1. Service Technique de la Navigation Aérienne NexSAT: Mission Hypothesis 20 may, 2003 STNA/31 ATM issues at horizon 2015 over ECAC Capacity: - VHF spectrum saturation mainly due to voice channel demand with a strong limitation on VHF data communication available capacity - doubling of air traffic compared with 2000 reference - existing system will continue to be used (e.g. VDL mode 2 or AMSS SATCOM) Organisation: - Sector size reduction and airspace reorganisation limits will be reached at that time - Controller productivity reachs its limit for tactical air traffic management Efficiency: - Institutional and technical evolution toward larger block of managed airspace (Single European sky objective)

2. Service Technique de la Navigation Aérienne NexSAT: Mission Hypothesis 20 may, 2003 STNA/32 ATC challenges for high density airspace Organisation: - Strategic vs tactical air traffic management More flights handled per sector/per controller Data-link as primary mean of communication (continuous data exchange between aircraft and ground system) Human factor: - New HMI and processes supporting data-link applications Safety: - Secured access to data-link applications - Protection improved w.r.t. VHF voice

3. Service Technique de la Navigation Aérienne NexSAT: Mission Hypothesis 20 may, 2003 STNA/33 AOC worldwide Main objectives: - Improve flight operations - Optimise the maintenance intervention - Facilitate flight crew communications Reduction of the airline operation contribution to delay (Commercial and economical impact in terms of fuel and market share) Constraints: - Reduce investment and running costs associated to these services (strong recommendation for common communication system to provide AOC and ATC applications)

4. Service Technique de la Navigation Aérienne NexSAT: Mission Hypothesis 20 may, 2003 STNA/34 Foreseen new data-link technologies

5. Service Technique de la Navigation Aérienne NexSAT: Mission Hypothesis 20 may, 2003 STNA/35 Mission requirements proposal (1) MR1: NexSAT must provide, on primary basis data-link for air traffic control at least, in complement to the other D/L system (e.g. VDL 2 or SATCOM), with voice as back-up using conventional system (VHF AM). NexSAt could also provide ATC voice services but it is not the main requirement for ATC MR2: NexSAT must provide AOC services, in complement to the other D/L system. NexSAT could also provide Cabin passenger services but it is not the main requirement for airlines

6. Service Technique de la Navigation Aérienne NexSAT: Mission Hypothesis 20 may, 2003 STNA/36 Mission requirements proposal (2) MR3: NexSAT must facilitate larger block airspace structure over ECAC. MR4: The architecture must cover ECAC, up to polar routes. The system must be expandable world wide. MR5: NexSAT must be interoperable with other regional satellite communication system used for ATC or AOC MR6: Security mechanisms have to be implemented to protect the access to safety applications.

7. Service Technique de la Navigation Aérienne NexSAT: Mission Hypothesis 20 may, 2003 STNA/37 Conclusion End-user(s) of NexSAT have to be clearly identified in order to define and prioritize the main services (essential requirements) and the other potential services that could be offered by the system Relevant target level of performance and QoS will then be derived Mission requirements could be validated in a first step using the SDLS demonstrator Institutional requirements have to be identified and must be addressed as soon as possible