1. Distance-Based GDPs Guillermo Lulli, Mike Ball (U of MD) Bob Hoffman (Metron)

2. Distance-Based GDP zReplaces Tier Approach zGDP options are defined by drawing a circle around the airport and including all enclosed airports: yAll flights whose origin is within circle and whose arrival time is within GDP time period are included. zAlternative programs obtained by increasing radius of circle.

3. Distance-based GDP vs Current Approach zFlexibility: a wider range of possible solutions is available. zDominance: for each tier-based initiative, there is a corresponding distance-based initiative. zSimplicity: the range of programs can be varied in a simple well-defined manner.

4. Airports considered zAtl 2 Nov 99 ft 16.54 19.00 - 23.00 aar 76 zBos 2 Feb 00 ft 17.02 19.00 - 00.59 aar 40 zDfw 10 Oct 98 ft 12.48 14.00 - 19.59 aar 64 zDtw 6 Apr 00 ft 15.14 16.00 - 21.59 aar 36 zEwr 27 Feb 00 ft 15.19 18.00 - 23.59 aar 36 (3)/40 (3) zIah 24 Feb 00 ft 17.02 19.00 - 00.59 aar 40 zOrd 3 Feb 00 ft 16.51 18.00 - 01.59 aar 76 (2)/80 (6) zPhl 13 Aug 99 ft 18.04 20.00 - 01.59 aar 40 zSfo 18 Aug 99 ft 13.32 16.00 - 21.59 aar 30 (3)/40 (3) zStl 19 Mar 99 ft 12.58 16.00 - 21.59 aar 32

5. Statistics used in our analysis: zTotal delay zAirborne Holding delay zUnrecoverable delay zAffected flights zMax delay zAverage delay zUnnecessary delay: part of delay that is not necessary to meet the increased AAR, if the program is cancelled if OTD<CT<ETA min{ CT- OTD, ETD-OTD, ETA-CT}, else 0.

6. Bos 2 Feb 99 Distances vs Tiers Aff flights Max Avg Unrec Air Hold

7. Bos 2 Feb 99 Average delay vs Unrec. delay Unrec Avg.

8. Trading Off Avg Delay and Unrecov Delay zChoose weights for each and consider: wgt 1 ave-delay + wgt 2 unr-delay zFind distance that minimizes this weighted sum. zNominal values for this analysis: wgt1 = 50 wgt2 = 1

9. Bos 2 Feb 99 Weighted trade-off between Avg and Unrec. delay Unrec Trade-off Avg

10. Bos 2 Feb 99 Varying Tradeoff Weights 1 98

11. Bos 2 Feb 99 Avoiding Inefficient Solutions Unrec Efficient solutions

12. Efficient Initiatives: numerical example zBy varying distances inefficient initiatives can be avoided (Bos 2 Feb 99)

13. Bos 2 Feb 99 Consideration of Fairness: Delay Variability Unrec Avg. Delay Var

14. Stl 19 Mar 99 Distances vs Tiers Air Hold Delay Max Avg Aff flight Unrec 1th2nd

15. Stl 19 Mar 99 Average delay vs Unrec. delay Unrec Avg

16. Stl 19 Mar 99 Weighted trade-off, Avg and Unrec. delay Unrec Avg Trade-off 2nd Tier

17. Stl 19 Mar 99 Different Weighted trade-off 20 68

18. Stl 19 Mar 99 Avg delay vs Unrec. Delay & Delay Variability Avg Delay Var Unrec

19. Sfo 18 Aug 99 Distances vs 6 & 10 west Avg Max Aff flights Unrec Air Hold 6W10W

20. Sfo 18 Aug 99 Weighted trade-off, Avg and Unrec. delay Avg Unrec Trade-off 6W10W

21. Unrecoverable Delay ==> Unnecessary Delay unrecoverable delay = ground delay incurred by start time of program: if program canceled at start then all of this delay is unnecessary but none is recoverable What if program is canceled earlier or later than start time of program?? unnecessary delay = ground delays applied to flights that push their CTAs past the program cancellation time expected unnecessary delay = expected value of unnecessary delay computed using distribution of possible cancellation time.

22. Sfo 18 Aug 99 Unnecessary delay (early cancellation time)

23. Sfo 18 Aug 99 Unnecessary delay (middle cancellation time)

24. Sfo 18 Aug 99 Unnecessary delay (late cancellation time)

25. Sfo 18 Aug 99 Unrecoverable vs expected Unnecessary delay Unrec Unnec

26. Sfo 18 Aug 99 Unrec., Unnec. delay and weighted trade-off weighted trade-off Unnec Unrec Avg local minimum

27. Conclusions: zDistance-based GDPs provider greater flexibility but are easy to understand and manipulate. zFlexible user interface could be developed to display and analyze options.