have been put in place to coordinate efforts. ASECNA is member of AFI⁷ Planning and Implementation Regional Group (APIRG), which regroups African and Indian Ocean countries

The thesis intends to investigate current systems' performance in ASECNA. It highlights regional shortcomings and needs, and examines the agency's modernisation strategy, CNS/ATM adopted solutions, and their implications on service provision for the next 15 years.

1.2. Research Questions

The main research question of the thesis is: Will ASECNA meet the needs of African Air Navigation for the 21^st Century?

Responding to that question requires that the following intermediate questions are dealt with:

⁶ ASECNA region

⁷ Africa and Indian Ocean

1. What are the needs and the priorities of African Air Navigation for the 21^st
century?

2. Are CNS/ATM systems the suitable tool with regard to regional characteristics?

3. Will ASECNA's modernisation strategy respond effectively to the needs?

1.3. Objectives

The objectives of the study are to:

1. Examine the state and the performance of air navigation service provision in

ASECNA

2. Study the potential benefits of CNS/ATM systems to the region

3. Analyse ASECNA's modernisation plans 1.4. Methodology

This research is based on an analytical approach to assessing ASECNA's capability to respond to airspace users' needs and requirements and regional air transport's interests. To answer to the first research question that aims at defining the needs and the priorities of African Air Navigation, we process as follows:

First, the region's air transport industry is assessed. This is done by examining local air transport characteristics:

1. Analysis of air travel demand

2. Assessment of air carriers types

3. Examination of air carriers performance

4. Examination of airport and alternative transport infrastructures

5. Overview of regulations and the factors that influence air traffic.

Secondly, the air navigation system's performance is studied, by analysing key performance areas and related indicators:

1. Traffic demand, Capacity, Delays

2. Complexity, Safety, Aircraft proximities

3. Performance of CNS and Met systems.

4. Fragmentation, Cost Effectiveness

5. Flight efficiency

6. Cooperation.

The analytical framework used is described in figure 1.2 below. The structure is based on a model developed by the Eurocontrol Performance Review Commission to assess European Air Traffic Management performance. It has been adapted for the present study.

Figure 1.2: Analytical Framework of ASECNA's performance analysis

Performance Drivers			Performance indicators
							ANS Key performance Areas
Fragmentation				Service provision cost
								Flight Efficiency

Cooperation

Safety

Complexity

Traffic
demand

AIRPROX

CNS Met
Systems
Availability

Cost
Effectiveness

Capacity

Delays

Productivity

ASECNA performance

Source: Eurocontrol, Performance Review Report 8, 2005

Finally, the impact of traffic growth is estimated. We apply forecasted growth rates to current data, in this case 2003.

To answer to the second research question, which aims at determining the relevance of CSN/ATM systems in ASECNA, we adopt the following method:

Based on the system's deficiencies and local characteristics drawn from the previous performance analysis:

1. Identification of potentially suitable CNS/ATM technologies and systems based on FANS performance during worldwide trials. These trials are performed under certain geographic and operational conditions; some of them match ASECNA area's characteristics.

2. Their affordability is assessed At last, the third research question is dealt with as follows:

1. Assessment of the technology solutions adopted

2. Assessment of the implementation process, and we analyse the strategies in the areas listed below:

a. Communication

b. Navigation

c. Surveillance

d. Met

e. Air Traffic Management

f. Training

g. Programme financing

h. Cooperation

3. Assessment of the timeframe by confronting the predicted timetable and realized projects.

When quantifiable data are not available, interviews allow to have an idea of the situation. Interviewees are ASECNA's high profile staff, airlines directors, and other ANSPs' personnel.

1.5. Structure of Thesis

The choice of performance areas is discussed in chapter 1. The overview of ASECNA region's air transport industry is discussed in Chapter 2. An insight of regional characteristics is given, which provides a better understanding of the operational environment and the context, as well as the importance of a performing air navigation system for the region. A detailed analysis of air navigation systems' performance is provided in Chapter 3. Local navigation characteristics are discussed, and predefined performance areas presented in chapter 1 are examined. That allows highlighting the areas that require improvements and to define what should be the priorities for the region. Chapter 4 presents CNS/ATM systems and concepts and looks at their potential benefits, with regard to local characteristics. Finally, the strategy adopted by the agency to respond to those priorities is examined in chapter 5.

1.6. Data Sources

The instruments for this study include a one week visit to ASECNA's headquarter in Dakar, Senegal, to collect data and documents, to discuss with professionals involved in daily operations and to observe the actual state of the implementation of the strategy on the ground. Telephone interviews, email-statements, internet documentation are intensively used. Key internet documents come from ICAO, ASECNA, IATA, and CANSO⁸'s CNS/ATM related literature.

1.7. Key Assumptions

The geographic boundaries of the study are clearly the region covered by ASECNA. However, as ASECNA⁹ is part of the wider geographic entity, the study of this region naturally implies to investigate its interactions with the neighbourhood.

⁸ Civil Air navigation Services Organisation

⁹ Seen here as a region, not the organization itself

A key assumption in the study is that average economic and air traffic prospects that are applicable to the African continent are applicable to ASECNA. This is a sensitive approach as the economic characteristics of the region are similar to the continent's patterns. However, the average growth figures may be driven up by air transport leading countries. In particular, air transport is less developed in ASECNA then Southern, Eastern Africa, and North Africa.

Another key assumption is that the relative importance of individual countries' air transport performance is frozen over the period studied. Therefore, the relative importance of airports size and spatial distribution of traffic flows within the region is supposed to remain unchanged.

1.8. Choice of performance indicators

A large number of indicators could be used to assess ASECNA's performance. How ever, for this study, several factors influenced the choice of indicators:

The availability of data: several other indicators could have been used but ASECNA does not collect the corresponding data. Moreover, some chosen indicators could have been broken down into more detailed data, but that has not been possible.

The effectiveness of chosen indicators in assessing an ANSP's performance:

Safety, Capacity, Flight efficiency, Cost Effectiveness, cross border cooperation are aspects of an ANSP operation that effectively evaluate the quality of service provision.

Safety

Safety performance measures are hardly available in ASECNA. However, indicative incidents reports are used to assess the safety level. A comparison with other Regions' safety records with respect to the level of traffic gives an idea of ASECNA's performance.

Capacity

Capacity is closely related to delays and the level of traffic. Although delays data are not available, interviews allow having an idea of influent factors.

Flight Efficiency

The availability of a maximum number of direct routes and the possibility to chose optimum flight levels are crucial to airlines as it allows reducing their fuel bill.

Cost effectiveness

The bill paid by airlines for service provision depends on ASECNA's ability to maintain low operating costs.

Cooperation

The level of technical and political cooperation indicates how states and ANSPs work together to avoid unnecessary costs to airlines, and make the airspace as seamless as possible.

1.9. Summary

This chapter laid the foundations for the thesis. It introduced the research problem and questions: Will ASECNA meet the needs of the African Air Navigation for the 21^st century? In addition, what are the problematic and the challenges related to the achievement of that mission? The research was justified, and the methodology, based on an analytical approach was detailed. Performance indicators have been presented and discussed. Key assumptions were presented.

Chapter 2: ASECNA's Air Transport Industry

The aim of this chapter is to find out the region's air transport industry's characteristics. This is an important step as it helps to understand in which environment ASECNA evolves, and the factors that may influence its activities. Further details on ASECNA as an organization and its history are included in appendix 1.

Figure 2.1: ASECNA area in this report

Source: ASECNA

2.1 Economic Characteristics

ASECNA comprises developing countries, mainly located in western or Central Africa, except Madagascar and the Comoros Islands located in the Indian Ocean (See map above). Their Economies are relatively weak. Mali, Niger, Chad, Burkina Faso Togo and the Central African Republic (CAR) are among the poorest country in the world. The general picture is one of underdevelopment, political instability, economic volatility and high poverty. Comparative Gross Domestic Products and populations between ASECNA, the world average and UK's performance reflect that situation (Table below).

Region	GDP ($ billion)	GDP /Capita ($ thousand)	Population (million)
ASECNA^1	93	1.7	141
WORLD	43920	9.5	6,526
UK	2218	31	60

Table2.1: Comparative GDP and populations;
Source: CIA World fact book, 2006

The region accounts for just 0.2 per cent of world GDP. But in contrast to its low share of economic activity worldwide, as the table above shows it, 141 million people live in ASECNA, which is 2.2 % of world population. That combination of low input and high population means the GDP per capita in ASECNA is the lowest among the world regions (1700 dollars). UK for instance is 24 times wealthier, and its GDP per capita is 26 times ASECNA's average. 46 per cent of the population lives under the poverty line in the region.

Countries in ASECNA remain to a large extent producers of raw materials. They export agricultural goods such as coffee, cocoa and cotton, or mineral such as crude oil and copper. Trade exchanges in ASECNA region tend to be dominated by agricultural exports.

¹ Data compiled from CIA world Fact book 2006

However, economic development is not homogeneous within the region. Noticeable disparities between countries exist. For example, while Equatorial Guinea represents only 0.4 per cent of regional population, it accounts for 8.3 per cent of GDP. In contrast, Madagascar that contains 13 per cent of total population accounts only for 4.9 per cent of regional GDP. (Figure 2.2)

Figure 2.2: Share of Population and GDP by country

20

18

16

(percentage)

14

12

10

8

6

4

2

0

% Population %GDP

Source: CIA fact book 2006

Ivory Coast, Cameroon, Senegal, Gabon and Equatorial Guinea account for almost 60 percent of ASECNA GDP and one third of the population, while Comoros, Niger, Mauritania, Togo, and CAR own 9.3 per cent of GDP and host 20 per cent of population.

Regional integration processes are on the way. ASECNA members countries located in West Africa are part of ECOWAS (Economic Community of West African States). Those located in Central Africa are members of CEMAC (Central Africa Economic and Monetary Union). The level of integration varies significantly. The ECOWAS is much more advanced than the CEMAC. But the two entities are confronted to the economic

disparities described above, which slow the pace of integration. The lack of a real political will in CEMAC, or persisting political instability and civil wars in key countries such as Ivory Coast, and the Republic of Congo have also had a damaging impact on regional economic and political integration.

In other respects, bad Governance is a common practice at the state level and in public companies. States continue to own a high number of companies in strategic sectors such Telecommunications, Water, Energy and Transports, although privatisations are spreading across the region, mainly on the basis of International Monetary Funds Recommendations (IMF). It is generally admitted that state ownership, «poor management and monitoring, and anti-competitive arrangements have bred corruption in Africa» and particularly in the ASECNA area (Morrell, 2005)

These factors, combined with the low level of investments (Foreign Direct Investments are among the lowest in the world), contribute to explain the underdevelopment of basic infrastructures, particularly in the transport sector.

2.2 Transport infrastructure

2.2.1 Roads

Roads are the predominant mode for freight and passenger transport in Africa (World Bank, 2005). But within individual countries, very often, only the main cities are linked by paved roads. Regional interconnection is very limited. There are only 39,000 Kilometres of paved roads in the entire region, which represents 18 percent of total road network. Moreover, these roads are often in a relatively bad state due to poor maintenance. In comparison, UK alone has 392,931 Kilometres of highways, which is ten times more. That situation renders economic exchanges very difficult and slows their intensity as well as it limits regional integration.

2.2.2 Railways

Railway links are very poor or do not exist within and between countries. Two third of the actual rail infrastructure were inherited from the colonial period (OEDC, 2005, P.22).

There are only 8228 Kilometres of railways in ASECNA countries (17300 in the UK). Some states such as Niger, Chad, Equatorial Guinea, Comoros, and CAR have simply no railway infrastructure, which means their economic activity depends heavily on the road system.

2.2.3 Ports

There are a dozen key ports in ASECNA. The most important of them is Dakar, with about 10 millions tonnes of goods. The essential of ASECNA countries trade activities is carried out through these ports. For instance, 98 per cent of exchanges between Cameroon and the outside world are done through Douala autonomous port, with about 5.2 millions tonnes per year (Mission Economique, 2006)

But, the reliability and the speed of exchanges of goods and mobility of people is a crucial factor for regional integration. Given the under performance of road, and rail systems, and the slowness of sea transport, the availability of an adequate air transport infrastructure is therefore of paramount importance for ASECNA countries as they try to integrate into the world economy.

2.3 Air Transport industry

A developed air transport industry is a driving force for economy, and a catalyst for development and trade. It facilitates exchanges between countries in which air transport substitutes, the road and rail systems are underdeveloped.

Passenger aviation is the principle mean of transport for business and tourism travellers. Airports link the movement of passengers and goods to national economies; they serve as a primary hub for the tourism industry, and as key logistical centre for international trade.

Stakeholders in ASECNA are the states, airlines, ANSPs, airports and international institutions. The study focuses on the relation between ANSPs and other stakeholders (Figure 2.3).

States are represented by civil aviation authorities and Governments. They make air transport policies, on the basis of strategic objectives, through legislations applying to all the others stakeholders in the region.

Airlines are of different types: International, Domestic, and Regional. Both ASECNA originated airlines and the others are considered.

Airports are divided into main and secondary airports.

The region only air navigation service provider is ASECNA. The institution has links with others neighbouring ANSPs.

Figure 2.3: The stakeholders²

Policy Makers
Governments
Civil Aviation

Authorities

Air Travel
Customers

Other ANS
Providers

Policy
Objectives

Cooperation

Airlines
Domestic
Regional

International

Legislations
Institutions

Air Navigation
Provider

ASECNA

Performance

Airports
Main
Secondary

2.3.1 Airport Infrastructure Main Airports

The airport infrastructure (airstrips, air terminals, aircraft hangars) of ASECNA member states comprises about 25 international airports (2400 to 3500 m of tarred runways) regularly used. The main airports are Dakar, Abidjan, Douala, Libreville, Brazzaville and Antananarivo. They are served by major regional, continental and intercontinental airlines. The service provided is acceptable, but is far from being good.

The airport sector is not free from financing, safety and security problems. Built for the
most part in the 1960s and 1970's, they present deficiencies. These vary from State to
State. Runways are generally in a bad state, taxiways and parking areas are often

² All the stakeholders are not taken into account: Ground Handling, Maintenance, Catering... etc

unsuitable; passenger terminals are cramped or saturated in peak hours. There are insufficient cargo hangars, refrigerating warehouses and fencing (African Union, 2005). There are needs for the updating of these installations to meet international standards. The inexistence of airport fences or in disrepair poses serious security and safety problems.

Secondary Airports

The region counts about 150 domestic airports (runways of 1000 to 2000 m, usually unpaved) and about 200 other national aerodromes (poorly maintained), with for several of them inexistent traffic. These airports do not often have adequate navigation aids, or basic airport commodities, which constrains their accessibility.

2.3.2 Airlines

In West Africa, and particularly in ASECNA, the liquidation of Air Afrique after 40 years of existence marked the end of a symbol of African airline integration.

Data from Air Transport Intelligence show that nearly 81 per cent of airlines serving ASECNA are African. 50 per cent are from member states and 31 per cent from other continents.

The main local carriers are Air Madagascar, Air Senegal international, Cameroon Airlines, Air Gabon, Air Ivoire, Air Burkina, Air Mauritania, Air Togo, and Toumai Air Tchad.

Domestic Airlines

The poor domestic markets are served by national carriers or very small companies of which the fleet is often constituted by a single aircraft.

Regional Airlines

Air Senegal International, Bellview (Nigeria), Air Ivoire, Cameroon Airlines, Toumaï Air Chad and Air Burkina have put in a lot of efforts to fill up the vacuum left following the demise of Air Afrique. These airlines propose flights to travel within the region from and to the main cities in the regions.

International Airlines

The region can be divided into two groups of countries:

1) Those that no longer have national long-haul carriers with their market largely dominated by foreign companies.

2) Countries that still have national airlines but these are facing strong competition from foreign companies (Cameroon, Gabon, and Madagascar).

Local Airlines

Cameroon Airline, Air Gabon, Air Madagascar and Air Senegal International are the three main local flag carriers. They link the respective countries to Africa and mainly Western Europe and less regularly the Middle East (During the hajj³)

Foreign Airlines

Air France-KLM is the dominant carrier on the long haul market. It serves all ASECNA's main airports. Swiss, SN Brussels, Iberia, Lufthansa and Alitalia also regularly flight to the region. An important figure to highlight is the percentage of international traffic ensured by Western airlines. In fact, according to ASECNA about 80 per cent of the commercial traffic is operated by these carriers⁴.

The Libyan carrier, Afriqiyah Airways is now operating to most of the defunct Air Afrique member countries transforming Tripoli into a hub for passengers connecting to Europe and the Middle East. Tunisia has also started flying to Bamako and Abidjan. Royal Air Maroc (RAM) has opened routes to Dakar, Douala and Gabon.

Ethiopian, South African Airways, Kenyan Airways and Air Inter⁵ also have regular connections with ASECNA.

2.3.3 Fleet

A study by Boeing showed that about 75 per cent of African fleet is composed by
regional jets or single aisle aircraft (Boeing, 2005). This does not take into account
secondary airports exclusively exploited by very small aircraft (Less than 30 seats).

³ Pilgrimage to Mecca

⁴ Air France-KLM, TAP, Alitalia, SN Bruxels, SWISS, Iberia, Lufthansa...

⁵ South African carrier

Most intra African routes are operated with narrow bodies, or very small jets or turbo propellers.

Figure 2.4: Proportion of Aircraft types in Africa

415

78%

92

17%

24

5%

Jets Turbo PropellersSmall size aircraft

Source: Afraa, 2005

Figure 2.5: Intra African market Fleet (Jets + Turbo Propellers)

Source: Ambraer, 2006

	New	Average	Old	Total	% of Old
Africa	162	111	316	589	54
America	1654	2581	1301	5536	24
Europe	1768	1363	237	3368	7
Asia	1154	969	295	2418	12
Middle East	240	144	155	539	29
Pacific	155	102	15	272	6
WORLD TOTAL	5371	5529	2712	13 612	20

Table 2.2: Situation of aircraft operated in the world
Source: African Union, 2006

About 54 % of aircraft operated in Africa are considered to be old or very old. Nearly 45 % of aircraft are more than 15 years old. 20 % are between 10 and 15. 13 % are aged between 5 and 10. Around 22 % are less than 5 years olds (figure 2.5). The average age of the fleet is comprised between 16 and 20 years old. A large proportion of aircraft still operated are aged over 25 and even 30. These aircraft are largely fuel inefficient.

Figure 2.6: African fleet annual utilization

2500

2000

3000

1500

1000

500

0

(Flights Hours per Aircraft)

Fleet age (Years)

45

40

25

20

35

30

5

0

15

10

TP20 TP35 J35 J44 _TP50 ^J50 _TP70 J70 J80 J100 J120 J150 J175 J250 J>300

African annual fleet utilization African Fleet Average Age

Source: Ambraer, 2006

The average annual utilization is 1167 hours per aircraft. There is a strong correlation between fleet utilization and fleet age (Coefficient of correlation equal to «- 0.8»).

Figure 2.7: African fleet Evolution from 2003 to 2023

392

Growth

309

Replaced

332 Stay

60

641 aircraft

701

Source: Airbus, 2005

Airbus estimates that African airlines will take delivery of about 641 new aircraft to replace the current fleet or to sustain growth (Figure above).

2.3.4 Performance

Figure 2.8: RPK, ASK (Billion) and Passengers load factors in Africa

Source: AFRAA, 2005

Load factors, RPK and ASK are improving. But the overall industry's health remains critical in Africa. Load factors may look remarkably high, but they highlight the airlines' dilemma in the African operating climate. The problem is that break even load factors remain higher.

Financial Performance

A sample of 8 airlines serving ASECNA region, comprising South African Airways, Royal Air Maroc, Ethiopian Airlines, Kenya Airways, Air Mauritius, Bellview airways, and Tunisair, made a net profit of over $200 million in 2005 (AFRAA, 2005, p.4). These are encouraging and remarkable results in a world where airlines made huge losses in the recent past But they do not reflect the real picture of the industry's performance. Most airlines, some very small, some bigger, are facing serious difficulties.

Excessive debts, uncoordinated operating networks, liquidation, bankruptcy, are examples of discrepancies generally observed (African Union, 2005). Airlines post very poor financial results. The issue of profitability is crucial in the region: as the market is narrow; it is difficult for local airlines to raise the necessary investment required by the standards of modern airlines. These airlines often operate the same routes. That competition leads to a price war resulting merely in weakening the economic health of these companies which have difficulties in covering their operating costs. Air Afrique⁶ best represents the airline industry's situation in the area. Air Afrique officially lost 194 million dollars between 1984 and 1996. It almost never made significant profit. In 2002, after years of financial crisis, the 11 states that owned the pan-African airline decided to file for bankruptcy. The Bankruptcy came after the failure of a restructuring plan brokered by the World Bank.

The Yaoundé treaty countries have revised their national carriers by designating them as the flag carriers. But they are left under the control of private interests, like Air Ivoire, Air Senegal International, Toumaï Air Chad... etc. Cameroon Airlines and Air Gabon, once the two leading carriers in the region, are now being liquidated or privatized.

High Fuel prices

Fuel price is constantly rising. Fuel represents on average 25 per of operating costs. One
barrel costs on average 70$ world wide and up to 90$ in Africa (2005). The trend is

⁶ Air Afrique was established in 1961 to provide passenger and cargo service within the 12 West African Nations of Benin, Burkina Faso, Central African Republic, Cote d'Ivoire, Congo, Mali, Mauritania, Niger, Senegal, Chad, Togo & Guinea Bissau.

expected to last. These sky-rocketing fuel prices are devastating the industry. As airlines are struggling to improve their bottom lines, fuel efficiency is critical.

