Presentation on theme: "Managing Interruptions, Distractions and Concurrent Task Demands"— Presentation transcript:
1 Managing Interruptions, Distractions and Concurrent Task Demands Key DismukesChief Scientist for Aerospace Human FactorsHuman Factors Research and Technology DivisionNASA-Ames Research CenterATA AQP Annual ConferenceOctober 2003
2 Our Research Team Immanuel Barshi LaQuisha Beckum Sean Belcher Rahul DodhiaJon HolbrookKim JobeTri LiLoukia LoukopoulosJessica Lange NowinskiMark Staal
3 Consequences of Inadvertent Procedural Omissions LaGuardia (1994): MD-82 ran off runway end after high-speed rejected take-offNTSB: Anomalous airspeed indications caused by failure to turn on pitot heatDetroit (1987): DC-9 crashed shortly after take-offNTSB: Flaps/slats not set to take-off positionDallas (1988): B-727 crashed shortly after take-offNTSB: Flaps/slats not set to take-off positionHouston (1996): DC-9 landed gear-upNTSB: Hydraulic pump not set to high positionIn 1994 an MD-82 ran off the runway at LaGuardia after the crew rejected the takeoff at high-speed because of anomalous airspeed indications. The NTSB determined that the anomalous indications occurred because the crew failed to turn on the pitot heat. Two major airline accidents occurred in the 80’s when the crews failed to extend flaps/slats before takeoff. More recently a DC-9 landed gear-up in Houston. The gear failed to extend because the hydraulic pump was not set to the high position. Obviously multiple factors were at play in each of these accidents, but a central aspect of each accident was the failure of the crew to execute a simple procedural step that they had performed many thousands of times in previous flights.Were the oversights by the crews of these accident flights unique anomalies? What do you think?
4 Were These Accidents Unique? Not according to recent ASRS reports:Rejected take-offsAnomalous airspeed indications (pitot heat not on)Configuration warning (flaps or trim not set)Other consequences of overlooked procedural stepsRunway incursionsBroken tow-barsTaxi into ditchEngine flame-outOvertemp engineFlew wrong departure routeGo-aroundUnnecessary costs and delaysBut for luck any of these incidents might have become accidentsDeparted with inadequate fuelAPU left running during takeoff -- firePacks failed in cruiseTook off without PDCDeviated from speed or altitude restrictionNose gear failed to retractetc.Not according to ASRS data. Within the last 12 months a crew reported to ASRS rejecting takeoff at 90 knots because of anomalous airspeed indications which they later discovered to have been caused by their failure to turn on the pitot heat. Fortunately this crew aborted the takeoff at a slower speed than the MD-82 at LaGuardia and no damage was done except to their pride. Each year pilots report to ASRS that they reject takeoffs when they receive configuration warning horns revealing that they forgot to set flaps or forgot to set trim to takeoff position.ASRS data reveals a long list of other consequences of inadvertently omitted procedural steps, ranging from runway incursions to broken tow-bars to engine flame-outs. Although these consequences occur in all phases of flight, a disproportionate number of them were caused by errors of omission that occurred before takeoff. Obviously these incidents cost money and cause substantial delays. And it is sobering to think that but for good luck some of these incidents might have become fatal accidents.
5 Why?Why would experienced crews forget a procedural step they normally perform day in and day out?Why fail to catch omissions with checklists?Why would highly experienced airline crews forget to perform a procedural step that they have executed thousands of times, day in and day out, without difficulty? And why did they fail to catch these omissions when they ran the checklists associated with the procedures?
