estimating requirements and costs of 4d atm in high density terminal areas gunnar schwoch dlr...

Estimating Requirements and Costs of 4D ATM in High Density Terminal Areas

Gunnar Schwoch

DLR Institute of Flight GuidanceBraunschweig, Germany

ICNS 201224th – 26th April 2012

www.DLR.de • Chart 1 • ICNS 2012 • Gunnar Schwoch • Estimating Requirements and Costs of 4D ATM in High Density Terminal Areas • 26th April 2012

Utopia

• More efficient procedures than holdings/trombones desired

• 4D trajectories with direct routing to increase efficiency

• High density TMAs pose a challenge to prediction and compliance

• Research starts with Utopia: - Ideal scenario - No uncertainties - Direct routing (two merge points only)

Upper bounds for efficiency gain What are the challenges?


Preliminary CondiserationsGround Side Trajectory Predictions

• Initial trajectory prediction based on aircraft model, atmosphere and weather forecast

• Example: Airbus A320 trajectory, 67 t TOM, using BADA 3.9

- Flight altitude (FL)- Ground speed- CAS- Mach * 100



• Error in trajectory prediction requires compensation measures

• Influence on flight time with errors in specific parameters 200 NM before touchdown (Airbus A320 BADA model):


Error in aircraft specific parameter

Difference in flight time

mass: +/- 5% +3.9s/-4.5s

thrust: +/- 10% +0.6s/-0.6s

drag: +/- 10% -20.3s/+24.8s


• Variability of the arrival time (Airbus A320 BADA model)

• „Snapshot“ of the aircraft‘s possibilities at 200 NM from touchdown

• Range approx. -105 s (high speed) to +165 s (low speed)


Scenario Design

• Based on an actual busy day of real traffic

• All scenarios contain 1377 identical flights

• Three runways (one for departures only)

• Two „families“ of scenarios are created:

- Conventional scenario family as a „lower bound“ for efficiency

measuring

- Utopia scenario family with (nearly) direct routing


Scenario DesignScenario Family Conventional

• Based on today‘s departure and approach patterns:- SIDs/STARs- Guidance along trombone (downwind-upwind legs)

• Variance in length of trombone- Shortest possible- Typical- Longest possible

• Conflict-free baseline scenario


Scenario DesignScenario Family Utopia

• Direct routing with as few waypoints as possible

• Arrivals: Great circle routes from airport of origin to one of two merge points, Continuous Descent Approach

• Assignment of merge point depending on location of airport of origin



• Direct routing with as few waypoints as possible

• Departures: Small straight segment for take-off, great circle route to destination airport, Continuous Climb Departure

• No additional requirements


departures


Basic Utopia:

• Runway threshold times as the only time constraint

• Flights are separated at threshold

• Fixed sequence since TOD

What kind of disturbances can be compensated?

What measures are necessary?


Scenario DesignAssessment method

Indicators are:

• Average flight timeLonger flight times indicate delay

• Average flight path lengthLonger flight paths indicate higher fuel consumption

• Average model fuel consumptionBased on BADA 3.9

• Number of trajectory planning conflicts-> Safety KPA

Simulation tool: TrafficSim (DLR)


Conflict Detection and ResolutionConflict Detection


Definition of a conflict in this scope:

• Lateral separation of less than 3.0 NM

and• Vertical separation of

- Less than 1000 ft (cruise)- Less than 3000 ft (at least one A/C

climbing/descending)

• Values for experimental purposes only!

