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1 OPPORTUNITIES FOR AND VULNERABILITIES TO ERROR IN EVERYDAY FLIGHT OPERATIONS Loukia D. Loukopoulos Key Dismukes & Immanuel Barshi NASA Ames Research.

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Presentation on theme: "1 OPPORTUNITIES FOR AND VULNERABILITIES TO ERROR IN EVERYDAY FLIGHT OPERATIONS Loukia D. Loukopoulos Key Dismukes & Immanuel Barshi NASA Ames Research."— Presentation transcript:

1 1 OPPORTUNITIES FOR AND VULNERABILITIES TO ERROR IN EVERYDAY FLIGHT OPERATIONS Loukia D. Loukopoulos Key Dismukes & Immanuel Barshi NASA Ames Research Center, Moffett Field, CA ATA/CRM Conference MARCH 2002

2 2 Opportunities for and vulnerabilities to ERROR in everyday flight operations research-oriented, theoretical approach errors happen even to the most expert pilots - why? Presented earlier this year at FAA annual review meeting Discussed in the context of Rapid Response Team’s recommendations regarding security measures Implications? workload and distractions how will measures, both outside and inside, the cockpit affect pilots’ performance? how to avoid unintended opportunities for error? BACKGROUND

3 3 Errors in everyday flight operations pre-9/11 Opportunities for error in work environment (operational factors) A qualitative analysis of line operations field observations (N=50) two U.S. carriers, B737 contrast between training and operating environment evidence from incident reports Focus on preflight and taxi Vulnerabilities inherent in human cognitive abilities (cognitive factors) Memory and attention limitations OUTLINE

4 4 “… error in everyday flight operations” “This would never happen to us…” è PREFLIGHT: While doing Before Start Engine checklist the agent brought in a jumpseat rider and I allowed the checklist to be interrupted. Engine Start and Push Back were normal. During Taxi I noticed the seat belt switch was in the “off” position. (ASRS 400770) è PUSHBACK: CA became involved in discussion regarding taxi instructions with FO just after communication with tug attendant. Assuming that tug had departed and that previous communication was confirmation of that, CA applied power to taxi and struck the tug. (NTSB CHI95LA170) è TAXI: FO busy starting #2 engine, then doing the After Start flow and Taxi flow in time to run the Taxi checklist prior to reaching the runway. CA taxied past the Hold Short line. (ASRS 317660) è CLIMB: Climbing through 16000ft, FA called and inquired about seat belt, rough ride, thunderstorms etc. This got both pilots occupied and to forget to do the Climb checklist, thus missing the altimeter setting change to 29.92. (ASRS 394580) è CRUISE: Master caution light illuminated. Preoccupied with handling problem (duct overheat), handling radios, stowing charts. Did not notice strong wind had blown aircraft E of course. (ASRS 427840) è APPROACH: Inbound to destination airport, thunderstorms all around. Unable to comply with instructions to hold at standard hold fix, then alternate fixes due to weather. Cleared to third hold fix. Meanwhile checking fuel, weather at alternate, talking to company, making PA, and interrupted by FA. Crew neglected to finish Descent checklist which was started several times. (ASRS 402510) è LANDING: While on visual approach crew could not get the ILS to tune or display. PM was busy trying to resolve the problem. Once inside the OM, both pilots turned their attention to the landing. With no one ahead of them and the runway clear, they missed the frequency change to Tower and landed while still on Approach frequency. (ASRS 453870)

5 Note: assume through flight, no change in aircraft or flight crew, 737-300/500 Note: this will not be a discussion of weather, fatigue, or personal/emotional factors OPPORTUNITIES FOR ERROR operational factors: Preflight

6 6 SOPs typically describe Preflight flow (memory) -separate for CA and FO -may include optional checks (e.g., standby power check) Preflight checklist (card) -not intended as “read and do” list -verification of “killer items” in preceding flow Manuals discuss (to varying degrees) Documentation required Dispatch Release (acquisition, duration, amendment) Weather Airport information Alternates Flight plan changes Fuel considerations PREFLIGHT: textbook version (any airline)

