Post on 01-Jan-2016
THE CHALLENGE OF ROUTINE FLIGHT OPERATIONS
Loukia D. LoukopoulosR. Key DismukesImmanuel Barshi
NASA Ames Research CenterMoffett Field, CA
U.S.A.
22nd European Annual Conference on Human Decision Making and Control2-4 June, 2003
Linköping University, Sweden
2
MOTIVATION
Complex operating environment (cockpit)• pilots• number of tasks• timing of tasks
FlowsChecklists
ProceduresPhase of flight structure
? • INTERACTIONS among tasks and operators
• Characterize nature of interaction• Characterize demand such interaction places on cognition• Errors?• Solutions?
3
METHODSComprehensive approach
• Cockpit jumpseat observation of routine flights (~100 hours) • Boeing 737; 2+ air carriers; 1- 4 hours per leg; U.S.-wide• notes; informal interviews
• Training (initial, transition/upgrade)• Written materials (manufacturer and carrier FOMs)• Incident reports (ASRS, NTSB)
Qualitative analysis applies to all phases of flight * use Preflight for illustration (Taxi Out in paper) *
4
real
Idealmanufacturer perspective (manuals)
ideal
assumed
PERSPECTIVES - layering
Assumedcarrier perspective (FOMs, training)
Errors pilot perspective (ASRS reports)
Real observer perspective (jumpseating)
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PHASE OF FLIGHT - ideal (manufacturer)
Goals:• Prepare aircraft for next phase of flight
Considerations:• Safety• Design specifications
Perspective:• Detached from operational reality
Preflight - ideal (manufacturer)
Begin checklist
Checklist complete
Begin checklist
Checklist complete
ENGINE START & PUSHBACK
Ask for checklist
Ask for checklist
CAPTAINCAPTAIN FIRST OFFICER FIRST OFFICER
CLEARANCE
checklist
checklist
procedure
procedure
9
PHASE OF FLIGHT - assumed (carrier)
Goals:• Prepare aircraft for next phase of flight
Considerations:• Safety• Design specifications
+ Additional constraints + Priorities (fuel, time, passenger comfort)+ Type of operations (short/long-haul, turn-arounds,
regions/airports, fleet)+ Philosophy (safety, efficiency)+ New technologies (ACARS, on-board performance computer)+ Coordination with agents (dispatch, maintenance, company)
Perspective:• Suggestive of operational reality
Preflight - assumed (carrier)
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
CAPTAINCAPTAIN FIRST OFFICER FIRST OFFICER
CLEARANCE
procedure
procedure
checklist
checklist
Cabin Attendant
Gate Agent
ACARs / OPC
Interphone
Ground/Company/Dispatch
Frequencies
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1
2
3
4
A
B
C
D
PHASE OF FLIGHT - assumed (carrier)
BOEINGFinal Flight Deck Preparation (down to the line)
Challenge ResponseFlight deck preparation CompletedLight test CheckedOxygen and interphone CheckedYaw damper OnNavigation transfer and display switches AUTO & NORMALFuel _ lbs. & pumps OnGalley power OnEmergency exit lights ArmedPassenger signs SetWindow heat OnHydraulics NormalAir conditioning and pressurization _ pack(s), bleeds On, setAutopilots DisengagedInstruments Cross-checkedAutobrake RTOSpeed brake Down detentParking brake SetStabilizer trim cutout switches NormalWheel well fire warning CheckedRadios, radar, transponder, and HUD SetRudder and aileron trim Free & zeroPapers AboardFMC/CDU SetN1 and IAS bugs set
BOEINGFinal Flight Deck Preparation (below the line)
Challenge ResponseDoors ClosedFlight deck windows LockedAir conditioning pack switches OffAnti collision light switch On
+ x
- y
if z then C’
CAPTAINCAPTAIN FIRST OFFICER FIRST OFFICER
INFORMATION
EVENT
PILOT-driven operation
Activities are:• Linear: task B always follows task A, in this sequence • Controllable: tasks initiated by pilot, independently
• Predictable: information available when needed communication possible when necessary
monitor
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COGNITIVE ASPECTS - (carrier perspective)
Activities are:
Linear, Controllable, Predictable
Are these good outcomes?