6 An Ongoing NASA Research Project “Carelessness” not an adequate explanationCrews 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 performedDemands tasks place on human cognitive processesOperating environmentNorms for actual line operationsThese questions are at the heart of a large project that my research group at NASA Ames Research Center has been working on for several years now. To foreshadow my talk, I can tell you that “carelessness” is not an adequate explanation. Accident investigators, airline managers, and even pilots themselves tend to assume that omitting a procedural step is evidence of simple carelessness or lack of vigilance, but substantial research on human performance reveals that skilled and conscientious pilots not infrequently make these kinds of error of omission. Furthermore this is true of experts in every domain of skilled performance, from medical doctors to mountain climbers. Obviously, skill and vigilance and conscientiousness are essential for safety, they are not by themselves sufficient to prevent error.Early in our project we discovered that airline crews are especially vulnerable to inadvertently omitting procedural steps when interrupted, when preoccupied with one of several concurrent tasks, or when forced to defer an action out of its normal sequence in the procedure. More broadly, human factors scientists in recent years have come to recognize that vulnerability to error among experienced pilots is to a large degree driven by the specific characteristics of the tasks performed, by the demands those tasks place on human cognitive processes, by the demands of the operating environment, and by the norms for actual line operations. By norms I mean what actually takes place in day to day normal operations, as opposed to the ideal expressed in flight operating manuals.I cannot emphasize strongly enough this point about the nature of vulnerability to error. If we persist in thinking that only inadequate pilots make errors, then we will never be able to reduce vulnerability to error.
7 Jumpseat Observation Study (Loukopoulos, Dismukes, & Barshi, 2003) Reviewed FOMs, observed line operations, analyzed ASRS, NTSB reportsAll phases of flight — focus today on preflight and taxiDiscovered disconnect between FOM/training and actual line operations in depiction of task managementGiven this perspective, it is crucial to collect data from actual line operations to characterize the nature of cockpit task demands and how those demands play out over time so we can analyze the challenges these demands place on human cognitive processes. Lt Commander Loukia Loukopoulos is a Navy officer who has been working with my group for the past three years in a study in collaboration with two major airlines. Loukia has reviewed flight operating manuals, sat in on ground training, and conducted a large number of jumpseat observations in 737 fleets. We have also analyzed a large number of accident and incident reports involving challenges in concurrent task management. Our study includes all phases of flight, but in the interests of time I will focus today mainly on airport surface operations. As you will see, we have discovered an interesting disconnect between the way that management of tasks is depicted in FOMs and training and the way that real-world demands for managing multiple tasks drive actual line operations.
8 Preflight - In theory (FOM) ENGINE START & PUSHBACK CAPTAIN FIRST OFFICERReview paperworkSign flight releasePrepare/review chartsReview Load ScheduleReview FMCTakeoff briefAsk for checklistObtain ATISObtain clearanceReview paperworkPrepare/review charts(Passenger count)(Load Sheet)Program FMCBegin checklistChecklist completeCabin AttendantGate AgentACARs / OPCInterphoneGround/Company/DispatchFrequenciesprocedureprocedureIn this slide we created a time-and-action graphic of each pilot’s tasks during preflight, as described in a typical FOM. We have made similar graphic depictions of each phase of flight but in the interests of time I will just show you the graphics of preflight and taxi-out. The time axis runs from top to bottom; the captain’s tasks are listed in sequence in which they are performed on the left side, and the first officer’s tasks are shown on the right. I deliberately made the fine print of the procedural flows and the checklists too small for you to read--all I want to convey is how the tasks are organized without getting into too much detail. Checklists, which require both pilots, are shown in the center, and horizontal arrows denote points at which the two pilots must communicate or coordinate an activity. Note that there is some interaction with outside parties, such as gate agents, but this interaction is limited and seems to integrate easily with the flow of the pilots’ tasks.checklistCLEARANCEchecklistENGINE START & PUSHBACK
9 Depiction of Cockpit Task Management in FOM/Training Tasks are serial and linear: task A task B task C in a fixed sequence.
10 Preflight - In theory (FOM) ENGINE START & PUSHBACK CAPTAIN FIRST OFFICERReview paperworkSign flight releasePrepare/review chartsReview Load ScheduleReview FMCTakeoff briefAsk for checklistObtain ATISObtain clearanceReview paperworkPrepare/review charts(Passenger count)(Load Sheet)Program FMCBegin checklistChecklist completeCabin AttendantGate AgentACARs / OPCInterphoneGround/Company/DispatchFrequenciesprocedureprocedureSo, for example, The first officer copies ATIS, obtains a clearance, and then reviews paperwork and charts and proceeds step by step on down the line. The FOMs make little mention of any possibility of any deviation from this ordered sequence and the whole process appears to be serial—there is no mention of anything happening in parallel.checklistCLEARANCEchecklistENGINE START & PUSHBACK
11 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.
