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Concurrent Task Demands and Pilot Error in Airport Surface Operations. Key Dismukes, Loukia Loukopoulos, Immanuel Barshi Human Factors Research and Technology Division NASA-Ames Research Center and U.S. Navy Aerospace Experimental Psychology November 2003 FSF IASS, Washington D.C.

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Slide1 l.jpg

Concurrent Task Demands and Pilot Error in Airport Surface Operations

Key Dismukes, Loukia Loukopoulos, Immanuel Barshi

Human Factors Research and Technology Division

NASA-Ames Research Center

and

U.S. Navy Aerospace Experimental Psychology

November 2003

FSF IASS, Washington D.C.


Consequences of inadvertent procedural omissions l.jpg
Consequences of Inadvertent Procedural Omissions

  • LaGuardia (1994): MD-82 ran off runway end after high-speed rejected take-off

    • NTSB: Anomalous airspeed indications caused by failure to turn on pitot heat

  • Detroit (1987): DC-9 crashed shortly after take-off

    • NTSB: Crew failed to set flaps/slats to take-off position

  • Dallas (1988): B-727 crashed shortly after take-off

    • NTSB: Crew failed to set flaps/slats to take-off position

      ------------------------------------------------------------------------

  • Houston (1996): DC-9 landed gear-up

    • NTSB: Hydraulic boost pump not set to high position


Were these accidents unique l.jpg

  • Departed with inadequate fuel

  • APU left running during takeoff -- fire

  • Packs failed in cruise

  • Took-off without PDC

  • Deviated from speed or altitude restriction

  • Nose gear failed to retract

  • etc.

Were These Accidents Unique?

Not according to recent ASRS reports:

  • Rejected take-offs

    • Anomalous airspeed indications (pitot heat not on)

    • Configuration warning (flaps or trim not set)

Unnecessary costs and delays

But for luck any of these incidents might have become accidents


Slide4 l.jpg
Why?

  • Why would experienced crews forget a procedural step they normally perform day in and day out?

  • Why fail to catch omissions with checklists?


An ongoing nasa research project l.jpg
An Ongoing NASA Research Project

  • “Carelessness” not an adequate explanation

  • Crews vulnerable to omissions when:

    • Interrupted or preoccupied with one of several concurrent tasks (Young, Dismukes, & Sumwalt, 1998).

    • Deferring tasks out of normal sequence (Loukopoulos, Dismukes, & Barshi, 2003).

  • Vulnerability to error among experienced pilots largely driven by:

    • Characteristics of tasks performed

    • Demands tasks place on human cognitive processes

    • Operating environment

    • Norms for actual line operations


Jumpseat observation study loukopoulos dismukes barshi 2003 l.jpg
Jumpseat Observation Study(Loukopoulos, Dismukes, & Barshi, 2003)

  • Reviewed FOMs, observed line operations, analyzed ASRS, NTSB reports.

    • All phases of flight — focus today on preflight and taxi

  • Discovered disconnect between FOM/training and actual line operations in area of task management.


Slide7 l.jpg

Preflight - In theory (FOM)

Ground/

Company/

Dispatch

Frequencies

Interphone

Cabin Attendant

Gate Agent

ACARs / OPC

CAPTAIN FIRST OFFICER

Review paperwork

Sign flight release

Prepare/review charts

Review Load Schedule

Review FMC

Takeoff brief

Ask for checklist

  • Ask for checklist

Obtain ATIS

Obtain clearance

Review paperwork

Prepare/review charts

(Passenger count)

(Load Sheet)

Program FMC

Begin checklist

Checklist complete

Begin checklist

Checklist complete

procedure

procedure

checklist

CLEARANCE

checklist

ENGINE START & PUSHBACK


Depiction of cockpit task management in fom training l.jpg
Depiction of Cockpit Task Management in FOM/Training

  • Linear: task A task B task C in a fixed sequence.


Slide9 l.jpg

Preflight - In theory (FOM)

Ground/

Company/

Dispatch

Frequencies

Interphone

Cabin Attendant

Gate Agent

ACARs / OPC

CAPTAIN FIRST OFFICER

Review paperwork

Sign flight release

Prepare/review charts

Review Load Schedule

Review FMC

Takeoff brief

Ask for checklist

  • Ask for checklist

Obtain ATIS

Obtain clearance

Review paperwork

Prepare/review charts

(Passenger count)

(Load Sheet)

Program FMC

Begin checklist

Checklist complete

Begin checklist

Checklist complete

procedure

procedure

checklist

CLEARANCE

checklist

ENGINE START & PUSHBACK


Depiction of cockpit task management in fom training10 l.jpg
Depiction of Cockpit Task Management in FOM/Training

  • Linear: task A task B task C in a fixed sequence.

