EUROCAE WG85 – 4D NAV Inputs to SC214/WG78

1. EUROCAE WG85 – 4D NAVInputs to SC214/WG78 Jean-Louis de Menorval – WG85 Chairman - Airbus SC214-WG 78 -WG85 inputs

2. WG85 presentation • Participants: • Eurocontrol, FAA, CAA, ASA, GE, Honeywell, Thales avionics, Thales Air systems, Indra, DSNA, NATS MUAC, INECO, AVTECH, MITRE, Boeing (1rst day), Airbus. • Objective • Identify the navigation capability needed to meet SESAR Initial 4D operational concept based on absolute time management taking into account the corresponding concept objectives, contribute to validation and ensure feasibility • Produce a revised navigation MASPS which provides the basis for development of certification criteria • 1rst meeting was Dec 9 and 10th 2009: good representation from all the types of stakeholders which enable to make significant progress • General orientations of the TOR were agreed • Good convergence on the vision of operational assumptions • WG85 gave its position on Nav Hot items of SC214/WG78 4DTRAD • Minutes edition is in progress • WG85 was tasked by SC214/WG78 to tackle following issues • ETAmin/ETAmax • 4D trajectory status • ETA accuracy SC214-WG 78 -WG85 inputs

3. WG85 results: ETAmin/ETAmax • Problematic • Need for the ground to be capable to compute min and max time over a specific waypoint of the flight plan for RTA negotiation or speed schedule • The WG85 agreed on the following proposal: • Downlink of Vmin and Vmax for each flight phase, to give to the ground the capacity to do a rough “what if” computation of the ETAmin/ETAmax • Avoid downlink of Vmin/Vmax on each waypoints which would increase significantly the size of the 4D trajectory downlink • Vmin/Vmax would include pilot entry if default speeds are not operationally acceptable • Computation and downlink of ETAmin/ETAmax on 1 waypoint selected by the ground through ADS-C • This would be done before RTA is inserted • This value would include pilot entry if default speeds are not operationally acceptable and meteorological pad necessary to meet RTA accuracy with a high probability (i.e. 95%) • It is left to WG78 the choice to put it as an option or compulsory depending on the acceptability of the disturbance linked to the difference between air and ground ETAmin/ETAmax SC214-WG 78 -WG85 inputs

4. WG85 results: 4D trajectory status • Problematic • In some specific cases the 4D trajectory prediction downlinked by the aircraft uses hypothesis which are not relevant. What solution is proposed to detect these cases • WG 85 results is that there is a need to ensure the fact to raise a flag when the hypothesis used within the prediction of the 4DT (by the aircraft) are not relevant (detection can be done by air or ground) • It is considered that the ATC tool has the capacity to detect and manage the cases where there is a deviation from the synchronised 4D trajectory • But not the case where meteorological data were not inserted correctly within the FMS • However, the previously proposed solution based on the detection of deviation and auto-pilot mode is considered not mature enough and not fully adapted to the minimum need SC214-WG 78 -WG85 inputs

5. New Airbus proposal for 4D trajectory status • If nothing is done, for Initial 4D Near future could be the following: • In 2013-2015, when aircraft will be flying Initial 4D, they will be sending 4DT prediction through ADS-C • First positive feed-back will be coming from initial implementation in specific part of the world. • Key values of Initial 4D will mainly be • Significant TP improvement with domino effect on overall ATM efficiency • RTA booking mechanism giving significant benefits to airlines • Other ANSP and airlines will be observing, and would like to gather information on this 4DT prediction and try to make statistics on 4DT predictions (from the aircraft) • Unfortunately, it seems that on many samples, the difference between predicted trajectory and real trajectory is very significant which causes the statistical accuracy of 4DT prediction to be poor. Will it be possible to disseminate this type of operation in this condition? • ….. SC214-WG 78 -WG85 inputs

6. New Airbus proposal for 4D trajectory status • Taking into account that: • WG85 considers that there is still a need to ensure that the ATCo and ATC tool be informed (whatever the source air or ground) of the non relevance of the hypothesis used by the 4DT predictions • Taking into account that there is a need to consolidate 4DT predictions in support of performance demonstration / analysis • WG85 estimated risk that there could be maturity risk with the logic of 4D trajectory status SC214-WG 78 -WG85 inputs

7. New Airbus proposal for 4D trajectory status • Airbus and Eurocontrol propose to downlink the following “raw parameters” as optional • Aircraft coupled with lateral flight plan (i.e Lateral managed mode on Airbus): Boolean • Aircraft coupled with vertical flight plan (i.e vertical managed mode on Airbus) : Boolean • Aircraft coupled with speed flight plan (i.e speed managed mode on Airbus) : Boolean • Last time meteorological model of the FMS was updated • Pros • Only small and simple parameters are downlinked • Versatile solution to adapt to uncertainties and support validation • ATCo and ATC tool need is satisfied • 4DT prediction accuracy can be easily statistically demonstrated • Cons • Need to add 3 Booleans and 1 time parameter to the standard SC214-WG 78 -WG85 inputs

8. New Airbus proposal for 4D trajectory status • Conclusion • This proposal is deemed sufficient for environment A as it covers the risk, supports validation, and it is simple enough to be implemented on a large proportion of aircraft types. • An improved solution could be foreseen for Env B when sufficient validation will be available SC214-WG 78 -WG85 inputs

9. Input for 4DTRAD SG Jean-Louis de Menorval – WG85 Chairman - Airbus SC214-WG 78 -WG85 inputs

10. WG85 results: general items • Acceptability of the downlink of aircraft GW • WG85 could not take a position • It is considered that it is the role of the users to give their position on the acceptability to downlink the aircraft weight • WG85 agreed that their could be several level of RTA accuracy targets which could be • 10s at 95% (TBC) • 30s at 95% (TBC) • 1 min at 95% (TBC) • Those Required Time performance (RTP) targets would depend upon area of use depending it RTA is used for: • Queue/sequence management in TMA • Crossing of traffic in en route • Flow management in en route SC214-WG 78 -WG85 inputs