7 7 PREFLIGHT checklist Oxygen Circuit Breakers IRS selectors Hydraulic pumps xxx xxx xxx Takeoff warning horn Parking Brake (10-15 items) textbook version FIRST OFFICER Obtain ATIS Obtain clearance Review paperwork Prepare/review charts Start PREFLIGHT flow Xxxxx Crew oxygen Xx xx xx x Xxx Xxx Air conditioning & Pressurization FMC Radios Xxx (20-30 items) Finish PREFLIGHT flow (Passenger count) (Load Sheet) Program FMC Start PREFLIGHT checklist PREFLIGHT checklist complete PUSHBACK CAPTAIN Review paperwork Sign flight release Prepare/review charts Start PREFLIGHT flow Xxxxx Crew oxygen xxxxxxx Fuel quantity Xxx xxxx x Xxx Xxxxxxxxxxxxxx Xxx Parking brake (20-30 items) Finish PREFLIGHT flow Review Load Schedule Takeoff brief Ask for PREFLIGHT checklist MONITOR Flight Interphone MONITOR Ground frequency Company/Dispatch frequency Cabin & cockpit temp Flight release Passenger count Load data Fuel slip Food Rest Personal Baggage Handlers Push Back Crew Jumpseat Rider(s) Cabin Crew Maintenance Crew Gate Crew Passengers

8 8 CAPTAIN Review paperwork Sign flight release Prepare/review charts Start PREFLIGHT flow Xxxxx Crew oxygen xxxxxxx Fuel quantity Xxx xxxx x Xxx Xxxxxxxxxxxxxx Xxx Parking brake (20-30 items) Finish PREFLIGHT flow Flight Release? Fuel Slip? Maintenance? Load/W&B schedule? Passenger count? Review Load Schedule Takeoff Brief Ask for PREFLIGHT checklist FIRST OFFICER Obtain ATIS Obtain clearance Review paperwork Prepare/review charts Start PREFLIGHT flow Xxxxx Crew oxygen Xx xx xx x Xxx Xxx Air conditioning & Pressurization Xxxxxxxxxxxxxx Xx FMC Radios Xxx (20-30 items) Finish PREFLIGHT flow (Passenger count) (Load Sheet) Complete programming FMC Start PREFLIGHT checklist PREFLIGHT checklist complete PREFLIGHT checklist Oxygen Circuit Breakers IRS selectors Hydraulic pumps xxx xxx xxx Takeoff warning horn Parking Brake (10-15 items) PUSHBACK real life demands (compiled observations) PDC unavailable Inoperative item Passenger count unavailable Still not picked up no time, familiarity Interruption Delay at gate Ramp and/or Ground? busy frequency Flight plan/ Departure runway change Conduct exterior walk-around no time, familiarity New PDC Still refueling FO busy/behind Load sheet unavailable Request pax count IRSs need 10 min for alignment Takeoff brief Call maintenance Look for ops/gate agent APU off for 2 min before off-loading Defer programming FMC Double-check charts Resume checklist Interruption Inoperative item Confirm Mx responded Confirm Mx departed Confirm resolution Confirm logbook on board Keep trying Check charts Communicate with company Compute new performance #s Re-program FMS Re-program FMC Check fuel quantity and pumps Ask for Checklist Re-brief Re-flow trim & other settings New flight release/PDC? Re-set MCP Resume flow Defer programming FMC

