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 Organisation for the Safety of Air Navigation 1

Merging of arrival flows with open loop radar vectors Efficient and flexible But… z Highly demanding as it imposes rapid decisions for the controller and time-critical execution by the flight crew Consequences z Peaks of workload z High frequency occupancy z Lack of anticipation z Difficulty to optimise vertical profiles and to contain the dispersion of trajectories z

Paris CDG, 2002, source: ADP

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Merging of arrival flows with Precision Area Navigation z

z z

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

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Examples

EDDF - 14/06/2007 (7:00-10:00)

Source: stanlytrack.dfs.de/stanlytrack/stanlytrackEDDF.jnlp 5

EDDF - 14/06/2007 (17:00-20:00)

Motivation

6

z

Key points z Maintain flexibility to be able to expedite or delay aircraft z Keep aircraft on Flight Management System trajectory z Maximise runway throughput

z

When investigating airborne spacing (ASAS), a specific method and route structure was defined to expedite or delay aircraft in the terminal area

z

Can we now apply this method and the route structure without airborne spacing…?

Principles z

z

We created a merge point with legs at a constant distance for path shortening or stretching

Merge point Envelope of possible paths

Merging is achieved through “direct-to” instructions to the merge point Sequencing legs (vertically separated)

7

Merge point

FL120

FL100

Sequencing legs NM 10

8

Series of experiments z z

A series of small-scale experiments to perform an initial assessment of feasibility, benefits and limits Experimental conditions z z z z z

z

9

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)

Airspace (baseline) Two frequencies: approach controller (APC) and final director (FIN)

FAF

Holding SUDOK: FL100 / 140 1 min / 220 kt TAMOT ° 065

SUDOK

0° 33

SIMON

PONTY CODYN

OKRIX

SIMON PONTY ILS 10

FL100 FL080 4000

Holding PONTY: FL080 / 140 1 min / 220 kt

Airspace (point merge) Two frequencies: approach controller (APC) and final director (FIN)

FAF LOMAN

Holding SUDOK: FL100 / 140 1 min / 220 kt TAMOT

NADOR FL080

SUDOK SIMON

FL100

MOTAR TOLAD PONTY

CODYN

OKRIX

SIMON/TOLAD MOTAR/NADOR ILS 11

FL100 FL080 4000

Holding PONTY: FL080 / 140 1 min / 220 kt

Density of instructions

1

16

1

Baseline

16

BOKET

Point merge

BOKET

FAF

FAF LOMAN

TAMOT

SUDOK

12

SIMON

TAMOT

PONTY

SUDOK

NADOR SIMON

MOTAR TOLAD

PONTY

Geographical distribution of instructions 60

Final director

Baseline

Approach controller Level Direct Heading Speed

Number of instructions

40

20

0 60

Point merge

Final director

Approach controller

40

20

0 0

13

5

10 15 20 25 30 35 40

30 35 40 45 50 55 60 65 70 75 80

Distance to reference point (NM)

Number of instructions 120

Final director

Approach controller Level Direct Heading Speed

100

Number of instructions

80

60

40

20

0

Baseline 14

Point merge

Baseline

Point merge

Number of instructions per aircraft

Number of instructions

Baseline Point merge

10

5

0 15

Heading Direct

Speed

Level

All

Frequency occupancy

100%

Final director

Frequency occupancy

80%

60%

40%

20%

0% 16

Approach controller Baseline Point merge

Spacing on final

Spacing at final appraoch fix (NM)

7

Point merge

6

5

4

3

2 17

Baseline

Max Max for 95% Mean+STD Mean Mean-STD Min for 95% Min

Trajectories

M3

TMA

Vectors

Baseline

M3

TMA

Similar distance and time flown: 70 NM during 18 minutes on average 18

Triangle

Point merge

Descent profiles 120

100

Point merge

Altitude in feet (*100)

Mean Std dev

80

60

40

Baseline Mean Std dev

20

0 0 19

5

10

15

20

25

30

35

40

45

Distance to final approach fix (NM)

50

55

60

65

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

20

Dissociated sequencing legs

Configurations tested (2/2) IAF 2

IAF 1

FAF

IAF 1

IAF 2

IAF 4

IAF 3

FAF1 IAF 1

FAF2

IAF 2

IAF 3 FAF IAF 4

IAF 3

21

IAF 4

22

23

Summary z z z z z z z z

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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

Conclusion

The “point merge” method z z z

25

Maintains flexibility to be able to expedite or delay aircraft Keeps aircraft on Flight Management System trajectory Maximises runway throughput

In perspective

The “point merge” method is z z z

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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)