# Presentation: 033966

## CONCURRENT TASK DEMANDS IN THE COCKPIT: 

**CHALLENGES AND VULNERABILITIES**
- Loukia D. Loukopoulos
- R. Key Dismukes
- Immanuel Barshi
** **NASA Ames Research Center
- Moffett Field, CA

- ALPA Training Council
- March 2003

## MOTIVATION

- Complex operating environments
- number
- timing
- and interaction of tasks

-  flows, checklists
-  procedures, phase of flight structure

-  automaticity
-  habit

- Characterize **nature** of interaction
- Characterize **demand** such interaction places on cognition
- Qualitative approach
- Jumpseat observation of routine flights
- Boeing 737; 2 air carriers; 1-4 hours per leg; nation-wide
- notes; informal interviews
- Training (initial, transition/upgrade)
- Written materials (manufacturer and carrier FOMs)
- Incident reports (ASRS, NTSB, ASAP)
- Work applies to _all phases of flight_: use Preflight and Taxi-out for illustration

## Ideal
	manufacturer perspective (manuals)

**Ideal**
- 	manufacturer perspective (manuals)

**LAYERING**

**Assumed**
- 	carrier perspective (FOMs, training)

**Real**
- 	observer perspective (jumpseating)

## Manufacturer’s representation? (ideal)

## PREFLIGHT - ideal (manufacturer)

**Goals**:
- Pre-check systems operating properly
- Configure aircraft for engine start and push-back (next phase of flight)
- Configure for takeoff
- Configure for flight
**Considerations**:
- Safe operation of aircraft
- Optimal performance of aircraft

## Preflight

**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 altitude**
**LANDING ALTITUDE indicator --- destination field elevation**
**Pressurization mode selector --- AUTO**
**         ****AUTOMATIC FAIL light --- Extinguished**

**Preflight**
**B737 Ops Manual**

## Preflight - ideal (manufacturer)

**L I S T**
**(24 items)**

*Preflight - ideal **(manufacturer)*

** **
**FLIGHT DECK PREPARATION procedure**
**F**
**L**
**O**
**W **
**(17 items)**
**Finish ****PREPARATION ****procedure**
**FINAL PREPARATION  procedure ****(2 items)**
**Start checklist**
**checklist complete**
**Start checklist**
**checklist complete**

**ENGINE START & PUSHBACK**

**FLIGHT DECK PREPARATION procedure**
**F**
**L**
**O**
**W**
**(57 items)**
**Finish ****PREPARATION ****procedure**
**FINAL PREPARATION procedure **
**(2 items)**
**Ask for ****BEFORE START ****checklist (down to the line)**
**Ask for ****BEFORE START ****checklist (below the line)**

**CLEARED FOR START**

**BEFORE START ****checklist**
**L I S T (4 items)**

## PHASE OF FLIGHT - ideal (manufacturer)

**Checklist is “meeting point”**
**Independent tasks**
**Independent operators **
**Reliance on habit (B always follows A) ****	****and triggers (F prompts G)**

**PHASE OF FLIGHT - ideal ****(manufacturer)**

_**                    **__**CAPTAIN**__**                         **_**	****                               ****	****                                     **_**                  **__** FIRST OFFICER **__**               **_

## Carrier’s representation? (assumed)

## PREFLIGHT - assumed (carrier)

**Goals**:
- Pre-check systems operating properly
- Configure aircraft for engine start and push-back (next phase of flight)
- Configure for takeoff
- Configure for flight
**Considerations**:
- Safety
- Performance of aircraft

_**Carrier (additional) considerations**_** **
**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)**

## PHASE OF FLIGHT - assumed (carrier)

**PHASE OF FLIGHT - assumed ****(carrier)**

_**                    **__**CAPTAIN**__**                         **_**	****                               ****	****                                     **_**                  **__** FIRST OFFICER **__**               **_

**Notes:**
(workload - yes) 
But also adds some complexity 
More sensitive
still fundamentally linear because an attribute of written expression 
No guidance on parallel activity