Figure 2.9: Trend in Aviation fuel cost

Source: Airbus, 2005

Yields and Unit Costs

Figure 2.10: Yields and Unit costs in Key markets

14,0

12,0
10,0
8,0
6,0
4,0
2,0
0,0

Europe Southern Europe Western Within Europe North Atlantic

Africa Africa

Yield Unit Cost Yield Cost Margin

Source: Airbus, 2005

Yields are declining and the margins remain low. The Southern Africa - Europe market has the lowest unit cost but also the lowest yields, and the lowest margins. Europe - Western Africa is a healthy market for efficient airlines, mainly European, with relatively high yields. Yields are also low in the domestic market. The industry is not expecting a significant improvement of yield.

Most African airlines are inefficient. This results into high unit costs as the figure below shows it. These airlines possess old fleets which are highly oil-consuming. High unit costs reflect low aircraft utilization rates, high maintenance, rental and insurance costs. High air navigation and airport unit costs reflect their old avionics, and their low aircraft utilization.

Figure 2.11: African Airlines ⁷ Operating costs (Unit cost $ per tonne per Km)

0,5 0,4 0,3 0,2 0,1

0

0,6

Fuel & Oil Flight Equipment Airport and Navigation

Charges

Avg inefficient Airline Avg Efficient Airline Avg Efficient Worldwide

Source: Airbus, 2005

⁷ Flight Equipment comprises maintenance, insurance, and rental. The others operating expenses are not mentioned here. But it's interesting to note that administration unit costs for non efficient airlines are extremely high, almost twenty times higher than an efficient airline' unit costs.

2.4 Regulatory

In the absence of valid local carriers, ASECNA states have liberalized their skies because bilateral agreements (Principle of reciprocity) are no longer functioning. Although the deregulation process is on the way, with the ongoing implementation of the Yamoussoukro⁸ liberalisation decision, the open sky agreements, civil aviation codes are still obsolete and not harmonised. Texts on competition are not fully applied: Current regulations impose restrictions over the number of operating airlines, and frequency and capacity.

Western carriers want more liberalization, and would like to see the process speeded up, as they are in a position to dominate the market further.

⁸ Ivory Coast, 1999

2.5 Air Travel demand

2.5.1 Traffic figures

Africa accounts for about 3% of global air traffic in term of Passenger Kilometres performed (African Union, May 2005).

Figure 2.12: Regional share of global international scheduled air passenger traffic

Europe Latin America and Caribbeans

North America Middle East

Asia Pacific Africa

587,998 (29%)

132,934 (7%)

Percentage share by region
( Passenger-kilometres performed in millions, 2004)

354,353 (18%)

64,326 (3 %)

88,027 (4%)

785,828 (39%)

Source: UNESCAP, 2005⁹

This situation reflects its low income, and the lack of air transport infrastructure. This being said, the situation of air transport in Africa is not uniform. It varies from one region to another. Northern, Southern and Eastern Africa's air transport performance is good (Kenyan airways, South African, Ethiopian and Royal Air Maroc). ASECNA area remains in a difficult situation with less traffic and unreliable structures. ASECNA's figures show that the region generates about 7 million passenger traffic per year (2003), which is below what South Africa alone represents in term of annual air passengers.

⁹ United Nation Economic and Social Commission for Asia Pacific

Propensity to travel

Given the low level of incomes, and the widespread of poverty across the region, the propensity to travel is very low. Moreover, the tariffs are «very high», 20 to 30% higher than the rest of the world according to the African Union. High air travel fares reflect the low level of traffic, and limited load factors in most of the routes. Moreover, there are little frequencies between city pairs. That increases aircraft operating costs.

Passenger Traffic¹⁰

Figure 2.13: Evolution of passenger traffic (1994-2003)

1994 1995 1996 1997 1998 1999 2000 2001 2002 2003

(Year)

8,0

7,3

(Million Passengers )

4,0

6,0

5,0

3,0

2,0

0,0

7,0

1,0

4,0

Source: ASECNA, annual reports (1994-2003)

Passenger traffic has grown by about 75% from 1994 to 2003, increasing from about 4 million to around 7 million in 2003. This evolution is due to a sustained economic growth on the continent and worldwide. Traffic recovery is particularly significant in some countries. After recent political unrests in Madagascar and Congo, passenger traffic in main airports grew respectively by 70 and 17 per cent between 2002 and 2003. The increase of figures in the region is also driven by oil- related activities in Chad and

¹⁰ Ässengers Traffic in ASECNA main Airports

Equatorial Guinea. The construction of the pipeline between that country and the oceanic coast through Cameroon has stimulated traffic.

Passenger Traffic by Airport

Figure 2.14: Average Airport Passenger Traffic (2000-2004)

Dakar (Senegal)

Abidjan (Ivory Coast)

Libreville (Gabon)

Douala (Cameroun)

Brazzaville (Rep Congo)

Antanarivo (Madagascar)

Pointe Noire (Rep Congo)

Bamako (Mali)

Malabo (Guinea)

Port Genrtil (Gabon)

Cotonou (Benin)

Yaounde (Cameroon)

Ouagadougou (Burkina)

LOME (Togo)

Nouakchott (Mauritania)

Ndjamena (Chad)

Niamey (Niger)

787

700

500

484

1336

0 200 400 600 800 1000 1200 1400 1600

(Thousand Passengers)

Source: ASECNA, annual reports (2000-2004)

Among the main airports, Dakar airport is the first in the region with more than 1 million passengers per year. It's has been the fastest growing airport in term of passenger volume. The important tourism activity in Senegal is the major factor that explains this performance. The traffic is globally increasing in other airports.

Secondary airports in ASECNA receive insignificant passenger traffic and are often served by very small aircraft.

Domestic passenger traffic

Domestic markets are particularly poorly developed across the region. People tend to travel by road or rail despite the poor state of the network. Only the elite, and business men who can afford it, use air travel to move within countries. Only Gabon has a relatively developed domestic market with more than 340,000 passengers in 2003 (Bergonzi, 2006, P7).

Regional passenger traffic

While regional traffic has significantly increased within the other African regions, it has stagnated in West and Central Africa from 1994 to 2001.

Political trips, seminars, regional emigration and business travels are the main drivers of regional traffic. However, the mobility from one country to another remains extremely difficult. It's sometimes easier to reach another country within the region through Paris for instance. On the 276 regional city pairs, only 5 per cent of them have 150 passengers per day (table below). The busiest city-pair is Abidjan - Dakar.

Daily passenger	Number of city pairs	Percentage (%)
More than 150	14	5
70 - 150	28	10
30 - 70	69	25
10 - 30	69	25
Less than 10	96	35

Table 2.3: Daily passenger traffic between city pairs.
Source: Délia Bergonzi, 2006

The most frequent connections in ASECNA are: Dakar-Bamako, Dakar-Abidjan, Bamako-Abidjan, Douala-Libreville, and Cotonou - Pointe Noire. They all have more then 100,000 passengers per year. Dakar and Abidjan are the two destinations with the highest regional passenger traffic, performing respectively 350000 and 200000 passengers per year (OEDC, 2005). Dakar has 15 direct links with others regional cities and Abidjan is directly linked to 12 others West African cities. The heaviest traffic flows are the Gulf of Guinea (Abidjan-Accra-Lagos corridor), then the Dakar/Abidjan axis.

The lack of air links in the Central and Western regions is at a damaging situation with the presence of a number of landlocked states (e.g. Congo, Central African Republic, Chad, Mali, Niger), where aviation is needed most.

International Passenger traffic

Almost 50% of passenger traffic (6 million out of 11 in 2003) in western and central Africa is international. Traffic at major airports in ASECNA is presented in table below.

	2000	2001	2002	2003
Dakar	803.8	863.2	918.3	1005.6
Abidjan	744.6	6448	301.9	3127
Douala	198.8	252.9	246	283.5
Bamako	168.2	132.2	112.1	197.1
Antananarivo	198.2	209.9	98.5	176.1
Libreville	246.4	203.9	198.9	149.6
Malabo	42	64	73,9	100.2

Table 2.4: International traffic at major regional airports (Thousand).
Source: ASECNA

In international traffic, for the West and Central Africa region, and particularly in ASECNA, the dominant connection is towards Europe.

This traffic can be divided in 3 groups: The ethnic Passenger Group, who has ties with the former European colonial powers, France mainly, creates a natural emigration of workers in both directions (South-North, North-South). The Leisure and Tourism group, concerns high-income people who travel to Europe, America or Asia for reasons such as shopping, Visits to family and friends. The Business travellers, because of economic ties with Europe, and oil companies are also important drivers for air traffic in the region. A large part of the traffic is also due to governmental, non-governmental and international bodies' staff.

Traffic towards the Middle East is increasing, mostly due to the attraction of Dubai and
pilgrimage to Mecca. North Africa / West and Central Africa traffic is also increasing

due to the dynamism of Maghrebian airlines, which take a large share of the 6th freedom¹¹ traffic departing from Paris to ASECNA.

There is also a significant traffic between African sub regions and ASECNA, mainly towards South Africa. Traffic towards the United States of America is carried out essentially via Europe.

Cargo Traffic

Figure 2.15: Evolution of Cargo traffic (1994-2003)

1994 1995 1996 1997 1998 1999 2000 2001 2002 2003

(Year)

(Thousand Tonnes)

134

180

160

140

120

100

80

60

40

20

0

98

Source: ASECNA, annual reports (1994-2003)

Freight traffic has regularly increased from 1994 to 2000 due to economic upturn. The
decrease observed since 2001 is explained by a dramatic reduction of cargo traffic at

11 The right to carry passengers or cargo from a second country to a third country by stopping in one's own country.

main cargo airports (Pointe Noire and Brazzaville in the republic of Congo). But overall cargo traffic has increased by nearly 37 per cent since 1994.

2.6 Conclusion

The aim of this chapter was to introduce to ASECNA's air transport industry, and to find out its main characteristics. This is what was found.

1. ASECNA region is characterised by under development and extreme poverty

2. Air Transport infrastructure is in a bad state or is largely insufficient and the substitutes to air transport are poorly developed.

3. The airline industry is very weak, and mostly composed of small aircraft

a. Local companies are facing economic and financial difficulties

b. Operating costs are hit by soaring fuel costs, and low aircraft utilisation

c. Yields and margins are low on the domestic market

d. Most local airlines are very small and very often inefficient

e. The fleets are very old

f. The long haul and medium haul markets are dominated by foreign carriers

g. The domestic market is insignificant

4. Air travel is still constrained

a. On the demand side by low incomes

b. On the supply side by regulations

5. Some changes are being observed

a. Aircraft manufacturers expect a fleet renewal over the next years

b. Liberalization policies are slowly being adopted on the basis of the Yamoussoukro decision

c. New entrants are expected, even low cost carriers

What do these characteristics mean for air navigation service provision and for ASECNA?

The poor development of air transport substitutes means air transport is crucial to ASECNA region and should be among the priorities. In order to develop safely and orderly, the region's air transport industry needs a reliable air navigation infrastructure and an adapted air navigation service provision. Air transport cannot develop without these conditions.

Airlines facing difficulties need to improve their efficiency to mitigate the effects of high fuel costs. With the very low level of yields on the domestic markets and on some international routes, and given the ultra competitive environment in a limited number of profitable routes in ASECNA, it is unlikely that there is significant scope for a recovery in the yields in the next years. Airlines are going to renew their assaults on costs according to African Airlines Association (AFRAA). These include flying the shortest routes, carrying optimum of fuel, cruising at optimum speed, minimizing flights at low altitude during descend and climb. Therefore ASECNA must deliver enough capacity and airspace flexibility to its customers

But efficiency also means that ASECNA must deliver a cost effective service provision.

These airlines' fleets are often very old. Ageing fleet means they are unable to cope with technological advancements and automation of security and safety systems. However the fleet renewal expected by manufacturers means higher speeds, and increased speed variability in ASECNA's airspace.

The predominance of foreign carriers in ASECNA means the agency must pay attention to their requirements as well as those of local airlines.

The liberalisation process and the growth of economies in the region will have a positive impact on competition and on air travel. ASECNA must anticipate these mutations, and their foreseeable impact on the air navigation system, and articulate its strategy to match the other exigencies mentioned above.

Chapter 3 : Air Navigation Performance review

The aim of this chapter is to analyse the performance of ASECNA's air navigation system, and to find out the current system's shortcomings. Figure 3.1 shows the region's Flight Information Regions (FIRs).

3.1 Introduction

The agency controls an area 1.5 times as large as Europe. The region is characterised by the presence of large inhospitable areas: Oceans, Deserts, and Forests.

The area is divided into 6 Flight Information Regions (FIRs): Antananarivo, Brazzaville, Dakar Oceanic, Dakar Terrestrial, Niamey, and N'Djamena¹. The airspace is divided into lower and upper zones. The FIRs encompass Terminal Control Areas (TMAs) or Upper Control Areas (UTAs) as required by ICAO.

ASECNA ensures the control of air navigation flows, aircraft guidance, the transmission of technical and traffic messages, airborne information. ASECNA delivers terminal approach aids for the region's 25 main airports², as well as for 76 secondary airports. This includes approach control, ground aircraft guidance and movements, radio aids, and fire protection services. The agency also gathers data, forecasts, and it transmits aviation weather information. Theses services are delivered for en route, terminal approach and landing phases of flights.

3.2 Airspace organization

3.2.1 Description of ASECNA's FIRs

Dakar's FIRs

They are located in western Africa. A large part is constituted of inhospitable desert
areas. It is composed of two parts: oceanic and continental. The area is

¹ These cities are respectively the capitals of the following countries: Madagascar, Congo, Senegal, Niger and Chad. The Senegalese FIR is divided into an Oceanic FIR and a terrestrial FIR.

2 Douala, Port Gentil, Mahajanga, Garoua, Malabo, Bamako, Bangui, Ouagadougou, Gao, Brazzaville, Bobo-Diolasso, Niamey, Pointe Noire, Nouakchottt, Dakar, Abidjan, Nouadhibou, N'djamena, Cotonou, Toamasina, Sarh, Libreville, Ivato, Lome.

classified Class G and F³ and D airspaces. The lower limit is flight level 245 (FL 245). There are about two dozens Prohibited, restricted and dangerous (P.D.R) zones in the area. The situation is critical above Ivory Coast where three large PDRs areas are located next to Abidjan's TMA.

Dakar's FIRs are bordered by the Following FIRs: Atlantico SBAO, SAL, Canaries, Alger, Accra (Ghana) and Niamey (Niger). Sierra Leone, Guinea and Liberia manage Roberts' FIR, which is a dismemberment of Dakar's FIR.

There are one Area Control Centre (ACC) in Dakar and one Flight Information Centre (FIC) in Abidjan.

N'djamena's FIR

It covers Chad and partly Cameroon, CAR, and Niger. The Airspace is classified G. The FIR is bordered by Khartoum's FIR in Sudan, Kano's FIR in Nigeria, and Tripoli's FIR in Libya. One ACC manages the airspace.

Niamey's FIR

It is located in Western Africa and largely covers an inhospitable desert area. The airspace is classified class G. The lateral and vertical limits are equivalent to those of Dakar's FIR. The FIR divided in two parts: East and West. It is bordered by Kano in Nigeria, Alger, Khartoum in Sudan, Tripoli in Libya and N'Djamena in Chad. One Flight Information Centre controls the airspace.

Brazzaville's FIR

Brazzaville's FIR (Congo) occupies a central position, between eastern southern and western Africa. The land below the airspace is an inhospitable virgin forest. The lower limit is FL 245. The Bordering FIRs are Kano, N'djamena; Kinshasa and Kisangani in Democratic Republic of Congo (DRC), Khartoum, and Luanda in Angola. One FIC manages the airspace.

³ Typically Class F Advisory airspace is designated where activities such as gliding, parachuting, high traffic training areas, and military operations take place and it would be of benefit to aircraft operators to be aware that such activities are taking place there.

Antananarivo's FIR

Antananarivo's FIR is in the trans-Indian ocean area, interfacing with the Asia pacific region, where there is high density traffic. The airspace is classified G, and the horizontal limit is FL 245. The Neighbouring FIRs are Maurice, Seychelles, Durban in South Africa, and Beira in Mozambique. One FIC manages the region.

3.2.2 Fragmentation

FIRs in ASECNA do not strictly follow the contours of national boundaries, and the delimitation of these FIRs is generally in line with operational requirements. Brazzaville's FIR for example regroups partly or entirely 5 countries: Cameroon, Congo, Equatorial Guinea, Gabon and a part of the Central African Republic (CAR). N'djamena's FIR regroups Northern Cameroon, Chad, Northern CAR, and Eastern Niger. Niamey's FIR is composed of Niger's airspace, Eastern Mali, and Burkina.

However, the neighbouring airspaces are managed by different countries: as said earlier, Sierra Leone, Guinea, and Liberia jointly control their airspaces. Ghana manages its airspace and that of Benin, Sao Tome and Principe and Togo from Accra's FIR. Cape Verde has an extensive oceanic airspace called Sal FIR. Nigeria's national airspace is composed of two FIRs: Kano in the North and Lagos in the South. Algeria, Morocco, Libya, Sudan, the DRC and South Africa also manage their own airspace separately. Aircraft that fly from one airspace to another have to switch to the local frequency. This goes along side with varying requirements and procedures from region to region, and proliferation of ATC systems and technologies according to national and regional considerations.

That fragmentation is an important cause of inefficiency, in term of cost-effectiveness and productivity. It contributes to the multiplication of fixed assets and costs, as well as to higher coordination and transaction costs:

1. Duplication of Air Navigation Service Providers

2. Duplication of Air Traffic Service Units (Area Control Centres, Approach Control Units)

3. Duplication of ATM Systems and Interfaces

4. Duplication of CNS infrastructure

5. Multiplication of Regulators

Figure 3.1: ASECNA'S FIRs

3.3 Traffic

Figure 3.2: Number of flights from 1993 to 2003

1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003

(Year)

(Number of Movements)

400 000

354 774

350 000

300 000

250 000

200 000

150 000

100 000

50 000

0

218 209

Source: ASECNA, annual reports (1994 - 2003)

As defined by ICAO, air traffic is the number of aircraft flights operated in a given airspace. In 2003, more than 354774 flights were operated in ASECNA, which represents a 63 per cent increase comparing to 1993. This represents 646 aircraft movements every day. The growth has been constant, at an average yearly rate of 5.3 per cent (Figure 3.2).

3.3.1 Airport Activity

During the last ten years, traffic in the region's airports has continuously grown. The number of aircraft movements has increased by 5.3 per cent per year on average. In 2003, international and local airlines' activity⁴ has increased, mainly driven by a noticeable economic recovery in the region, with a 3.1 per cent average growth (ASECNA, 2003) and between 4 and 5 per cent in 2004.

⁴ Air Madagascar, Air Senegal International, Air Mauritanie, Nouvelle Air Ivoire, Air France, Air Burkina SA, Societe de Transport Aerien Malien, National Airways Gabon, UTAGE, Afriqyah Airways, Afric Aviation, Air Excellence, West African Airlines.

Figure 3.3: Number of aircraft movements at 15 key airports

Source ASECNA, annual report (2003)

Libreville is the busiest airport in the region in term of movements as Figure 3.3 shows it. Dakar and Douala are respectively second and third.

Runway Capacity

Runway capacity is often the limiting factor for airport capacity. The queuing theory indicates that smoother arrival flows allow increased throughput and reduced delay. It allows the trade off between capacity and delay to be improved. To maximise the use of runway capacity, it is essential to accurately guide aircraft at the final approach fix (FAF).

There were about 18.66 aircraft movements per hour in ASECNA's airports from 2000 to 2003. Libreville's airport had 3.37 movements per hour, followed by Dakar and Douala, respectively 1.99 and 1.95. Six international airports had less than one movement per hour. Of course, these average figures do not take into account the variation of traffic. However, even during busy periods, the busiest platforms, like Libreville or Dakar hardly reach 9 movements per hour. The runway occupancy remains at very low levels. This clearly indicates that runway capacity is not an issue of concern in the region as it is in European or North American airports.

3.3.2 En route Traffic

The main Airstreams

The statistics from 2001 to 2003 indicate that the segmentation of en route traffic is stable, and is mainly composed of intra Africa activities, and flows between Africa and European countries (Table 3.1).

The heaviest traffic flows are the Gulf of Guinea (Abidjan-Accra-Lagos corridor), followed by the Dakar/Abidjan axis and the North-South traffic flow. The East-West traffic is less dense. The traffic between European countries and the region which represents 25 per cent of all activities is driven by Air France-KLM. The activity is less important towards other parts of the world: Traffic towards the middle is low. Exchanges with America are relatively poor. However, routes between that part of the world and Europe go through ASECNA's FIRs (Figure 3.4).

	1999	2000	2001	2002	2003
Intra-Africa	175693	199172	224374	225398	236812
Europe-Africa	80628	82568	80492	78081	84690
Europe-America	21012	22257	23651	22175	21843
Middle east-Africa	3579	3927	3982	4609	4838
America-Africa	3748	4266	4894	4460	4788
Divers	23368	2565	2671	2969	1803
Total	287008	314755	340064	337692	354774

Table 3.1: The main Airstreams in ASECNA

	2001	2002	2003	Average
Antananarivo	35893	28157	35086	33045
Abidjan SIV	24339	23312	26861	24837
Niamey	31825	32694	34703	33074
N'Djamena	23030	24588	25747	24455
Brazzaville	59987	62385	63811	62061
Dakar	57887	57725	58889	58167

Table 3.2: Traffic by FIR

Figure 3.4: Areas of Routing.

