airline based en route sequencing and spacing field test … · 2011-06-03 · previous tests (e.g....

© 2011 The MITRE Corporation. All rights reserved.

F044-B11-015

Airline Based En Route Sequencing and Spacing Field Test Results

Peter Moertl

June 2010

ATM Seminar, Berlin

1

Approved for

public release

Case number:

11-0212


F044-B11-015

Interval Management

Interval Management –Spacing (IM-S)

Interval Management –Delegated Separation (IM-

DS)

Flight Deck Based IM-DS (FIM-DS)

FIM-DS with Wake Risk Management

Ground IM-S (GIM-S)

Ground IM-DS (GIM-DS)

Flight Deck Based IM-S

(FIM-S)

Interval Management

• Interval Management (IM) describes a set of applications to improve sequencing and spacing of converging flights

– Automation supported speed management on ground and/or flight deck)

2


F044-B11-015

ABESS

• Airline Based En Route Sequencing and Spacing (ABESS) is a GIM-S application for airlines

– Early version of IM, prior to ATC implementation

– Development activity has been completed

– Preconditioning of flights through the uplink of minor speed advisories

(2) Conduct

Departure Terminal Enroute Terminal Landing

Top of

Climb

Setup

Enroute

Merge

Fix

Fine-tune

Spacing

Speed

Adjustability

Period (SAP)

Earl

y S

AP

Late

SA

P

(1) ABESS Setup

(3) ABESS Termination

Pre Dep.

3


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Related Concepts

• 3-D PAM

– Sweet (2008) “3D-PAM”

• Attila

– Presentation at Air Traffic Control Association (ATCA), March 22, 2005, “Self-Metering Airport Arrival System Gaining Recognition,” Alexandria, VA.

• AMAN Products

– Eurocontrol (2010), Arrival Manager: Implementation Guidelines and Lessons Learned

• Main differentiation with ABESS

– ABESS is airline based

– Extended metering horizon

4


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ABESS Expected Benefits

• Increase in aircraft efficiency via use of early, minor speed adjustments that avoid costly, low altitude maneuvering

• Provide appropriate spacing for the initiation of new applications such as Flight-deck based Interval Management (FIM) and Optimized Profile Descents (OPDs)

• Realization of desired arrival sequences that are optimized for airline needs

• Reduce both ATC workload and radio frequency congestion

5


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Information Exchange

6


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ABESS User Interface At Airline Operations Center

7


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ABESS Concept Development

• Development started in 2005 with cooperation between FAA, NASA, MITRE, and UPS

• Concept development was embedded in a series of exploratory field tests with UPS:

– October 2006

– May / November 2008

– Spring 2009

– June 2010

- Objective of exploratory field tests was to develop procedures and functional requirements

- Resulted in multiple iterations of the concept

8


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Exploratory Test Environment

9

Field Test Participants - UPS dispatchers - Pilots - Air traffic controllers - Software engineering - Human factors researchers

“Off-the-shelf” ground tools from NASA and MITRE were initially used and then refined

Field Test Traffic: UPS West Coast aircraft to UPS hub in Louisville


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ABESS Aircraft Position Data Feeds

• Track data from Enhanced Traffic Management System (ETMS)

– One minute updates

– Lower (truncated) position precision

• ADS-B data

– About 1 sec updates

• Radar data

– About 12 sec updates

10


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June 2010 Test

• June 7 – 9 and 14 – 16, 2010

– ABESS testing during night

• Objectives

– Measure ability to predict fix crossing times over extended look-ahead time periods (e.g. up to 80 min)

– Measure accuracy of spacing problem resolution

– Determine the operational acceptability of ABESS for controllers, pilots, and AOC personal

11


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RESULTS

12


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Results Overview

• Fix crossing time predictions

• Spacing predictions

• Metering conflict detections

– True / missed detections

– Nuisance detections

– Causal factors

• Speed advisory determination

• Observed spacing at fix

13


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Fix Crossing Time Predictions

14

-120

-60

0

60

120

180

240

300

Pre

dic

ted

Min

us

Act

ual

Err

ors

in

Seco

nd

s

Metering Fix Prediction Errors, June 9

-120

-60

0

60

120

180

240

300

Pre

dic

ted

Min

us

Act

ual

Err

ors

in

Seco

nd

s


-120

-60

0

60

120

180

240

300

Pre

dic

ted

Min

us

Act

ual

Err

ors

in

Seco

nd

s


-120

-60

0

60

120

180

240

300

UPS843 UPS857 UPS957 UPS907 UPS905 UPS945 UPS919

Pre

dic

ted

Min

us

Act

ual

Err

ors

in

Seco

nd

s


Only flights are shown here for which no speed advisories were

executed as changes in speeds would have impacted the actual

crossing times.