  • Controllable: tasks are initiated by crew at their discretion.

  • Predictable:

    • Information available to crew when needed.

    • Individuals can communicate as needed.


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Preflight - In theory (FOM)

Ground/

Company/

Dispatch

Frequencies

Interphone

Cabin Attendant

Gate Agent

ACARs / OPC

CAPTAIN FIRST OFFICER

Review paperwork

Sign flight release

Prepare/review charts

Review Load Schedule

Review FMC

Takeoff brief

Ask for checklist

  • Ask for checklist

Obtain ATIS

Obtain clearance

Review paperwork

Prepare/review charts

(Passenger count)

(Load Sheet)

Program FMC

Begin checklist

Checklist complete

Begin checklist

Checklist complete

procedure

procedure

checklist

CLEARANCE

checklist

ENGINE START & PUSHBACK


Slide12 l.jpg

Taxi-out - In theory (FOM)

CAPTAIN FIRST OFFICER

Captain

Start taxiing

Ask for checklist

Receive takeoff clearance

Ask for checklist

Line up with runway

First Officer

Receive taxi clearance

Start checklist

Checklist complete

Receive takeoff clearance

Start checklist

Checklist complete

MONITOR

Ground

Company/Dispatch

MONITOR

Ground

Company

TaxiClearance

MONITOR

Captain taxiing

Takeoff Clearance

TAKEOFF


Depiction of cockpit task management in fom training13 l.jpg
Depiction of Cockpit Task Management in FOM/Training

  • Linear: task A task B task C in a fixed sequence.

  • Controllable: tasks are initiated by crew at their discretion.

  • Predictable:

    • Information available to crew when needed.

    • Individuals can communicate as needed.

  • Overall picture: flight operations are pilot- driven and under moment-to-moment control of crew.


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Review paperwork

Sign flight release

Prepare/review charts

Review Load Schedule

Review FMC

Takeoff brief

Ask for checklist

Ask for checklist

Preflight - the reality

Conduct exterior walk-around

no time, familiarity

Ramp and/or Ground?

Check charts

busy frequency

Keep trying

Double-check charts

no time, familiarity

Interruption

Interruption

Resume flow

Still refueling

Check fuel quantity

and pumps

Inoperative item

Inoperative item

Call maintenance

Confirm Mx responded

Passenger count unavailable

Confirm resolution

Request passenger count

Confirm Mx departed

Data unavailable

Confirm logbook on board

Defer programming FMC

Flight release still not picked up

Look for ops/gate agent

New PDC

Delay at gate

Re-program FMC

New flight release/PDC?

Re-set MCP

Time pressure

FO busy

Re-flow trim & other settings

Ask for checklist

Takeoff brief

Flight plan/

Departure runway change

Interruption

Resume checklist

Communicate with company

Compute new performance #s

Re-program FMS

Re-brief

CAPTAIN FIRST OFFICER

Obtain ATIS

Obtain clearance

Review paperwork

Prepare/review charts

(Passenger count)

(Load Sheet)

Program FMC

Begin checklist

Checklist complete

Begin checklist

Checklist complete

Ground/

Company/

Dispatch

Frequencies

Interphone

Cabin Attendant

procedure

Gate Agent

ACARs / OPC

procedure

procedure

checklist

CLEARANCE

checklist

ENGINE START & PUSHBACK


Slide15 l.jpg

Review paperwork

Sign flight release

Prepare/review charts

Review Load Schedule

Review FMC

Takeoff brief

Ask for checklist

Ask for checklist

Preflight - the reality

Conduct exterior walk-around

no time, familiarity

Ramp and/or Ground?

Check charts

busy frequency

Keep trying

Double-check charts

no time, familiarity

Interruption

Interruption

Resume flow

Still refueling

Check fuel quantity

and pumps

Inoperative item

Inoperative item

Call maintenance

Confirm Mx responded

Passenger count unavailable

Confirm resolution

Request passenger count

Confirm Mx departed

Data unavailable

Confirm logbook on board

Defer programming FMC

Flight release still not picked up

Look for ops/gate agent

New PDC

Delay at gate

Re-program FMC

New flight release/PDC?

