ASAS Resolution Manoeuvres • Finite time-horizon (look ahead time 5-10 minutes) • Lateral manoeuvre requirement only • Third-party aircraft assumed isolated from ASAS designated pair • Two well-established resolution manoeuvre classes have been assessed • Turning point manoeuvre • Offset manoeuvre

ASAS Resolution Manoeuvres • Turning point manoeuvre • Minimizes the number of resolution manoeuvre stages • May be achieved through autopilot lateral functionality

ASAS Resolution Manoeuvres • Offset manoeuvre • May be compatible with Flight Management System (FMS) functionality • A track alteration of 30 degrees has been assumed

Contents • ASAS Resolution Manoeuvres • Operational Procedure • Fast-Time Simulation Results • Operational scenarios • ASEP-LC&P algorithms assessment • Conclusions

Operational Procedure - Phases Controller Set-up Phase Flight crew Set-up Phase Identification Phase Clearance Phase Execution Phase Termination Phase

Operational Procedure - Example Setup phase + Identification phase ATCO assesses the opportunity of ASAS lateral crossing manoeuvre ATCO: CSA6662For Lateral Crossing, identify Target AF534

Operational Procedure - Example Pilot: CSA6662 Identify AF534

Operational Procedure - Example Pilot: CSA6662 Target Identified AF534, two o’clock, 38NM

Operational Procedure - Example Clearance phase ATCO: CSA6662Pass behind [AF534], report clear of traffic, then proceed to MOKDI

Operational Procedure - Example Pilot: CSA6662 Pass behind AF534 then proceed to MOKDI (Clearance entered and solution evaluated)

Operational Procedure - Example Flight crew aligns aircraft track by means of the Flight Control Unit. Alternatively, the solution can be coupled to the FMS functionalities.

Operational Procedure - Example Execution phase ATCO: AF534BHfor information you are under ASAS separation

Operational Procedure - Example Pilot monitors the expected separation (by means of relative ground speed vector)

Operational Procedure - Example Clearance aircraft near the Closest Point of Approach.

Operational Procedure - Example Clearance aircraft passed CPA and close to Clear of Traffic.

Operational Procedure - Example Pilot: CSA6662 clear of traffic, proceeding to MOKDI

Operational Procedure - Example Termination phase ATCO assesses that separation at COT is OK and resumes responsibility for separation ATCO: Roger, CSA6662, (instruction)

Operational Procedure - Example End of ASAS – pilot resumes navigation monitoring. Pilot: CSA6662 Proceeding to MOKDI

Contents • ASAS Resolution Manoeuvres • Operational Procedure • Fast-Time Simulation Results • Operational scenarios • ASEP-LC&P algorithm assessment • Conclusions

Fast-Time Simulation Results • Operational scenarios • Derived from pairwise crossing encounters in radar airspace in two adjacent sectors in southwest France:

Fast-Time Simulation Results • The selected radar set is modified such that aircraft are flying directly from the entry point to the exit point of the sector. • Only encounters for which the initial separation is greater than 5 NM are considered (a total of 309 encounters). • The clearance aircraft (ASAS equipped aircraft) is assumed to be the aircraft with the lowest airspeed • Pass behindmanoeuvres are simulated

Fast-Time Simulation Results • Navigation accuracy model: • The aircraft is assumed to follow a succession of waypoints. • The aircraft is assumed to be equipped with a track-hold autopilot. • Lateral positioning errors are included in the track-hold autopilot control to simulate the required 95% accuracy navigation positioning.

Fast-Time Simulation Results • Example of an encounter with 1 NM navigation error for both aircraft

Fast-Time Simulation Results • Simulations were performed for each of the selected encounters for each of nine wind fields and three navigation error categories: • Wind fields: {0 kts, 30 kts, 60 kts} x {0˚, 90˚, 180˚, 270˚} • Navigation positioning categories: {0, 0.3, 1} NM • Focus on the set of uncontrolled encounters for which the separation is lower than 5 NM (1086 encounters)

Contents • ASAS Resolution Manoeuvres • Operational scenario example • Fast-Time Simulation Results • Operational scenarios • ASEP-LC&P algorithms assessment • Minimum lateral separation • Maximum cross track deviation • Conclusions

Fast-Time Simulation Results • The objective of the ASEP-LC&P algorithms is to achieve a prescribed minimum lateral separation (5 NM in this case) • Two performance metrics are used to assess the ASEP-LC&P algorithms: • Minimum lateral separation achieved • Maximum cross-track deviation

Fast-Time Simulation Results • For each encounter/wind field/navigation accuracy scenario, each of the performance metrics was assigned to one of the bin sets: • Bin 1: the metric value is between 0 NM and 2 NM • Bin 2: the metric value is between 2 NM and 4 NM • Bin 3: the metric value is between 4 NM and 6 NM • … • Bin 7: the metric value is greater than 12 NM

ASEP-LC&P Algorithms Assessment • Minimum lateral separation • No lateral crossing manoeuvre Percentage of encounters per bin category Minimum lateral separation

ASEP-LC&P Algorithms Assessment • Minimum lateral separation • Turning point manoeuvre Percentage of encounters per bin category Minimum lateral separation

ASEP-LC&P Algorithms Assessment • Minimum lateral separation • Offset manoeuvre Percentage of encounters per bin category Minimum lateral separation

ASEP-LC&P Algorithms Assessment • Example of unresolved conflict: • Despite a separation of 19.4 NM at the beginning of the encounter, the two aircraft cross at 2.3 NM. • This example basically shows that if the clearance is issued late, the radius of turn may not be sufficient to enable the clearance aircraft to correctly perform the lateral crossing manoeuvre.

ASEP-LC&P Algorithms Assessment • Maximum cross-track deviation • Turning point manoeuvre Percentage of encounters per bin category Maximum cross-track deviation

ASEP-LC&P Algorithms Assessment • Maximum cross-track deviation • Offset manoeuvre Percentage of encounters per bin category Maximum cross-track deviation

Contents • ASAS Resolution Manoeuvres • Operational scenario example • Fast-Time Simulation Results • Operational scenarios • ASEP-LC&P algorithms assessment • Conclusions

Conclusions • Two well-established resolution manoeuvre classes have been investigated using a state-based geometric resolution algorithm: • Turning point manoeuvre and • Offset manoeuvre • Only pass behind manoeuvres have been investigated as far as they are perceived by air traffic controllers as safer than pass in-front manoeuvres

Conclusions • Assessment, conducted using a set of modified radar encounters, indicates that: • Turning point manoeuvres perform better than offset manoeuvres but provide a greater maximum cross track deviation. • In addition, navigation errors (either from the ownship or from the target) significantly increase the percentage of unresolved conflicts by the airborne system. • Close links should exist between future airborne separation standards and navigation performance.

Conclusions • A static manoeuvre envelope may not be adequate to take advantage of lateral crossing manoeuvre opportunities. • Depending on the initial position and velocity configuration of the conflicting aircraft, a static envelope may be over- or under-sized. • Envelope issues could be overcome by means of a dynamic manoeuvre envelope or by broadcasting the intended lateral crossing manoeuvre.

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