OPA

1. OPA WG78/SC214 SG-meeting 24-28 Oct 2011

2. ATSU ACSP AIRCRAFT ATSU System Comm. service Aircraft System Controller Flight crew Composition Initiating message Initiator Reaction: Responder TRN RCP RCTP Closure Response Recognition CPDLC Operational Transaction • RCP : E-t-E performance in support of an ATS function • TRN : Pseudo E-t-E and monitoring purposes • RCTP: Technical systems (AC, ATSU, ACSP) for data communication • Initiator : Msg composition and recognition, including HMI manipulations • Reaction : Thinking time and response composition of Responder, including HMI manipulations

3. Core Principles • Realistic times for RCTP • ENR-2 allows larger times than CONT • Current ‘78/214’ draft considers RCTP Specs for RCP120 as lowest common denominator for future Continental RCP specs: • Worst case msg = Route Clearance ~15 Waypoints Msg size = 2Kbyte • Realistic Human Response times • Complex UM requires more FC time than simple UM • WILCO response is a truly closure response and includes the time the pilot has evaluated and is able to complete the instruction. • STANDBY is an Interim response Does not count for transaction closure. • ATSU & AC Delays Idea is to have same delay values for Aircraft, independent from RCP Spec • AC value in RCP240/400 (OCR) =10s (95%). AC value for RCP120/300 (CONT) =7s (95%). • AC value will become 10s as common value With equal E-t-E, Responder becomes slightly less for CONT RCPs. 4. Common approach for timing allocations • Based on Exponential Statistical distribution • Requires change of RCP240 and RCP400 Spec Is this acceptable?

4. RCP Specs in ENR-1, TMA, APT Core principles from slide 2 has led to • RCP120: ATC Comm-simple/VCM • Certainty that perf is correct: Systems (VDLM2-M) are designed to meet it. • RCP300: DCL and 4DTRAD • Complex CPDLC msg Operations • Uncertain they are correct • FAA/DCL – simulations are ongoing • Need to wait for 4DTRAD validation • Observed that RCP assignments in Updated ATS functions section for DCL & 4DTRADdo not match

5. Current draft SPR timings:ENR-1, TMA, APT, using VDLM2-M Need to become 10s 99.9% value to be changed

6. First Perf findings: FAA-DCL Sim Current draft against RCP300 (1), using POA Fits into SIM results POA 7s need to be changed ACSP slightly less

7. First Perf findings: FAA-DCL Sim Current draft against RCP300 (2), using POA • Pilot Response time for complex DCL clearance shows that RCP300 is not met • 181sec vs 136sec • RCTP (POA) time for complex DCL clearance shows that specified RCTP is not met • 25sec vs 15 sec • Q: POA timing based on future AC traffic demands and high rate of AOC messages? • RCP400 fits the DCL Sim results

8. Impact POA on RCTP120 • Current SPR draft specifies RCTP(95%)=15s. • Based on practical experience (LINK2000+) and Ops approved products. • A/G-sub-network: VDLM2-multichannel (ATS + AOC traffic). • Current performance should drive the future data comms. • Wrong signal that future performance is worse than current performance • Impact on POA based RCTP in En-Route • Evaluation not started by FAA: • POA  Larger RCTP (25s at 95%). It is known that POA perf can be worse than 25s. • AOA  RCTP TBD • Consequences larger RCTP times: • For same E-t-E value, Responder time is compromised for large RCTP times • POA  Not used in EUR for DL-IR due to its unpredictable performance. • Usability of CPDLC service in dense ER degrades.

9. RCP120: Draft SPR vs RCTP POA=25s POA

10. RCP300: Draft SPR vs RCTP POA=25s POA

11. Conclusions • Until DCL and ER simulations are done: • Suggest to keep tentatively RCP120/300. • Come back to it in 2012/2013 • Make a note: • DCL tend to become RCP400, pending final FAA simulations. SPR stays draft until mid/end 2013! • ACSP and ATSU are recommendations-> Importance is that (ACSP + ATSU + AC) need to meet RCTP. • Also Responder & Initiator times are recommendations for HMI design, training and operations. • Requirements are: RCP, TRN, RCTP and AC • Make AC delay 10s (95%) for all Specs; Amend 99.9% value

12. Time and Continuity Distribution of Exchanged Transaction Transaction Failed Transaction valid 95% of the Transactions Prob 95% Lost messages 8 99.9% Time TT95 ET99.9

13. SRs related to Expiration Time • In absence of response, at certain moment dialogue becomes operationally invalid. Indication required for safety reasons: • SR-GD-CPDLC-15 (Continental) The ground system shall indicate to the controller when a required response for a message sent by the ATSU is not received within the required time ET(TRN). • SR-14 (Oceanic) The ATSU system shall indicate to the controller when a required response for a message sent by the ATSU is not received within the required time ET(TRN). • Local option (FAA) to have pre-warning, set at TT(95) to indicate to the controller outstanding UM • 1 out of 20 msg  warning • Probably worse than 1 out of 20 due to unpredictable POA perf! • Tuning required!

14. RCP Specs ENR-2

15. Timings ENR-2: GOLD-v1

16. Demo New Timings ENR-2 • At one hand desire to use a single approach (Stats • On the other hand, large population of AC are certified/ops approved with curent GOLD specs • Users understand curent GOLD and are used to it. • Better not to touch with one exception: • Current GOLD should be changed for 99.9% Responder. • Stats shows this is constantly not met. Seize the opportunity to amend? • Did Statistical approach for demo, based on the following: • ATSU and AC delays as in RCP120/RCP300 • RCP240 only operated with SATCOM • Based on statistics, mentioned at SG-mtg Sep11, ACSP is reduced to 60s(95%) • RCP400 satisfies HFDL operations • Kept Human Response time the same for RCP240/400 • Same time 99.9% and 95% not realistic  see previous slide

17. Demo Timings ENR-2