## Preflight - assumed (carrier)

**L**
**I**
**S**
**T**

*Preflight - assumed **(carrier)*

** **
**Obtain ATIS**
**Obtain clearance**
**Review paperwork**
**Prepare/review charts**
**FLIGHT DECK PREPARATION procedure**
**F**
**L**
**O**
**W **
**Finish ****PREPARATION ****procedure**
**(Passenger count)**
**(Load Sheet)**
**Program FMC**
**Start BEFORE START checklist**
**BEFORE START ****checklist complete**

**Review paperwork**
**Sign flight release**
**Prepare/review charts**
**FLIGHT DECK PREPARATION   procedure**
**F**
**L**
**O**
**W**
**Finish ****PREPARATION ****procedure**
**Review Load Schedule**
**Review FMC**
**Takeoff brief**
**Ask for ****BEFORE START ****checklist**

**MONITOR **
**Interphone**

**MONITOR **
**Ground frequency**
**Company/Dispatch  frequency**

**ENGINE START & PUSHBACK**

## ... and so it should all work as expected...

- ... or maybe not?

## 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... 

**“****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... **

**TAXI-OUT -real**

**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**_**. **

## Line representation (real)

## PREFLIGHT errors attributed to “distractions” (incident reports)

**Obtain ATIS**
**Obtain clearance**
**Review paperwork**
**Prepare/review charts**
**FLIGHT DECK PREPARATION procedure**
** **
**Finish ****PREPARATION ****procedure**
**(Passenger count)**
**(Load Sheet)**
**Program FMC**
**Start BEFORE START checklist**
**BEFORE START ****checklist complete**

**Review paperwork**
**Sign flight release**
**Prepare/review charts**
**FLIGHT DECK PREPARATION   procedure**
**Finish ****PREPARATION ****procedure**
**Review Load Schedule**
**Review FMC**
**Takeoff brief**
**Ask for ****BEFORE START ****checklist**

*PREFLIGHT **errors** attributed to “distractions” ****(incident reports)***

**ENGINE START & PUSH-BACK**

## TAXI-OUT errors attributed to “distractions” (ASRS incidents)

**Set ****flaps **
**Request taxi clearance**
**Monitor radios**
**Receive taxi clearance**
**Acknowledge taxi clearance**
**Form mental picture of taxi route**
**Check for obstacles**
**Perform PRE-TAKEOFF flow **
**(above line)**
**Start PRE-TAKEOFF checklist**
**Monitor radios**
**Monitor traffic**
**Monitor position on airport chart**
**Checklist complete**
**Monitor aircraft movement**
**Switch to Tower and monitor**
**Receive clearance **
**Acknowledge takeoff clearance**
**Perform PRE-TAKEOFF flow (below line)**
**Start checklist**
**Checklist complete**** **

**Ask for flaps **
**Ask for taxi clearance**
**Monitor radios**
**Receive taxi clearance**
**Form mental picture of taxi route**
**Check for obstacles**
**Start taxiing**
**Perform PRE-TAKEOFF flow (above line)**
**Ask for PRE-TAKEOFF checklist**
**Monitor radios**
**Monitor traffic**
**Maintain positional and situational awareness**
**Monitor Tower**
**Receive clearance**
**Perform PRE-TAKEOFF flow (below line)**
**Ask for PRE-TAKEOFF checklist**
**Line up with runway**

**TAKEOFF**

*TAXI-OUT **errors** attributed to “distractions” ****(ASRS incidents)***

## WHY?

**Wide range of outcomes **
**Large number of omissions not caught by later checklist**
**Consequences spill into all phases**

**WHY?**

**$$$ ramp mishaps **
**$$$ taxiway/runway incursions**
**$$$ rejected takeoffs**
**$$$ time, fuel**

**Notes:**
Flight Safety Foundation Ground Accident Prevention initiative
Announced at FSF and SAE Aerospace in Atlanta, Feb 2003
Steering committee has been formed  and established objectives: to increase awareness, collect and analyze data, study and recommend improvements in education, training, management and regulatory processes, and ramp facilities, equipment and operations.
Develop taxonomy: list of issues need to look into

