Merging arrival flows without heading instructions Bruno Favennec, Eric Hoffman, François Vergne, Karim Zeghal, EUROCONTROL Experimental Centre Ludovic Boursier, Direction des Services de la Navigation Aérienne, France Aymeric Trzmiel, Steria Transport Division, France ATM seminar, July 2007 European 1 Organisation for the Safety of Air Navigation
Merging of arrival flows with open loop radar vectors Paris CDG, 2002, source: ADP Efficient and flexible But Highly demanding as it imposes rapid decisions for the controller and time-critical execution by the flight crew Consequences Peaks of workload High frequency occupancy Lack of anticipation Difficulty to optimise vertical profiles and to contain the dispersion of trajectories 2
Merging of arrival flows with Precision Area Navigation Use of area navigation (RNAV, P-RNAV) to revisit the merging of arrival flows Definition of new route structures, e.g. trombones Merging achieved through route modification But 3
Limitations... at high traffic loads, the controllers inevitably revert to radar vectoring in order to maximise capacity. EUROCONTROL TMA2010+ Business Case for an Arrival Manager with PRNAV in Terminal Airspace Operations (AMAN-P) The main disadvantage of RNAV procedures is that they reduce the flexibility that radar vectoring affords the controller and experience has shown that, without the help of a very advanced arrival manager, controllers tend to revert to radar vectoring during the peak periods. EUROCONTROL Guidance Material for the Design of Terminal Procedures for Area Navigation, Edition 3.0, March 2003 4
Examples EDDF - 14/06/2007 (7:00-10:00) EDDF - 14/06/2007 (17:00-20:00) 5 Source: stanlytrack.dfs.de/stanlytrack/stanlytrackeddf.jnlp
Motivation Key points Maintain flexibility to be able to expedite or delay aircraft Keep aircraft on Flight Management System trajectory Maximise runway throughput When investigating airborne spacing (ASAS), a specific method and route structure was defined to expedite or delay aircraft in the terminal area Can we now apply this method and the route structure without airborne spacing? 6
Principles We created a merge point with legs at a constant distance for path shortening or stretching Merging is achieved through direct-to instructions to the merge point Merge point Envelope of possible paths Sequencing legs (vertically separated) 7
Merge point FL120 FL100 10NM Sequencing legs 8
Series of experiments A series of small-scale experiments to perform an initial assessment of feasibility, benefits and limits Experimental conditions High traffic load (36 to 40 arrivals per hour with 20% heavy) Various wind conditions (no, moderate and strong) Various airspace configurations (two, three and four entry points) Various configurations of legs (same or opposite direction, parallel or non parallel) Various geometries of legs (straight segments, segments approximating concentric arcs, with or without intermediate points) Initial measurement of benefits with today s method (open loop vectors) as baseline (2 x 3 runs) 9
Airspace (baseline) Two frequencies: approach controller (APC) and final director (FIN) FAF Holding SUDOK: FL100 / 140 1 min / 220 kt TAMOT SUDOK SIMON 065 330 PONTY Holding PONTY: FL080 / 140 1 min / 220 kt CODYN OKRIX SIMON FL100 PONTY FL080 ILS 4000 10
Airspace (point merge) Two frequencies: approach controller (APC) and final director (FIN) FAF Holding SUDOK: FL100 / 140 1 min / 220 kt TAMOT SUDOK LOMAN NADOR FL080 MOTAR FL100 SIMON TOLAD PONTY Holding PONTY: FL080 / 140 1 min / 220 kt CODYN OKRIX SIMON/TOLAD FL100 MOTAR/NADOR FL080 ILS 4000 11
Density of instructions 1 16 Baseline 1 16 Point merge FAF BOKET FAF BOKET LOMAN TAMOT SIMON TAMOT NADOR SIMON MOTAR TOLAD SUDOK PONTY SUDOK PONTY 12
Geographical distribution of instructions 60 Final director Baseline Approach controller 40 Level Direct Heading Speed Number of instructions 20 0 60 40 Final director Point merge Approach controller 20 13 0 0 5 10 15 20 25 30 35 40 Distance to reference point (NM) 30 35 40 45 50 55 60 65 70 75 80
Number of instructions 120 100 Final director Approach controller Level Direct Heading Speed 80 Number of instructions 60 40 20 0 Baseline Point merge Baseline Point merge 14
Number of instructions per aircraft Baseline Point merge Number of instructions 10 5 15 0 Heading Direct Speed Level All
Frequency occupancy 100% Final director Approach controller 80% Baseline Point merge Frequency occupancy 60% 40% 20% 0% 16
Spacing on final 7 Baseline Point merge Spacing at final appraoch fix (NM) 6 5 4 3 Max Max for 95% Mean+STD Mean Mean-STD Min for 95% Min 17 2
Trajectories Baseline Point merge M3 TMA Vectors M3 TMA Triangle Similar distance and time flown: 70 NM during 18 minutes on average 18
Descent profiles 120 Altitude in feet (*100) 100 80 60 40 20 Point merge Mean Std dev Baseline Mean Std dev 19 0 0 5 10 15 20 25 30 35 40 45 50 55 60 65 Distance to final approach fix (NM)
Configurations tested (1/2) Merge point Straight sequencing legs Segmented sequencing legs Common point Merge point 3 flows, with 2 sequencing legs of same direction Dissociated sequencing legs 20
Configurations tested (2/2) IAF 1 IAF 2 FAF IAF 1 IAF 3 IAF 4 IAF 2 FAF1 IAF 1 FAF2 IAF 4 IAF 2 IAF 3 FAF IAF 4 IAF 3 21
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Summary Method found comfortable, safe and accurate, even under high traffic load, although less flexible than open loop vectors Predictability and anticipation increased, workload and communications reduced Open loop radar vectors no longer used and aircraft remained on lateral navigation mode Final approach spacing as accurate as today Descent profiles improved (potential for continuous descent from FL100) Flow of traffic more orderly with a contained and predefined dispersion of trajectories All these elements should contribute to improve safety No specific airborne functions or ground tools are required initially, except P-RNAV capabilities 24
Conclusion The point merge method Maintains flexibility to be able to expedite or delay aircraft Keeps aircraft on Flight Management System trajectory Maximises runway throughput 25
In perspective The point merge method is A transition towards extensive use of P-RNAV A sound foundation to support further developments such as continuous descent (CDA) and target time of arrival (4D) A step to the implementation of airborne spacing (ASAS) 26