key dismukes chief scientist for aerospace human factors human factors research and technology...
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Key DismukesChief Scientist for Aerospace Human Factors
Human Factors Research and Technology Division
NASA-Ames Research Center
ATA AQP Annual Conference
October 2003
Managing Interruptions, Distractions and Concurrent
Task Demands
Our Research Team• Immanuel Barshi• LaQuisha Beckum• Sean Belcher• Rahul Dodhia• Jon Holbrook• Kim Jobe• Tri Li• Loukia Loukopoulos• Jessica Lange Nowinski• Mark Staal
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: Flaps/slats not set to take-off position
• Dallas (1988): B-727 crashed shortly after take-off
– NTSB: Flaps/slats not set to take-off position
• Houston (1996): DC-9 landed gear-up
– NTSB: Hydraulic pump not set to high position
Were These Accidents Unique?
• Rejected take-offs– Anomalous airspeed indications (pitot heat not on)– Configuration warning (flaps or trim not set)
• Other consequences of overlooked procedural steps– Runway incursions– Broken tow-bars– Taxi into ditch– Engine flame-out– Overtemp engine– Flew wrong departure route– Go-around
• Unnecessary costs and delays• But for luck any of these incidents might have become accidents
Not according to recent ASRS reports:
– 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.
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
• “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)
• 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 depiction of task management
CAPTAINCAPTAIN FIRST OFFICER FIRST OFFICERPreflight - In theory (FOM)
Obtain ATIS
Obtain clearance
Review paperwork
Prepare/review charts
(Passenger count)
(Load Sheet)
Program FMC
Begin checklist
Checklist complete
Begin checklistChecklist complete
ENGINE START & PUSHBACK
Review paperwork
Sign flight release
Prepare/review charts
Review Load Schedule
Review FMC
Takeoff brief
Ask for checklist
•Ask for checklist
CLEARANCE
procedure
procedure
checklist
checklist
Cabin Attendant
Gate Agent
ACARs / OPC
Interphone
Ground/Company/Dispatch
Frequencies
Depiction of Cockpit Task Management in FOM/Training
• Tasks are serial and linear: task A task B task C in a fixed sequence.
CAPTAINCAPTAIN FIRST OFFICER FIRST OFFICERPreflight - In theory (FOM)
Obtain ATIS
Obtain clearance
Review paperwork
Prepare/review charts
(Passenger count)
(Load Sheet)
Program FMC
Begin checklist
Checklist complete
Begin checklistChecklist complete
ENGINE START & PUSHBACK
Review paperwork
Sign flight release
Prepare/review charts
Review Load Schedule
Review FMC
Takeoff brief
Ask for checklist
•Ask for checklist
CLEARANCE
procedure
procedure
checklist
checklist
Cabin Attendant
Gate Agent
ACARs / OPC
Interphone
Ground/Company/Dispatch
Frequencies
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.
CAPTAINCAPTAIN FIRST OFFICER FIRST OFFICERFirst Officer
Receive taxi clearance
Start checklist
Checklist complete
Receive takeoff clearance
Start checklist
Checklist complete
Captain
Start taxiing
Ask for checklist
Receive takeoff clearance
Ask for checklist
Line up with runway
Taxi Clearance
MONITORGround
Company
Takeoff Clearance
MONITOR Ground
Company/Dispatch
MONITOR Captain taxiing
TAKEOFF
Taxi-out - In theory (FOM)
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.
Obtain ATIS
Obtain clearance
Review paperwork
Prepare/review charts
(Passenger count)
(Load Sheet)
Program FMC
Begin checklist
Checklist complete
Begin checklistChecklist complete
ENGINE START & PUSHBACK
Review paperworkSign flight releasePrepare/review charts
Review Load Schedule
Review FMC
Takeoff brief
Ask for checklist
Ask for checklist
CAPTAINCAPTAIN FIRST OFFICER FIRST OFFICER
CLEARANCE
procedure
Cabin Attendant
Gate Agent
ACARs / OPC
Interphone
Ground/Company/Dispatch
Frequencies
Preflight - the reality
Interruption
FO busy
Interruption
busy frequencyKeep trying
Ask for checklist
Resume flow
Inoperative item
Time pressure
Inoperative item
Flight release still not picked up
no time, familiarity
Interruption
Delay at gate
Ramp and/or Ground?
Flight plan/Departure runway change
Conduct exterior walk-around
no time, familiarity
New PDC
Still refueling
Data unavailable
Passenger count unavailable
Call maintenance
Look for ops/gate agent
Double-check charts
Resume checklist
Confirm Mx responded
Confirm Mx departed
Confirm resolution
Confirm logbook on board
Check charts
Defer programming FMC
Communicate with companyCompute new performance #s
Re-program FMS
Re-program FMC
Check fuel quantity and pumps
Re-brief
Re-flow trim & other settings
New flight release/PDC?Re-set MCP
Takeoff brief
Request passenger count
procedure
procedure
checklist
checklist
Obtain ATIS
Obtain clearance
Review paperwork
Prepare/review charts
(Passenger count)
(Load Sheet)
Program FMC
Begin checklist
Checklist complete
Begin checklistChecklist complete
ENGINE START & PUSHBACK
Review paperworkSign flight releasePrepare/review charts
Review Load Schedule
Review FMC
Takeoff brief
Ask for checklist
Ask for checklist
CAPTAINCAPTAIN FIRST OFFICER FIRST OFFICER
CLEARANCE
procedure
Cabin Attendant
Gate Agent
ACARs / OPC
Interphone
Ground/Company/Dispatch
Frequencies
Preflight - the reality
Interruption
FO busy
Interruption
busy frequencyKeep trying
Ask for checklist
Resume flow
Inoperative item
Time pressure
Inoperative item
Flight release still not picked up
no time, familiarity
Interruption
Delay at gate
Ramp and/or Ground?