FIR Dakar

FIR Brazzaville

FIRs Niamey & N'Djamena

Source: ATNS

In Dakar's FIRs, major traffic flows are driven by airstreams from the Americas and Europe. The FIRS are involved in air activities between Europe and South America, and in the Atlantic Ocean interface between the North Atlantic, Africa, and South America regions. Input traffic also comes from the Coastal routes over the Gulf of Guinea and from Trans-Sahelian operations (Figure 3.4). Dakar's FIRs accounted for about 25 per cent of all ASECNA's traffic on average from 2001 to 2003.

Niamey's FIR is mainly involved in Trans-Saharan traffic flow and Europe to southern Africa routes. These routes receive an important traffic due to the activity generated by South Africa mainly. Fourteen per cent of the traffic went through Niamey during the period considered.

N'djamena's FIR's activity is mainly constituted of over flights from southern, eastern and central Africa. The area accounted for about 10 per cent of activities during the period. Traffic density is low.

Brazzaville accounted for 27 per cent of flights during the period. A large part of traffic in Brazzaville's FIR comes from South Africa.

En route Capacity⁵

	Flights per Day	Flights per Hour	Percentage (%)	Number of ATCO^6	Traffic Density
Dakar	159	6.6	24	42	Low
N'Djamena	67	2.8	10	40	Low
Niamey	91	3.8	14	33	Low
Brazzaville	170	7.1	27	23	Low
Antananarivo	91	3.8	14.5	27	Low
Abidjan	68	2.8	10.5	26	Low
ASECNA	646	26.9	100	391	Low
Eurocontrol	22920	955	100	NA	Very High

Table 3.3: Average traffic density from 2001 to 2003
Sources: ASECNA, internal document (appendix 10), and annual reports (2001-2003).

Eurocontrol, Performance Review Reports (2001-2004)

Dakar's ACC and Abidjan's FIC manage on average 227 flights per day, which is equivalent to 9.4 movements per Hour and 1 movement every 7 minutes. But this does not take into account the time and period distribution of flights.

Brazzaville is the second busiest FIR as the FIC manages about 170 flights per day, which represents 7.1 movements per hour and one every nine minutes.

About 67 flights are managed by N'djamena's ACC each day, representing 2.8 flights per hour and about one flight every 21 minutes,

In Antananarivo, on average, 91 aircraft movements are managed every day, 3.8 flights per hour, and 1 every 17 minutes.

Traffic density in ASECNA is very low when compared to the level of traffic in Europe.

⁵ The average number of flight per day and per are obtained by dividing the number of flights per year by 365.

⁶ Air Traffic Controllers (2004 figures).

Controllers' Productivity

Productivity is defined as the average number of aircraft controlled per hour per air Traffic Controller (ATCO). It is calculated by dividing the total number of aircraft movements in the FIRs by the total number of ATCOs. A better way to measure productivity would have been to measure the number of flight-hours controlled per controller-hour in duty, but the data were not available. Eurocontrol's figure is derived from the average flight-hours controlled per ATCO-Hour in duty, and annual number of IFR flights and the number of flight-hours. The average flight-hours controlled per controller-hour in duty was 0.8 (Eurocontrol). There were 12.2 million flight-hours and 8.9 million IFR flights in Europe in 2004. This means 1.37 Hours per flight on average. Therefore, each controller controls 0.8 divided by 1.37 (0.583) flight per hour.

Figure 3.5: Average flights controlled per hour and per controller in ACCs

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0.0

(Control Centres)

ATCOs' productivity in ASECNA varies from one ACC to another. The busiest ATCOs are those of Dakar and Brazzaville. Each air traffic controller controls on average 0.1 flight per hour in ASECNA, whereas the equivalent figure is about 0.6, which is 6 times higher.

3.4 Delays

Air transport delays are given by the scheduled departure and arrival times. Delays can be broken down by phase of flight.

When traffic demand is anticipated to be higher than the actual ATM capacity in en-route control centers, or at the airports, Air Traffic Units may apply Air traffic Flow Management (ATFM) regulations. This means that airplanes subject to that regulation are held at departure airports. The AFTM delay is then allocated to the busiest ATC unit.

In ASECNA, delays are almost never the result of Air traffic services. Except during bad weather periods, the totality of delays is due to airlines' preflight operations. There is no ATFM unit like in Europe for instance (Ngoué Celestin, Head of Air Navigation, ASECNA). Many airlines managers confirmed that reality, which is also corroborated by the availability of sufficient airspace capacity.

3.5 Impact of future trends 3.5.1 Prospects

All aircraft manufacturers (Boeing, Airbus...) or airlines organisations (IATA, ICAO) use roughly the same methodology for assessing long term traffic forecast. It is based on the assumption that long-term demand for air travel is driven by economic developments, notably the growth of world and regional income levels.

Figure 3.6: Projected traffic growth over the next decade

Percentage

4,8

4,6

4,4

4,2

5,2

4

5

Source: Boeing, Airbus, ASECNA, IATA.

Western and Central Africa countries economies are expected to grow at an average pace of 4.5 per cent during the next decade according to African bank of development (BAD). It can be assumed that air travel and air traffic are going to follow that pace. Depending on the industry's estimate taken into account, air traffic will grow in Africa between 5 and 7 per cent over the next 15 years. ASECNA expects even a 7 per cent growth. However, Africa's overall share of traffic is expected to decrease to 2 per cent instead of the current of 3 per cent.

The average growth rate for the next 15 years is 5 per cent yearly. This means there will be about 737550 flights in ASECNA by 2020; traffic will have doubled.

3.5.2 Impact on Runway Capacity

With the projected growth rate, there would be about 41 landings or take-off each hour in all ASECNA area airports. If the relative importance between airports does not change, Libreville will handle around 7 movements per hour followed by Dakar and Douala with respectively with 4.7 and 4.3 operations per hour on average (Figure 3.7).

Comparatively, the busiest hour at London Heathrow in 1999 saw 93 movements per hour on the airport's two runways.

Figure 3.7: Projected Runway Occupancy in main airports (flights per hour)

0

8

7

6

5

4

3

2

1

Source: ASECNA, compiled from annual report 2003. 3.5.3 Impact on en route Capacity

	Flights per Day	Flights Per Hour	Percentage of Total	Number of ATCOs	Traffic Density
Dakar	332	13.8	24	104	Low
N'djamena	140	5.8	10	60	Low
Niamey	189	7.9	14	76	Low
Brazzaville	354	14.7	27	76	Low
Antananarivo	189	7.8	14.5	72	Low
Abidjan	141	5.9	10.5	35	Low
ASECNA	1343	56	100	699	Low

Table 3.4: Average traffic density by 2015

ASECNA's FIRs would receive about 1342 flights per day (56 per hour). It is insignificant when compared to Europe's records, 30,000 flights per day, and one operation handled every 3 seconds (CFMU, 2005).

Controllers' productivity

Figure 3.8: Projected Controllers' productivity in 2015

0.6

0.5

0.4

0.3

0.2

0.1

0.0

Controllers' productivity would remain lower than European controllers' 2003 record.

3.6 Traffic complexity

A good analysis would require additional data such as flow structure (horizontal intersection per miles), traffic mix (standard deviation of aircraft speed), and traffic evolution (number of flight level changes per miles, horizontal intersection per miles). These information were not available. However, traffic density is low and will remain so in ASECNA. All the busiest routes are north and south bound. These routes generate the highest levels of passenger traffic. They link major local airports to Europe. Domestic traffic is inexistent and East-West routes are not really busy, except the golf of Guinea corridor, and routes between certain capital cities. But,

seasonally, during the pilgrimage period, routes towards Saudi Arabia (East-West) cross major North-South traffic flows, and create convergent points generating traffic complexity (Samake Wodiaba, ASECNA). The projected growth suggests that traffic complexity is going to increase as east-west flows are going to grow faster than north-south operations.

3.7 Safety

Safety is the prime objective of ATM. In ASECNA's safety reports, events are composed of 6 elements: Air proximities (Airprox), users' claims, Aviation security, Bird strikes and Accidents. The period considered goes from 1999 to 2004. 2004 figures in the chart below are only partial data.

3.7.1 Air Proximities

An airprox is a situation in which, in the opinion of a pilot or a controller, the distance between aircraft as well as their relative positions and speed have been such that the safety of the aircraft involved was or may have been compromised. The number of Air proximities is constantly high with regard to the low traffic density in ASECNA.

Figure 3.9: Evolution of Air proximities

	30
	25
Air proximities	20 15 10
	5 0

250 275 300 325 350

Number of flights (000)

Source: ASECNA, annual reports (1999-2003)

The situation seems to improve with the increase of traffic (Correlation between the number of air proximities and traffic figures is equal to «-0.8»). This may reflect a better surveillance and communication capability in the region. The number of safety-related events seems to vary significantly between ASECNA's regions. Central Africa concentrated 50% of total events during the year 2004. It is not clear whether or not this is due to differences in reporting practices, or the concentration of traffic on certain corridors not properly furnished with surveillance means.

Figure 3.10: Evolution of incidents during the last six years

Source: ASECNA, (unpublished document).

3.7.2 Users' claims

Users' claims accounted for about 20 per cent of reported events. These are made by airspace users. ASECNA statistics do not tell if every claim is investigated. It's likely that many are purely ignored, due to the lack of mean to conduct an efficient investigation.

3.7.3 Birdstrikes

Birdstrikes are very frequent in ASECNA. 28 per cent of incidents during the period
were related to aircraft engines «swallowing» birds, very often at the vicinity of airports.

Accidents reported are not always related to air navigation events. They nearly constitute 26 per cent of events. Most of them occur on the ground, at major or secondary airports (runway incursions). The figures presented on Figure 3.10 are probably optimistic as many accidents or incidents are not reported at all, particularly at remote airports.

3.7.4 Safety Review System

Four features are essentials to make incident reporting useful for accident prevention and safety management:

1 A reliable, timely and large enough information flow

2 Data analysis

3 Severity Classification

4 Exposure of the data

For every incident assessed ASECNA determines one or more causal factors. These tell the agency why events started in each instance and signposts the lessons to emerge. ASECNA has safety committees that perform that job. It is self evident that attention paid to the cause of an accident is worthwhile because it is likely to deliver and promote better prevention and to establish the responsibilities. ASECNA is often responsible for safety related events. But the agency does not seem to systematically investigate incidents, and information on safety data is hardly available. When it is, it's not adequately classified.

3.8 Efficiency

3.8.1 Flight efficiency

Flight efficiency is the next key performance Area considered in this study. Flight efficiency has implications for fuel burn, pollution and its environmental impact. Flight efficiency has horizontal and vertical components, which can be split into en-route and terminal flight phases. The report focuses on en-route flights. Insufficient information is currently available to address vertical flights efficiency. Moreover, it has not been

possible to study the most «constraining points⁷» in ASECNA.The safest routes in ASECNA are controlled routes. These routes are equipped with ground based navigation aids pilots have to follow. That compulsory process increases routes length and reduces flight efficiency. Major routes link South Africa to Western Europe. Aircraft have to go through Brazzaville, Niamey or N'Djamena. To go from Douala (DLA, Cameroon) to Dakar (DKR, Senegal), pilots have to use the following routes:

1. UB 737 from Douala to Sao Tome and Principe (TMS)

2. UA 400 from Principe to Abidjan (ABJ)

3. UR 979 from Abidjan to Dakar, or UB 600 through Monrovia (Liberia) and Conakry (Bissau) (Figure 3.11).

Figure 3.11: Flight Paths between Douala and Dakar.
(In Red: Direct path. In dash Blue: Conventional path)

3.8.2 Fuel Efficiency

The fuel efficiency of an airline is determined by many factors. Some are directly under airlines control, others are not. The later are related to market, technology, and infrastructure.

⁷ The most constraining point is the point along a trajectory that contributes the most to the additional distance. This point generates additional costs.

Figure 3.12: The different phases of a flight

Source: Mitre Corporation

To illustrate this requirement of fuel efficiency, the following is an estimation of extra costs related to flight inefficiency on the route Douala (DLA) - Dakar (DKR). Only the cruise portion of the flight is considered.

The aircraft operated is a B737-300⁸. Its seat capacity is 140 and range is 4320 Km. The range is chosen such that the effect of load factor that have an influence when the aircraft is operated at the limits of range can be neglected. The fuel consumption for a B737-300 is estimated at 26 g/ seat.km (Japan Airlines, 2005). Most of the aircraft weight is then considered to be fuel and hull. We assume that the flight altitude on the cruise portion is 32800 feet, and the weather condition are ideal, and the traffic is not complex and does not generate holding patterns.

The cruise speed is supposed to be constant at 815 km/h. The descent starts about 100 km from each airport. The Descent phases of flight (Vertical profile) and the taxi times are not considered, although we already know that efficient approach operations allow fuel saving. The Fuel Density is 800g/litre; and the current spot fuel cost around the world is about US$1.80 / US gallons.

⁸ Details from (Air Charter International, 2005)

Conventional Flight (Following ground Navigation aids)

Distance Flown during the horizontal profile: 3640 Km - 2*100⁹ = 3440 Km Seat.Km: 512560

Fuel Burn: 13327 Kg, which is equivalent to 16659 litres, and 4401 US gallons¹⁰ Fuel cost: 7922 US$

Direct Flight

Distance Flown during the horizontal profile: 3211 Km - 2*100 = 3011 Km Seat.Km: 448639

Fuel Burn: 11665 Kg, which is equivalent to 14582 litres, and 3853 US gallons Fuel cost: 6936 US$

Comments

The difference in term of Fuel consumption is about 2077 litres, 12.5 per cent. The savings on the horizontal profile only would be about 986 US$. For 6 legs per week, the total reduction in fuel cost is 5916 US$. Assuming continuous operations without disruptions during the whole year, the savings would be 307,632 US$ on that single route. But a large part of fuel inefficiency also lies on the problem of aircraft age. Old aircraft generally consume more fuel than newly built ones as shown in chapter 2.

Flying the direct route would also free 164 hours during the year that a company could use to improve aircraft utilization. But this would depend on the slot structure at the served airports.

Beyond the improved aircraft economics, the positive impact on environment is also substantial. On this case, the reduction in Carbon Dioxide (CO2) emission would be about 1815 tonnes¹¹ during the year.

⁹ We assume that that the descent phase begins 100 Km before the airport

¹⁰ 1 USGAL = 3.785412 Litres

¹¹ 1 Kg of fuel burn produces 3.5 Kg of CO2 (Japan Airlines, )

3.9 Cost effectiveness

3.9.1 Navigation charges

Figure 3.13: Evolution of Air Navigation charges (Unit Rate) in ASECNA (Euros)

120 100 80 60 40 20 0

DOMESTIC FLIGHTS REGIONAL FLIGHTS

INTERNATIONAL FLIGHTS

1999 2000 2001 2004 2005 2006

Source: ASECNA

ASECNA's current charging policy is as follows: Charge for use of en-route facilities and services managed by the agency are payable whatever are the conditions in which the flight is accomplished (IFR or VFR) and whatever are the departure and the destination aerodrome. Charging varies depending on the nature of the flight (national, regional, international). For regional or domestic flights, users pay a fixed price. For international flights, users pay a price that varies with the weight of the aircraft and the distance flown.

From 1999 to 2005, charges for international flights increased by 40 per cent. But, the price is stabilized since 2004 thanks to an agreement with IATA. The price of regional flights is being reduced since 2001, and the price of domestic flights is stable.

3.9.2 Air Navigation Services Costs

Evolution of Costs¹²

Figure 3.14: Personnel, ANS and Transport costs from 1996 to 2003

100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0%
	1996 1997 1998 1999 2002 2003

Costs of Personnel Cost of ANS Other Costs Cost of Transport

Source: ASECNA, annual reports (1996 - 2003)

The costs of personnel represent more half of total costs. They have increased continuously since 1996. ANS and personnel costs accounted for about 80 per cent of expenses in 2003, and their share is stable. Transports costs are stable.

¹² ANS costs include supplies and materials. ANS personnel costs are included in personnel costs

Figure 3.15: Evolution of the average cost per flight from 1996 to 2003 (Euros)

290

280

270

260

250

240

230

220

300

1996 1997 1998 1999 2002 2003

Trend Line

Source: Compiled from ASECNA's annual reports (1996 - 2003)

The average unit cost is increasing. The cost per flight was about 288 Euros in 2003. Unit cost has increased by 18 per cent on average from 1998 to 2003, which represents an annual increase of 3.6 per cent. On average, ASECNA's unit cost is the lowest as shown on the table below. But that figure does not reflect the exact reality, as domestic and regional airlines only paid a fixed price, whereas international flights are much more expensive. It means international airlines pay a much higher unit cost per flight. Nearly 80 per cent of these charges are paid by major western and international airlines (ASECNA, 2003).

ASECNA	288^13
Eurocontrol	591
FAA	351^14

Table 3.5: Average ANS cost per flight (Euros)

in Europe ASECNA and the USA (2003)

The totality of charges above is passed to users. En route revenues have continuously increased since 1996 by 11.6 per cent on average per year (Figure 3.16)

¹³ ASECNA's figure includes all personnel costs. ANS personnel costs were not available separately

¹⁴ 357 dollars

Figure 3.16: Evolution of En route revenues from 1996 to 2003 (Million Euros)

180

160

140

120

100

40

20

60

80

0

1996 1997 1998 1999 2002 2003

Source: ASECNA, annual reports (1996 - 2003)

3.10 Cooperation

ASECNA cannot deliver a satisfactory service without interacting with other air navigation authorities in the region. The agency encircles large blocks of airspaces like Nigeria, and Ghana as described in chapter 2. It also shares common airspace borders with huge entities such as the Canaries, SADC, Algeria, Libya, Sudan and others. Nigeria has deep infrastructural deficiencies, which gave rise to the blacklisting of their airspace by some international organizations: Obsolete navigation and landing aids as well a collapsed surveillance system. The navigation and landing aids are not functional most of the time, the six terminal approach radar stations are broken down and air traffic control service are not provided to some en-route traffic (Nigeria Airspace Management, 2005).

Figure 3.17: Regional Fragmentation of ATM sectors

Source: CANSO

Clearly cooperation is needed between all these states to develop a seamless and cost efficient ATM system at a regional level. Harmonisation provides much of the answer. The region needs a plan to achieve common standards procedures and technology, and ensure interoperability between various systems. Multi-national cooperation among provider States and users are essential to minimize investment costs, ensure compatibility and avoid duplication of effort. Moreover, by agreeing on common technologies, ANSPs and state would increase their bargaining power when buying new systems.

Trans-national bodies provide coordination (ICAO's AFI CNS/ATM regional Sub-Groups). But still, there are challenges in bringing the regulators and the governments to commit to an efficient air navigation system. African states, airspace users, ATC service providers, and equipments suppliers do not have the same motivations and benefits. Moreover, «different regulatory models, different regulatory requirements undermine moves towards harmonisation. Sovereignty issues, slowness in administrative and legislations procedures, differences in time frames, often contribute to delay advances in the system» (Yoro Amadou Diallo, ASECNA).

3.11 Training

Traffic is growing and complexity is increasing. ASECNA needs to go hand in hand with changes. In Africa, many air ANSPs have unfortunately tended to invest in equipment but have hardly paid attention to the training needs of the human beings who must operate it.

ICAO has established minimum standards for approved ATC training and has approved institutions in several African countries like in ASECNA. ASECNA trains part of its controllers in its own institutions it manages in Niamey, Niger.

However, the total capacity of these institutions is less than 30 per cent of the total training requirements of Africa. Many African ANSPs are compelled to train their students in foreign ATC training institutions. Since there is a global shortage of air traffic controllers, most ATC training institutes outside Africa are fully booked to train their own nationals to meet local needs. In addition, training fees keep increasing as a result of growing demand.

3.12 Financing

Figure 3.18: Financial results from 1994 to 2003

Operating revenue Operating Expenses

Operating Result Operating ratio

Million Euros

%

40

80

60

20

0

180

160

140

120

100

1994 1995 1996 1997 1998 1999 2000 2001 2003

180

160

140

120

100

80

60

40

20

0

Source: ASECNA, annual reports (1994 - 2003)

One of the major concerns for management of air navigation systems is the financial requirements for developing countries like in ASECNA. «Member states do not always have the means to finance air navigation infrastructure improvement as they have other priorities, such as health, education, poverty reduction» (M. Marafat, ASECNA).

A survey conducted by ICAO's technical cooperation bureau estimated that 97 per cent of the least developed countries and 83 per cent of the developing states require technical and financial assistance to improve their air navigation systems (ICAO-Rio Conference 1998).

ASECNA regularly posts good financial results. Its operating revenue almost doubled from 1996 to 2003, and its operating ratio is constantly very high (144 per cent on average during the last 10 years).

3.13 CNS and Aviation Weather Management issues

3.13.1 Shortcomings of conventional systems used by

ASECNA

It is recognised that current air navigation systems suffers from technical, operational and procedural shortcomings, which has serious economic impact on air transport community. These shortcomings amount to the following factors.

