resource allocations within constrained airspace october 31, 2001 metron aviation, inc. robert...

Resource Allocations within Constrained Airspace

October 31, 2001

Metron Aviation, Inc.

Robert Hoffman, Ph.D.

10/17/2001 2

What is equitable allocation of limited resources (EALR)?

• an allocation scheme is deemed fair, or equitable, if the parties with a stake in the allocation process deem that their individual allotments are reasonable and in accordance with the treatment received by their competitors, given the operational constraints on the procedure itself and the original motivation for the allocation.

10/17/2001 3

What is EALR? – Airport Case

Arrival Demand

Capacity

Controlled Arrivals

• Airport Case: Assignment of available capacity to demand– Assign Airport Arrival Slots by Delaying Some Flights– In a Fair Manner

10/17/2001 4

Sector Demand

What is EALR? – Sector Case

• Allocate Sector Capacity– Spatial allocation: re-Route Some Flights– Temporal allocation: delay Some Flights– In a Fair Manner

10/17/2001 5

What is EALR? - Interdependence

West-East Traffic

DTW

Overhead traffic favored over departures (easiest flow to shutoff)

• Need for flow balancing: consideration must be given to departures

10/17/2001 6

Collaborative Decision Making (CDM) Trends

• Movement away from central-decision making• No more “black box solutions”• FAA often answers to carriers for rationale of

traffic flow initiatives– daily basis

– regular CDM meetings: air carrier feedback

10/17/2001 7

Equity-Efficiency Tradeoff

• Efficient but not equitable (En route example)– Let overhead traffic go; hold merging departures

– Throughput maximized but not fair to departures

• Equitable but not efficient (GDP example)– Ground all flights by the same amount

– Equity achieved but airport throughput suffers

10/17/2001 8

Why do we need equity?

• User satisfaction– FAA is a service provider

• Promotes User participation – data submission

– collaborative flow management

10/17/2001 9

The Many Facets of Equity

• Long haul Vs. Short haul flights• GA Vs. Scheduled Carriers• Regional Vs. Majors• Overhead stream Vs. Departures• Equity across flights, carriers, ARTCCs, airports,...

• No single vantage point serves for all occasions

10/17/2001 10

How To Measure Equity?

• What is the resource to be rationed? (e.g., arrival slot)

• Who is vying for the resources?• How to quantify fairness? (e.g., FSM variance

metrics)

• Must have:– Participant (FAA and carrier) feedback

– Understanding of contextual nuances and TFM objectives

10/17/2001 11

0

20

40

60

80

100

120

140

160

1

62

123

184

245

306

367

428

489

550

611

672

733

794

Cumulative minutes (from start of program)

Cum

. Sub

s (%

of f

lts in

gdp

)

User Participation

• Virtual arrival slots created in anticipation of reduced capacity

• Slots rationed to carriers/flights in order of scheduled arrival time (RBS)

• Carriers re-allocate slots among their operations

10/17/2001 12

Group B

Group A

FCA

En Route Competition for Alternate Airspace

10/17/2001 13

Ground delay

Origin Destination

Downline delays

Air delay

Total Imposed Delay = (Ground delay) + (Air delay) + (Downline delay)

More Global Equity via Total Imposed Delay

10/17/2001 14

Equitable Allocation of En Route Resources

• How to allocate constrained routes in an equitable manner while incorporating User preferences?

• How to encourage submission of early (and accurate) User intent?

?

Ground delay

Reroute

Original Route

Alternative Route

10/17/2001 15

Some Possible Rationing Concepts

• Equitable distribution among traffic flow classes (e.g., DFW arrivals, east-west traffic)

• RBS-like assignment of en route resources (route slots). But then what is OAG time?

• Preference given to those flights with existing delays

• Delay is weighted sum of notice time and scheduled time

10/17/2001 16

Issue:Analysis of Enroute Resource Limits

• Enroute capacity has not been systematically measured– How can resources be rationed if they have not been

quantified?

– Data is Available

• Recommendation:– Develop resource-throughput analysis capability for all

NAS enroute elements• Average and peak performance for all sectors over long periods

• Correlation with weather events and TFM actions

10/17/2001 17

Issue: Communication Channels

• Dynamic response to changing capacity is limited by communication channels– Strategic Planning Team and ATCSCC communicate

through TMUs to supervisors to controllers

– Multiple layers of telephone communication slow the response of the ATC system

• Recommendation:– Initiate study of communication procedures and support

tools that could facilitate more direct communication between ATCSCC, ARTCCs, AOCs, ...

10/17/2001 18

Issue: Demand/Capacity Uncertainty

• Equitable Allocation of Limited Resources is subject to uncertainty– TFM Planning Time Horizon

– Weather/Capacity Uncertainties

– Demand Uncertainties

– Data Quality

• Recommendation:– Develop research thrust in demand/capacity uncertainty

10/17/2001 19

Demand Variability ZOB48

1200 Outlook for 1600-2000 (9.28.01)

0

10

20

30

40

50

60

Predicted Actual Predicted Actual Predicted Actual Predicted Actual

Time

Fli

gh

ts Pop-up

Common

1600 1800 19001700

10/17/2001 20

Demand Variability ZOB48

1300 Outlook for 1600-2000 (9.28.01)

0

10

20

30

40

50

60

Predicted Actual Predicted Actual Predicted Actual Predicted Actual

Tim e

Fli

gh

ts Pop-up

Common

1600 1800 19001700

10/17/2001 21

Demand Variability ZOB48

1400 Outlook for 1600-2000 (9.28.01)

0

10

20

30

40

50

60

Predicted Actual Predicted Actual Predicted Actual Predicted Actual

Time

Fli

gh

ts Pop-up

Common

1600 1800 19001700

10/17/2001 22

Demand Variability ZOB48

1500 Outlook for 1600-2000 (9.28.01)

0

10

20

30

40

50

60

Predicted Actual Predicted Actual Predicted Actual Predicted Actual

Time

Fli

gh

ts Pop-up

Common

1600 1800 19001700

10/17/2001 23

Flights Flown but did not File ZID88

37 Flights Filed for ZID98

5 Flights Filed for Lower ZID Sectors

+ 18 Flights Filed Around ZID88

60 (out of 218) Flew but did not File ZID88

_______________________________________________________

10/17/2001 24

Issue:Airport Surace Operations

• Airport surface operations create a ‘black hole’ in current TFM planning– What are the delays?

– When will a flight depart?

– This contributes significantly to the demand uncertainty issue

• Recommendation:– Integrate research and development of the surface

management system with TFM tools• SMS can feed accurate predictions of flight departure times to FSM

for GDP planning

10/17/2001 25

Overall

• EALR has many manifestations • There are clear tradeoffs between equity and

efficiency• The real question is: do the system operators

perceive there to be a proper balance between efficiency and equity

10/17/2001 26

Metron EALR Activities

• Equity Analysis and Modeling (POET, FSA, FSM)• Distance-Based GDPs• Multi-Airport, Multi-Fix GDPs• Departure Delay Predictor• Equitable Allocation of En Route Resources• C-Flow• Complexity Metrics/Dynamic Density