√ Standardization (between pilots/crews)
√ Accurate, efficient, “safe” performance
Training and repeated Practice on the line build:
• Automaticity (reduced cognitive requirements)
• Habit (speed, accuracy)
• Reliance on triggers (memory aid)
• (task 2 triggers task 3)
• (Captain’s request for the checklist cues FO to begin checklist)
PREFLIGHT Captain’s ASRS Report (edited)
“At this point the scheduled flight is about 1.5 hours behind schedule. Prior to our arrival we experienced some problems with the autopilot system and had to call maintenance for approval to continue operations in accordance with the MEL. I discussed this with FO who contacted company, and called for fuel. I went inside the terminal to call Maintenance.
I headed back to the aircraft… the passengers were boarding and the FO was at the back of the aircraft. As we both got into the cockpit, the FO started the Load Manifest and I completed the write-up in the logbook. I then started the Before Start checks but was distracted by the events of a final baggage and passenger count. There were other flights on the ground and I had seen the fuel truck moving about.
With the passengers and bags onboard and the doors closed, the engines were started and a call for taxi made. The main runway has been closed for construction and we were given a shorter runway. After a look at the takeoff data, winds, and weights, we advised Tower we needed a different runway. When cleared for takeoff we had not completed the checklist so we advised Tower we needed some more time. Once completed, we departed with a climb in VFR conditions. After climbing through 12000 ft I was scanning the instruments and noticed the fuel quantity only showed 980 lbs.
The series of events from the first landing until takeoff was about 15 minutes. I feel there were many distractions that interrupted the flows on the preflight check and items were skipped.”
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
CAPTAINCAPTAIN FIRST OFFICER FIRST OFFICER
CLEARANCE
PREFLIGHT errors attributed to “distractions” (incident reports)
Omitted review of (SID) charts - distractions - speed violation on departure
Failed to program new departure - interruptions during preflight - discover after takeoff
Forgot to request updated PDC - distractions; misled because preflight already complete - take off with expired PDC
Skipped checklist item - interruption - push back with Seat Belt signs off
Omit requesting Load sheet - defer during preflight; ACARS inoperative - takeoff without load sheet
Omitted check of circuit breakers - busy with preflight; rushing - unable to start engine after pushback
Never finished review of maintenance log - interruptions - aircraft flown with “open” item in logbook
Checklist item read but not verified - interruption - pushback with emergency door slides armed
Entered wrong weight into FMS - tail strike at takeoff
Missed checking main tank fuel quantity - distractions - departed with insufficient fuel
Neglected to add MEL to flight release - multiple distractions, busy with preflight - discovered en route
Skipped over checklist item - interruption - departed without lobgook
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
Forgot to call maintenance - distractions - depart with hatch installed backwards
Forgot to request PDC - deferred when instructed to request by voice, not ACARS - discover after takeoff
Forgot to complete preflight flow - interruption - took off with APU running
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
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
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•Wide range of outcomes
•Large number of omissions not caught by later checklist
•Consequences spill into all phases
•Potential for accidents
•$$$ time, fuel, ramp mishaps, taxiway/runway incursions, rejected takeoffs
ERRORS
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
CAPTAINCAPTAIN FIRST OFFICER FIRST OFFICER
CLEARANCE
procedure
procedure
checklist
checklist
Cabin Attendant
Gate Agent
ACARs / OPC
Interphone
Ground/Company/Dispatch
Frequencies
Preflight - real (compiled observations)
procedure
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
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1
2
3
4
A
B
C
D
PHASE OF FLIGHT - real
*monitor z
z1z2z3z4z5
Activities are:
Linear:
x y
z
*Wait
CAPTAINCAPTAIN FIRST OFFICER FIRST OFFICER
BOEINGFinal Flight Deck Preparation (down to the line)
Challenge ResponseFlight deck preparation CompletedLight test CheckedOxygen and interphone CheckedYaw damper OnNavigation transfer and display switches AUTO & NORMALFuel _ lbs. & pumps OnGalley power OnEmergency exit lights ArmedPassenger signs SetWindow heat OnHydraulics NormalAir conditioning and pressurization _ pack(s), bleeds On, setAutopilots DisengagedInstruments Cross-checkedAutobrake RTOSpeed brake Down detentParking brake SetStabilizer trim cutout switches NormalWheel well fire warning CheckedRadios, radar, transponder, and HUD SetRudder and aileron trim Free & zeroPapers AboardFMC/CDU SetN1 and IAS bugs set
BOEINGFinal Flight Deck Preparation (below the line)
Challenge ResponseDoors ClosedFlight deck windows LockedAir conditioning pack switches OffAnti collision light switch On
CLEARANCE
PILOT-driven
Dynamic
Inter-dependency of tasks and operators
Unpredictable interactions (nature and timing)
ENVIRONMENT-driven operation
Predictable:
Controllable:
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• Multiple interactions among operators and tasks
(within, outside cockpit)• Pervasive and unnoticed: most often dealt with successfully• Training
• does not adequately reflect reality • does not adequately prepare pilots for line flying (learn on the job)
• Interactions are not well characterized• Effects (challenges) are underestimated• Vulnerability to errors are not appreciated
• Neither is the potential for such errors to lead to accidents
Results
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• Characterize nature of interaction• Characterize demand such interaction places on cognition
So what are these Interactions?