Calculated at the time when the last aircraft entered the SAP


F044-B11-015

Average Fix Crossing Time Prediction Errors

• Average prediction accuracy is similar to that found in previous tests (e.g. Moertl et al. 2009)* where average prediction errors were on average less than 30 sec for the last 100 minutes prior to the metering point

15

*Moertl, P., Arthur, W. C., Pollack, M. P., Stein, J., Zheng, L. (2009). Field Test Results of an Airline Based En Route

Sequencing and Spacing Tool. Proceedings of the 28th Digital Avionics Conference, October 25 – 29, 2009.

Signed (sec) Unsigned (sec)

Average 26 44

Median 16 27

Minimum -62 1

Maximum 261 261

• Calculated at the time when the last aircraft entered the SAP


F044-B11-015

Spacing Predictions

• The correlation between actual versus predicted spacing is an indicator for the quality of spacing predictions

• Correlation was calculated when the last aircraft in the flow entered the freeze horizon

16

y = 0.9594x + 24.16R² = 0.905

0

200

400

600

800

1000

1200

0 200 400 600 800 1000 1200 1400

Pre

dic

ted

Sp

acin

g (i

n

Seco

nd

s)

Actual Spacing (in Seconds)

Predicted versus Actual Spacing, June 9 - 16th

Correlation between predicted

and actual spacing r = 0.95 over

4 days combined


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Metering Conflict Predictions True Detections

• Over the 4 nights of regular ABESS operations, ABESS detected 142 “metering conflict” aircraft pairs

– Aircraft were predicted to reach the metering point with less than the target spacing of 120 sec.

• There were 32 true conflict aircraft pairs

– ABESS successfully identified all of these, except 3

– 92 % of conflict aircraft detection

17


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Metering Conflict Predictions Nuisance Detections

• Nuisance detections should be kept to a minimum

– likely to reduce the tools usefulness and may reduce operator trust in the tool

• Calculation of nuisance detections:

• Resulted in 75 % nuisance detections

– Only 25 % of ABESS identified conflicts were “true”

18

* Successful speed advisories removed the conflict spacing that caused

the speed advisory to be given.

*


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Identified Contributors to Nuisance Rate

• Data instability

– Variability of groundspeed (see Moertl et al. 2009)

– Requires heuristics to correctly “smooth” data

• Wind prediction inaccuracy

– Contributions of error sources to overall nuisance rate remain to be determined

• ATC clearances

– Unforeseen trajectory changes

19


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Observed Variability of Speed Reports

20

Altitude


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Working Around Variability of Speed Reports

• To account for the variability in ground speed, the ABESS trajectory modeler uses the speed that is filed in the flight plan

• Once non-conformance between trajectories and true position reports is detected, the trajectories are updated with consideration of reported ground speed

– However, even in cases of non-conformance, the modeled speed is still strongly influenced by filed speed

– This work-around procedure delays the modeler’s ability to detect speed changes for a flight

• This is graphically shown on the next slide

21


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Effect of Speed Report Variability

22

The trajectory modeler

is delayed in picking up

the increase in

airspeed

Once the modeler

detects the (unexpected)

increase in speed, the fix

crossing time errors decrease


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Speed Advisory Determination

• Two alternatives for speed advisories

– “Global” speed advisory solutions resolved not only the conflict between two aircraft but also between all other aircraft in that stream

• The ABESS tool created global solutions that consisted of multiple speed advisories, thereby resolving each conflict

– “Non-global” speed advisory solutions resolved only individual conflict pairs

• Sometimes “global” solutions required aircraft to fly speeds outside their allowable speed envelope