12 Taxi-out - In theory (FOM) CAPTAIN FIRST OFFICERCaptainStart taxiingAsk for checklistReceive takeoff clearanceLine up with runwayFirst OfficerReceive taxi clearanceStart checklistChecklist completeReceive takeoff clearanceMONITORGroundCompanyMONITORGroundCompany/DispatchTaxi ClearanceMONITORCaptain taxiingTakeoff ClearanceThis assumption of predictability is illustrated in this time-action graphic of taxi-out as portrayed in the FOM. In this slide, after the crew has had a chance to complete their procedural flows and all the items on the above the line portion of the Before Takeoff checklist, they receive their take-off clearance. They then have time to complete the below the line procedures and checklist--and only after all this is done do they taxi out to the runway.TAKEOFF
13 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.So, the overall picture we would get if we did nothing but read the FOM is that flight operations are pilot driven and under moment-to-moment control of the crew.
14 Preflight - the reality Review paperworkSign flight releasePrepare/review chartsReview Load ScheduleReview FMCTakeoff briefAsk for checklistPreflight - the realityCAPTAIN FIRST OFFICERObtain ATISObtain clearanceReview paperworkPrepare/review charts(Passenger count)(Load Sheet)Program FMCBegin checklistChecklist completeInoperative itemTime pressureFlight release still not picked upno time, familiarityInterruptionDelay at gateRamp and/or Ground?Flight plan/Departure runway changeConduct exterior walk-aroundNew PDCStill refuelingData unavailablePassenger count unavailableCall maintenanceLook for ops/gate agentDouble-check chartsResume checklistConfirm Mx respondedConfirm Mx departedConfirm resolutionConfirm logbook on boardCheck chartsDefer programming FMCCommunicate with companyCompute new performance #sRe-program FMSRe-program FMCCheck fuel quantityand pumpsRe-briefRe-flow trim & other settingsNew flight release/PDC?Re-set MCPTakeoff briefRequest passenger countGround/Company/DispatchFrequenciesInterphoneInterruptionFO busybusy frequencyKeep tryingAsk for checklistResume flowCabin AttendantprocedureGate AgentACARs / OPCprocedureprocedureOur jumpseat observations reveal a rather different, far more complex story. We expected real-world operational demands to add some complexity to the straight-forward ideal representation. We did not anticipate the extent to which interactions among human agents outside the cockpit and variations in operational circumstances force major deviations from the linear, predictable sequence depicted by the FOM.In this slide we have superimposed some of the many events not described in the FOM that impose demands on the crew. These demands are depicted in dark-colored boxes. For example, the final passenger count may not be available, there may be a maintenance problem, or the crew may receive a new PDC—each of these events requires additional activity by the crew. This additional activity is depicted in light-colored boxes. You can see that each of these unplanned events disrupts the normal sequence of crew tasks.checklistCLEARANCEchecklistENGINE START & PUSHBACK
15 Preflight - the reality Review paperworkSign flight releasePrepare/review chartsReview Load ScheduleReview FMCTakeoff briefAsk for checklistPreflight - the realityCAPTAIN FIRST OFFICERObtain ATISObtain clearanceReview paperworkPrepare/review charts(Passenger count)(Load Sheet)Program FMCBegin checklistChecklist completeInoperative itemTime pressureFlight release still not picked upno time, familiarityInterruptionDelay at gateRamp and/or Ground?Flight plan/Departure runway changeConduct exterior walk-aroundNew PDCStill refuelingData unavailablePassenger count unavailableCall maintenanceLook for ops/gate agentDouble-check chartsResume checklistConfirm Mx respondedConfirm Mx departedConfirm resolutionConfirm logbook on boardCheck chartsDefer programming FMCCommunicate with companyCompute new performance #sRe-program FMSRe-program FMCCheck fuel quantityand pumpsRe-briefRe-flow trim & other settingsNew flight release/PDC?Re-set MCPTakeoff briefRequest passenger countGround/Company/DispatchFrequenciesInterphoneInterruptionFO busybusy frequencyKeep tryingAsk for checklistResume flowCabin AttendantprocedureGate AgentACARs / OPCprocedureprocedureTake, for example, the instance of an aircraft that is still being refueled when the captain reaches the procedural item requiring verification of sufficient fuel on board. The captain will have to defer that procedural