Re-set MCP

Time pressure

FO busy

Re-flow trim & other settings

Ask for checklist

Takeoff brief

Flight plan/

Departure runway change

Interruption

Resume checklist

Communicate with company

Compute new performance #s

Re-program FMS

Re-brief

CAPTAIN FIRST OFFICER

Obtain ATIS

Obtain clearance

Review paperwork

Prepare/review charts

(Passenger count)

(Load Sheet)

Program FMC

Begin checklist

Checklist complete

Begin checklist

Checklist complete

Ground/

Company/

Dispatch

Frequencies

Interphone

Cabin Attendant

procedure

Gate Agent

ACARs / OPC

procedure

procedure

checklist

CLEARANCE

checklist

ENGINE START & PUSHBACK


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Taxi-out - the reality

CAPTAIN FIRST OFFICER

Ice/Snow

Defer takeoff flaps

Ramp and/or Ground?

Check charts

Keep trying

Unfamiliarity with airport

Consult charts

busy frequency

Consult charts

“Clear” ramp area

Form mental picture of route

Unfamiliarity with airport

Acknowledge clearance

Ice/Snow

Busy airport/ departure rush

Form mental picture of taxi route

De-icing

Checklist

Confirm CA’s understanding

MONITOR

airport traffic

MONITOR

aircraft position on chart

APU? Packs?

Extended taxi delay

Restart engine

Delayed engine start

Just-in or new load data

traffic, FO busy

Repeat checklists

Before/After StartChecklist

Defer checklist

Calculate & reset

Performance data

New/ Additional

taxi instructions

FMC: program/verify

Remember taxi instructions

Id taxiways and turns

Keep head up/ outside

Interruption

Inform Company (new #s, delays)

Resume checklist

Remember to follow aircraft

Identify aircraft to follow

Cross check with CA

Remember to hold short

Id correct place to hold short

busy frequency

MONITOR

Tower frequency

APU off for 2 min before off-loading

Keep trying

Change in

takeoff runway

Accept new runway?

Acknowledge clearance

Consult charts

Confirm CA’s understanding

Brief new runway

Strobes

FMC update

Change in

takeoff sequence

Shoulder harnesses

FO’s leg

Landing

lights

Repeat Checklist

Take control of aircraft while finishing checklist

Radar?

“Clear” runway

Start taxiing

Ask for checklist

Receive takeoff clearance

Ask for checklist

Line up with runway

Receive taxi clearance

Start checklist

Checklist complete

Receive takeoff clearance

Start checklist

Checklist complete

MONITOR

Ground//Dispatch

MONITOR

Ground/Company

Taxi Clearance

MONITOR

Captain taxiing

Takeoff Clearance

TAKEOFF


Line observations reveal a different story l.jpg
Line Observations Reveal a Different Story

  • Each pilot must juggle several tasks concurrently.

  • Crews are frequently interrupted.

  • External demands arrive at unpredictable moments.

  • Conditions sometimes force task elements to be performed out of normal sequence.

  • Normal line operations are quite dynamic:


Line observations reveal a different story18 l.jpg
Line Observations Reveal a Different Story

  • Normal line operations are quite dynamic:

  • Each pilot must juggle several tasks concurrently.

  • Crews are frequently interrupted.

  • External demands arrive at unpredictable moments.

  • Conditions sometimes force task elements to be performed out of normal sequence.

  • Crews must at times struggle to maintain control of the timing and sequence of their work tasks.

    • Little guidance or training.


Slide19 l.jpg

Conflict Between Theory and Reality

  • FOM is a powerful tool for safety by providing:

  • Operational reality disrupts ideal execution of procedures

  • Explicit description of how each task is to be performed

  • Standardization across crews

  • Checklists and checking procedures


So what l.jpg
So What?

  • Pilots become accustomed to concurrent task demands, interruptions, distractions and disruptions.

  • However these situations substantially increase vulnerability to error, especially omission of critical procedural steps.


Slide21 l.jpg

Skipped over checklist item - interruption - departed without lobgook

Forgot to call maintenance - distractions - depart with hatch installed backwards

Neglected to add MEL to flight release - multiple distractions, busy with preflight - discovered en route

Forgot logbook at ramp - kept deferring to check it; distractions; busy with preflight - discovered en route

Never finished review of maintenance log - interruptions - aircraft flown with “open” item in logbook

Omitted review of (SID) charts - distractions - speed violation on departure

Missed aircraft not refueled - checklist interrupted - return to airport after taking off

Skipped over checklist item - fuel pumps deferred during preflight because refueling - engine starvation in flight

Skipped over checklist item - interruptions - discover insufficient fuel after pushback