– In that case, the operator selected the speed advisory that resulted the most in the desired change

• Required repetitive user actions for each conflict

23


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Process for Speed Advisory Determination

24

ABESS detects

spacing conflict

ABESS provides

speed advisory that

resolves conflicts

for ALL

aircraft in stream

ABESS does NOT provide

speed advisory

Operator selects

appropriate

speed advisory

Operator assesses speed

advisory feasibility based

on flight’s speed envelope

and indicated airspeed

Operator views list of possible

speed advisories and associated

predicted meter time changes

Operator selects

speed advisory

with predicted meter time

that resolves conflict

Repeat for

every conflict

pair

2. N

on

-G

lob

al

So

luti

on

s

1. G

lob

al S

olu

tio

ns

OR

Operator communicates

speed advisory

to dispatcher

Next Slide


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Comparison with Indicated Airspeed

• Knowledge of indicated airspeed would have allowed the ABESS operator to determine speed advisory feasibility

– No indicated airspeeds were available to the ABESS operator

• Even if indicated airspeed had been available, instantaneous readouts (e.g. all 9 min at UPS) fluctuate considerably such that they can be confusing

• Operator had two ways to estimate speed advisory feasibility

1. Request readout of indicated airspeed from dispatcher

• Workload intensive and sometimes inaccurate

2. Rely on ABESS “modeled” indicated airspeed

• Not always reliable

25


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Speed Advisory Coordination

• Complex process of speed advisory communication resulted in average duration of 12 minutes, ranging between 4 to 31 minutes

– Uplink path + feedback path combined

26

ABESS provides

speed advisory

ABESS operator

- dispatch supervisor

Dispatch supervisor

- dispatcher

Dispatcher - flight deck Dispatcher - flight deck Dispatcher - flight deck

Uplink Path Feedback Path


F044-B11-015

Observed Spacing at Fix Slow Downs

27

-0.01

-0.03

-0.01

-0.02 -0.02

-0.02

-0.02-0.02

-0.02

-0.02

-0.02

-0.02

-0.04

-0.02

-0.01-0.03

-0.02

0

60

120

180

240

300

UPS921 UPS903 UPS957 UPS945 UPS973 UPS941 UPS905 UPS921 UPS913 UPS907 UPS857 UPS905 UPS921 UPS973 UPS797 UPS913 UPS903 UPS941

Seq

ue

nci

ng

(se

con

ds)

Aircraft Spacing-Slow Downs

Predicted

Actual

Goal

-0.01


F044-B11-015

Observed Spacing at Fix Speed Ups

28

+0.01

+0.04

+0.01

+0.01+0.02

0

20

40

60

80

100

120

140

UPS913 UPS921 UPS913 UPS919

Se

qu

en

cin

g (

seco

nd

s)

Aircraft Spacing - Speed Ups

PredictedActualGoal


F044-B11-015

Summary

• Exploratory field test results indicate promise and limitations for using speed advisories during extended metering

– Average (signed) fix crossing time prediction errors were 26 sec for up to 80 min prior to the metering fix

– Actual and predicted spacing correlates at r = 0.95

– 92 % conflict detection rate

– 75 % nuisance detection rate

– 17 % success rate for spacing achievement

• Further research and development for extended metering algorithms

– Development of data processing heuristics

• Utilization of indicated airspeed information

– E.g. facilitate detection and correction of wind prediction errors

– Speed advisory algorithm refinement

• Achieve acceptable balance between missed / nuisance advisories

29


F044-B11-015


F044-B11-015 31

Approved for Public Release: 11-0212

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under Contract Number DTFA01-01-C-00001 and is subject to Federal Aviation Administration

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MITRE Corporation. For further information, please contact The MITRE Corporation, Contract

Office, 7515 Colshire Drive, McLean, VA 22102, (703) 983-6000.

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accuracy of the views expressed herein.

2011 The MITRE Corporation. The Government retains a nonexclusive, royalty-free right to

publish or reproduce this document, or to allow others to do so, for “Government Purposes Only”.

airline based en route sequencing and spacing field test … · 2011-06-03 · previous tests (e.g....

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