9 9 CAPTAIN Review paperwork Sign flight release Prepare/review charts Start PREFLIGHT flow Xxxxx Crew oxygen xxxxxxx Fuel quantity Xxx xxxx x Xxx Xxxxxxxxxxxxxx Xxx Parking brake (20-30 items) Finish PREFLIGHT flow Flight Release? Fuel Slip? Maintenance? Load/W&B schedule? Passenger count? Review Load Schedule Takeoff Brief Ask for PREFLIGHT checklist FIRST OFFICER Obtain ATIS Obtain clearance Review paperwork Prepare/review charts Start PREFLIGHT flow Xxxxx Crew oxygen Xx xx xx x Xxx Xxx Air conditioning & Pressurization Hydraulics FMC Radios (20-30 items) Finish PREFLIGHT flow (Passenger count) (Load Sheet) Complete programming FMC Start PREFLIGHT checklist PREFLIGHT checklist complete PREFLIGHT checklist Oxygen Circuit Breakers IRS selectors Hydraulic pumps xxx xxx xxx Takeoff warning horn Parking Brake (10-15 items) PUSHBACK errors observed (ASRS incidents) Omitted check of CBs: unable to start engine, return to gate, call Mx skipped Hydraulics item - rudder found “stiff” on flight controls check: return to gate, call mx Forgot to request updated PDC: take off without one Fuel pumps deferred because still refueling, then missed on checklist: engine starvation in flight Jumpseat rider interrupts checklist: forget to turn seat belt sign on Interruptions during preflight: failed to program new departure Missed aircraft not refueled/ insufficient fuel: discover in flight, return to airport Defer looking for logbook when noticed it was missing: depart without it Interruptions, workload, Defer notifying Mx of item noticed during walk-around: forgot to place call Acars inop, defer getting load sheet: takeoff without Interruptions, CA fails to notice FO programmed wrong flight plan Distractions, improper setting of pressurization:- cabin altitude warning light in cruise Distractions, omit throttles item: pushback with throttles open, damage to aircraft CA failed to notice FO had programmed wrong squawk: confusion on climb out Assumed other pilot had new PDC: depart without one Omitted check of circuit breakers: landing gear horn at destination, go around Omitted thorough check of CBs (flap): configuration warning horn at takeoff Omitted careful review of charts, missed speed restriction on SID- speed violation missed aircraft not refueled/ insufficient fuel: return to gate prior to taking off

10 10 Non-linear structure no predictable sequence of input events e.g., passenger count may be delivered before/after FMS has been programmed no prescribed sequence of output events e.g., conduct departure brief before/after checklist Flexible structure no one prioritization scheme is prescribed e.g., manage security concern vs. conduct flow no one scheme is applicable in every situation Non-dependency of actions step 2 does not always imply (previous ) step 1 has been accomplished e.g., can calculate performance data before starting checklist if time permits Concurrent activity simultaneous involvement of many external “agents” (experts) e.g., gate/operations agents, Ground, Maintenance, pushback crew, cabin crew, company lack of awareness about others’ responsibilities, stressors, pressures, language technically impossible not to pressure/interrupt one-another PREFLIGHT: characteristics 1 of 2

11 11 Inherent expectation that all systems are still “good to go” just landed a “good” aircraft Rhythm of ‘pushing ahead’ (even in the absence of real time pressure) reinforced by repetitive nature and philosophy of operations “blurs” the details of actions among many preflights in a given workday 63% of ‘Hurry Up’ errors originate at preflight (68% of which are joint errors) Constant interruptions and distractions defer/delay actions interleave activities, often in new, never practiced ways prioritize and juggle concurrent demands è Inadvertent deviations from SOPs or personal habits can occur and easily remain undetected by self and/or other pilot PREFLIGHT: characteristics 2 of 2