check and in the interest of time press on with the rest of the procedure, hopefully making a note to herself to go back and complete the necessary check when refueling is complete. While conducting other procedures, she must monitor activity outside the cockpit door, expecting a completed fuel slip to be delivered prior to pushback. If that does not happen, she will need to remember to ask for it or risk finding after takeoff that there is not sufficient fuel on board.Another example is the first officer who finds the load data are not available at the time he ordinarily programs the FMC forcing him to defer programming until later. The FO will continue with the preflight checks and will plan to execute the programming task immediately upon receiving the necessary paperwork. If it is not made available to him until just before pushback, he will have to further defer it until after the engines have been started and the aircraft is on its way to the runway. This means he will have to go head-down during taxi, preventing him from monitoring the taxi and disrupting the habitual point of initiating the taxi checklist early in the taxi sequence.Thus instead of the straight arrow proceeding directly down through the first officer’s tasks we saw in the ideal view, we now see this dotted line going back and forth among tasks.checklistCLEARANCEchecklistENGINE START & PUSHBACK
16 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.In sum, normal line operations are quite dynamic:-Each pilot must juggle several tasks concurrently. For example, during taxi-out the FO runs the taxi checklist procedures, communicates with both ATC and company, communicates with the flight attendants, and often must update the FMC. And while he is performing all these tasks, we expect the FO to monitor where the CA is taxiing the airplane.-Crews are frequently interrupted, especially during preparations to start the engines, when gate agents, mechanics, and flight attendants are popping in and out of the cockpit.-External demands arrive at unpredictable moments, for example, last minute runway changes occur both during taxi out and during approach to landing.-Essential information is sometimes not available when needed. For example, final weight and balance information is often not available before pushback.-Conditions sometimes force task elements to be performed out of the normal prescribed sequence. For example, a slushy taxiway may require that flaps be held until the end of the taxi.
17 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:Thus the reality is that line operations are far from linear because of all the parallel activity and variations in the sequence of tasks. Task demands are not entirely predictable. And crews must at times struggle to maintain control of the timing and sequence of their work tasks because of the demands of people outside of the cockpit. Unfortunately,pilots receive virtually no guidance or training in how to deal with these disruptions and concurrent tasks demands not described in the FOM.Crews must at times struggle to maintain control of the timing and sequence of their work tasks.Lack of guidance
18 Conflict Between Theory and Reality FOM is a powerful tool for safety by providing:Operational reality disrupts ideal execution of proceduresExplicit description of how each task is to be performedStandardization across crewsChecklists and checking proceduresSo, to summarize what I’ve said so far, there is a conflict between theory and reality. The FOM is an enormously important tool for safety because it provides an explicit description of how each task is to be performed, it provides standardization, and it provides specific safety measures such as checklists. However operational realities often prevent crews from executing procedures in the ideal way portrayed in the FOM.
19 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.Well, so what, why is this a problem? Juggling several tasks concurrently is so common and interruptions and other disruptions of procedures are so frequent that many pilots just deal with them in a rather blasé fashion. Because pilots are very skillful at performing each cockpit task by itself, they tend to underestimate their vulnerability to error when performing several tasks concurrently or when they are interrupted or distracted. But what we find is that these situations substantially increase pilots’ vulnerability to error, especially errors of omission, omitting critical procedural steps.