Communications

Despite recent improvements in ATC such as new radar scopes, voice switching systems, today's air traffic control primarily relies on a single tool to actually separate aircraft: a highly congested voice radio frequency. The current ATC system uses voice communications between air traffic controllers and pilots to relay instructions and other information critical to operate safely. These communications are necessary to support coordination of aircraft movements in all phases of flight, to ensure aircraft separation, transmit advisories and clearances, and to provide aviation weather services. Skies over international airports are made more dangerous by the lack of standardised terminology or proficiency levels in English for flight crews and air traffic controllers. Language confusion is a frequent cause of pilot error. Although English was made the

common language of world aviation in 1951, miscommunication and crashes in which communication was a contributing factor are common. These include ambiguities and misnomers. Phrases are not derivations of a master plan as they should be. The inability of English to express specific instructions to pilots without confusion disqualifies it as a language for permanent use by aviation (Kent Jones, 2005).

One speaker at a time: The voice communications link between controllers and pilots is similar to a conference call, with the controller and all pilots flying within an airspace talking over the same channel.

This is very similar to ATC voice communications in congested airspaces. It is not unusual for pilots to key their microphone and accidentally "step on" the communication of other pilots or a controller. These are time consuming routine messages. They waste more time on the ATC voice channel as repeated attempts to communicate are made. This problem will only get worse as air traffic continues to increase. Each voice radio exchange takes a certain amount of time for the originator to transmit and the receiver to respond, and there is a point of saturation where a controller physically cannot fit in any additional voice radio communications. At this point, no additional aircraft can be handled within the controller's assigned airspace (Mitre-Caasd, 2005).

Navigation

Fixed airways: Airlines are currently required to plan their flights on the basis of a fixed route structure, which is largely defined by ground-based navigation aids. The fixed point-to-point route segments, indirect routings, which rely mostly on ground based navigation aids, are not the most efficient way of getting from one place to another. That limits enroute capacity and reduces efficiency. But it has been necessary because of the limitations in air traffic control technology (Department of Foreign Affairs and Trade, 2005).

Range Limitations:The current system of land-based navigation requires to over-flight
certain VOR sites, intersections and one-way airways to organize the flow. This means,

as mentioned previously, that airways depend on the geographic location of navigation aids. Moreover, airways are like a highway system on the ground. Like the later, at intersections with crossing traffic, some aircraft can get stuck waiting for the «light to change» (holding). By creating airways independent of the geographic location of a ground navigation aid, those airways can be spread out. Spreading the traffic out increases capacity and safety (Zelechosky et Al, 2005).

Large amount of airspace between each aircraft: Conventional air guidance systems on board the aircraft and are not precise enough. Therefore, Control centres have to maintain a 15 minutes horizontal separation between aircraft. As a result, there is a large amount of space is lost.

Surveillance

Basically, the surveillance systems presently in use can be divided into two main types: dependent surveillance and independent surveillance. In dependent surveillance systems, aircraft position is determined on board and then transmitted to ATC. The current voice position reporting is a dependent surveillance system in which the position of the aircraft is determined from on-board navigation equipments and then conveyed by the pilot to ATC by radiotelephony. Independent surveillance is a system which measures aircraft position from the ground.

Ground-based separation assurance: The Separation ensures that an aircraft maintains a safe distance from other aircraft, terrain, obstacles. Capabilities include ground based separation functions on the airport surface and in the terminal, en route, and oceanic domains. New on-board systems such as the Traffic Alert and Collision Avoidance System (TCAS) can allow the pilot to execute an evasive manoeuvre. But all aircraft are not fitted with such systems, especially, local small airlines in regions like ASECNA area.

Primary Surveillance Radar (PSR): PSR radars operate by radiating electromagnetic energy and detecting the presence and the character of echoes returned from reflecting objects. It is an active device using its own controlled illumination for target detection based on reflected radar energy. However, detection depends on radar cross-section and line-of-sight and it requires high energy transmission results in costly implementation

on ground. The fact that the antennas rotate limits the detection to the beam direction and suppresses targets within the cone of silence. Moreover, PSRs offer no possibility to identify the target: It only allows detection. At last, it is very sensitive against reflections (clutter, sea, weather), and detection depends on a sufficient signal to- noise ratio.

Secondary Surveillance Radar (SSR): SSR radars transmit coded interrogations to receive coded data from any aircraft equipped with a transponder. It provides a two-way data link on separate interrogation and reply frequencies. Replies contain either positive identification (1 of 4096) or aircraft pressure altitude. But they have similar drawback to PSRs' ones. Even the identification is only limited to 4096 codes, and they are subject to FRUIT (False Replies from Interfering Transmissions), Garble (reply overlap at the ground receiver) and over-interrogation (due to a high number of interrogators). All these reduce the probability of detection.

Airport Operations

Airport movements severely restricted during low visibility: During good visibility conditions the landing capacity of major airports is mainly limited by the final approach separation minima defined by ICAO, and that sequences accuracy and runway occupancy times. When the visibility deteriorates and becomes less than a certain limit the use of landing runways is stopped because pilots cannot maintain visual separation in case of simultaneous missed approaches for instance (Hans Offerman, 2005). Moreover, during these conditions, separation requirements between aircraft increase to avoid runway incursions. All this results into decreased «airport capacity» and increased controllers' workload.

Aeronautical information and weather services (AIS)

Disparate formats and standards: The objective of AIS is to ensure the flow of
information necessary for safety, regularity and efficiency of flight operations. In that
respect, each state is required under international agreements to provide this service and

is responsible for the information provided¹⁵. It is provided to pilots in face-to-face briefings at the aerodrome AIS unit, or in flight, through air traffic control. Communication of the latest information to users is effected through the aeronautical fixed telecommunication network (AFTN) in the form of notices to airmen (NOTAM). This information is however not already available in real time due to technical limitations.

3.13.2 ASECNA's systems' performance VHF coverage

ASECNA area is 16,000,000 Square kilometres large. A VOR Beacon range is 240 KM. therefore the number of VORs necessary to cover the entire area is equal to 88.46. This means that to cover its entire airspace with VHF capability and makes it available for flights, 89 VORs are necessary. In 2003, ASECNA had only 60 in operation, which represents 68 per cent coverage of the area. But VHF technics that use VSAT (Very Small Aperture Terminal) and SATCOM technologies to extend the VHF coverage in inhospitable areas have improved the situation. Many VSAT have been installed in the region, and there are other projects under implementation. The most frequently used means for Aeronautical Mobile Service (AMS - air/ground and air/air communications) is the HF, which has an extended range but presents drawbacks and the VHF. These technologies operate well on the whole in ASECNA. But on the one hand, the VHF is increasingly used and has considerably improved; both from the point of view of quality and availability (Table 3.6 below), and on the other hand, the HF is still the only available mean in several sectors, like in the oceanic FIR, and large parts of the Sahara desert and forests.

The Aeronautical Fixed Service (AFS), which ensures the transmission of flight plans
and other aeronautical messages between specific fixed points, operates fairly well,

¹⁵ Conventional aeronautical information services consist on the provision of hardcopy documents in the form of the Integrated Aeronautical Information Package (IAP), which contains information for the entire territory and also areas outside the territory for which a State is responsible for the provision of air traffic services. The information must be provided in a suitable form and must be of high quality, be timely and include, as necessary, aeronautical information of other States. In addition, pre-flight and in-flight information services must be provided.

especially at main airports. The Fixed Service is often backed up, or replaced by the SITA¹⁶ network, a private network generally used by airlines.

Equipments	2000	2001	2002	2003	Average (%)
Navigation Aids	96.4	96.8	96.9	93.6	95.9
Terrestrial station	96.0	98.2	98.1	98.2	97.6
Communication Equipments	91.1	94.4	95.8	97.2	94.6
MET Equipments	91.0	92.3	94.5	93.3	92.8
Energy Equipments	96.0	96.2	98.1	98.1	97.1
Average	93.6	95.4	95.2	95.9	95.0

Table 3.6: Equipments availability in 2003. Source: ASECNA, annual report, 2003

Transmission speed

The requirement of a minimum modulation rate of 1200 bauds is not met by some main circuits. The following AFTN main circuits do not meet this requirement: Niamey /Addis Abeba, Dakar/Casablanca. Tributary circuits connected to the main centres of Brazzaville, Dakar, Johannesburg and Niamey have been upgraded to higher transmission speeds, while the outgoing main circuits are operated still at 50 baud.

Use of analogue technology

The level of digitalization is rather low: only 29 out of 65 circuits (44.3%) are digital circuits in the region, which limits the bandwidth and the data processing capability. Statistics show that the requirements of 5 minutes maximum for high priority messages and 10 minutes maximum for other messages are not met most of the time.

Navigation

The main navigational aids in the region operate fairly well. However, many of them
have reached their age limit, especially the Instrument Landing Systems. VORs coupled
or not with DMEs, are implemented in all international aerodromes and are generally

¹⁶ Société internationale des télécommunications aéronautiques

operational. All these ground facilities work towards providing safe navigation in the ASECNA. Navigation aids equipments' availability rate (95.9 on average) is below international standards (Table 3.6). Secondary airports do not often have Landing aids, and some international airports, like in Equatorial Guinea, do not posses such systems.

Surveillance

The use of radar is very rare in ASECNA area and in West Africa in general. The explanation given is that ICAO recommends that states should use radar only if the situation really warrants it. If this is taken as a rule, it would apply to the Gulf of Guinea States (Ivory Coast mainly). A secondary radar system has been undergoing tests in Abidjan for the past few years. Its official commissioning has been delayed because of a problem between the government and ASECNA. It has nonetheless proven very useful. As an example, recently, a few hours after a recent takeoff from Accra, an aircraft heading west realized that its navigation instruments were no longer functioning. It therefore decided to land in Accra, its point of departure. Soon after, it was seen on the Abidjan radar screens heading north. The Ivorian controllers were able to guide it safely to its final destination.

FIRs ASECNA	Routes Length in the FIR (NM)	Controlled routes Length (NM)	Percentage of Controlled routes (%)
ANTANANARIVO	9554	5954	62
BRAZAVILLE	11467	8329	73
DAKAR TERRESTRIAL	17471	13826	79
DAKAR OCEANIC	3973	3973	100
NIAMEY	11315	10270	91
NDJAMENA	8349	8163	97.7
Total length	62129	50515	81.3

Table 3.7: Air circulation control: Controlled routes

The absence of radar is strongly felt. Authorities are frequently informed of violations of their airspace by pilots who come across illegal traffic. They are also aware that aircraft operators can operate with impunity in their sphere of sovereignty, without their knowledge. This situation is mainly due to the large number of uncontrolled routes as shown in table 3.7. Only 81.3 per cent of routes are controlled, and most of them by conventional means of which limitations have been presented. It can be noted that all the routes in the oceanic FIR are controlled. These routes are used by airlines flying from South America to Europe.

In spite of the absence of radar, ASECNA's air traffic services still provide the classic elements of control, which is to prevent collision between aircraft in the air and on the ground, and to speed up and regulate air traffic generally.

Aviation Weather

Table 3.6 reveals that MET equipments' availability rate (92.8 %) is below international standards. The performance of weather data collection systems are not better as shown in the figure 3.19 which represents the system's efficiency¹⁷ in June 2005. Only 68 per cent of TAF messages were received, and the figures are event lower for METAR messages, with 43 per cent success. Met stations' efficiency varies from 77 per cent to 100 per cent. These bad performances have to be link to the poor quality of transmission systems we presented earlier.

¹⁷ Number of messages received on-time divided by the number of messages due to be receive

Figure 3.19: OPMET availability rate

350000

300000

250000

200000

150000

100000

50000

0

Metar required Metar received TAF required TAF received

Source: ASECNA, annual report, 2003

A large number of OPMET messages are received more than 15 minutes after their transmission. This impacts pilots and controllers' ability to quickly react in case of severe weather conditions.

More than 40 per cent of weather irregularities are related to low visibility. Another 40 per cent are due to storms, and the others are windshears, strong winds, and rains. Pilots are often confronted to these conditions following inaccurate forecasts. Very often they have to engage deviation manoeuvres. Go-Around, Release, Landing delayed, half turn. These are extra fuel consuming operations for airlines.

3.14 Conclusion

The aim of this chapter was to analyse the performance of ASECNA's air navigation system, and to highlight its shortcomings. Air navigation characteristics are as follows:

1. Traffic and complexity are increasing, though they remain at low levels when compared to Europe or North America.

2. The airspace is strongly fragmented at a continental level, though there is relatively low fragmentation within ASECNA's own airspace. There is little harmonisation and more cooperation is required with neighbouring providers to improve cost effectiveness and deliver a seamless airspace to users.

3. Capacity is not a priority as traffic density and controllers' productivity remain low despite projected traffic growth

4. Delays are not the result of air traffic services

5. Safety is the critical issue of concern in ASECNA, as the region, though recent figures show improvements. The number of safety events remains very high relatively to the level of traffic. Conventional systems used are often outdated and unreliable as they do not achieve international standards. It is also shown that ASECNA is characterised by wide inhospitable areas that render the access to equipments and their maintenance very difficult.

6. There is not a proper safety management system, and data are not systematically collected and thoroughly analysed. Safety data are not made available to the public.

7. The use of conventional navigation aids generates flight inefficiency, and is costly to users. But it would be unachievable to reduce inefficiencies to zero. Performance targets need to be set, but there is a trade-off to be done with other performance areas, such as safety.

8. ASECNA's airspace is used by airlines from around the world. 80 per cent of ASECNA's revenues come from foreign or international airlines. This means the agency must adapt its service, and responds to their needs.

9. ASECNA is relatively cost effective when compared to Europe and the USA. But there are rooms for improvement as the cost staff costs are very high.

10. ASECNA is a solvent organisation. Its operating ratios and its borrowing power are good.

Chapter 4: CNS/ATM Systems and Concepts

The aim of this chapter is to present the main CNS/ATM systems and concepts, and to determine suitable solutions for ASECNA, based on experimental performances and local characteristics.

4.1 Introduction

The process of getting an aircraft safely and efficiently from its origin to its destination requires effective Air Traffic Management systems supported by three key functions: Communications, Navigation and Surveillance (CNS). The concept is based primarily on the following technologies: data link communications, digital aeronautical information services (AIS), the Global Navigation Satellite System (GNSS) and Automatic Dependent Surveillance (ADS).

CNS systems are a set of technologies employing digital techniques, including satellite navigation systems, together with various levels of automation. These are applied to support a global Air Traffic Management system. The strategic vision is to foster a global ATM system that enableS airspace users (Aircraft operators), to better meet their schedules, and to adhere to their preferred flight profiles with fewer constraints. Of course, this has to be done without lowering the safety levels. These technologies will enable the transformation of air traffic management to provide for collaborative decision-making (CDM)¹, dynamic airspace management, strategic conflict management, flexible use of airspace and all weather operations.

The airline industry is looking for ways to improve its bottom-line profitability as shown in chapter 2. It is focusing its efforts on the need for change. One Sky, global ATM is the industry's vision of a global air navigation system that improves Safety and Efficiency whilst accommodating worldwide air traffic growth in an airspace that is

¹CDM brings together airlines, civil aviation authorities and airports in an effort to improve air traffic
management through information exchange, data sharing and improved automated decision support tools.
This philosophy of collaboration promises to become the standard in aviation. CDM enables information
sharing and facilitates decision making processes by ensuring that stakeholders are provided with timely
and accurate information, essential for the planning of their operations (IATA)

seamless and devoid of national borders. According to IATA, achieving this vision will result in a wide range of benefits such as, environmental benefits (Reduced emissions), and lower overall costs for the airlines through operational improvements, efficiency, avionics equipage and equitable user charges.

Therefore, CNS/ATM systems are crucial to the industry, in their attempt to simplify the business, and to gain more freedom in the way they operate.

ANSPs expect that better communications, navigation and surveillance systems will undoubtedly increase the level of safety. With the use of voice and data communications, satellite and precision navigation, SSR Mode S and ADS surveillance, and all the other new concepts, ANSPs will significantly reduce the hazards due to the use of conventional systems.

A common digital aeronautical information exchange model is the industry's objective. The new systems make possible the sending of right information to the right user at the right time. Particularly, satellite technology and data link provide, where it is used for aviation weather purposes, a highly reliable, fast and efficient method of communication. Faster and more-efficient transmission methods ensure that much more information can be made available. Suppliers of meteorological aviation data can therefore provide a more comprehensive service to airline operators.

Capacity will be increased thanks to the implementation of new ATM practises and concepts. RVSM (reduction of vertical separation limits) has already brought consequent capacity gains where it is been applied (In Europe and Northern America for instance). More capacity also means increased safety margins in non-congested airspaces.

States consider Air transport industry as a critical component, and a development tool for their economies as explained in chapter 2. A performing and safe air navigation system that can absorb air traffic growth and guarantee safety must be considered as a matter of strategic importance. Developing states like those in ASECNA are provided with a timely opportunity to enhance their air navigation infrastructures. Countries in ASECNA, as many developping nations continue to have large parts of their airspace available but unsusable because they are unsafe as shown in chapetr 3. This is due to the cost of maintaining the necessary ground infrastructure. According to ICAO,

CNS/ATM systems offer them opportunities to modernize at a low cost, their air navigation system. Moreover, the impact of air transport on environment increases with the industry's growth. States are committed to reducing aviation emissions. By allowing efficient aircraft operations and fuel consumption reduction, CNS/ATM systems appear to be a part of solution to achieve that goal. That's why states have to assist the industry in that modernasation process, by facilitating financing and cooperation.

4.2 Suitable CNS/ATM systems for ASECNA

The following tables summarize ASECNA's characteristics and indicate the corresponding current solutions used, and CNS/ATM alternatives, that are supposed to bring significant improvements.

4.2.1 Geographic characteristics

Characteristics	Current systems	CNS/ATM
Inhospitable areas
Deserts	HF , Deported VHF	CPDLC, ADS-B, ADS-C
Oceans	HF	ADS-B, VDL, HF data link
Forests	HF, Deported VHF	ADS-B, VDL, HF data link

4.2.2 Efficiency

Characteristics	Current systems	CNS/ATM
Fixed routes	VOR, DME, NDB	GNSS, RNAV, RVSM, RNP
Fuel Inefficiency	VOR, DME, NDB	CPDLC, RNAV, RVSM
Low airport accessibility	ILS, DME	GNSS
Fragmentation	Duplication of Equipments, Separated Civil aviation authorities	Regional Harmonisation
MET data accuracy	Low Speed Transmission, AFTN	Digital Transmission, ATN
Controllers' Productivity	ATC	ATM, CPDLC, ADS-B

4.2.3 Capacity for Safety

Characteristics	Current systems	CNS/ATM
Poor safety records	Voice Communication, Ground based separation assurance, strips, primary radars	Data Link, CPDLC, Radars mode S

4.2.4 Surveillance

Characteristics	Current systems	CNS/ATM
Poor surveillance	Primary radars, Voice reporting	ADS-B, HF data link, radars mode S
Runway incursions	Visual surveillance	Multilateration
Range limitation	Satellite based VHF, HF	AMSS

4.3 Study of selected systems 4.3.1 Communication systems

The communication requirements for each phase of flight depend on the controller-pilot communication needs. These requirements vary with the traffic complexity and density, the weather conditions, the controller's needs to issue clearances and vector² the airplane or to establish contact with the aircraft crew. Enhanced communication performance is provided through air-ground data link communications integrated into the Aeronautical Telecommunication Network (ATN) to complement the current voice communications means (see ATN page 83). Voice communication will be used for critical messages, such as vectoring to avoid traffic and landing clearance at airports with heavy traffic. It will also serve as back up.

² Headings by the ATC to an aircraft, for the purpose of providing navigational guidance

Figure 4.1 : Aeronautical communication links

Aircraft 1

Ground: ATC, ANSPs, AOC

Communications

Satellite

Ground: ATC, ANSPs, AOC

Aircraft i

Data Link

A key feature of communication is the use of digital Data Link as a primary means for exchanging aeronautical information and delivering ATC services: pre-departure clearance (PDC), digital Automatic Terminal Information Service (ATIS), selected Flight Information Services (FIS) and oceanic ATC services for instance. Today's most prominent Data Link advanced features are CPDLC and VDL, Mode S Data Link.

CPDLC (Controller Pilot Data Link Communication)

CPDLC is an important tool that addresses the problems generated by the growth in aviation communications and the accompanying needs for effective communications, and acceptable safety levels (Hancock, 2005). CPDLC resolves a number of drawbacks. For instance, it provides automatic data entry capabilities. This permits ground systems and airborne flight management computers to enter critical information, such as flight routes... etc. It cuts down on errors resulting from manual data entry. It also permits a significant reduction in transmission time, thus reducing the congestions. It eliminates misunderstanding due to a deficient quality of the voice received, propagation problems, dialects and the possibility of having instant access to previous voice transmission recording. The following figure represents a screen shot of a CPDLC message between

a controller and a Pilot. The ATC ask the pilot to climb at a certain altitude, and the pilot replies that the aircraft performance could not tolerate this manoeuvre.

Figure 4.2 CPDLC test message on SAS³ B737-600 LN-RRZ MCDU

Source: SAS, 2005 CPDLC Trials

As explained, CPDLC supplements the essential communications bridge between controllers and pilots. It helps to reduce routine workload, non-time critical exchanges from the voice channel to a data channel, freeing the voice channel for time critical communications such as vectors around weather or traffic.

Voice channel occupancy: In high fidelity simulations conducted at the Federal Aviation Administration's (FAA) Technical Centre, the voice channel occupancy decreased by 75 percent during realistic operations in busy en route airspace. The net result of the decrease of voice channel occupancy is increased flight safety and efficiency through more effective communications between controllers and pilots, with fewer missed, repeated, and misunderstood communications.