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Interactions 1
Pilots are constantly being interrupted
Interruptions demand attention (to note and assess)
and action (to resolve)
Observations from the jumpseat
• The first officer monitored the Ground frequency throughout the preflight preparations. A call with departure information interrupted her as she was setting the pressurization panel (a prescribed step in the procedure). She continued “dialing” the destination altitude before interrupting the procedure to acknowledge the call from Ground. She then copied the memorized information on the load sheet before resuming the interrupted procedure.
23
Interactions 2
Pilots must often perform >1 tasks concurrently•Some combinations are often practiced together•Others combinations are new & must be carried out on the spot
From the jumpseat…
• The captain monitored the cockpit interphone while performing his preflight duties and expecting to be contacted by the push back crew. A flight attendant notified him of a potential issue with a passenger. He relied on the cabin crew to resolve it with the help of the Gate Agent and continued with the preflight procedure. At the same time, he continued to monitor the conversation taking place right outside the cockpit door, intending to intervene if necessary.
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Interactions 3
Pilots do not/cannot always initiate actions• Circumstances may not be right for an action• Information/tool/agent may not be available
From the jumpseat…
• CA reached the point on his preflight procedure calling for verification of sufficient fuel on board. He looked around for a fuel slip but quickly realized that it had not yet been brought to the cockpit - that implied that refueling was still underway. He formed the intention to return to the fuel quantity action item later and proceeded on with the remaining procedural steps.
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Challenge 1
In order to respond to the multiple, complex, and unpredictable interactions, a pilot must …
Suspend/Defer activities
i.e., must resume the suspended task … or
start the deferred task at a later time
The first officer monitored the Ground frequency throughout the preflight preparations. A call with departure information interrupted her as she was setting the pressurization panel (a prescribed step in the procedure). She continued “dialing” the destination altitude before interrupting the procedure to acknowledge the call from Ground. She then copied the memorized information on the load sheet before resuming the interrupted procedure.
requires• forming an intention (acknowledge call, copy information)
• maintaining the intention (while continuing primary activity)
• remembering what/when suspended/deferred (call from Ground)
• noticing when it is time to resume/start intended task (once finished with primary activity)
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Challenge 2In order to respond to the multiple, complex, and
unpredictable interactions, a pilot must …
Interleave activities
i.e., combine habitual or novel activities …
in previously-encountered or new ways
requires• shift attention between activities• remembering the activities • remembering to check on the progress of each activity• deciding when/how often to check progress
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Research Implications
• Events in the environment continue to flow in habitual sequence and with their usual timing
• “Triggers” for sequence of activities are disrupted or even lost altogether
Memory
esp. Prospective Memory (for intentions)
Attention
continuous sampling of environmental stimuli monitoring (essentially a continuous PM demand)
Pilots are vulnerable to errors under such circumstances because…
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Practical Implications (carriers)
• Acknowledge pilot fallibility• Examine procedures and checklists, incident (ASAP)
reports• Blank-slate approach
• source• nature• timing of challenges in everyday operations
• Design robust procedures• warning signs (red flags)• triggers for items at risk (tie critical functions to fixed
reference points)