20 ERRORSattributed to concurrent task demands, interruptions, and disruptions (ASRS reports)Forgot logbook at ramp - kept deferring to check it; distractions; busy with preflight - discovered en routeSkipped over checklist item - fuel pumps deferred during preflight because refueling - engine starvation in flightOmitted review of charts - distractions - speed violation on departureEntered wrong weight in FMS - tail strike at takeoffImproper setting of pressurization during preflight flow - interruptions - cabin altitude warning light in cruiseOmitted flow and checklist items - interruptions; delay; change in departure runway - discover insufficient fuel at ftRead but not verify checklist item - distractions - pushback with throttles open, damage to aircraftStarted taxi without clearance - crew discussing taxi instructions - struck pushback tugNeglected to set flaps -preoccupied with new departure clearance and packs-off operation - aborted takeoffFO failed to monitor CA – busy with flow; night taxi – taxi in wrong directionFO failed to monitor CA -runway change; busy reprogramming FMC - taxied past intended taxiwayOmitted setting flap - busy with delayed engine start; rushed to accept takeoff clearance - aborted takeoffFailed to verify new clearance - monitoring convective activity on radar - flew wrong headingPREFLIGHT > PUSHBACK > TAXI > TAEKOFF > CLIMB > CRUISE > DESCEND > LANDOmitted climb checklist - busy copying hold instructions - missed setting altimeter and overshot altitudeFailed to reset bleeds on - complex departure; multiple ATC calls; traffic - altitude warning and 02 mask deploymentDid not notice wind - preoccupied with annunciator light; handling radios - track deviationThis is a list of just a few of the errors pilots have reported making in conjunction with concurrent task demands, interruptions, or distractions. I realize this is a busy slide and I don’t expect you to read the details. These errors occur in all phases of flight, and most of them in one way or another involve inadvertently omitting a normal procedural step.Forgot to reset altimeters - distracted by FA in cockpit - TCAS RA and overshot arrival fixFailed to monitor PF - busy reprogramming FMS; weather changes - go aroundFailed to verify FMC settings - PNF giving IOE to PF; multiple ATC calls; hold instruction - flew pattern in wrong directionATC instructions too close to turn fix - busy slowing aircraft; approach checklist; radios - failed to make published turnVectored too close - busy catching up with glideslope; not instructed to switch to Tower - landed without clearanceForgot to switch to Tower at FAF - last minute runway change; busy reconfiguring aircraft - landed without clearanceUnstabilized approach - accepted runway change right before FAF; did not review charts or make callouts - tailstrikeDid 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
21 Why So Vulnerable to These Errors? Why are we so vulnerable to these kinds of error performing tasks at which we are quite skillful? I have to get a little bit technical now but I think I can keep the science grounded in operational reality. If you will, think back to when you were first learning to fly big airplanes on the line, how challenging it was to keep up with all that had to be done. In fact, if we performed a task analysis, we would see that just to get the airplane ready to fly and out to the runway requires the crew to perform a very large number of procedural steps. However as you gained experience, the workload seemed to go down drastically, it was no longer a challenge to keep up. In reality the amount of work to be done did not change, but what did change is how your brain learned to process the information and to perform these tasks as you gained experience. You no longer had to consciously think about how to perform each of the procedures and when to perform them, your body now just seems to perform each task automatically. And that is exactly what happens—when we practice tasks a great deal the brain develops procedures that allow the tasks to be executed automatically with a minimum of conscious supervision.The same thing happened when you were learning to drive a car as a teenager. At first you had to consciously think about every step and it was very clumsy, but with experience driving became quite automatic, the procedures flowed easily, and you now longer have to think about what to do step by step. Now when you are driving you are able to focus your conscious attention on other tasks such as navigating.
22 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.1) “Controlled” processingCorresponds to conscious attentionSlow, serial, and effortful: low capacityRequired for tasks with novel aspects2) Automatic processingFast, minimal effort, high capacityDevelops with extensive practice of habitual procedureRequires minimal conscious supervisionTo put this in scientific terms, the brain has two ways of processing information to perform tasks. “Controlled” processing corresponds to our conscious awareness, what we attend to consciously and think about as we perform a task. Controlled processing is slow, serial, and effortful. We have to think about each step of the task and execute one step at a time. Any time we are learning a new task we have to use controlled, that is conscious processing. But we also have to use controlled processing even with familiar tasks if those tasks have novel aspects. For example communication requires our full attention because it involves novel information--we don’t know what the other person is going to say.When we practice a procedure over and over, performing it exactly the same way each time it becomes automatic. Automatic processing is fast, and requires minimal effort and requires minimal conscious supervision.Cockpit tasks vary from requiring mainly controlled processing to being largely automatic. For example, your preflight flow is automatic, you don’t have to think about how to do it because your have practiced it so much it has become habitual and it does not have any novel aspects. Programming the FMC requires a mixture of controlled processing and automatic processing. Some aspects, such as selecting the correct page, become automatic with experience, but the information we type in with the keypad requires our conscious attention because the information is novel.