Capacity Gains and Workload reduction: A real-time simulation performed at
Eurocontrol's experimental centre during the year 2000 investigated the use of voice
radio frequency at three levels of traffic volume: baseline study day traffic, and 150%

³ Scandinavian Airways

and 200% of the baseline volume, and at four levels of Data Link aircraft equipage: 0%, 50%, 75% and 100%. A clear positive correlation was obtained between aircraft equipage level and reduction in voice frequency usage. The following figure presents the results (Boeing, 2000).

Figure 4.3: Estimated Capacity gained as a function of percentage of CPDLC equipage

Source: Mitre Corporation, 2005

Working with these data, Eurocontrol used findings from previous non-data link studies conducted by National Air Traffic Services (NATS), in the United Kingdom and the Centre d'Études de la Navigation Aérienne (CENA) in France to estimate reductions in total sector workload associated with communication under current voice-only conditions (table 4.1). These earlier results indicated that communications normally constitute 35% to 50% of total sector workload. Based on the reductions in frequency usage previously identified in the real-time simulation, Eurocontrol calculated total sector workload reduction due to CPDLC for each level of data link equipage using the conservative estimate of communications workload (35%). The link between sector workload and airspace capacity was estimated using prior results obtained with an ATC Capacity Analyser tool.

Percentage Aircraft Equipage	Workload Reduction
0%	0%
50%	16%
75%	22%
100%	29%

Table 4.1 Workload reduction as a function of aircraft equipage

(Boeing, 2000)

The results suggested that proportional sector capacity increases are approximately one-half of the amount of workload reduction achieved in a sector. The results of the workload reduction calculations performed by Eurocontrol in 1999 are presented in table 4.1 above.

Delays reduction: Eurocontrol investigated the impact of traffic and capacity variations on Air Traffic Flow Management (ATFM) delays in the European airspace. The traffic sample and the airspace used for the delay calculations were identical to those used in the real-time simulation baseline described previously. The results are shown in table 4.2 below.

Percentage Aircraft Equipage	ATFM Delay reduction	Overall Delay reduction
0%	0%	0%
25%	10%	2.5%
50%	31%	8%
75%	44%	11%
100%	53%	13%

Table 4.2: Delays Reduction as a Function of aircraft Equipage
(Boeing, 2000)

As suggested earlier, future efforts should allow to identify and to quantify benefits that will be gained not only by airspace users, but also by ANSPs. For the later, benefits flow directly from the increase in productivity (controllers' workload, capacity) associated with the use of CPDLC. However, they are realized as an alternative means to increase airspace capacity without increasing the number of en-route control centres. The keys to assessing the benefits of CPDLC lie in an understanding of how CPDLC facilitates the job of air traffic controllers, and how these changes affect the effective capacity of airspace and the associated costs of maintaining a safe and efficient air traffic system and the cost of using it.

The physical infrastructure that supports the CPDLC is the VHF Data Link (VDL) presented below.

VHF Data Link (VDL)

VHF analog communication means available today are not compatible with CNS/ATM technologies. VHF Data Link operations require a VHF digital radio. VDL is essential for Data Link; VDL formats specify a protocol for delivering data packets between airborne equipments and ground systems similar to that used in Aircraft Communication Addressing and Reporting SystemS (ACARS). The difference is that VDL provides a capacity 10 times greater than the equivalent of 25 KHz VHF channel.

VDL Mode 1: VDL mode-1 is a low speed bit oriented data transfer system. It uses carrier sense multiple access (CSMA⁴) protocol. The new development has overtaken VDL mode-1, which is no longer in use.

VDL Mode 2: It is an improved version of VDL Mode 1 and it uses the same technology and Differential 8 Phase Shift Keying (D8PSK) modulation. It is supported by VHF and HF capabilities. Its average data transmission is 31.5 kbps⁵. This is over 13 times the VHF ACARS 2.4 kbps rate using Double Sideband Amplitude Modulation (DSB-AM). It employs a globally dedicated common signalling channel⁶ (CCS) of 136.975 MHz.

VDL Mode 3: it is an integrated digital data and communication system allows to use up to four voice and/or radio channels on a single carrier with 25 KHz spacing. The data link technology used is called TDMA⁷. The data capability provides a mobile sub network that is compliant to the Aeronautical Telecommunication Network.

⁴ Carrier sense means that every device on the network listens to the channel before it attempts to transmit the information. Multiple access means that more than one network devise can be listening at the same time, waiting to transmit the data.

⁵ Kilo Byte per second

⁶ Signalling is the use of signals for controlling communications. CCS means that a data channel in combination with its associated signalling terminal equipments. It only requires one signalling channel for up to 1000 data communication channels and is able to do this by only signalling when required.

⁷ TDMA is a technology for delivering digital wireless service using time-division multiplexing (TDM). TDMA works by dividing a radio frequency into time slots and then allocating slots to multiple calls.

VDL Mode 4: It uses a data link technology called self-organizing time division multiple access (STDMA). In this mode, stations transmit their geographical position together with data message in time slots that are dynamically modified at frequent intervals.

Before starting a transmission using the STDMA technique, the aircraft keeps listening on the frequency to be used and establishes a track and a table of time slots for all other aircraft. An algorithm in the aircraft transceiver selects a free slot or takes the slot of the most distant aircraft. This modulation system allows distant stations to transmit in the same slot with little interferences. The aircraft is not involved in any manual frequency tuning for any station change. Reception of the geographic position gives a surveillance capability. VDL mode 4 is a candidate technology for ADS-B operations.

Airlines prefer VDL Mode 2. The technology is perceived as the only logical choice because it is a globally accepted standard supported by the communication service providers such as SITA⁸ and ARINC⁹. VDL Mode 2 has been standardized as a digital data link to be shared by Air Traffic Services (ATS) and Aeronautical Operational Control Centres (AOC). This is done within the framework of ICAO's standardized Aeronautical Telecommunications Network (ATN).

Mode S Data Link (Mode Select)

Mode S is use for surveillance as it's will be explained later in page 96. Nevertheless, it also makes available an air-ground data link, which can be used by ATS in high-density airspace.

Mode S Transponders send and receive data link messages via Mode S message formats. During normal operation, ATC ground stations and other aircraft automatically receive altitude, discrete address, and transponder code via interrogate and reply formats.

⁸ Societe International des Telecommunications Aeronautiques

⁹ Aeronautical Radio Inc

The Mode S ground interrogator transmits a sequence of pulses. The timing, the level and the sequence of the pulses determine the interrogation mode. The ground interrogator can distinguish between the surveillance function and the data link function due to the availability of different pulses, pulse amplitudes and pulse times. Mode S data link function uses four distinct pulses.

Aeronautical Mobile satellite System (AMSS)

AMSS are geostationary communications satellites, designed especially for mobile communications, which offer wide/near global coverage and voice and data communications. The digital voice component of AMSS is designed to interface with terrestrial public switched telephone network (PSTN) and to provide high quality telephone service both for aeronautical passenger communications (APC), ATS & Aeronautical operational control (AOC). The use of AMSS is particularly suitable for cross-oceanic flights.

High frequency Data Link (HFDL)

The HF data link provides an air-to ground data link that is ATN-compatible. Its development within lCAO has progressed rapidly and appears to provide an alternative and possibly cheaper communication medium than SATCOM for data. HF data link is also an excellent standby system for the AMSS presented above, in oceanic and remote areas. Aiircraft can contact three or more HFDL ground stations constantly and its hub can become ATN routers. The dependence on HF voice continues to remain the backbone for ANSPs communication systems in oceanic and remote regions.

AMSS, VDL, Mode S and HF data link use different data transmission techniques. Individually, they all use the same network access protocol in accordance with International Standardization Organisation (ISO). This allows the interconnection between these technologies and other ground-based networks. The communication service that allows ground, air-ground and avionics data network to interoperate is the Aeronautical telecommunication Network presented in figure 4.4.

Aeronautical Telecommunication Network (ATN)

«Without ATN, there is no CNS/ATM». (Dr Hilaire Tchicaya, Head of Aeronautical Telecommunications, ASECNA). In fact, ATN is the inter-networking infrastructure for the technologies presented above and others. ATN will link the various air-ground data systems together.

A variety of ground networks, implemented by states, a group of states or commercial networks that use packet switching techniques and are compatible with ISO's OSI reference model will be able to use ATN's internetworking services. With the gradual implementation of ATN, the use of the current Aeronautical Fixed telecommunication network that serves to transmit messages between ANSPs, and between ANSPs and users. AFTN will diminish. However, during the transition period, interconnection of AFTN terminals to the ATN will be possible via special gateways.

Figure 4.4 Aeronautical Telecommunication Network concept

Source: ICAO, 2002, p.69

Airline Data Base

FMS

HF
Link

Private
Ground
Network

Flight crew
Interface

Gate
Link

Airline Admin Service

Airline Operation Control

Airborne
Network

Gateway to PDN

Router

VHF
Link

Router

Cabin Crew
Interface

Mode S
Link

ATS

ATS
ground
Network

PAX
Interface

Satellite
Link

ATFM

ATN allows communication between all the stakeholders. The design provides for incorporation of different air-ground sub networks and different ground-ground sub networks, resulting in a common data transfer service. The two aspects are the basis for interoperability that will provide a reliable data transfer service for all users. Furthermore, the design is such that user communication service can be introduced in an evolutionary manner.

As shown in Figure 4.4 above, the routing of messages over ATN are controlled by routers. The routers direct data messages to their destinations. ATN aims at operating globally, encompassing all aeronautical data communication services.

4.3.2 Navigation systems

CNS/ATM navigation technology improves the accuracy of the position and provides better predictions of future positions to enable aircraft to fly more accurately.. Improvements in navigation include the progressive introduction of area navigation (RNAV) and required navigation performance (RNP) capabilities along with the global navigation satellite system (GNSS). These systems provide for worldwide navigational coverage and are being used for en-route navigation and for non-precision approach. With appropriate augmentation systems and related procedures, it is expected that these systems will also support precision approaches even under bad visibility conditions.

Global navigation satellite System (GNSS)

GNSS is a satellite system that is used to pinpoint the geographic location of a user's receiver anywhere in the world. Two GNSS systems are currently in operation: the American system: Global Positioning System (GPS), and the Russian's Global Orbiting Navigation Satellite System (GLONASS). A third one, Europe's Galileo, is slated to reach full operational capacity in 2008. Each system employs a constellation of orbiting satellites working in conjunction with a network of ground stations.

Satellite-based navigation systems use a version of triangulation¹⁰ to locate the user, through calculations involving information from a number of satellites. Each satellite transmits coded signals at precise intervals. The receiver converts signal information into position, velocity, and time estimates. Using this information, any receiver on or near the earth's surface can calculate the exact position of the transmitting satellite and the distance (from the transmission time delay) between it and the receiver. Coordinating current signal data from four or more satellites enables the receiver to determine its position. There are nearly 30 satellites giving an accurate positioning and timing information worldwide. They can be used to give positioning accuracies of better than 10 metres and timing accuracies of better than 30 nanoseconds.

World Geodetic System coordinates (WGS-84): An important tool in implementing these navigation principles are the World Geodetic System coordinates (WGS-84).

¹⁰ Triangulation is a process by which the location of a radio transmitter can be determined by measuring either the radial distance, or the direction, of the received signal from two or three different points. Triangulation is used in aviation to pinpoint the exact geographic position of an aircraft for instance.

WGS-84 coordinates system is a conventional earth model, established in 1984 from assembled geometric and gravitational data. This model portrays the earth as being ellipsoidal, contradicting former beliefs that the earth was spherical (ASECNA, 1996). The origin of this system is the earth's Centre of mass (assuming for simplicity that the earth rotates at a constant speed around a fixed meridian pole).

The WGS-84 system responds to the present navigational needs: RNAV, RNP, ATS routes and satellite navigation. In 1989, ICAO adopted WGS-84 as the standard geodetic reference system for future navigation (For further information, refer to Appendix 3).

Satellite Based augmentation Systems (SBAS): There are four Satellite Based Augmentation Systems being developed: EGNOS in Europe, GAGAN in India, MSAS in Japan and WAAS in the USA. These are all civil-controlled regional systems and there is a form of coordination to ensure that they are interoperable to provide a seamless worldwide navigation system so that one SBAS/GPS receiver can be used all of them. Each SBAS provides GPS corrections to improve positioning accuracy to around 1 metre horizontally and 3 metres vertically. Timing accuracy is enhanced to better than 10 nanosecondes.

ASECNA has chosen the European Augmentation Systems EGNOS as part of his satellite navigation strategy.

European Geostationary Navigation Overlay Service (EGNOS): EGNOS, the European Geostationary Navigation Overlay Service, is a SBAS that is being deployed to provide regional satellite-based augmentation services aviation, maritime and land-based users in Europe. EGNOS is the first step in the European Satellite Navigation strategy that leads to Galileo. Availability is improved by broadcasting GPS look-alike signals from up to three geostationary satellites; accuracy is improved to between 1 and 2 metres horizontally and between 2 and 4 metres vertically; Integrity and Safety are improved by alerting users within 6 seconds if a malfunction occurs in EGNOS or GPS. The following are the benefits that are derived from EGNOS.

Figure 4.5: Comparison between EGNOS and GPS

Source: ESA, 2004

EGNOS enables Precision Approach Operations (APV 2 and APV 1)¹¹. They are achievable on every runway. The Integrity of EGNOS vertical guidance protects aircraft against CFIT¹² accidents. Thanks to SBAS APV1, all non-precision approach (NPA) procedures are suppressed. New SBAS APV1 services open the door to new feeder routes between secondary and inter national airports. New APV1 procedures suppresse the need of CAT-1 service for many runways

A major advantage of this system is that it requires less costly ground installations than is required by present conventional systems. It allows the full coverage of navigational services over sparsely populated, desert and forest areas. It must be highlighted that there is no technical requirement for the implementation of EGNOS ground stations in each African country. In other words, this means that EGNOS service provision scale is at regional (i.e. sub-continental) supra-national level.

¹¹ Approach Procedure with Vertical guidance

¹² Controlled Flight Into Terrain

EGNOS Trials

The aim of the flight trial was to assess EGNOS' capability to provide aircraft guidance during two different approach types:

1) Straight-in ILS look-alike approaches: Guidance was provided by the flight director and autopilot of the aircraft's Flight Management System.

2) Curved approaches: Guidance was provided by the flight director of the Research

The following parameters among others that are not reported here have been investigated:

Accuracy: The navigation system error (NSE¹³), the total system error (TSE¹⁴), Integrity, and Noise Contour.

13 The navigation system error (NSE) is defined as the difference between the actual flight path (i.e. Trimble reference position) and the flight path indicated by the navigation system in the lateral and vertical plane.

14 The Total System Error (TSE) is defined (See figures above) as the difference between the desired flight path and the actual flight path (i.e. Trimble reference position).

The Results

The Total System Error (TSE)

Distance to the runway Distance to the runway

Figure 4.6: Lateral and Vertical TSE for three approaches.
(Red=1^st approach, Green = 2^nd, Blue = 3^rd approach. A minus sign means Left/Below
desired position; a plus sign means right/Above desired position).

The performance in terms of the Horizontal NSE and the Vertical NSE were found to be in the order of 1-4 m (95%) in the lateral and vertical plane and can be rated as very good according to Eurocontrol. The lateral APV-II and CAT I requirements as specified in ICAO SARPs were easily met (tables 4.3, 4.4 and 4.5 below). The vertical APV-II criteria specified in the SARPs were met during all curved approaches.

Procedure	95% Accuracy
	Lateral (m)	Vertical (m)
Nice results	3.9	4.9

Table 4.3

Results for lateral vertical accuracy

ICAO SARPS	95% Accuracy
	APV I	APV II	CAT I
Lateral (m)	220	16	16
Vertical (m)	20	8	4-6

Table 4.4

Results for Availability Vs ICAO's SARPs

	Availability
	APV I	APV II	CAT I
Nice	100%	(100-99,92) %	100%
ICAO	0.9999	0.9999	0.9999

Table 4.5: ICAO's SARPs for lateral and
vertical accuracy

In general, the aircraft arrived at the runway threshold slightly right of centreline during the curved approaches. The navigation system error was relatively small.

Noise Contour: This noise impact study confirmed that the Riviera approach reduces annoyance for the local area, especially at the located right below the ILS eastward approach trajectory. The study also revealed that the use of a SBAS navigation system might bring further improvements around the southeast local area by considerably reducing the dispersion of aircraft trajectories. However, for the SBAS scenario all aircraft were assumed to have the same 3D trajectory, which is a strong assumption. The benefits of SBAS guidance in terms of noise will strongly depend on the way it is implemented and how pilots and controllers respect procedures.

GNSS and improvements in avionics allow better navigation and approach manoeuvres. Area Navigation and Required navigation performance are two of the main concepts made possible by these CNS/ATM tools.

RNAV (Area Navigation)

Area Navigation is a method of navigation that enables an aircraft to fly in any desired path within the coverage of referenced air navigation aids, or within the capacity of self contained systems or a combination of both. The use of routes and procedures based on RNAV, improves access and flexibility, through point-to-point navigation. These routes are not restricted to the location of ground based NAVAIDs. Safety of such operations is achieved thanks to a combined use of navigation accuracy, ATC monitoring, communication, multilateration¹⁵, or increased separation.

RNAV was developed to provide more lateral freedom and a better use of available airspace. This method of navigation does not require a track directly to or from any specific radio navigation aid as explained above, and has three principal applications:

1) A route structure can be organized between any given departure and arrival point to reduce flight distance and traffic separation.

¹⁵ Multilateration is today's version of triangulation (use of three satellites to locate an object), where the location of an object is determined by taking its bearing from several different places.(Refer to appendix 2 for more details)

2) Aircraft can be flown into terminal areas on varied pre-programmed arrival and departure paths to expedite traffic flow.

3) Instrument approaches can be developed and certified at certain airports, without local instrument landing aids at that airport.

The following figures represent the navigation performance when using RNAV or RNP. They clearly show the advantages of new systems in term of efficiency.

Figure 4.7: Comparison between RNAV, RNP and Conventional navigation

Inefficiency with Conventional systems

Improved Efficiency with RNAV

Optimised Efficiency with RNP

Source: Federal Aviation Administration, 2006

Trials have been conducted and RNAV is already implemented in many parts of the world since the year 2000. The following are the results from trials in Atlanta (USA).

RNAV Trials

As the next figure depicts it, Non RNAV flights are characterised as follows:

1) Departures are vectored

2) Headings, altitudes and speeds issued by controllers

3) Large number of voice transmissions required

4) Significant dispersion

5) Tracks are inconsistent and inefficient and there are limited exit points

Results

Figure 4.8: Atlanta SID trials: Non RNAV tracks

Source: IATA, 2005

Flights with RNAV capabilities give the following results: Figure 4.9: Atlanta SID, RNAV tracks

Source: IATA, 2005

The results are as follows:

· Departures fly RNAV tracks are not vectored

· Headings, altitudes and speeds are automated via avionics

· Voice transmissions reduced by 30-50%

· Reduced Track Dispersion

· Tracks are more consistent and more efficient

· Additional exit points available

RNP (Required Navigation Performance)

RNP operations are RNAV operations that use on-board containment¹⁶ and monitoring. The ability of the aircraft navigation systems to monitor its achieved performances, and to indicate to the crew whether the operational requirement is being met during an operation, is a critical component of RNP. Aircraft RNP capability is important in determining the separation requirements to ensure that containment is met. RNP approach is already being implemented in some American airports.

In the Caribbean and Latin America regions, introduction of RNAV is generating an annual reduction of around 40,000 tonnes of CO2 emissions. In cross polar-routes, satellite based navigation has enabled flights over previously untravelled territory using Russian, Canadian and US airspace close to the North Pole. The first official polar route flight between North America and Asia by a commercial airline was conducted in July 1998. Currently, more than 200 flights per month use near polar routes between Europe and Asia and Asia and North America thereby benefiting airlines and passengers through significant time and fuel savings and associated emissions reductions.

Figure 4.10: Projected RNP-RNAV capability, RNP capable aircraft:

Source: Eurocontrol, 2002

¹⁶ Onboard containment is onboard alerting and monitoring capability that reduces the reliance on Air Traffic Control intervention, via Radar or ADS, multilateration...

American and European aviation regulators have recently approved the integrity of navigation data provided by Boeing. It enabled carriers to use the information for precision area navigation procedures: Carriers using the navigation data will be able to implement new precision area navigation (P-RNAV) procedures. They require that aircraft are able to maintain a track with lateral accuracy of 1nm (1.85km) for 95% of the time (Kaminski-Morrow, August 2005)

As the figure 4.10 suggests, aircraft RNP and RNAV capability will be greater than 90 per cent by 2010. Which means no ANSP could ignore that, and therefore they need to prepare themselves consequently to be able to offer that service to their users.

RVSM (Reduced Vertical Separation Minimum)

The goal of RVSM is to reduce the vertical separation above flight level (FL) 290 from the current 2000-ft minimum to 1000-ft minimum. This will allow aircraft to safely fly more optimum profiles, gain fuel savings and increase airspace capacity. The process of safely changing this separation standard requires a study to assess the actual performance of airspace users under the current separation (2000-ft) and potential performance under the new standard (1000-ft).

RVSM was successfully implemented across 41 European and North African States in January 2002. During the first summer of operations, ATM capacity in European airspace was increased by approximately 15%.

4.3.3 Surveillance systems

Secondary Surveillance Radars are still being used, along with the gradual introduction of Mode S presented below, in both terminal areas and high-density continental airspace. The major innovations are the introduction of Automatic Dependent Surveillance (ADS), Mode S surveillance and multilateration. The latter is not presented here although it has great potential.