Omitted flow and checklist items - interruptions; delay; change in departure runway - discover insufficient fuel at 12000 ft

Missed checking main tank fuel quantity - distractions - departed with insufficient fuel

Forgot to request updated PDC - distractions; misled because preflight already complete - take off with expired PDC

Improper setting of pressurization during preflight flow - interruptions - cabin altitude warning light in cruise

Entered wrong weight into FMS - tail strike at takeoff

Failed to program new departure - interruptions during preflight - discover after takeoff

Omit requesting Load sheet - defer during preflight; ACARS inoperative - takeoff without load sheet

Forgot to complete preflight flow - interruption - took off with APU running

Forgot to request PDC - deferred when instructed to request by voice, not ACARS - discover after takeoff

Omitted check of circuit breakers - busy with preflight; rushing - unable to start engine after pushback

Checklist item read but not verified - interruption - pushback with emergency door slides armed

Skipped checklist item - interruption - push back with Seat Belt signs off

Read but not verify checklist item - distractions - pushback with throttles open, damage to aircraft

Sample of Preflight errors

CAPTAIN FIRST OFFICER

Review paperwork

Sign flight release

Prepare/review charts

Review FMC

Takeoff brief

Ask for checklist

Obtain ATIS

Obtain clearance

Review paperwork

Prepare/review charts

(Passenger count)

(Load Sheet)

g

Program FMC

Begin checklist

Checklist complete

Begin checklist

Checklist complete

CLEARANCE

ENGINE START & PUSHBACK


Slide22 l.jpg

Start taxiing without lobgook

Ask for checklist

Receive takeoff clearance

Ask for checklist

Line up with runway

Omitted call for flaps -rushed to clear ramp/gate area for arriving aircraft -aborted takeoff

Started taxi without clearance - trouble-shooting problem with engine start - nearly hit ground handler

Started taxi without clearance – rushed by other aircraft waiting to pull into gate; radio congestion; marshaller’s headset inoperative – query by ground controller

CA taxied without having fully understood instructions - busy looking at other aircraft on taxiway and ramp - ground controller issued warning

Started taxi without clearance - crew discussing taxi instructions - struck pushback tug

Incorrect trim setting - checklist interrupted after item had been read but not verified - aborted takeoff

Failed to start engine #-2 - distracted while discussing special operations for destination; omitted checklists - delay takeoff

Neglected to set flaps -preoccupied with new departure clearance and packs-off operation -aborted takeoff

FO failed to monitor CA - busy checking and correcting calculations of load data - taxi past hold short line

Omitted flaps - crew discussing problem with APU, delayed flaps due to snow - aborted takeoff

Flaps incorrectly set, missed noticing during checklist - crew busy with fuel problem, runway changes, programming FMC - aborted takeoff

FO failed to monitor CA – busy with flow; night taxi – taxi in wrong direction

Omitted checking reason for bleed air indicator light-busy with delayed engine start and checklists - takeoff without troubleshooting

Confuse own position on taxiway diagram - new terminal; studying NOTAMs; runway change – taxied into ditch

Fail to confirm flap position - evaluating heavy rain showers; rushed to accept takeoff clearance - aborted takeoff

FO failed to monitor CA -runway change; busy reprogramming FMC -taxied past intended taxiway

FO failed to monitor CA - busy with pre-takeoff preparations - aircraft crossed hold short line

Omitted flaps - checklist interrupted by thrust reverser light; crew busy troubleshooting - aborted takeoff

Omitted checklist - busy with delayed engine start and checklists; rushed to accept takeoff clearance - flaps not set, aborted takeoff

Misunderstood Tower instruction - new FO on IOE, CA coaching FO - taxi onto runway w/o clearance

Flaps incorrectly set - late paperwork ; runway change; programming FMC; short taxi; rushed to accept takeoff clearance- aborted takeoff

Omit above-line Checklist - running late, checklist interrupted by Tower, unexpected clearance for takeoff - abort takeoff

Omitted flaps - checklist interrupted by Tower; crew rushed to accept takeoff clearance - aborted takeoff

Sample of Taxi-out errors

CAPTAIN FIRST OFFICER

Receive taxi clearance

Start checklist

  • TAKEOFF


Why so vulnerable to these errors l.jpg
Why So Vulnerable to without lobgookThese Errors?


Why so vulnerable to these errors24 l.jpg

1) “Controlled” processing without lobgook

Corresponds to conscious attention

Slow, serial, and effortful: low capacity

Required for tasks with novel aspects

2) Automatic processing

Fast, minimal effort, high capacity

Develops with extensive practice of habitual procedure

Requires minimal conscious supervision

Why So Vulnerable to These Errors?