23 Automatic processing has enormous advantages but also has serious vulnerabilities This automatic processing has an enormous advantage over controlled (conscious) processing because it allows skilled experts to perform a large number of complex tasks fluidly and rapidly. In fact, without automatic processing humans could not hope to manage complex tasks such as flying airplanes and accomplish everything that has to be done in the time available. But the brain’s automatic processing has serious vulnerabilities in certain situations.
24 PREFLIGHT Flow (B73-300 - as trained) Aft OverheadAft OverheadPREFLIGHT Flow (B as trained)(checklist items are marked *)****Forward OverheadForward Overhead******Mode Control PanelMode Control Panel****First OfficerInstrument*CaptainInstrumentCenter InstrumentCenter Instrument**CaptainInstrument*First OfficerInstrument***Forward ElectronicForward Electronic**Consider a typical cockpit task, which consists of a series of procedural steps, for example, the FO’s pre-start flow. This is a picture of the pre-start flow as taught at one airline. The way the brain performs this highly practiced task is as a chain. When you execute the first step of the procedure, this automatically triggers retrieval from memory of the next step and that triggers the next—you don’t have to think about it, it happens automatically without effort once you become proficient. You can test the power of this chaining mechanism yourself. Someday when you are bored, try running your preflight flow backwards. You will find that it goes very slowly if you can do it at all.ControlStandControlStand****AftElectronicFUEL107, 22, 53 WHAftElectronic*FLIGHTPLANSlakfj aslkfj890SlkdfjSlkafj f095j 019Lskd SFAS ALSKFJSa;lskdfjlXLKAF ALKDFJJ;ALPDCSlakfj aslkfj890SlkdfjSa;lskdfjlSlkafj f095j 019LskdSlkf9 9oy99A;slkg eri kgj skj 9SlkdfjLOADSlakfj aslkfj890SlkdfjSa;lskdfjlSlkafj f095j 019LskdSlkf9 9oy99A;slkg eri kgj skj 9SlkdfjJEPP107, 22, 5• •xPAX CT3 WH107, 22, 5ATISSlkdfjSlakfj aslkfj890Slkafj f095j 019Sa;lskdfjlLskd***Logbook/Gear PinsLogbook/Gear Pins
25 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.Do you see the vulnerability here? If we interrupt the procedural flow to perform a different task, the chain is broken—a long pause between two procedural steps prevents the first step from triggering retrieval of the next step from memory. Also if we are forced to perform a task out of its normal sequence the chain is broken.Another vulnerability of automatic processing is that to initiate a highly practiced procedure we depend upon receiving a signal or cue normally present in our environment that triggers automatic execution of the task. For example, in many airlines SOP calls for the FO to set flaps to takeoff position on command of the captain. This procedure is practiced so often it becomes automatic. But what happens if the captain forgets to call for flaps? Because this is such an automatic process, operating largely beyond the FO’s conscious awareness, there is a good chance the FO will not notice the captain did not not call for flaps and will not set them, especially if both pilots are preoccupied thinking about other tasks or are rushing to make their slot time. Or let’s say slushy taxiways force the crew to defer setting flaps until after taxi. The normal environmental cues that remind the captain to call for the flaps are no longer present. And because flaps are normally set before the taxi, nothing in the pilots’ automatic habit pattern reminds them that in this instance the flaps were not set.
26 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 vulnerabilityThe third problem is that when we perform a procedure or checklist thousands of times we are vulnerable to developing a “looking without seeing” pattern of responding. Have you ever seen a pilot whose verbal responses to the checklist were so fast that the response came out before the other pilot finished reading the challenge? Even if that pilot does look at the item to be checked he may not notice the one time in a thousand that it is not properly set. With extensive repetition the verbal response tends to become automatic and de-coupled from the act of visually inspecting the item to be checked.We can protect ourselves against these vulnerabilities of automatic processing if we use our conscious attention to supervise the automatic process. For example if we take the time to deliberately look at the item to be checked and think about it we will see its true status. But that’s catch 22: we normally depend on automated processes to execute procedures because we do not have time to consciously think about each step of the procedure. If our workload is high or if we are rushing we will not be able to consciously supervise automatic execution of highly practiced procedures.