ADS systems allow the aircraft to calculate its position, its heading and other data such
as speed and useful information contained in the flight management system. The data

are automatically transmitted to the air traffic control unit. ADS data are transmitted via satellite or the communication means presented earlier (Data Link...). The position of the aircraft is displayed on a screen like with a radar display. ADS is defined as the true merging between Navigation and Communication technologies. Along with enhanced ground systems' automation, ADS helps to improve ATM, especially in oceanic airspaces.

The need for new HF radios on Atlantic routes has been averted through the gradual introduction, over the past few years, of ADS waypoints reporting, which allows better flight plan conformance monitoring and a reduction in gross navigation errors.

There are presently three types of ADS: ADS-A, ADS-B and ADS-C. These are presented below.

ADS-A (Addressable)

ADS-A enables appropriately equipped aircraft to send position information messages at predetermined geographical locations or at specified time intervals. ADS-A can be relayed via high frequency data link, satellite communication, and very high frequency. Some pacific ATS providers already use Automatic Dependent Surveillance-Addressable to apply 50 nm longitudinal separation between aircraft. ANSPs' systems in countries like New Zealand, Australia, Tahiti, and Fiji support the use of FANS 1/A ADS-A operating systems in Pacific oceanic airspace (Cirillo, 2004).

ADS-B (ADS-Broadcast)

ADS-B involves broadcast of position information to multiple aircraft or multiple ATM units. ADS-B-equipped aircraft or ground vehicle periodically broadcast their position and other useful data derived from on-board equipments. This is called aircraft derived data (ADD). The position is calculated through GPS and associated augmentation systems. Any user, either airborne or ground-based, within range of this broadcast, can process the information. It will remove the reliance on voice reports and is expected to add significant en-route safety. The technology is also envisaged to be applied for surface movements, thus being an alternative to surface radars such as airport surface detection equipment.

Figure 4 .11: ADS-B operational capabilities.

Source: RockwellCollins.com

The figure above (figure 4.11) illustrates the operational capabilities of the technology. It will bring significant operational enhancement in airport surface management, air-to air and air-to-ground communications, and in surveillance operations. On airports' surface, it will enhance pilots' situation awareness, and above all, it will reduce runway. In-flight, ADS will improve separation standards.

ADS-B Operational trials (Bundaberg, Australia)

In recent years, Australia has been active in the field of automatic dependent surveillance-broadcast because the technology offers the possibility of continent-wide coverage.

In 2002, Air Services Australia installed a single ADS-B ground station at Bundaberg
and equipped a number of aircraft with ADS-B avionics. They modified Australian
ATM system to process and display ADS-B tracks. The data link technology used was

Mode S extended squitter¹⁷. The focus of Bundaberg's trials was to improve lower level surveillance coverage to allow early insurance of clearances as aircraft climbed into controlled airspace. 28 ADS-B ground stations are planned nationwide. Some will replace 11 secondary surveillance radars, saving a fortune in maintenance cost. Each ADS-B station costs $1 million. It will replace a $US10 million worth radar that costs $US1 million per year to maintain. The other ADS systems will provide coverage in airspace that has never had radar.

Results

The systems performance exceeded expectations. Detection coverage, position accuracy, velocity vector accuracy and update rate were found to be better the conventional fast rotating monopulse secondary surveillance radar used (Dunstone, 2005).

Gotzenhein (Germany) Operational trials

This site was chosen because Frankfurt had been evaluated as the region with the highest FRUIT density world-wide. The ADS-B antenna elements were positioned either side of the airport radar tower for 360° coverage.

Results

Evaluated as a Terminal application (100 Nm) with a 4 second update rate,the Probability of Detection (Pd) was greater than 99.8%.

Evaluated as an En-route application (150 Nm) with a 6-second update rate, the Pd was above 99.6%.

As shown on the following figure (Figure 4.12), ADS-B is far better than Radar. While radar data gated to 150 NM, ADS-B was only limited by terrain screening. The results also showed a higher update rate, which allow a better accuracy (Wakefield, 2005).

¹⁷ Works on 1090 megahertz, and is recommended as initial worldwide interoperable ADS-B Link

Figure 4.12: Comparison between ADS and Radar's.

Source: Wakefield, 2005

ADS-C (ADS-Contract)

ADS-C is another ICAO standardised technique that allow aircraft to report data items, including position, identity, intent, etc, to the ground over a point-to-point data-link. It has been deployed mainly in oceanic areas and uses satellite communications. However, it can also be used over any point-to-point data-link (VHF, HF... etc). The technology is presently used only in areas of low traffic density because of bandwidth limitations in point-to-point data-links.

Secondary Surveillance Radar Mode S (SSR-Mode Select)

Mode S radar is a relatively new type of secondary radar that is also based on the use of a transponder on board the aircraft, responding to interrogations from the ground. The radar thereby detects the aircraft with better link means, and above all retrieves information that can help identify the aircraft at the same time.

Communication between conventional secondary radar and a conventional transponder
uses the modes A and C. When interrogated in mode A, the transponder replies by

transmitting its code with the same name (allocated to the flight by air Traffic Control, and entered by the pilot into the transponder via the interface). When interrogated in mode C, the transponder replies by giving its altitude.

The radar mode S operates at the same frequencies (1030/1090 MHz). The Mode S provides more accurate position information and minimizes interferences by discreet interrogations of each aircraft. Its selectivity is based on precise identification of an aircraft by its 24-bit address. That address can be considered as its communication address and is linked to the aircraft, or at least to its transponder. But it does not replace the Mode A code which is linked to a flight or a flight plan. There are also plans for recovery of the A and C codes via Mode S.

4.3.4 Air Traffic Management

The future domestic ATM

Using satellite-based navigation and communication networking technologies presented above, the future domestic and oceanic ATM systems will be seamless. They will employ similar systems and procedures regardless of location. However, complete transition to the new environment may not be completed in the near term. Therefore, the near-term domestic CNS concept must maintain some reliance on current ground ATC capabilities, albeit upgraded, particularly in terminal areas. Terminal air traffic controllers will continue to separate and sequence aircraft. Pilot-controller connectivity will include both voice and data. Radar will continue to provide some aircraft position information but the introduction of Mode S secondary radars will facilitate the selective interrogation of aircraft. In addition, ADS-B will be introduced in the en route structure where aircraft broadcast position information derived from GPS and corrected by augmentation systems to the ATM system. SBAS corrections will be transmitted from ground earth stations through communications satellites. GPS and Augmentation systems may also provide precision approach information in the future for aircraft, eliminating the need for ILSs and precision approach radar (PAR). Data link networks will route CNS data as presented earlier.

The future oceanic ATM

In the near future, the greatest changes will occur in the oceanic environment. Here we expect the full implementation of satellite-based CNS (ADS, Data-Link... Etc). Aircraft will relay GPS/Augmentation-derived positions to ATM systems through satellites. The same satellites will be used to relay aircrew requests and ATC instructions, many of which will involve ATM to aircraft data links. The data link network will route CNS information accordingly. In the oceanic environment, the first implementation of aircrew-based separation is expected. Today, some airlines are already using a TCAS «in-trail climb» procedure in which aircrews coordinate manoeuvres that allow aircraft to pass one another.

4.4 Transition

The transition toward future systems needs to be accomplished gradually. A Cost Benefit Analysis should precede each step. The FANS II committee developed the transition's guidelines (ICAO, 2002). These encourage that the states introduce some of CNS components early enough in order to get rapid return on investments. The conventional and the new system will have to co-exist during the transition period to ensure people become familiar and confident with the new technology before completely relinquishing existing technology. The two systems will have to inter-operate (interoperability). But the guidelines aim at minimizing this period to the extent practicable. But because of great difference in the level of ATM in various parts of the world and other factors that have to be taken into account, a reliable time frame can not be specified. Basing the transition to CNS/ATM systems on improvements in ATM and structural and procedural changes is ideal. Airspace reorganisation is required.

Commercial factors are also crucial and investments in satellite based systems by ANSPs need to match that of domestic and international customers. Moreover, integrity of the air navigation systems must be maintained throughout the transition phase. Any removal of existing navigation aids has to be done after consultations with the users. Planning and implementation of improved ATM systems should also include

consideration of training needs. The aviation community (Air operators, institutions and service providers, manufacturers, states) have to cooperate to achieve these goals.

4.6 Affordability

With ICAO's ATM Operational Concept and Global Air Navigation Plan, and IATA's ATM Implementation Roadmap, the airline industry has the potential to implement a global airspace environment that will bring substantial operational and financial benefits. However, implementing CNS/ATM systems will cost the industry money as they will have to:

1) Upgrade aircraft avionics systems

2) Train the crews for the new systems and procedures

Progress towards the new systems have been slow. This lack of movement towards full FANS implementation was not due to any particular technical problem, as the industry effort had focused primarily on development of the technological case for CNS/ATM, with many resulting competing technologies. The business case for CNS/ATM had primarily been addressed at a cursory level, resulting in estimates of operational savings without details on the benefit mechanisms. The ATM system must be considered as a set of technologies; but it must also be considered as a business. The lack of consideration of the economics of transition to the new operational concept has slowed the pace of the implementation process (Allen et Al, 2005).

Airplane and ground system upgrades were slowed until they were confident that the expenditures were justified. For an air carrier, a business case evaluation would include, among other factors, assumptions about the impact on its costs of expected changes in en-route charges and the impact on revenues of changes in air carrier fares and rates, where these changes are associated with the implementation of CNS/ATM. These impacts are in addition to the direct investment costs and operating cost savings attributable to the new systems and identified in the cost/benefit analysis. The impact of route charges will depend on the outcome of the policies and evaluations of the service providers. Assumptions about fares and rates will reflect competitive pressures in air travel and freight markets.

Most of the basic practical guidance required relating to organizational options, cost/benefit analysis, financial control, cost recovery and financing has been developed following ICAO guidelines. The industry is confident that the new systems will bring significant benefit to undertake such investments, and is participating to trials and implementation programmes worldwide in collaboration with other industry's stakeholders (i.e. joint ASECNA and Air Afrique¹⁸ GNSS trials from 1994 to 2000).

For ASECNA, implementing new systems to improve the service will require significant finance power. Between 2000 and 2010, installation and commissioning amount to $US 276 million. This does not include interests on loans or depreciation. A cost-benefit analysis for the 1995-2005 period shows investments of $US 235 million including depreciation and interests. Expected incomes amount to $US 259 million, essentially from air navigation charges. Airlines' investments needs amount to $US 309 million. Expected comes amount to $US 341 million.

Big companies will be able to upgrade their fleet. But many small companies, which own old fleet, will not be able to afford it. ASECNA will have to find adapted solutions for them.

4.7 Conclusion

This chapter has allowed us to present the basic components of CNS/ATM systems. How the proposed CNS/ATM technologies work, and how they actually deliver the expected benefits to ASECNA has been studied. The study shows that the systems are suitable to ASECNA as trials indicate that they could respond to its characteristics and its problems. Satellite based navigation, data communication, and improved radar surveillance, will render air traffic management much more efficient.

Future communication and satellite-based technologies will allow better exchanges between pilots and controllers on both continental and oceanic airspaces. Trials presented have shown that CPDLC, relying on high bit rates and more capacitive data link techniques such as VDL, Mode S and satellite communication reduces communication errors and reduce voice channels saturation and interferences. This

¹⁸ Before the airline's bankruptcy

means a safer communication environment. As controllers and pilots will loose less time in unnecessary communications, this will have a positive effect on airspace capacity, and increase safety margins. Moreover, controllers' workload will significantly been reduced, particularly in areas where traffic is relatively dense, which will improve productivity and cost effectiveness in peak periods. In areas where traffic is less dense, the new system will not have a significant impact, as controllers' workload is already very low. At last, ATN will improve the quality, the speed and the integrity of data transmission between users and service providers

Satellite navigation, in providing more navigation accuracy in conjunction with augmentation systems, will allow aircraft to flight efficient trajectories and make a better use of airspace with less dispersion, potentially avoiding diversion cost in bad visibility conditions. Secondary airports will be accessed without the need of landing aids. RNAV, RVSM, and RNP will increase route efficiency, safety, and capacity.

New surveillance technologies performance during trials (ADS, Radar Mode S) show that aircraft detection and identification are improved in remote areas such as oceans or deserts, and allow ANSPs to deliver a safer service at a significantly lower acquisition and operating cost.

Big air operators are fitting their fleet with these capabilities. Small carriers will not have the means to upgrade their old fleet. ASECNA has to adapt to each category's particular needs. At last, transition between the old and the new system requires cooperation between the different stakeholders. To ensure a smooth shift in technologies, interoperability between the systems is essential.

Chapter 5: Analysis of ASECNA's Modernisation Strategy

The aim of this chapter is to present and analyse ASECNA's modernisation strategy, for each CNS/ATM component.

5.1 Description 5.1.1 Communications

ASECNA's objective is the full deployment of an ATN environment with the possibility to accommodate FANS1/A and the highest degree of functionality possible.

Fixed Network: ASECNA has embarked in the modernization of AFTN by high-speed links and in the integration of its telecommunication systems. The Interconnection of sub-regional communication networks and the setting up of an independent satellite digital telecommunication network within its area, for AFTN and mobile communications needs and for exchanges of meteorological data to assist ATM are being implemented.

Data Communication: The use of secured and efficient protocols is expected to increase end-to-end reliability of data transmission. A Flight data automation program is engaged: The FIR Antananarivo already has FDPS, CPDLC and ADS-C capabilities. Trials for similar systems and testing of a VDL sub-network and HFDL are being conducted in Dakar.

VHF coverage: The VHF coverage programme is well advanced. Plans suggest that almost all ASECNA's routes will be covered and controlled by means of VHF radio, except the Oceanic FIR. VHF has been deported to Agades, Zinder, Tessalit, GAO, Dirkou (FIR

Niamey- Areas of Routing 3-4-9), Faya-Largeau (FIR N'Djamena AR-3) by means of VSAT stations. Others are being implemented in Bir Moghrein, Nema, Taoudennit, Tombouctou, Nouadhbou (FIR Dakar continental, AR 1-9), Moroni, Toamassima, Tolangnaro (FIR Antananarivo,AR-10), Sao Tome and Principe, Bria, Makokou and Pointe Noire (FIR Brazzaville, AR-4-5). A program to modernise VHF and HF

Chapter 5: Analysis of ASECNA's Modernisation Strategy

equipments and installation of VSAT TS Direct speech facilities in other places are also on the way.

5.1.2 Navigation

Successful flight trials in May 2005 from Dakar to Nairobi have been conducted, using EGNOS. These followed other trials in West and Central Africa, conducted in February 2003 in Dakar, Senegal and in June 2003 at many airports of the States of Central Africa (Nigeria, Cameroon, Gabon and Equatorial Guinea). GNSS approach procedures are already available for all major airports in ASECNA.

As it is necessary to maintain adequate navigation service during the transition period, ASECNA has launched a program to replace Navaids (VOR, ILS, and DME...) in certain locations before the full implementation of GNSS. The use of satellite technologies has allowed the Agency to implement 21 RNAV routes over its upper airspace since 2004.

RVSM are already implemented in Antananarivo, Brazzaville, Dakar, N'djamena and Niamey's Flight Information Regions in accordance with ICAO regional agreements. Since the beginning of 2006, operators wishing to penetrate this airspace received RVSM aircraft airworthiness and operational approval from the appropriate state authority.

5.1.3 Surveillance

Voice position reports remain the dominant procedure. However in high and medium traffic density terminals and approach areas, SSR will be required while ADS will be progressively introduced.

ADS/CPDLC

Antananarivo's and N'djamena's FIRs have already implemented ADS/CPDLC. ASECNA was the first to develop ground equipments in the AFI region for the ADS. It served to demonstrate the potential advantages of ADS displays in the AFI region. These were the first ADS trials on the continental scale.

Chapter 5: Analysis of ASECNA's Modernisation Strategy

As part of a surveillance exercise, ASECNA is currently carrying out ADS/CPDLC trials in Dakar. Implementation plan (2001-2005) provides for the installation of ADS systems in Dakar and in Sal Island (cap Verde) to monitor the oceanic FIRs. These systems have screen displays capabilities in order to monitor the aircraft position at the control centres. The display technologies used are:

1. FPDS (Flight Data Processing System)

FPDS contains Flight Plan Air Situation Display - FPASD - that deliver a graphic representation of flights not fitted with FANS1/A equipments. The system is capable of managing both paper and electronic strips.

2. ADS

Any aircraft fitted with ADS is able to automatically exchange data with the ATS system. The aim is to simplify the coordination between traffic adjacent control centres.

3. CPDLC

The system will use CPDLC data exchanged between pilots and controllers to automatically update corresponding flight plans.

Trials were still on-going in June 2005. But regulatory and normalisation requirements slow the decision process.

Radar Mode S

It is planned to install 5 Monopulse SSR mode S radars with full ADS/CPDLC capabilities in N'djamena, Dakar, Niamey, Brazzaville. Abidjan's radar is already operational. They should all be operational within 2 years (2007). Trials are being conducted in N'djamena, Dakar and Brazzaville. The new system will be able to manage at least 17 airspace sectors simultaneously, and will permanently be monitored by 12 controllers, including optional positions, instead of 5 today. A total of 24 to 30 controllers, forming teams of 4 to 5 people, will be trained in that purpose. Other surveillance projects include multilateration surveillance systems at Bir Moghreim, Taoudenit, Tessalit, Agadez Bria, and Faya Largeau.

Chapter 5: Analysis of ASECNA's Modernisation Strategy

5.1.4 On-board the aircraft

The aircraft of major international airlines linking Africa to Europe are already equipped with built-in onboard CNS/ATM systems. Aircraft only flying national or sub-regional routes are equipped with RNAV-1 systems and autopilot. A low-cost CNS/ATM system composed of a VHF data link, an ADS mode and GNSS for navigation is added to it. Communications and ADS surveillance benefit from VHF cover and ATM automation on the ground. These aircraft are to be equipped with a C-mode transponder for surveillance radar requirements in some terminal regions. The design approach for the configuration of avionics is modular, to allow the evolution from one ATM level to another.

5.1.5 Aviation weather

To better meet the airline demands, ASECNA is integrating the requirements expressed via IATA into its equipment plans. Over the period 2000-2006, ASECNA has strengthened the capacities of its meteorological centres by making the following major investments:

1. Renovation and upgrading of systems (digital barometers, satellite imagery receiving stations, etc.), meteorological information distribution and visualization systems and forecasting systems (SADIS, RADAR, SYNERGIE, etc.);

2. Installation of the two-directional SADIS link in Dakar (Senegal) to serve as backup to the AFTN for OPMET data exchange;

These systems have not all been implemented yet, but the process is well advanced. ASECNA is progressively migrating onto the Second Generation Weather Satellites (MSG), with greater capacity of data processing (Flight planning dossiers, Turbulence, Obstacle...etc) (Ndobian Kitagoto, Met Engineer, ASECNA).

Chapter 5: Analysis of ASECNA's Modernisation Strategy

5.1.6 Air Traffic Management

ASECNA's ATM Concept is primarily instituted between airports rather than gate-togate¹. Departure/arrival management will be implemented through SIDs and STARs and not through fully integrated management like in ECAC for instance. The airspace will offer some flexibility sizing capability, whereas ECAC will implement a dynamic flight-to-flight adjustment. The agency has also planned to offer its users their preferred routes within the filed flight plans, with some collaborative decision-making between aircrew and controller using ADS/CPDLC, instead of free flight with autonomous operations. Three dimensional RNAV based on GNSS and RNP has been preferred to full autonomous aircraft with airborne conflict avoidance and separation assurance.

Under an agreement with the ATM systems manufacturer Thalès, EUROCAT² air traffic management system is being installed in Dakar (Senegal), Abidjan (Ivory Coast), Brazzaville (Congo) and in Niamey (Niger). The EUROCAT advanced air traffic management system provides safe and efficient operations in high density, complex airspace. Its operational displays, radar networks and flight plan processing comply fully with ICAO standards requirements. It integrates radar, ADS-C, CPDLC and ADS-B surveillance facilities for the management of traffic over oceanic and large continental areas. It will provide area and approach air traffic control. There will be a combined total of 28 working positions across all four centres which will provide controllers with advanced flight plan and radar processing, and the capability for several centres within a FIR to use a common and centralised database for improved co-ordination between centres and for sharing and handing over of flight information, search for and resolution of conflicts, flexible and dynamic track processing and ATN interface and Flight data link service, especially for aeronautical weather.

¹ Gate to Gate operational concept is based on better collaboration between ATM actors and better planning to enhance the exchange of accurate and reliable data, resulting into increased capacity and safety (Hugo de Jong & Marc Soumirant, june,1st,2004).

² The Eurocat air traffic management system is a highly integrated air traffic management system, currently used operationally in more than 100 flight information regions. To date, 130 EUROCAT air traffic management systems, in multiple configurations, have been purchased by more than 50 civil aviation authorities all over the world.

Chapter 5: Analysis of ASECNA's Modernisation Strategy

Airspace rationalisation

Within the framework of airspace rationalisation and controls extension, ASECNA, plans to create 2 sectors within the upper airspace (>FL 245) in the Dakar continental FIR, and integrate the existing UTAs.

The long term objective of ASECNA is to reform ATM procedures by reducing the number of number of UIRs (upper flight data regions) and the number of FIRs and control centres, harmonizing TMA limits and integrating of sub-regional ATM systems.

RVSM

In order to increase its airspace capacity, ASECNA has implemented RVSM in parts of its airspace. RSVM implementation³ in ASECNA's area comes after what was done in the Oceanic FIR, and in the EUR/SAM corridor.