12 OPPORTUNITIES FOR ERROR operational factors: Taxi Out

13 13 FIRST OFFICER Set flaps Request taxi clearance Monitor radios Receive taxi clearance Acknowledge taxi clearance Form mental picture of taxi route Check for obstacles Perform TAXI flow Start TAXI checklist Monitor radios Monitor traffic Monitor position on airport chart TAXI checklist complete Monitor CA and aircraft movement Switch to Tower and monitor Receive clearance Acknowledge takeoff clearance BEFORE TAKEOFF flow Start checklist Checklist complete CAPTAIN Ask for flaps Ask for taxi clearance Monitor radios Receive taxi clearance Form mental picture of taxi route Check for obstacles Start taxiing Perform TAXI flow Ask for TAXI checklist Monitor radios Monitor traffic Maintain positional and situational awareness Monitor Tower Receive clearance BEFORE TAKEOFF flow Ask for checklist Line up with runway Xxx Xxx xx xxxxxx "0" Fuel Weight FMC xx Xx xx xxx xxxx Xxxx xx xxx Xx xxxxxxxxxxx Flaps Xxx xx x x xx Xxx xxx x Xxx xxxxxxx x Takeoff Briefing Xx xx xx Recall Xx x xxx Transponder xx X xx xxxx xxxxxxx TAKEOFF real life demands (compiled observations) MONITORMONITOR TAXITAXI busy frequency Delayed engine start De-icing pad Environmental conditions no time no time, familiarity short taxi, no time New/ Additional taxi instructions Interruption Ramp and/or Ground? busy frequency traffic, FO busy) no time, familiarity Change in takeoff runway Just-in or new load data Change in takeoff sequence Program, set, verify Extended taxi delay Before/After Start Checklist APU? De-icing Checklist Flaps before takeoff Landing lights Remember taxi instructions Id taxiways and turns Remember to follow aircraft Identify aircraft to follow Remember to hold short Id correct place to hold short Resume checklist Double-check charts Keep trying Ask for Checklist Brief New runway Consult charts Accept/Plan/Request new runway Keep head up/ outside Calculate & reset Performance data Inform Company (new #s, delays) Resume checklist Shoulder harness Strobes Check charts Restart engine Repeat checklists Repeat Checklist? FMC update Shoulder harness Radar? Cross check with CA Stow OPC

14 14 FIRST OFFICER Set flaps Request taxi clearance Monitor radios Receive taxi clearance Acknowledge taxi clearance Form mental picture of taxi route Check for obstacles Perform TAXI flow Start TAXI checklist Monitor radios Monitor traffic Monitor position on airport chart TAXI checklist complete Monitor CA and aircraft movement Switch to Tower and monitor Receive clearance Acknowledge takeoff clearance BEFORE TAKEOFF flow Start checklist Checklist complete CAPTAIN Ask for flaps Ask for taxi clearance Monitor radios Receive taxi clearance Form mental picture of taxi route Check for obstacles Start taxiing Perform TAXI flow Ask for TAXI checklist Monitor radios Monitor traffic Maintain positional and situational awareness Monitor Tower Receive clearance BEFORE TAKEOFF flow Ask for checklist Line up with runway Xxx Xxx xx xxxxxx "0" Fuel Weight FMC xx Xx xx xxx xxxx Xxxx xx xxx Xx xxxxxxxxxxx Flaps Xxx xx x x xx Xxx xxx x Xxx xxxxxxx x Takeoff Briefing Xx xx xx Recall Xx x xxx Transponder xx X xx xxxx xxxxxxx TAKEOFF errors observed (ASRS reports) Forget to confirm tug clear - taxi into tug Omit - overrun runway hold line Mistook clearance to other aircraft for own - taxi without clearance Confuse position - taxi into ditch CA briefed and FO set wrong flaps for aircraft type - warning horn at takeoff Busy starting engine & running delayed engine xlist and taxi xlist - runway incursion Busy running checklist - force other aircraft to go around Inadvertently hit flip-flop switch - delay APU bleed source - lost both packs in flight - enter pre-stall buffet while troubleshooting Omit or incorrectly set- warning horn at takeoff Omitted checklist and has not restarted engine #1 - delay Misunderstand tower instructions - taxi onto runway w/o clearance Preoccupied with new departure clearance and packs-off operation and omit - aborted takeoff New FO on IOE expected to hear “position and hold” - runway incursion Squawk incorrectly set during preflight - rush and fail to notice error before takeoff Fail to stop when lost - other aircraft had clearance canceled Forgot to request new flight release after 1 hr ground stop “Rushed” by aircraft pulling into same gate - omitted flaps - aborted takeoff Forget to turn ignition switch on - overtemp engine Congested frequency - delay - start taxi mistakenly assuming clearance rec’d Assumed only need to contact ramp - taxied onto active runway behind gate

