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E lectronic separation Cl earance E nabling the C rossing of T raffic under I nstrument meteorological C onditions. ECLECTIC: What is it?. To assess operational feasibility and acceptability of ASAS Crossing Procedures (ACP)
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Electronic separation Clearance Enabling the Crossing of Traffic under Instrument meteorological Conditions
ECLECTIC: What is it? • To assess operational feasibility and acceptability of ASAS Crossing Procedures (ACP) • Procedures which allow the flight crew to provide separation with respect to one aircraft designated by ATC • The controller remains responsible for separation of other aircraft • Airborne separation Minima • A CENA Project : prospective study for Package 2 • European context : EEC, NUP II, MFF, MA-AFAS
ECLECTIC: How? • First step • A demonstrator running on PC unit • Several scenarios of crossing • Different crossing angles • Different altitudes and speeds • Different horizontal separation at CPA before ASAS manoeuvre • Controller radar display • Flight deck MMI example (CDTI + control unit) • Automatic or manual initiation of ACP and piloting (through pseudo A/P) • Further steps • Experimentations with traffic simulator and real controllers • Traffic scenarios with several aircraft
ECLECTIC: An example of ACP • ASAS « lateral crossing procedure »: « Clear of Traffic » New waypoints introduced by ASAS algorithms Crossed (« designated ») aircraft Initial planned trajectory Manoeuvring envelope New « ACP » trajectory Aircraft cleared for ACP
Considerations & assumptions • ACP considered as a « standard » procedure • Proposed by ATC • If impossible, flight crew will advise ATC immediately • No monitoring by ATC • ACP is considered as safe as today’s procedures • Airborne separation value may be different from the radar one • Radar separation minima are not the same everywhere • The airborne value may depend on the equipment • Contingency in case of « ASAS unavailability » • The ACP abortion does not mean immediate risk of collision • ATC should be able to recover • ATC may use half vertical separation as a last resort • ACAS
Scenarios • Different crossing angles: « Same route » « crossing » « Head-on »
Different solutions • Pass behind… • Or in front
Issues • The phraseology must remain simple and robust • The « other aircraft » designation is still an open issue • Unambiguous • Must not generate confusion with traffic not involved • The need to lock the navigation of the other aircraft and to advise it about the ASAS crossing, to be discussed • End of procedure: • At « Clear of Traffic », or • After resuming navigation?
Example of phraseology • Atc: ABC123, for ASAS separation, identify traffic <other a/c id *, position> • Pil : Traffic <other a/c id> identified, ABC123 • Atc: ABC123, pass behind traffic, maintain airborne separation, report clear of traffic (or : resuming navigation) • Pil : Passing behind traffic, maintaining airborne separation, ABC123 • … ( the controller is NOT required to monitor the crossing) • Pil : ABC123, clear of traffic (or: resuming navigation) • Atc: ABC123, roger. * note : the unambiguous identification of the other aircraft is still an open issue, which may be solved through data-link communication
How does it work ? • Traffic scenario • Simplified aircraft simulator • ASAS algorithm + parameters computes alternative routes for separation • The aircraft is piloted in real time though A/P commands • The HMI (ND) is for demo and experimentations purpose, not a proposal for implementation
Crossing at 120° angle (1/6) The other aircraft has been identified Its flight path is displayed (magenta track) Current distance between aircraft: 153NM (display range 320NM)
Crossing at 120° angle (2/6) • The ASAS system has been switched on: an alternative route (with offset solution) is proposed to the pilot (yellow dotted line) • (display range 160NM)
Crossing at 120° angle (3/6) • The alternate route is activated : its colour is changed to green • The separation is assured at the required value (here: 8NM) • (display range 160NM)
Crossing at 120° angle (4/6) • The aircraft is following the new route • (display range 80NM)
Crossing at 120° angle (5/6) • (display range 40NM)
Crossing at 120° angle (6/6) • Aircraft have passed the CPA at (slightly less than) the required separation value… • Own aircraft can resume its navigation (here, « direct to ») • (display range 40NM)
First results of achieved separation • Parameters: • Offset solution • Required separation value : 8NM • Angle of deviation : • 60° (crossings at 23°) • 30° (crossings at other angles) • Crossings : • 23° : • 60° : • 120°: • Head-on
Further work • Other parameter values • 5NM, 3NM as examples for separation • Other angles of deviation • « Pass in front » • Other algorithms • One waypoint solution • Open angle of deviation • Manoeuvring Envelope • Simulations