5.1.7 Cooperation Technical aspects

ASECNA is cooperating with its neighbours within the framework of ICAO's CNS/ATM regional planning. Technical cooperation includes telecommunications, and some aspects of airspace rationalisation. Main cooperation activities are done with ENNA (Etablissement National de la Navigation Aerienne, Algerian ANSP) and SADC (South African Development Cooperation) led by ATNS.

In the light of the drawbacks in the interface and the experience acquired, ASECNA and ENNA have established an efficient and viable co-operation framework that could enable them to carry out their mission of ensuring the security and regularity of air traffic more efficiently. A master plan establishing a framework of cooperation has been established since 2000. The aim of the master plan for coordination and harmonisation context, is to tackle the scope and diversity of the problems caused by the extension of the FIR interface under ASECNA and ENNA management, the shortcomings in terms of communications, the volume of air traffic today and the

³ Between FL 290 and Fl 410 included. RVSM will be implemented with the upper lateral limits of the following UIRs: Antananarivo, Brazzaville, Dakar continental, Dakar Oceanic, N'djamena, Niamey, and SAL oceanic.

Chapter 5: Analysis of ASECNA's Modernisation Strategy

envisioned growth, the application of the new ICAO civil aviation navigation system. Ultimate goals are better coordination and harmonisation aiming at: harmonising working procedures and methods; creating air routes; harmonising their means of coordination; joint use of technical equipment; co-ordinating development activities and exchanging information, particularly, with regard to CNS/ATM systems and the exchange of personnel.

Considered as the appropriate framework for promoting the security and regularity of air traffic, this plan which conforms to the ICAO recommendations will make it possible to homogenise the levels of performance of the two systems.

Cooperation with SADC is well advanced. The interconnection of the SADC and ASECNA VSAT networks allows Johannesburg to communicate with Congo Brazzaville and Madagascar (Antananarivo) through the AFISNET⁴ network whilst Antananarivo communicates with Beira (Mozambique) and Dar es Salaam (Tanzania) through the SADC network. In ensuring a balanced solution, ATNS installed a SADC terminal in Antananarivo and ASECNA installed the AFISNET terminal in Johannesburg. The agency has migrated on Intelsat 10.02 with Nigeria, Ghana, and other neighbouring Airspaces. It's waiting for the others (CAFSAT, SADC) to join them on the same satellite transponder.

Cooperation with Nigeria is very limited as this country has just started to build a viable air navigation system. Nigerian Airspace Management agency (NAMA) was created in 2000 following the Kenya Airways Airbus crash off the coast of Cote d'Ivoire, killing 69 Nigerians on board, after it could not land in Lagos due to poor visibility and the unavailability of instruments landing systems. The Agency has since launched an ambitious modernisation programme and is cooperating with ASECNA

⁴ In view of the difficulty of developing a network on a landline infrastructure, the AFISNET West Africa sub-network is the first slice of this AFISNET aeronautical network developed by ASECNA. It is based on the installation of Earth stations sited directly on the major operating sites (airports, VHF remote antenna). The Earth stations of Bangui, Brazzaville, Douala, Libreville, and N'djamena have been in service since April 1995. The Dakar and Abidjan Earth stations have been in service since 1996. ASECNA operates and maintains the oldest and largest international satellite network dedicated to the needs of air navigation. The AFISNET network is composed of about fifty Earth stations, grouped into two sub-networks:

Chapter 5: Analysis of ASECNA's Modernisation Strategy

which calibrates its Navaids equipments. Nevertheless, Nigerian airspace is developed to meet domestic requirements.

Like in ASECNA, EUROCAT systems have already been planned elsewhere across Africa including Nigeria, Sudan, Algeria, Egypt, South Africa and Mauritius. By implementing similar systems each ANSP can benefit from a greater regional interoperability and enhances the continent's air safety. As ASECNA is the most advanced form of air navigation integration, it's calling for the others to adopt its model, in order to deliver a seamless airspace.

The concept of «single African sky»

ASECNA and ATNS (South Africa Service Provider) jointly hosted African air navigation service providers in Senegal in 2002 to discuss the challenges facing air navigation in the region. The focus was on the benefits of regional service provision to reduce duplication of services, the importance of the interoperability of systems, as well as a continued drive for the commercialisation of air navigation service providers to ensure that aviation revenue is reinvested into aviation (ATNS, 20002).

Within that framework, in 2003, in Yaoundé, Cameroon, ASECNA and other African service providers agreed that the concept of a single African sky should be a long term objective that needs to be studied. It should be the result of a gradual process comprising the following steps:

1 Harmonisation of ATM systems and procedures, including training programs.

2 Rationalisation of service areas

3 Cross boundaries cooperation between ANSPs

4 Consolidation if necessary of air navigation services, based on costs-benefits, the elimination of discontinuities, and the necessity of a flexible system taking into account the users needs.

Chapter 5: Analysis of ASECNA's Modernisation Strategy

5.1.8 Training

Seminar/workshops to raise awareness about CNS/ATM techniques are provided in the region. ASECNA has introduced courses on the new systems into the training programme for engineers and technicians in its training centres, with the participation of the ICAO's TRAINAIR programme (established to encourage states to use standardised training methodology, and develop international training systems sharing). An air traffic management training centre for air traffic controllers will be installed at ASECNA's training school (EAMAC) in Niamey. Fitted with an ATM simulator, it will significantly increase ASECNA's ability to train its controllers and permits ASECNA to standardise its training procedures and the qualification of its controllers. In order to improve the quality of its services, ASECNA considerably increased its training budget between 1998 and 2004 to meet the shortage of technical staff and put the required number of staff in place. During that period, the number of technical staff increased from 781 to 1,116 graduates. ASECNA has already trained controllers for the introduction of RVSM although it is not implemented yet.

5.1.9 Financing

The principle of funding of the business case is that the planned CNS/ATM technologies for ASECNA are economically viable investments with adequate financial returns for both ASECNA and airlines.

The life cycle of the investment is assumed to be 15 years. The total capital investment in this case can be fully recovered through the provision of user charges. The result of this analysis indicates a life cycle net present value (NPV⁵) (i.e. present value revenues minus present value costs) of $23.5 million. The payback period, the point at which cumulative revenues equals cumulative expenses would be 12 years from the implementation of the plan. Both CNS/ATM and current ground-based systems were assumed to operate in parallel during this phase of the implementation.

⁵ The NPV approach requires predictions of the future profiles of the annual costs and benefits associated with the implementation of CNS/ATM systems. Once all the year-by-year expenditure and benefits are established, the net benefit (benefit minus cost) for each year are calculated and discounted back to the base year in accordance with standard accounting practices.

Chapter 5: Analysis of ASECNA's Modernisation Strategy

Sources of Financing

ASECNA has signed financing convention with different financial institutions worldwide and Political Organizations. These include the European Bank of Investment, the African Development Fund, The West African Development Bank, The Central African Bank of Development, The European Union and others.

CNS/ATM demonstrations and tests are generally self-financed and sometimes financed by subsidies from these financing structures. For the actual implementation of the system, the agency's usual financers (mainly European and African) indicate that they are ready to deal with and continue the adventure with ASECNA in upgrading its equipment to the next generation.

Cost effectiveness sequencing

ASECNA's current charging policy is as follows: Charge for use of en-route facilities and services managed by the agency are payable whatever are the conditions in which the flight is accomplished (IFR or VFR) and whatever are the departure and the destination aerodrome. Charging varies depending on the nature of the flight (national, regional, international) and the weight of the aircraft. However, these incremental costs (A in the Figure 5.1) are unique to CNS/ATM systems, and would not be incurred if the systems were not implemented (ICAO, 1995). In this later case, incremental expenditures on present technology would be required in order to continue operating the existing system (B in Figure 5.1). These would be avoided if CNS/ATM is fully implemented. Substantial annual expenditures are common to current and future systems (C in Figure 5.1). These expenditures would be incurred even if CNS/ATM is implemented. CNS/ATM costs also comprise conversion costs (D in the Figure 5.1). In the case of ASECNA, agency will have to pass these incremental costs to users as said previously. This means that charges will progressively increase during the life cycle of the investment (15 years), in order to reconcile current and future revenues and capital expenditure. The investment program amounts for about $276 million dollars from 1995 to 2010 (235 up to 2005). Assuming that a proportionate investment will be consented during the following ten years, and that current and future systems coexist, users will have to bear 225 million $US from 2005 to 2020, that is to say 16.5 million dollars per year if a margin of 10 % is taken into account. ASECNA collected about 170

Chapter 5: Analysis of ASECNA's Modernisation Strategy

million dollars in 2004. This means that the navigation charges could potentially increased by 9.7 per cent per year over the period⁶.

Figure 5.1: Classification of Costs

Cost

Existing
system

CNS/ATM
Implementation

C

B

D

A

C

Source: ICAO, 1995

5.1.10 ASECNA's implementation schedule up to 2015 ? Step 1: 2005 to 2010

- Progressive removal of ground based systems that are necessary to

FANS systems: HF, NDBs, VORs, DMEs, ACARS, ILS/MLS Cat 1, Radioborne... etc.

- Progressive introduction of CNS/ATM systems

- Participation to the end of global transition plan

? Step 2: 2010 to 2015

- Transition completed and FANS systems are unique to be operated. The

plan will be updated according to the technologies available

⁶ The payback period may be different, and probably lesser, which will increase the annual rate

Chapter 5: Analysis of ASECNA's Modernisation Strategy

ASECNA is slightly late in its implementation plans. The removal of ground based Navaids has not started. The Agency is even reinforcing ground based navigation in some countries. However, this is consistent with the pace of global implementation.

5.2 Analysis

The strategy depicted above clearly shows that ASECNA is aiming at tackling three operational aspects: Safety, Efficiency and Capacity. These objectives are in line with the industry's requirements that have been identified and defined earlier. In fact, the agency is fully implementing ICAO's CNS/ATM transition guidelines.

ASECNA's high level strategic goal appears to be the consolidation and the modernisation of existing systems, getting the future ready by gradually introducing CNS/ATM systems that interoperate with the conventional means, in order to be operational when these systems will be fully required.

For Communications, the strategy is to extend VHF coverage along international major traffic flows and inhospitable areas. The modernisation of the telecommunication network infrastructure and systems through digitalisation is a step towards greater data transmission and processing accuracy, efficiency and capacity. Recent deregulation of the telecommunication markets in the region is what allows ASECNA to implement suitable systems for its operations.

For Navigation, the agency aims at ensuring the good maintenance of existing means during the transition phase, establishing tests beds and technological survey for satellite based navigation, and carrying-on the implementation of WG-84 coordinates. Once completely introduced, satellite navigation will also be used in remote airports that actually lack instrument landing means. It potentially concerns 76 secondary airports. Depending on the quality of ground infrastructures, and the availability of practicable runways, this will increase their availability for operations, and could create potentials for air travel growth. Introducing RVSM in its airspace, the agency is permitting homogenous navigation areas between EUR CAR/SAM, ASIA/PAC and ASECNA. More than 90 per cent of Western airlines' aircraft will be fitted with RNP and RNAV

Chapter 5: Analysis of ASECNA's Modernisation Strategy

capabilities (as mentioned earlier in Chapter 4) by the beginning of next decade, whereas local airlines could not have the means to upgrade their old fleet to that level. Hence, ASECNA is adopting a modular approach by setting up flexible ATM systems that will be able to cope with multiple aircraft navigation capabilities. By initiating ADS-B trials for the Atlantic Antananarivo and Dakar's FIRs, the agency is anticipating traffic characteristics in the EUR/SAM corridor and the Indian Ocean.

This dual strategy will certainly respond to both the needs of large and small airlines, but this is questionable, as it is clear that it could not be cost-efficient. The fleet of certain national and sub-regional aircraft operators is heterogeneous, and they have limited means. There are greatest concerns about their capacity to respect the transition schedule. A well organized transition is costly in terms of regulations, installation, testing and training for all of the means, on the ground and onboard. Badly organized transition is even more expensive: maintaining dual ground and onboard installations, delay in receipt of benefits.

Equally questionable is the ability of the agency's strategy to deliver a fully efficient navigation system. In fact, the strategy does not suggest a desire to totally cover the airspace, but only the most frequented routes. The rigid routes structure being maintained, it's obvious that the benefits that could be derived from RNP and ADS capabilities will significantly be limited in the continental airspace.

For Surveillance, ASECNA's strategy is to progressively install modern surveillance technologies such as SSR-Mode S and ADS/CPDLC in each one of its ACC and where they are mostly needed for safety reasons.

For ATM, airspace rationalisation and cross boundaries operational harmonisation of rules and procedures are the agency's ultimate aims. But rationalisation is oriented towards navigation efficiency rather than capacity in term of saturation. Cooperation with other ANSPs is limited to technical collaboration and local operational cooperation. Airspace redesign, as suggested by the project of a single African Sky, similar to what is being studied in Europe through the Single European Sky initiative (Functional Airspace Blocks) is probably for the very far term.

Chapter 5: Analysis of ASECNA's Modernisation Strategy

For Weather, the plans are to follow technology evolution and to adapt the infrastructure accordingly.

Finally, the pan African organization intends to finance its strategy through loans from international finance establishments and appear to have the financial backing to reach objectives.

Figure 5.2: Possible airspace redesign in 2030

Source: CANSO, 2005

The geographical distribution of new air navigation means suggests that the agency is not anticipating a substantial growth of air travel domestic markets for the short or medium term. City-pairs market is insignificant (as explained chapter 1) mainly between Central and Western Africa. Moreover, local airlines have no interest in operating these non profitable routes, and prefer to operate the gulf of guinea corridor to improve their load factor. Therefore ASECNA's strategy to concentrate on main regional and trans-regional corridors actually responds to both local and western airlines' needs.

5.3 Conclusion

ASECNA's strategy is coherent with the region's needs. The dual strategy perfectly responds to the requirement to accommodate both big and small airlines. But the cost effectiveness of this plan is questionable: Maintaining dual equipments is costly, and will certainly impact users' charges.

Chapter 5: Analysis of ASECNA's Modernisation Strategy

Dakar's ADS system programme is two years late for example and Brazzaville's Radar project is also late. It is difficult to predict whether or not the Agency will fully respect its schedule. The success depends on many factors that are not directly under its control. Partly because the implementation of new air traffic concepts requires that member states update their legislations, which is often a long and slow process. Moreover the lack of means in local airlines, and the high cost of upgrading their equipments also add to the uncertainty. It is doubtful that CNS/ATM systems will have been fully implemented by all stakeholders in ASECNA by 2010.

However, the time frame is similar to those of other countries worldwide, and the implementation process is more or less at the same stage as other regions like Asia. ASECNA is even more advanced than areas like Europe on some aspects of the programme such as airspace integration since its airspace is already integrated.

Chapter 6: Recommendations and Conclusion

The primary objective of the thesis was to analyse the state of Air Navigation in ASECNA area in order to find out regional needs and priorities, which responds to the first research question. The study found that the needs are as follows.

1. Air traffic demand remains very low although the region's economies are growing. The growth is driving air travel demand. Moreover, real liberalization is looming, based on the Yamoussoukro's decision. Which is expected to boost the growth. But that increased activity is observed on a restricted number of routes linking Europe to main cities in ASECNA. These routes are operated by several carriers that dominate the market.

Airlines can be divided into two groups: International airlines, and domestic carriers. The first are mostly foreign carriers and are relatively healthy. They operate high yield routes, possess young fleets and have a strong financial power. The second are mostly domestic carriers, in a bad state. They operate low yield routes, their fleets are very old and their have little financial margins. The region's airline industry dramatically needs to be supported by an efficient and a cost effective air navigation service to help them to reduce their costs.

2. Fragmentation is limited in ASECNA's airspace. The airspace is organised respond to operational requirements. However, at a continental level, airspace is very fragmented. Cooperation and harmonization are needed to avoid unnecessary duplication of equipments, which is cost ineffective. The agency is leading the move towards integration. More remains to be done to reach complete harmonisation, particularly with the Nigerian interface.

3. Capacity appears not to be a real need in ASECNA as traffic is very low and the airspace is very wide. But as the traffic is concentrated in a limited number of lucrative routes, extra capacity is needed to keep efficient operations, and to maintain safety margins in a context of growing traffic in these specific routes.

4. Safety records are extremely poor in ASECNA. Relatively to the level of traffic, the number of air proximities, runway incursions and accidents is high, and the agency is often engaged. But what is more preoccupying is the way the agency manages these problems. Given the results of investigations, it can be asserted that the agency does not have a proper safety management system to systemically process and analyse safety data. It is rudimentary for the least. The quality, quantity and consistency of safety data are not adequate for managing safety. A review system should be established, providing a clear severity classification and disseminating findings. ASECNA needs to establish such a system if it wants to improve its safety records and restore users' confidence.

5. Inefficiency is mainly due to the use of conventional systems. These render the system very rigid, with fixed routes. They have operational limitations that prevent the optimal use of the available airspace which is costly to users. These systems also have technical insufficiencies in term of communication, surveillance and air traffic management that degrade safety records. The agency needs to upgrade its infrastructure to deliver a service that responds to modern requirements, in term of systems' availability, and data quantity, quality and integrity.

6. Cost effectiveness is good in ASECNA when compared to Europe and the USA. But given the high proportion of staff and superfluous expenditures, the performance can be improved, by reducing unnecessary staff in some areas with very poor traffic. That would help to raise controllers' productivity, and decrease support costs.

The secondary objective of the thesis was to study CNS/ATM technologies and their relevance to ASECNA region. It responds to the second research question.

Based on the region's geographic characteristics, and its needs presented above, the study found that the new systems brings better efficient, increases safety margins and capacity, enhances data processing, and allows the extension of services. They will be cost effective on the long term, as they will help to curb the maintenance costs, and reduce airspace fragmentation as their implementation requires international cooperation, and a substantial level of operational and technical harmonisation on the continental level.

The third objective was to analyse ASECNA's on-going modernisation strategy, to assess whether it will respond to the needs and the priorities highlighted. It responds to the third research question.

The agency has technical objectives to improve the current system, and to implement future air navigation systems. Some systems have already been installed, and others are progressively being made available to users. But the agency is confronted to the need to accommodate both small and big carriers which do not have common interests. Given the predominance of foreign carriers and the necessity to assist local airlines to help maintaining an acceptable level of air service within the region, ASECNA has decided to put in place evolutionary new systems, allowing each type of carriers to upgrade its fleet with regard to their means and their operations.

However, the segmentation of the agencies operating revenues being overwhelmingly in favour of transcontinental activities, the agency has chosen to firstly and progressively equip strategic areas of routing with CNS/ATM systems and concepts. That responds to profitability imperatives. But it does not address the immediate safety concerns all over its areas of responsibility particularly in remote regions. The agency is not prioritising domestic markets where most accidents occur as most of conventional systems are maintained there.

The airspace reorganisation process that is taking place will certainly reduce unit costs. The introduction of new systems is also expected to reduce maintenance costs. But no study measuring the economic impact of newly introduced systems is available for the time being.

The users will have to bear the costly equipment upgrade, and will be passed the totality of costs of acquiring, installing and operating CNS/ATM systems. In addition, the fact that the agency is maintaining a dual system will inflate costs. The agency has planned to increase navigation charges by 10 per cent increase per year. That is not a cost effective sequencing given the general state of the airline industry. In particular, navigation charges should not inflate as the result of the introduction of new systems because it could have a negative impact on the local airline industry. Recent agreements between the agency and IATA that have frozen navigation charges during the past three years suggest that ASECNA is reconsidering its charging strategy. It shows that the agency has adopted a pragmatic policy in the interest of its users.

Despite limited delays in the implementation process, ASECNA has already done a huge work to modernize its infrastructure and its procedures. Its strong financial situation and the support of local governments and international financial institutions guarantee that the agency will not lack means to carry on its programmes. However, the slowness and the variability of legislation procedures and the fragmentation of regulation authorities could generate additional delays. A key point in reaching its objectives is how ASECNA will collaborate with states and civil aviation authorities to speed up the process. Moreover, experts doubt that small local airlines will be able to respect the schedule, which will delay the moment of benefits. Actually, the question is not whether ASECNA will be able to deliver a modernised service and infrastructure to match the needs; its local users and regional authorities constitute the real threat to the programme.

The agency has a solid training policy, and is training air navigation staff in its own schools to prepare the future and respond to the growing demand. That long term human resource strategy guarantees the availability of sufficient skilled staff.

The agency cooperates with neighbouring air navigation service providers within the framework of ICAO's modernisation plans. A certain level of technical integration has already been reached, in particular between ASECNA and South Africa. As the agency is a leader in term of airspace integration on the continent, it's coordinating harmonization efforts.

To conclude, and in response to the main research question, it can be stated that the ability of ASECNA to meet the needs of African Air navigation the 21^st will depend on the following key factors:

1. The respect of CNS/ATM systems' implementation process.

2. The reconciliation of interests of major and small airlines.

3. The strengthening of ties with other African ANSPs.

4. The involvement and the commitment of member states and civil aviation authorities.

5. And the availability of means to finance the modernisation programme

ASECNA can help the Airline Industry reducing its costs through technology advances. But will it be substantial? In fact, deep structural changes are required in airlines' management practices in Africa. These necessary reforms, together with a real liberalisation, could secure a consistent growth. Nevertheless, even deep structural changes could only have limited impact if the demand side is not dealt with appropriately. High air travel taxation is a common practice in the region. States should revise that policy in the interest of economies.