Flight plan/Departure runway change
Conduct exterior walk-around
no time, familiarity
New PDC
Still refueling
Data unavailable
Passenger count unavailable
Call maintenance
Look for ops/gate agent
Double-check charts
Resume checklist
Confirm Mx responded
Confirm Mx departed
Confirm resolution
Confirm logbook on board
Check charts
Defer programming FMC
Communicate with companyCompute new performance #s
Re-program FMS
Re-program FMC
Check fuel quantity and pumps
Re-brief
Re-flow trim & other settings
New flight release/PDC?Re-set MCP
Takeoff brief
Request passenger count
procedure
procedure
checklist
checklist
– 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.
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.
Line Observations Reveal a Different Story
• Normal line operations are quite dynamic:
• Crews must at times struggle to maintain control of the timing and sequence of their work tasks.
– Lack of guidance
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?
• 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.
ERRORS attributed to concurrent task demands, interruptions, and disruptions (ASRS reports)
Omitted review of charts - distractions - speed violation on departure Entered wrong weight in FMS - tail strike at takeoff
Omitted flow and checklist items - interruptions; delay; change in departure runway - discover insufficient fuel at 12000 ft
Skipped over checklist item - fuel pumps deferred during preflight because refueling - engine starvation in flight
Improper setting of pressurization during preflight flow - interruptions - cabin altitude warning light in cruise
Read but not verify checklist item - distractions - pushback with throttles open, damage to aircraft
Forgot logbook at ramp - kept deferring to check it; distractions; busy with preflight - discovered en route
Neglected to set flaps -preoccupied with new departure clearance and packs-off operation - aborted takeoff
FO failed to monitor CA -runway change; busy reprogramming FMC - taxied past intended taxiway
Omitted setting flap - busy with delayed engine start; rushed to accept takeoff clearance - aborted takeoff
Started taxi without clearance - crew discussing taxi instructions - struck pushback tug
FO failed to monitor CA – busy with flow; night taxi – taxi in wrong direction
Failed to verify new clearance - monitoring convective activity on radar - flew wrong heading
Omitted climb checklist - busy copying hold instructions - missed setting altimeter and overshot altitude
Failed to reset bleeds on - complex departure; multiple ATC calls; traffic - altitude warning and 0 2 mask deployment
Did not notice wind - preoccupied with annunciator light; handling radios - track deviation
Unstabilized approach - accepted runway change right before FAF; did not review charts or make callouts - tailstrike
Did not complete checklist - TCAS alerts; parallel runways in use; GPWS alert - did not extend gear for landingDid not extend gear; checklist interrupted; TCAS alerts; parallel runways in use; GPWS alert - struck ground on go-around
Forgot to reset altimeters - distracted by FA in cockpit - TCAS RA and overshot arrival fix
Failed to monitor PF - busy reprogramming FMS; weather changes - go around
Failed to verify FMC settings - PNF giving IOE to PF; multiple ATC calls; hold instruction - flew pattern in wrong direction
ATC instructions too close to turn fix - busy slowing aircraft; approach checklist; radios - failed to make published turn
Vectored too close - busy catching up with glideslope; not instructed to switch to Tower - landed without clearance
Forgot to switch to Tower at FAF - last minute runway change; busy reconfiguring aircraft - landed without clearance
PR
EF
LIG
HT
> P
US
HB
AC
K >
TA
XI >
TA
EK
OF
F >
CL
IMB
> C
RU
ISE
> D
ES
CE
ND
> L
AN
D
• Brain has two ways of processing information to perform tasks:
• Cockpit tasks vary from requiring mainly controlled processing to being largely automatic.
Why So Vulnerable to These Errors?
1) “Controlled” processing– 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
Aft Overhead
Logbook/Gear Pins
PREFLIGHT Flow (B73-300 - as trained)(checklist items are marked *)
**
*
*
**
*
**
*
***
*
*
*
*
*
Aft Electronic
Center Instrument
Mode Control Panel
CaptainInstrument
First OfficerInstrument
Forward Overhead
Forward Electronic
ControlStand
Logbook/Gear Pins
**
* *
*
* *
*
*
*
**
*
Aft Overhead
First OfficerInstrument
ATISSlakfj aslkfj890Slkdfj 3409589Slkafj f095j 019Sa;lskdfjlLskd
LOADSlakfj aslkfj890Slkdfj 3409589Slkafj f095j 019Sa;lskdfjlLskd
Slkf9 9oy99SlkdfjA;slkg eri kgj skj 9
FLIGHT PLANSlakfj aslkfj890Slkdfj 3409589Slkafj f095j 019Sa;lskdfjlLskd SFAS ALSKFJ
XLKAF ALKDFJJ;AL
PAX CT107, 22, 53 WH
FUEL107, 22, 53 WHPDC
Slakfj aslkfj890Slkdfj 3409589Slkafj f095j 019Sa;lskdfjlLskd
Slkf9 9oy99SlkdfjA;slkg eri kgj skj 9
JEPP107, 22, 5
• •x
Forward Overhead
CaptainInstrument
Center Instrument
Forward Electronic
ControlStand
Aft Electronic
Mode Control Panel
Vulnerabilities of Automatic Processing
• 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 Processing
• 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
1) Actions airline operations and training departments can take
2) Actions individual pilots can take
Ways Airlines Can Reduce 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 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).
• 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
• 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 (e.g. checklist in
throttle quadrant)
• Develop habit of deliberate execution of procedures and checklists to allow controlled supervision of habitual responses.
• Avoid rushing.
Ways Pilots Can Reduce Vulnerability• 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 (e.g. checklist in throttle
quadrant)
• 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).