• Gained data: Conflict area (4D positions of aircraft at begin/end of conflict)

Conflict Detection and ResolutionConflict Detection


Detection by type of conflict:

• Arrival-arrival conflict/ Departure-departure conflict

- Rare in this scenario (sequence building)

- If any: Solved by sequence change or slight time modification

• Arrival-departure conflict- Majority of conflicts as a result of crossing tracks

- Different resolution strategies

Conflict Detection and ResolutionConflict Resolution


Conflict Resolution by constraining departures

• Climb procedure is interrupted by level segment below conflict area

• Lateral border: Conflict area

• Vertical border: Lowest altitude of both aircraft within conflict area



Conflict Resolution by constraining arrivals Strategy 1 (V1)

• Arriving aircraft‘s descent profile is modified to stay above the conflict area

• Conflict area is avoided by interrupting descent and flying a level segment

• Lateral path stretching manoeuvre becomes necessary as aircraft has passed its TOD

New conflicts at merge points may be induced

9000

TOD_CDA TOD_MOD

32000

28000

24000

20000

16000

12000

8000

4000

730 740 750 760 770 780 790 800 810 820

ft

A1A2



Conflict Resolution by constraining arrivals Strategy 2 (V2)

• Arriving aircraft‘s descent profile is altered to stay below the conflict area

• Top of Descent has to be moved

• No lateral route change

No further conflicts are induced

9000

15000V2V2*

V1V1*

CDA V1 V2

32000

28000

24000

20000

16000

12000

8000

4000

730 740 750 760 770 780 790 800 810 820

ft



Conflict Resolution by constraining arrivals Top of Descent comparison

• V1 leaves TOD (nearly) intact

• CDA passes through conflict area

• V2 moves TOD by approx. 20 NM

9000

15000

V2 V2*

V1 V1*

CDA V1 V2

20000

16000

12000

8000

4000

800 810 820

ft



Conflict Resolution by constraining arrivals Top of Descent comparison

• V1 leaves TOD (nearly) intact

• CDA passes through conflict area

• V2 moves TOD by approx. 20 NM

Conflict Detection and ResolutionCreating the conflict-free scenario Utopia


• Example scenario Utopia with 1377 flights

• 76 conflicts detected

• Automatic conflict resolution applied

Kind of Conflict

Iteration no. and Resolution action Dep-Arr Dep-Dep Arr-Arr New conflicts

Scenario Utopia

(0) Original scenario68 8 0 n/a

(1) Departure level segment 14 7 0 5

(2) Arrival TOD modification (V2) 1 7 0 0

(3) Manual sequence change 1 0 0 0

(4) Manual conflict resolution

Scenario Utopia deconf0 0 0 0

ResultsUtopia vs. Conventional scenario


• Results for travel times and BADA fuel usage

• Conflict resolution has a very small influence

• Most gains in last 40 NM

Per Arrival200 NM to THR 40 NM to THR

Flight time [s] BADA fuel [kg] Flight time [s] BADA fuel [kg]

Utopia 2177 1264 809 319

Utopia deconf 2179 1265 810 322

Conv. short 2536 1521 1059 520

Conv. medium 2645 1605 1167 604

Conv. long 2990 1860 1516 844

ResultsUtopia vs. Conventional scenario


• Results for travel times and BADA fuel usage

• Conflict resolution has a very small influence

• Departure gains smaller: Controllability is on the ground

Per DepartureTHR to 40 NM THR to 200 NM

Flight time [s] BADA fuel [kg] Flight time [s] BADA fuel [kg]

Utopia 545 1271 1878 3067

Utopia deconf 546 1264 1882 3070

Conv. 549 1286 1950 3155

Conclusions


• Laboratory environment for estimation of costs/requirements established

• Conflict-free scenario Utopia possible with- Little cost- No lateral re-routing

Conclusions


• Laboratory environment for estimation of costs/requirements established

• Conflict-free scenario Utopia possible with- Little cost- No lateral re-routing

but

• Precise trajectory prediction necessary: deconfliction starts before TOD

• Separation criteria are a mix of used and expected values

• Used model environment:- No wind, standard atmosphere- 100% equipped aircraft

Future work


• Situation dependent conflict resolution

• Variation of separation minima

• Introduction of weather (forecasted and actual)

• Inclusion of

- Overflights

- Traffic to/from surrounding airports

Thank you!


Questions?

estimating requirements and costs of 4d atm in high density terminal areas gunnar schwoch dlr...

Documents

s slide

estimating requirements

s high speed

efficiency high density

d trajectories

conventional scenario

ideal scenario

germany icns