27 Vulnerability to Errors of Omission Can Be Reduced 1) Actions airline operations and training departments can take2) Actions individual pilots can takeFortunately there are ways to reduce vulnerability to error when managing concurrent tasks, interruptions, and distractions. We do not have all the answers yet. We are still in the middle of this research project, but I don’t want to leave you hanging here five or six years while we go off and finish our research. So here are some general suggestions for things airline operations and training departments can do and for things individual pilots can do to reduce vulnerability to these forms of error.
28 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).It is highly desirable to do everything possible to minimize disruptions of normal procedures. Management can start by going out on the line, as we have done, and carefully observing each phase of flight to identify points at which the ideal expressed in the FOM is frequently disrupted. For example, if the final passenger count is frequently not available until immediately before pushback, expecting the first officer to complete programming the FMC before taxi is unrealistic. Far better to design procedures to reflect and deal with the actual timing and sequence of events as they typically occur in actual line operations. Critical activities should be planned for points in time when the probability of interruption is relatively low.Also it is best to avoid as much as possible “floating” procedural items that are allowed to be performed at varying times during a phase of flight. For example, it’s desirable to anchor the call for setting takeoff flaps to a specific place in the sequence of getting ready to taxi rather than allowing this procedural step to float around.
29 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.LOSAOf course we cannot completely control interruptions and other concurrent task demands and some errors will always occur. Obviously rigorous use of checklists and adherence to bottom-lines, such as stabilized approach criteria, are a primary defense against error. But, as I have explained, automaticity can subtly undermine the effectiveness of checklists, even when crews are going through all the motions of using the checklist. It’s important for airlines to observe actual fleet operations periodically to see what the norms are for how the checklist is executed not just whether it is used. LOSA can be a powerful tool for this sort of observation and analysis.It is highly desirable to train to the reality of line operations, especially to train for concurrent task management. Unfortunately, because of time and cost constraints, much of training is directed to getting the pilot through the checkride. Even in LOFT and LOE, in which we attempt to be realistic, we do not fully expose crews to the challenges of concurrent task management, interruptions, and distractions. This is especially true in simulation of ground operations, which typically provide only a bare skeleton of what actually happens on the line. I suggest that the airlines, the FAA, and NASA might collaborate to develop realistic training. The FAA must be involved because as a practical matter individual airlines cannot afford to expand training unless there is some incentive. But if we did develop realistic simulations, then instructors and crews could in their debriefings examine how well the crew managed concurrent task demands and discuss techniques for dealing with the challenges.Train with realistic concurrent task demands.
30 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 resumeCreate 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.There are also several things individual pilots can do to reduce their vulnerability. Simply being aware of your vulnerability to omitting steps when procedures are disrupted can reduce your vulnerability by helping you be alert for errors. For example, it turns out ironically that one of the biggest dangers of abnormal situations is not the abnormal itself but that the crew will forget to perform some normal procedural step because the abnormal demands attention and disrupts the normal, habitual flow of procedures.When you are interrupted, first take a moment to note that you are suspending a task and must return to complete it later. Our laboratory research shows that this substantially improves the likelihood of remembering to complete the interrupted task. When you are interrupted or must defer a task, if possible, try to create a conspicuous cue to remind yourself that the task has not been completed.Try to develop the habit of deliberately pacing and consciously attending execution of procedures and checklists. This will allow you to consciously supervise the automatic processes that underlie habitual responses. In the same vein, avoid rushing. I know this is easy for me to say and hard for you to do because there are a lot of time pressures in line operations. But the truth of the matter is rushing gains very little time, and it increases your vulnerability to error enormously because it removes your ability to consciously supervise your brain’s automatic execution of habitual procedures.
31 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 resumeCreate 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 that everything is ready before moving on to the next stage—for example, pause before taking the runway. It takes a lot of self-discipline to do this, especially after delays in getting to the runway when we are focused on getting in the air.And as Captain Sumwalt told us last year, treat monitoring as an essential task rather than a secondary task. Monitoring is a primary defense against many kinds of threats and errors. Companies can help pilots in this regard by explicitly assigning monitoring duties and specifying in the FOM when and what pilots are to monitor.I realize that there is nothing profoundly new in these suggestions for reducing vulnerability to errors of omission. What I hope I have done is give you a better understanding of why even the best of pilots are vulnerable to these errors and have given you an more explicit rationale than you had before for why these countermeasures can be effective.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).
32 For further information: 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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