Given that the programme is already well advanced, and taking into account the fact that ASECNA's top management is committed to modernize the agency, and to keep its reputation as a leading and exemplary institution in Africa, it is highly probable that the Pan African institution will make adequate technologies available to its users, although there is no assurance that the time frame will be met. Whether states and air carriers will be able to fulfil their obligations in term of regulations and equipments modernisation remains uncertain. There are clear indications that they will not.

Limitations and Suggestions for further research

The contribution of this research was to give the reader an insight of an African region rarely studied, and one of its leading organisations that tries despite numerous environmental and structural constraints, to conduct a sound and successful strategy towards modernisation.

However the work has several limitations. Many real-world problems were simplified or ignored because their solutions were outside the scope of this research. Particularly, political interferences in the management of the agency, non-harmonised civil aviation regulations together with intrinsic social and cultural characteristics that definitely influence the agency's performances, are examples of research studies that could be conducted by future students. However in a context of globalization and liberalization, studying the impact of an hypothetic privatisation of ASECNA on the quality of service would be a good contribution.

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41. Kaminsky-Morrow, D. EASA and FAA approve Jeppesen data for P-RNAV, Air Transport Intelligence, [Online], available: http://www.rati.com/frameset/ frameset_f.asp? target=../ news/news.asp [Accessed July 2005].

42. Kent-Jones, R. Miscommunication between pilots and air traffic control, [Online], available: http://www.benjamins.nl/jbp/series/LPLP/27-3/art/0002a.pdf [Accessed July 2005].

43. Maj P, Zelechosky J. Basic Area Navigation, [Online], available:
http://afsafety.af.mil/magazine/htdocs/marmag98/brnav.htm [Accessed July 2005].

44. Mission Economique, Transport fluvial et maritime du Cameroun, [Online], available: http://www.missioneco.org/cameroun/Sectdetail.asp?Sect=51 [Accessed September 2005]

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46. Morrell, P. 2005. Airlines Finance Lecture: Airlines Privatisation, Cranfield University, Department of Air transport Management. [Course notes].

47. Nigeria Airspace Management (NAMA), 2005. CNS/ATM: On-going projects, [Online], available: http://www.nama-nig.com/cnsatm.html [Accessed June 2005].

48. OEDC, 2005, Atlas Régional des transports et des télécommunications dans la CEDEAO, [Online], available: http://www.oecd.org/dataoecd/6/33/35183559.pdf

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http://www.roke.co.uk/download/datasheets/Multilateration.pdf [Accessed May 2005].

51. Stavan, P.M, 2001. An Analysis Mechanism for Automation in Terminal Area , University of Virginia, Charlottesville, [Online], available: http://historical.ncstrl.org/ tr/ fulltext/tr/icase/TR-2001-32.txt

52. Tara Weidner, J, 1998. (Seagull Technology, Inc.) Capacity-related benefits of proposed cns/atm technologies, [Online], available : http://atm-seminar-98.eurocontrol.fr/final papers/track3/weidner1.pdf

53. UNESCAP, 2005. Review of Development in Transport Infrastructure in ESCAP region, [Online], available: http://www.unescap.org/ttdw/Publications/TPTS_pubs/ pub_2392/ pub_2392_fulltext.pdf

54. Wakefield, M, 2005. ADS-B, [Online], available: http://www.icao.int/icao/en/ro/apac/2005 /ADSB_ADSB_TF3/SP07.pdf

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56. Wikipedia, Distance Measurement Equipment (DME), [Online], available: http://www.answers.com/main/ntquery?method=4&dsid=2222&dekey=Distance+Measuri ng+Equipment&gwp=8&curtab=2222_1&linktext=DME [Accessed August 2005].

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http://www.answers.com/topic/instrument-landingsystem?hl=distance&hl=measuring&hl=equipment [Accessed August 2005].

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http://www.answers.com/topic/vhf-omnidirectional-range [Accessed August 2005].

APPENDIX 1: Presentation of ASECNA

History: An example of inter-African and Malgasy cooperation

«L'Agence pour la Sécurité et la navigation aérienne en Afrique et a Madagascar» (ASECNA) was founded in 1959, in Senegal. It is a multinational organization, created by 16 African countries¹, 14 from Western and Central Africa, plus Madagascar, and France. The group was joined by the Comorian Union in 2004. The agency is presented as the best example of North to South cooperation, as well as the structure for civil aviation excellence. ASECNA has managed to last more than half a century because it adapted itself to the political economic context. When it was created, ASECNA was mainly a cooperation organisation between France and African French speaking countries and Madagascar. But years after it was founded, the Malgasy and inter-African cooperation become Predominant. This transformation was translated in the facts, by the transfer of the Agency's head quarter from Paris to Dakar, and by the «Africanisation» of the management. In 1974, the Dakar convention was signed by the 15 countries (All the current members states, without Equatorial Guinea who joined the organisation in 1987). The Dakar convention remains opened to integrate any candidate country.

Mission: Air Navigation safety

ASECNA is governed by the Dakar convention, and essentially exercises community activities in accordance with article number 2; but it also manages national aeronautical activities, on a purely subsidiary basis, on the behalf of some individual states and other organizations.

¹ Benin, Burkina Faso, Cameroon, Central African Republic, Chad, Comores, Congo, Equatorial Guinea, Ivory Cost, Gabon, Madagascar, Mali, Mauritania, Niger, Senegal, Togo.

Community activities

The agency controls an area 1.5 as large as Europe. This area is divided into 6 Flight Information Regions (FIRs): Antananarivo, Brazzaville, Dakar Oceanic, Dakar Terrestrial, Niamey, and N'Djamena².

It ensures the Control of air navigation flows, aircraft guidance, the transmission of technical and traffic messages, airborne information. It also gathers data, forecasts and transmits aviation weather information. Theses services are applied for both en route, terminal approach and landing phases of the flights.

ASECNA ensures terminal approach aids for the 25 main airports³ of the region, as well as 76 secondary airports. This includes airports control, approach control, ground aircraft guidance and movements, as well as radio aids and fire protection services. For these reasons, ASECNA has the responsibility to maintain the equipments necessary to deliver these services, a part from the runways.

National activities

Articles 10 and 12 of the Dakar Convention allow member states to entrust ASECNA to manage, maintain and the install of aeronautical infrastructures. Benin, Burkina, Central African Republic, Gabon, Equatorial Guinea, Mali, Senegal and Chad signed specific contracts with the organization under article 10.

² These cities are respectively the capitals of the following countries: Madagascar, Congo, Senegal, Niger and Chad. The Senegalese FIR is divided into an Oceanic FIR and a terrestrial FIR.

3 Douala, Port Gentil, Mahajanga, Garoua, Malabo, Bamako, Bangui, Ouagadougou, Gao, Brazzaville, Bobo-Diolasso, Niamey, Pointe Noire, Nouakchottt, Dakar, Abidjan, Nouadhibou, N'djamena, Cotonou, Toamasina, Sarh, Libreville, Ivato, Lome.

Organisation and functioning

Statutory structures

The Committee of
Ministers

Commission for Accounts verification				The Board of Directors
					General Direction
Accounting Agency								Financial Control

Organization Chart

The Committee of Ministers, composed of member states' transport or aviation ministers defines the general policy of the agency. It meets at least once a year. The Presidency of the committee is revolving on an annual basis, which constitute a problem to the efficiency of the agency.

The Board of Directors takes necessary measures to ensure the well functioning of the organization. But above all, it appoints the accounting agent, the commissioners for accounts verification, and the financial controller.

External representations

In Each member state, the missions of the agency are ensured by a local representation, organised as follows:

Representative

Air Navigation Operations

Radio Electrical Infrastructure

Administration and Finances

Aviation Weather

Civil Engineering Infrastructure

Payment services

External representations organization chart

The agency also has two delegations, one in Paris, and the other in Montreal; The one in Paris (DELP) ensures essentially missions for the general direction:

- Links with aviation administrations, airlines, international organizations;

- Air Navigation fees collection

- Aeronautical information edition

- Purchase and routing of equipments

The one in Montreal represents the agency in ICAO. The delegate is member of the international organisation air navigation commission. He participates to the work of the air navigation experts group, and has permanent links with the ASECNA's member states delegations in ICAO.

Financial

ASECNA resources are essentially derived from:

· Aeronautical fees (Landing and en-route)

· Member states contributions on their national activities entrust to ASECNA

· Loans from banks, institutions and states

The agency has posted remarkable operating and net results for years, and has always been a profitable organization.

Appendix 2: Ground Based Navigation Systems Principles

1 How the VOR works

Each VOR operates on a radio frequency assigned to it between 108.0 megahertz (MHz) and 117.95 MHz, which is in the VHF (very high frequency) range. The channel width is 50 kHz. VHF was selected because it travels only in straight lines, resisting bending due to atmospheric effects, thereby making angle measurements accurate. However this also means that the signals do not operate "over the horizon", VOR is line-of-sight only, limiting the operating radius to 100 mi (160 km).

VOR systems use the phase relationship between two 30 Hz signals to encode direction. The main "carrier" signal is a simple AM tone broadcasting the identity of the station in morse code. The second 30 Hz signal signal is FM modulated on a 9960 Hz subcarrier. The combined signal is fed to a highly directional antenna, which rotates the signal at 30 times a second. Note that the transmitter need not be physically rotating--all VOR beacons use a phased antenna array such that the signal is "rotated" electronically.

When the signal is received in the aircraft, the FM signal is decoded from the sub carrier and the frequency extracted. The two 30 Hz signals are then compared to extract the phase difference between them. The phase difference is equal to the angle of the antenna at the instant the signal was sent, thereby encoding the direction to the station as the narrow beam washed over the receiver.

The phase difference is then mixed with a constant phase produced locally. This has the effect of changing the angle. The result is then sent to an amplifier, the output of which drives the signal pointers on a compass card. By changing the locally produced phase, using a knob known as the Omni-Bearing Selector, or OBS, the pilot can zero out the angle to a station. For instance, if the pilot wishes to fly at 90 degrees to a station, the OBS mixes in a -90 phase, thereby making the indicator needle read zero (centred) when the plane is flying at 90 degrees to the station (Wikipedia, ).

VOR station; Source: ATSEEA, 2005

2 How DME works

The DME system has a UHF transmitter/receiver (interrogator) in the aircraft and a UHF receiver/transmitter (transponder) in the ground station. The interrogator transmits interrogation pulses to the transponder, which in reply transmits a sequence of reply pulses with a precise time delay. The DME receiver then searches for two pulses with the correct time interval between them. Once the receiver is locked on, it has a narrower window in which to look for the echoes and can retain lock. The time difference between interrogation and reply is measured by the interrogator and translated into a distance measurement which is displayed in the cockpit.

A typical DME transponder can provide concurrent distance information to about 100 aircraft. Above this limit the transponder avoids overload by limiting the gain of the receiver. Replies to weaker more distant interrogations are ignored to lower the transponder load.

DME frequencies are paired to VHF omnidirectional range (VOR) frequencies. So generally a DME interrogator is designed to automatically tune to the corresponding frequency when the colocated VOR is selected. An airplane's DME interrogator uses frequencies from 1025 to 1150 MHz. DME transponders transmit on a channel in the 962 to 1150 MHz range and receive on a corresponding channel between 962 to 1213 MHz. The band is divided into 126 channels for interrogation and 126 channels for transponder replies. The interrogation and reply frequencies always differ by 63 MHz. The channel width is 100 kHz.

One important thing to understand is that DME provides the physical distance from the aircraft to the DME transponder. This distance is often referred to as 'slant range' and depends trigonometrically upon both the altitude above the transponder and the ground distance from it (Wikipedia, ).

3 How ILS works

The ILS stations are usually installed at airports which have full traffic. Today, ILS stations are installed in almost all ASECNA's international Airports. ILS is used to give to the pilot, precision information when trying to land the aircraft.

The system's reliability depends on equipments, the quality of installations and the environmental conditions (mountains, buildings, climatologic conditions).

There are three categories of ILS as the table below present it:

Category Permits a precision approach at an altitude up to 200 feets, above the ILS I Reference point. The ILS Reference point is located about 150 metres from the aircraft touch down point. Category Permit a precision approach at an altitude up to 100 feets, above of the ILS II Reference point. Category Permit a precision approach at an altitude up to surface of the landing runway III with no Runway Visibility

ILS stations include the followed equipments: Localizer

Localizer is a transmitter which gives information about azimuth with regard to the Centre Line of the landing runway. Together with the glide slope transmitter (Glide path), a precision approach can be performed.

The localizer antennas are located at the far end of the runway. They consist on a linear array of multi-element antennas, with thick, staggered elements. Localizers transmit between 108 and 118 MHz.

Glide path

Glide path is a transmitter which gives information of the correct angle slope with regard to the horizontal level of the straight of aircraft slide, during the landing. The angle is 3⁰.

ILS Marker Beacon and Compass Locator Stations

Marker Beacons are two or three transmitters which give information about the precision approach, as control points for the aircraft, correct direction of the landing runway extension. Marker beacons are VHF transmitters operating at 75 MHz. The Outer Marker (OM) is used to indicate that an aircraft should intercept the glide path when over the transmitter. The Middle Marker is used to indicate that the aircraft is at the Decision Height (DH) for most approaches (Wikipedia, ).

4 Multilateration

A multilateration system consists of a number of antennas receiving a signal from an aircraft and a central processing unit calculating the aircraft's position from the time difference of arrival (TDOA) of the signal at the different antennas.

The TDOA between two antennas corresponds, mathematically speaking, with a hyperboloid (in 3D) on which the aircraft is located. When four antennas detect the aircraft's signal, it is possible to estimate the 3D-position of the aircraft by calculating the intersection of the resulting hyperbolas.

Source: (Roke Manor Research, August 2005)

When only three antennas are available, a 3D-position cannot be estimated directly, but if the target altitude is known from another source (e.g. from Mode C or in an SMGCS environment) then the target position can be calculated. This is usually referred to as a 2D solution. It should be noted that the use of barometric altitude (Mode C) can lead to a less accurate position estimate of the target, since barometric altitude can differ significantly from geometric height.

With more than four antennas, the extra information can be used to either verify the correctness of the other measurements or to calculate an average position from all measurement which should have an overall smaller error.

Appendix 3: WGS-1984

Source: ASECNA 1996

In 1989, ICAO adopted WGS-84 as the standard geodetic reference system for future navigation with respect to the international civil aviation. In 1994, ICAO adopted Amendment 28 to Annex 15.

WGS 84 is an earth fixed global reference frame, including an earth model. It is defined by a set of primary and secondary parameters:

· The primary parameters define the shape of an earth ellipsoid, its angular velocity, and the earth mass which is included in the ellipsoid reference

· The secondary parameters define a detailed gravity model of the earth.

Since January 1^st 1998, geographic coordinates (latitude and longitude) are published in term of WGS-84 geodetic reference system. Geographic coordinate obtained through conversion to the WGS-84 system but for which the degree of original accuracy measured in the field does not meet the specifications of Annex 11 and Annex 14, are pointed out by an asterisk. The degree of accuracy required for civil aviation is determined as given in Annex 11.

Appendix 4: ASECNA'S Telecommunications Network

Source: Boeing 2005 outlook

Appendix 5: Air Traffic Projected Growth by world region

Appendix 6 : ICAO's Navigation SARPs

Appendix 7: ASECNA's Satellite Navigation Circuits

Appendix 8 ASECNA'S ATS/Direct Speech Network

APPENDIX 9: Introduction to CNS/ATM Systems

Drivers and Origins

Background

The air transport industry has grown dramatically and rapidly, more than other industries during the last two decades of the 20th century according to ICAO. The organization's statistics show that from 1985 to 1995, world air passenger travel and air freight respectively grew at an average annual pace of 5 and 7.6 per cent (ICAO, 2002). The annual variations worldwide are shown by the figure below. The number of aircraft departures gained almost 45 per cent from 1970 to 1995. A projected annual increase in traffic between 1992 and 2010 estimated that traffic would increase by about 2.5 per cent in North America, more 4 per cent in Europe, and 6 per cent in Asia, with the rest of the world following the same trend (Gallotti , 1999).

Annual Changes in scheduled aircraft movements worldwide
Source: ICAO, 2002

The picture below of a congested airspace best suggests how close some parts of the world are to the gridlock. In some parts of Europe and North America, traffic is restrained to preserve safety margins. Delays are growing, and this is hitting aircraft operators' bottom lines. On some days in the summer of 1999 European air traffic was near to collapse. According to airlines' representatives, delays have never been so bad, at least not since 1959 (Spaeth, 1999, Para 2). IATA recently estimates that delays in Europe have an annual cost of US$1.5 billion and 15 million minutes of unnecessary flight.

instant traffic situation display over the US airspace.

Source: FAA, 2002

Elsewhere, in remote areas and over oceans, considerable improvements to ANS are required, as the current technology has limitations. These are discussed in the next chapter.

ICAO's Global Implementation Plan and Monitoring

FANS Committees Work

Having considered the steady growth of international civil aviation before 1983, and taking into account the projected growth at that time, the council of ICAO determined in 1983 that conventional air navigation systems and procedures that were supporting civil aviation were approaching their limits, and that time had come to develop new

approaches that will better suite modern air transport exigencies. In that purpose, it established a Special Committee on Future Air Navigation Systems (So called FANS committee).

In 1989, the FANS committee concluded that new systems had to be developed to meet the pace of air transport development worldwide. It had also established that the shortcomings of conventional systems could have a negative impact on the development of air navigation almost anywhere. It also recognised that the new systems' objectives should be to provide a cost-effective and efficient system adaptable to all type of operations in as near four-dimensional freedom (space and time) as their capability would permit. The committee recommended that this had to be done at a global scale. In the wake of these conclusions, the ICAO council established a committee in charge the monitoring and coordination of Development and transition planning for FANS (So Called FANS committee II).

Tenth Air Navigation Conference

In 1991, the ICAO's tenth Air Navigation Conference (AN-Conf/10 endorsed the FANS concept, as proposed by the ad-hoc committees. The Conference concluded (Recommendation 1/1 - Endorsement of the global ATM operational concept) that ICAO, the States and the regional planning and implementation groups (PIRGs) consider the global ATM operational concept as the common global framework to guide planning for implementation of ATM systems and to focus all ATM work development.

Theses concepts eventually came to be known as the CNS/ATM systems. In 1993, FANS II committee concluded that the implementation of these new technologies, and their expected benefits had to be gradual. This meant that an action plan was needed, in order to progress toward implementation of CNS/ATM technologies and systems. The emphasized was put on the important role states and the regions had to play, through PIRGs, with regard to the planning and implementation processes. The Planned evolution of the process is as shown on the following figure.

Evolution of CNS ATM implementation. Source: ICAO, 2002

The regional planning process

The regional planning process is ICAO's main planning and implementation tool. A top down approach is used, comprising a global guidance and regional harmonization measures. This converges with the bottom-up approach formed by states and aircraft operators and their proposals for implementation options.

Organizational and financial issues

The organizational and financial aspects in the implementation process of CNS/ATM systems are the major challenges for the civil aviation community. Many CNS/ATM systems are characterised by a multinational dimension, which requires an international cooperation.

Developed states have the means to finance and develop their national CNS/ATM
plans. Australia is a good example. The implementation process is well advanced. But,
developing and poor countries (the majority of states), require assistance in many fields:

- Needs assessments and project development

- Transition planning

- Financing arrangements

- Systems planning, specification, procurement, installation and

commissioning

- Human resource planning and development.

Legal issues

The legal framework that governs the conduct of service providers and users is the Chicago Convention and its annexes. Many concerns are about the Global Navigation satellite (GNSS) that shall be compatible with international law, including the Chicago Convention, its annexes and all the relevant rules applicable to outer space activities. Particularly, universal access to GNSS services without discrimination, the preservation of states sovereignty, authority and responsibility. Aircraft operators and providers of air navigation services rely on foreign systems, as the current GNSS facilities are controlled by one or several states (USA, EU, Russian Federation).

The continuity of GNSS services is also a matter of concern among the community, as the state provider could decide to stop them, and force the users to rely on inefficient conventional backup systems.

Appendix 10: Evolution of controllers Workforce from 2006 to 2011 in ASECNA

Centres	Workforce End 2005	Retirement 2006	Forecast workforce (2-3)	Necessary workforce (2007 - 2011)	Gap (4- 5)
1	2	3	4	5	6
Abidjan	26	0	26	35	-9
Antananarivo	27	0	27	72	-45
Bamako	24	0	24	35	-11
Bangui	10	0	10	17	-7
Bissau	7	0	7	9	-2
Bobo Dioulasso	3	0	3	4	-1
Brazzaville	23	0	23	76	-53
Cotonou	9	0	9	11	-2
Dakar	42	0	42	104	-62
Douala	23	0	23	35	-12
Gao	0	0	0	4	-4
Garoua	4	0	4	4	0
Libreville	22	0	22	35	-13
Lome	11	0	11	11	0
Mahajanga	3	0	3	4	-1
Malabo	8	0	8	11	-3
Mopti	2	0	2	4	-2
Moroni	7	0	7	11	-4
Ndjamena	40	2	38	60	-22
Niamey	33	0	33	76	-43
Nouadhibou	5	0	5	8	-3
Nouakchott	14	0	14	23	-9
Ouagadougou	23	1	22	11	11
Pointe Noire	6	0	6	11	-5
Port Gentil	5	0	5	9	-4
Sarh	2	0	2	4	-2
Toamasina	4	0	4	4	0
Yaoundé	8	0	8	11	-3
Total	391	3	388	699	- 311

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