15 15 Aft Overhead * * * * Forward Overhead Aft Overhead FIRST OFFICER Instrument CAPTAIN Instrument Aft Electronic Center Instrument Forward Overhead Mode Control Panel Forward Electronic Control Stand TAXI OUT CA flow FO flow CA, FO Checklist Checklist item SEATBELT AND SHOULDER HARNESS FLAPS SEATBELT AND SHOULDER HARNESS TAKEOFF BRIEFING

16 16 VULNERABILITIES TO ERRORS cognitive factors

17 17 INTERRUPTIONS & DISTRACTIONS  Interruption: event that causes (momentary) suspension of ongoing activity  Distraction: event noticed and noted but remains ‘in background’ - pilot does not suspend task but mental processing may be impaired Can be either expected or unexpected nature and timing always unpredictable Often underestimated because they are an integral part of everyday operations “there aren’t any” - “it’s all one big interruption” lack of research and training on the topic Contributing factors in 50% of air carrier major accidents of past decade Distractions: caused by non-related crew dialogue led FAA to impose ‘Sterile Cockpit Rule’ in 1981

18 18 AUTOMATICITY Highly practiced procedures become automatic (vs. controlled) absence of conscious mental effort desirable outcome of training Advantages allows fast, smooth execution of a task frees up attention resources Disadvantages no conscious control of accuracy and timing led (misled) by environmental cues Automated procedures are vulnerable to omission when they are interrupted performed outside normal sequence or context

19 19 DEFERRED TASKS 1 of 2 Forced deferment interruptions (flight attendant interrupts departure brief) environmental/operational factors (defer flaps at taxi in icing conditions) Elected deferment time pressure (defer consulting charts because pilot has fair idea of taxi route) workload reduction (defer programming FMC until final load numbers) Deferred task = intention to remember to do something in the future (prospective memory) Cannot maintain delayed intentions in focal attention must retrieve from memory when opportunity for execution arises retrieval requires noticing some cue associated with intention availability of cues and noticing cues is haphazard Thus, memory lapses are commonplace

20 20 DEFERRED TASKS 2 of 2 Remembering deferred intentions e.g., call from Ground interrupts FO conducting preflight checklist -physical cue available and practical (finger, card) e.g., new load numbers during taxi, must inform company after takeoff -physical cue not available or practical, but create artificial ‘trigger’ by tying deferred task to habitual future action (calling time off/out upon climb out) e.g., delivery of passenger count interrupts CA conducting a takeoff brief -interruption not noted, no ‘red flag’ and no cue is practical Chances of remembering increase with use of cues as reminders (ASRS 398323) During walkaround I discovered a discrepancy (open access panel) that required a call to maintenance. I finished the walkaround and intended to call maintenance… upon reentering the aircraft I allowed myself to become distracted with other problems and forgot to place the call. Aircraft would not pressurize after takeoff.

21 21 SIDETRACKING Attention drawn partly away from ongoing task e.g., in response to an interruption (to assess its importance, priority, and implications) (ASRS 425830) I discovered the logbook was missing (during Preflight flow)... I allowed myself to get sidetracked during my search for it by FA concerns in the back. FO also realized it’s absence during preflight but decided to call it later... a jumpseat rider entered and interrupted the checklist at the point where absent logbook would have been noticed. Aircraft departed the airport without the aircraft logbook. PREOCCUPATION Attention drawn exclusively away from one task at the expense of another e.g., in response to a change in conditions affecting future task (weather, traffic) anxiety (emergency, new procedure) (ASRS 455570) CA working with maintenance on APU problem. With ten minutes to go, FO discovers departure runway has changed, is reprogramming new departure and intends to review unfamiliar departure. CA pushing to start engine #1 before APU quits and to run checklists. Crew pushes back, APU fails again, so crew now has to coordinate a crossbleed start and get approval for dispatch without APU… both pilots failed to review restrictions on SID and company page, and exceed speed restriction on climb out.