• traps (strict decision criteria not to cross unless all expected activities fulfilled)
• Develop (better) guidance for Monitoring
Cognitive Performance in Aviation Training and Operationshttp://human-factors.arc.nasa.gov/flightcognition/
PANEL OFF light --- Extinguished Set panel --- As desired WARNING: Do not key HF radio while airplane is being fueled. Injury to personnel or fire may result
FLIGHT ALTITUDE indicator --- cruise altitudeLANDING ALTITUDE indicator --- destination field elevationPressurization mode selector --- AUTO AUTOMATIC FAIL light --- Extinguished
PreflightB737 Ops Manual
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TAXI - ideal (manufacturer)
Goals:• bring aircraft to departure runway• configure it for takeoff (next phase of flight)
Considerations:• safe operation• within performance limitations and design specifications
Receive taxi clearance
Start checklist
Checklist complete
Receive takeoff clearance
Start checklist
Checklist complete
Receive taxi clearance
Start taxiing
Ask for checklist
Receive takeoff clearance
Ask for checklist
Line up with runway
Taxi - ideal (manufacturer)
TAKEOFF
CAPTAINCAPTAIN FIRST OFFICER FIRST OFFICER
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PHASE OF FLIGHT - ideal (manufacturer)
A
B
C
D
1
2
3
4
CAPTAINCAPTAIN FIRST OFFICER FIRST OFFICER
Activities are:
• Linear: task B always follows task A, in this sequence
• Controllable: tasks initiated by pilot, independently
CLEARANCE
• Predictable: information available when needed communication possible when necessary
36
TAXI - assumed (carrier)
Goals:• bring aircraft to departure runway• configure it for takeoff (next phase of flight)
Considerations:• Safe operation• Within performance limitations and design specifications
+ Carrier (additional) considerations + Priorities (fuel, time, passenger comfort)+ Type of operations (short/long-haul, turn-arounds,
regions/airports, fleet)+ Philosophy (safety, efficiency)+ Technologies on-board (ACARS, laptop)+ Coordination with agents (Ground, Tower, dispatch, other
aircraft)
Receive taxi clearance
Start checklist
Checklist complete
Receive takeoff clearance
Start checklist
Checklist complete
Start taxiing
Ask for checklist
Receive takeoff clearance
Ask for checklist
Line up with runway
Taxi - assumed (carrier)
Taxi Clearance
MONITORGround
Company
Takeoff Clearance
MONITOR Ground
Company/Dispatch
MONITOR Captain taxiing
TAKEOFF
CAPTAINCAPTAIN FIRST OFFICER FIRST OFFICER
TAXI-OUT -real Captain’s ASRS Report # 425357 (edited)
“The aircraft we had for this flight had an inoperative fuel gauge, and an inoperative APU… DFW was in the midst of a departure rush. Since we had to do a crossbleed start, we did not do the After Start checklist immediately...
There were many distractions leading up to this incident which should have been warning signals.
There was a time pressure element, we were running late and knew we had an airplane change in a short ground time in Denver before our next flight.
The APU and the necessity for the crossbleed start precluded the normal flow of calling for flaps and the before takeoff checklist as we taxi from the gate.
I was distracted by calling for taxi, so ground control knew we were ready to move.
Immediately after that call we were given a complicated taxi route with hold short and follow instructions and we were concentrating on finding the taxiways in the dark…”
We got clearance to taxi and requested a spot to do the start. We stopped ... as instructed and completed the start. As we were finishing, ground control was giving instructions to aircraft taxiing mentioning us in reference. We heard this, completed the after start checklist, and told ground we were ready to taxi.
We were given instructions to hold short of taxiway WJ, give way to opposite direction traffic, then proceed N to taxiway Z to taxiway HY to taxiway Y across the bridge to taxiway J to taxiway EF for takeoff on runway 17R, follow an ACR aircraft. With all the above, taxiing to a new and unfamiliar runway (for this crew) in the dark, we didn't complete the before takeoff checklist. As we were cleared for takeoff and applied power, the takeoff warning horn sounded and we immediately realized that the flaps had not been extended for takeoff.