  • Brain has two ways of processing information to perform tasks:

  • Cockpit tasks vary from requiring mainly controlled processing to being largely automatic.



Slide26 l.jpg

JEPP serious vulnerabilities

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PREFLIGHT Flow (B737-300 - as trained)

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Forward Overhead

*

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Mode Control Panel

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Instrument

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Aft

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Vulnerabilities of automatic processing l.jpg
Vulnerabilities of Automatic Processing serious vulnerabilities

  • If procedural flow is interrupted, chain is broken.

    • Pause prevents one step from triggering the next.

  • Initiation of automatic process depends on receiving signal or noticing a cue in the cockpit environment.

    • If signal does not occur, individual is not prompted to initiate procedure.


Vulnerabilities of automatic processing28 l.jpg
Vulnerabilities of Automatic Processing serious vulnerabilities

  • If procedural flow is interrupted, chain is broken.

    • Pause prevents one step from triggering the next.

  • Initiation of automatic process depends on receiving signal or noticing a cue in the cockpit environment.

    • If signal does not occur, individual is not prompted to initiate procedure.

  • Highly practiced procedures and checklists tend to develop “look without seeing” automatic responses.

  • High workload and/or rushing prevent conscious supervision of automatic processes — exacerbates vulnerability.


Vulnerability to errors of omission can be reduced l.jpg
Vulnerability to Errors of Omission Can Be Reduced serious vulnerabilities

1) Actions airline operations and training departments can take

2) Actions individual pilots can take


Ways airlines can reduce vulnerabilities l.jpg
Ways airlines Can Reduce Vulnerabilities serious vulnerabilities

  • Analyze actual line ops write procedures to minimize opportunities for disruptions.

  • Avoid “floating” procedural items allowed to be performed at varying times.

    • Anchor critical items (e.g., setting takeoff flaps) to distinct step that cannot be forgotten (e.g., before start of taxi).


Ways airlines can reduce vulnerabilities31 l.jpg
Ways airlines Can Reduce Vulnerabilities serious vulnerabilities

  • Analyze actual line ops write procedures to minimize opportunities for disruptions.

  • Avoid “floating” procedural items allowed to be performed at varying times.

    • Anchor critical items (e.g., setting takeoff flaps) to distinct step that cannot be forgotten (e.g., pushback).

  • Analyze actual fleet “norms” for how checklists are executed and bottom-lines observed.

    • LOSA


Ways airlines can reduce vulnerabilities32 l.jpg
Ways airlines Can Reduce Vulnerabilities serious vulnerabilities

  • Analyze actual line ops write procedures to minimize opportunities for disruptions.

  • Avoid “floating” procedural items allowed to be performed at varying times.

    • Anchor critical items (e.g., setting takeoff flaps) to distinct step that cannot be forgotten (e.g., pushback).

  • Analyze actual fleet “norms” for how checklists are executed and bottom-lines observed.

    • LOSA

  • Train with realistic concurrent task demands


Ways pilots can reduce vulnerability l.jpg
Ways Pilots Can Reduce Vulnerability serious vulnerabilities

  • Being aware of vulnerability reduces threat.

    • Especially vulnerable when head-down, communicating, searching for traffic, or managing abnormals.

  • When interrupted or deferring a task:

    • Pause to encode intention to resume

    • Create conspicuous cue as reminder

  • Develop habit of deliberate execution of procedures and checklists to allow controlled supervision of habitual responses.

  • Avoid rushing.


Ways pilots can reduce vulnerability34 l.jpg
Ways Pilots Can Reduce Vulnerability serious vulnerabilities

  • Being aware of vulnerability reduces threat.

    • Especially vulnerable when head-down, communicating, searching for traffic, or managing abnormals.

  • When interrupted or deferring a task:

    • Pause to encode intention to resume

    • Create conspicuous cue as reminder

  • Develop habit of deliberate execution of procedures and checklists to allow controlled supervision of habitual responses.

  • Avoid rushing.

  • Pause at critical junctures to review.

  • Schedule / reschedule activities to minimize concurrent task demands (e.g., brief before TOD).

  • Treat monitoring as essential task (Sumwalt).


Slide35 l.jpg

For further information: serious vulnerabilities

http://human-factors.arc.nasa.gov/ihs/flightcognition/

This work is supported by NASA’s Airspace Systems Program and by the FAA (AFS-230), Dr. Eleana Edens, program manager.


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