22 22 “COMPLACENCY” Blanket excuse for errors: “I’ll be more careful next time,” “Fatigue” Just a label? Real reasons Appearance of normalcy -repetitive nature of flight operations -high probability of success Habit capture -virtually impossible to resist automatically performing a well-practiced, habitual task -natural to be unable to put thought and effort into performing tasks that have become automatic Tempo of flows and checklists -inadvertently “fly through” checklists and procedures Assumptions -Assume other pilot has copied taxi instructions correctly -Assume entire radio set up correctly when dialing in new frequency -Assume no obstacles because Ground is sequencing all aircraft on taxiways (look but not see) Expectations -runway used in previous x number of takeoffs or on PDC -approach typically used at this airport at this time of year -type of aircraft usually flown (ASRS 453640) FO set FMC at gate, I verified route and performance data, noted the cruise altitude he had set and checked the pressurization system. I did not crosscheck the cruise altitude with the PDC as is my usual practice. He had set everything up for FL310 while paperwork indicated FL350… I had relaxed my vigilance because the FO and I flew same aircraft in military and knew some of the same people. Contributing factors may be lower alertness due to early wake-up.

23 23 TRIGGERS Many actions rely on natural ‘triggers’ environmental cues (reset altimeter at specific altitude) preceding actions (brief approach after receiving ATIS) others’ actions (start checklist when PF asks for it) Certain events disrupt presence of ‘triggers’, or remove them entirely environmental factors (pushing back on one engine) addition/deletion of task (security brief) abnormal indication/situation (respond to FA’s concerns about a cabin situation) pressure (receive pushback clearance and proceed to start without ensuring cabin ready) … In the meantime, events continue to occur in their normal sequence Difficult to notice absence or disruption of triggers Pilots devise their own ‘triggering’ strategies finish After Start checklist, put hand on Flap lever (ASRS 379824) At completion of pushback I set the parking brake, completed engine start and verbally released the pushback crew - they acknowledged. We completed the After Start checklist, received taxi clearance, and began to taxi. Just as we moved the aircraft, they ran into my visual area and signaled an emergency stop. I then realized that I had not received nor responded to an “all clear” signal. The problem occurred because an inordinately long time elapsed after verbally releasing the ground crew and when we normally receive a “clear” signal… during that time frame, which was 3 times longer than normal, I completed all checklists, got clearance, and forgot that I had not been given the “thumbs up’ signal.

24 24 Opportunities for error in work environment  Vulnerabilities inherent in human cognitive abilities  Illustration using an NTSB incident report Errors happen even to the most expert pilots - WHY?

25 25 PREFLIGHT case study Distraction Good technique: resume checklist prior to interruption Interruption Distraction Interruptions Interruption Rushing through checklist: 2 challenges together Interruption Omits check(?) and response Leads to step normally later in checklist Preoccupation Interruption Sidetrack: brings maintenance issue back to foreground Distraction Leads to step normally later (“fuel panel” never responded to,7 other challenges never mentioned) Automaticity: accept double challenge; 1 response to 2 challenges Automaticity, habit capture Distraction Expectation, assumption Distraction Defer starting preflight flow NYC01LA077 Throttle check Throttles not fully closed

26 26 OPPORTUNITIES FOR AND VULNERABILITIES TO ERROR IN EVERYDAY FLIGHT OPERATIONS ATA/CRM Conference MARCH 2002 Loukia D. Loukopoulos Human Factors Division, MS 262-4 NASA Ames Research Center Moffett Field, CA 94035 650-604-2843 llouko@mail.arc.nasa.gov


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