Receive taxi clearance
Start checklist
Checklist complete
Receive takeoff clearance
Start checklist
Checklist complete
TAKEOFF
Start taxiing
Ask for checklist
Receive takeoff clearance
Ask for checklist
Line up with runway
TAXI-OUT errors attributed to “distractions” (ASRS incidents)
Failed to start engine #-2 - distracted while discussing special operations for destination; omitted checklists - delay takeoff
Omitted call for flaps -rushed to clear ramp/gate area for arriving aircraft -aborted takeoff
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
Omit above-line Checklist - running late, checklist interrupted by Tower, unexpected clearance for takeoff - abort takeoff
FO failed to monitor CA - busy checking and correcting calculations of load data - taxi past hold short line
FO failed to monitor CA – busy with flow; night taxi – taxi in wrong direction
CA taxied without having fully understood instructions - busy looking at other aircraft on taxiway and ramp - ground controller issued warning
FO failed to monitor CA - busy with pre-takeoff preparations - aircraft crossed hold short line
Flaps incorrectly set - late paperwork ; runway change; programming FMC; short taxi; rushed to accept takeoff clearance- aborted takeoff
Started taxi without clearance - trouble-shooting problem with engine start - nearly hit ground handler
Started taxi without clearance - crew discussing taxi instructions - struck pushback tug
Omitted flaps - checklist interrupted by Tower; crew rushed to accept takeoff clearance - aborted takeoff
Omitted flaps - checklist interrupted by thrust reverser light; crew busy troubleshooting - aborted takeoff
Misunderstood Tower instruction - new FO on IOE, CA coaching FO - taxi onto runway w/o clearance
Confuse own position on taxiway diagram - new terminal; studying NOTAMs; runway change – taxied into ditch
Started taxi without clearance – rushed by other aircraft waiting to pull into gate; radio congestion; marshaller’s headset inoperative – query by ground controller
Omitted checking reason for bleed air indicator light-busy with delayed engine start and checklists - takeoff without troubleshooting
Fail to confirm flap position - evaluating heavy rain showers; rushed to accept takeoff clearance - aborted takeoff
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 checklist - busy with delayed engine start and checklists; rushed to accept takeoff clearance - flaps not set, aborted takeoff
Incorrect trim setting - checklist interrupted after item had been read but not verified - aborted takeoff
CAPTAINCAPTAIN FIRST OFFICER FIRST OFFICER
TAKEOFF
Receive taxi clearance
Start checklist
Checklist complete
Receive takeoff clearance
Start checklist
Checklist complete
Start taxiing
Ask for checklist
Receive takeoff clearance
Ask for checklist
Line up with runway
Taxi Clearance
MONITORGround/Company
Takeoff Clearance
MONITOR Captain taxiing
Taxi-out - real (compiled observations)MONITOR
Ground//Dispatch
Acknowledge clearance
Form mental picture of taxi routeConfirm CA’s understanding
Remember taxi instructionsId taxiways and turns
Remember to follow aircraftIdentify aircraft to follow
Remember to hold shortId correct place to hold short
New/ Additional taxi instructions
Unfamiliarity with airport
CAPTAINCAPTAIN FIRST OFFICER FIRST OFFICER
Strobes
LandinglightsRadar?
“Clear” ramp areaConsult charts
Shoulder harnesses
FMC update
“Clear” runway
APU off for 2 min before off-loading
Keep head up/ outside
Calculate & reset Performance data
Inform Company (new #s, delays)
Cross check with CA
FMC: program/verify
Keep trying
MONITORaircraft position on chart
MONITORTower frequency
MONITOR airport traffic
Acknowledge clearanceConfirm CA’s understanding
Defer takeoff flaps
Defer checklist
Restart engineRepeat checklists
Brief new runway
Check charts
De-icing Checklist
APU? Packs?
Repeat Checklist Take control of aircraft while finishing checklist
Accept new runway?
Consult charts
Keep trying
Consult charts
Before/After StartChecklist
Form mental picture of route
Resume checklist
Just-in or new load data
busy frequency
Interruption
Ice/Snow
Ice/Snow
traffic, FO busy
Change in takeoff runway
Change in takeoff sequence FO’s leg
Ramp and/or Ground?
Extended taxi delay
Busy airport/ departure rush
Unfamiliarity with airport
Delayed engine start
busy frequency
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components
MOTIVATION: study complex operating environment as an entity
nature (constraints)
operator(s)
external agents
tasks
hardware/software
• Characterize nature of interactions• Characterize their effects on the (routine flight) operation• Develop or help guide development of tools/solutions to mitigate errors
cognitive abilities
tools (solutions)
flows checklists
procedures (SOP)
phase of flight structure
(mfgr/engineers) (design - $$$ -
technology)
interactions ?
?
number timing