Research for Ground Delay Program Enhancements October 31, 2001 Metron Aviation, Inc. Robert...
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Transcript of Research for Ground Delay Program Enhancements October 31, 2001 Metron Aviation, Inc. Robert...
Research for Ground Delay Program Enhancements
October 31, 2001
Metron Aviation, Inc.
Robert Hoffman, Ph.D.
10/17/2001 2
Main Thrusts of GDP-E Research
• Allocation of Arrival Resources among– single airport, using distance (“distance-based GDP”)
– multiple arrival fixes (“multi-fix GDP”)
– multiple airports (“multi-airport GDPs”)
10/17/2001 3
FAA Ground Delay Programs
• Single airport scenario with a demand-capacity imbalance
• Apply FAA-assigned ground delays to flights bound for a common destination airport
• Ground delays reduce rate of arrival flow– alleviates airborne holding
– transfers airborne queues to the ground
10/17/2001 4
Central (deterministic) GDP Issues
• Demand predictions (carrier supplied data)• Capacity predictions (runway config, AARs)• Geographical scope of the program• Temporal scope of the program
– start/end time, model time, potential cancellation time
• Equity among– flights
– air carriers
10/17/2001 5
Stochastic GDP Issues
• Demand uncertainty– pop-up flights (FA delays)
– cancellations (compression)
– departure times questionable
– en route time
• Capacity uncertainty– capacity prediction usually based on weather forecast
10/17/2001 6
Ground Delay or Air Delay?
• Aggressive program – ground delay lots of flights over long time
– risk of unrecoverable ground delays
• Hedge against weather forecast – ground delay fewer flights over less time
– risk of excessive airborne arrival queues
10/17/2001 7
Current practices
• Geographic scope of GDP set via combinations of ARTCCs (“centers”)
• Tiers (first, second, …) commonly used• Power Run enumerates options
Avg Delay 54 49 32 31Max Delay 115 109 77 77Unrecov Delay 407 390 525 507
10/17/2001 8
How distance-based GDPs can help
• Choose inclusion to program via proximity to GDP airport– e.g., flights within 1500 miles subject to ground delays
• More options than tiers/centers– can only improve quality of solution
– fine tune geographic scope
• Leverage off distance to – mitigate uncertainties
– improve optimization (Power Run)
10/17/2001 9
Sample Tradeoff:Avg Delay Vs. Unrecov Delay
300
350
400
450
500
550
600
650
300 350 410 540 700 760 910 1000 1090 1600 >1600
1100
1150
1200
1250
1300
1350
1400
1450
1500
Efficient solution
Unrec
Trade-off
Avg
BOS 2 Feb 1999
10/17/2001 10
Prototype GraphicTradeoff Curve
200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800
1020 2040
Miles
UnRecov and
Avg Delay
(wtd sum)
Tier 1 Tier 3Tier 2
Recommended
Not Recommended
Max Delay: 271 MinAvg Delay: 135 MinTotal Delay: 1557 MinFlight Count: 139Ooh ooh, pick me!
10/17/2001 11
Tradeoff Curve is a function of MinExpected Duration of GDP
200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800
Miles
Tier 1 Tier 3Tier 2
Hours0102030405060708091011
User Set
Unnecessary Delay
220
200
180
160
140
120
100
80
60
40
20
10/17/2001 12
New Power Run
Air HoldOuch
220
200
180
160
140
120
100
80
60
40
20
Minutes
Unrecoverable Delay
Average Delay
200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800
Miles
Air HoldUnrecov DelayAverage DelayMax Delay
160
58
37
10/17/2001 13
10/17/2001 14
Can we optimize GDP settings?
• Yes, but – single parameter searches stronger than multi-
dimensional searches
– must be tempered with traffic flow expertise
• Limitations– quantification of equity principles
– cost/objective functions harder than constraints
• Successes/Benefits– more uniform GDP settings
– first formal treatment of stochastic factors
10/17/2001 15
Multi-fix GDPs
• Current model of flow into airport (during GDP) is a single queue
10/17/2001 16
Multi-fix GDPs
• In reality, flow into an airport is multiple queues over fixes.
10/17/2001 17
Objective of Multi-fix GDP
• To develop algorithms/procedures for controlling multiple flows into GDP airport
• Note: in FSM, we have single fix control capabilities only
10/17/2001 18
Issues in Multi-fix GDP
• Effective arrival fix balancing• Equity among fixes (distribute delay evenly)• Modify current substitution practices
– open arrival slot over one fix does not mean opan arrival slot over another
10/17/2001 19
Multi-Airport GDP Objective
• To develop algorithms/procedures to coordinate GDPs at several airports
• Issues:– efficient use of regional airspace
– equitable access to regional airspace by all airports
– modify current substitution practices
Arp1 Arp2
Arp3Arp4
10/17/2001 20
Multi-Fix Vs. Multi-Airport GDP
• Abstractly, each problem balances multiple flows into a common resource
• Solution to one is solution to the other
Arp1 Arp2
Arp3Arp4
10/17/2001 21
Most General Problem
• Flows into fixes, into airports
• Multi-fix solution must work with multi-airport solution
Origins Fixes Airports
N
S
E
W
EWR
LGA
JFK
TEB
A
B
C
D
10/17/2001 22
Case Study: New York City area
10/17/2001 23
Multi-queue/Multi-resource Allocation Issues
• Added equity consideration– equity among airports (or fixes)
• Greedy algorithms (e.g., RBS) no longer optimal– how sub-optimal is sub-optimal?
• Equity vs. Efficiency greater issue than ever before
10/17/2001 24
Progress on Multi-airport GDP
• Space-time flow model has been developed with equity a primary consideration
• Complex model has simple RBS-like solution
• Integer program, multi-commodity?
N
S
E
W
R E G
L G A
E W R
N
S
E
W
R E G
L G A
E W R
N
S
E
W
R E G
L G A
E W R
,, 2N L G At tE
,, 1N L G At tE
, 1L G At te
, 2L G At te
10/17/2001 25
Deployment Path
• Finalize algorithms and analysis• Dialogue with operational people• Prototyping, war games• Validation
– need to communicate to others
– intuitively explainable?
– how realistic?
• Plug into FSM ultimately
10/17/2001 26
Welcome By-product
• New ideas for rationing– apply to the single airport case
• Avoid RBS side effect– carriers with flights in rear of GDP get disproportionate
delays
• Revamp rationing algorithm for single airport?
10/17/2001 27
Future work (multi-airport/fix)
• Finalize flow model and alternative approaches• Select best balance of mathematical modeling,
flow representation, and practicality• Open questions:
– how inefficient is the equity model?
– how inequitable is the efficiency model?
• Merger of multi-airport/fix (long range)