$3 billion annual loss due to ramp damage to aircraft, airport structures, and ground service equipment (Airports Council International, 2000) = equivalent value of 15 Boeing 737-400s.  (Refers to wide range of causes, perhaps primarily to those attributable to ramp personnel - percentage of those attributable to cockpit crew is unknown.)
182 incidents involving ramp operation of part 121 or 135, 2-crew aircraft, where damage to aircraft or ground equipment, or injury  occurred, and that directly involved flight crew: 

Of 125 incident reports involving time-related pressures, 63% originated in preflight.  (McElhatton a& Drew, 1993)

## PHASE OF FLIGHT - real

**PHASE OF FLIGHT - real**

_**                    **__**CAPTAIN**__**                         **_**	****                               ****	****                                     **_**                  **__** FIRST OFFICER **__**               **_

## Preflight - real (compiled observations)

**Obtain ATIS**
**Obtain clearance**
**Review paperwork**
**Prepare/review charts**
**FLIGHT DECK PREPARATION procedure**
** **
**Finish ****PREPARATION ****procedure**
**(Passenger count)**
**(Load Sheet)**
**Program FMC**
**Start BEFORE START checklist**
**BEFORE START ****checklist complete**

**Review paperwork**
**Sign flight release**
**Prepare/review charts**
**FLIGHT DECK PREPARATION   procedure**
**Finish ****PREPARATION ****procedure**
**Review Load Schedule**
**Review FMC**
**Takeoff brief**
**Ask for ****BEFORE START ****checklist**

**ENGINE START & PUSH-BACK**

**BEFORE START checklist**
**L**
**I**
**S**
**T**

**MONITOR **
**Flight Interphone**

**MONITOR **
**Ground frequency**
**Company/Dispatch  frequency**

***Preflight - real ******(compiled observations)***

## Taxi-out - real (compiled observations)

**(above line)**
**L**
**I**
**S**
**T**

**Set ****flaps **
**Request taxi clearance**
**Monitor radios**
**Receive taxi clearance**
**Acknowledge taxi clearance**
**Form mental picture of taxi route**
**Check for obstacles**
**Perform PRE-TAKEOFF flow **
**(above line)**
**Start PRE-TAKEOFF checklist**
**Monitor radios**
**Monitor traffic**
**Monitor position on airport chart**
**Checklist complete**
**Monitor aircraft movement**
**Switch to Tower and monitor**
**Receive clearance **
**Acknowledge takeoff clearance**
**Perform PRE-TAKEOFF flow (below line)**
**Start checklist**
**Checklist complete**** **

**Ask for flaps **
**Ask for taxi clearance**
**Monitor radios**
**Receive taxi clearance**
**Form mental picture of taxi route**
**Check for obstacles**
**Start taxiing**
**Perform PRE-TAKEOFF flow (above line)**
**Ask for PRE-TAKEOFF checklist**
**Monitor radios**
**Monitor traffic**
**Maintain positional and situational awareness**
**Monitor Tower**
**Receive clearance**
**Perform PRE-TAKEOFF flow (below line)**
**Ask for PRE-TAKEOFF checklist**
**Line up with runway**

**TAKEOFF**

_**PRE-TAKEOFF checklist**_
**(below  line)**
**L**
**I**
**S**
**T**

***Taxi-out - real ******(compiled observations)***

## Challenge 1

**Pilots are constantly being interrupted**
**Interruptions demand attention and action**
**Such demands are unpredictable both in timing and in nature**
**	**
**	****(e.g., Ground controller announces change in planned departure while crew involved in preflight procedures at the gate)**

_**Observed event **_**: the FO received a call from Ground control notifying the crew of a change to their flight plan regarding the initial climb altitude in their departure.  At that time, she was involved in setting the Pressurization panel as part of the Preparation flow ... She suspended that activity and reached over to dial in the new altitude in the Mode Control Panel (MCP) altitude window while glancing over at the CA.  She knew she had to verbally inform him of the change and to point out that she had already updated the MCP.  She noticed that the CA was busy coordinating a luggage loading issue with the baggage handlers and Company, so she maintained the information in memory and formed an intention to carry out those actions at a later time.  The FO resumed her flow, but monitored the CA’s activity.  As soon as the luggage issue was resolved and the CA became available and able to redirect his attention to her again, she proceeded to inform him of the initial climb altitude change and the update to the MCP.**

**Notes:**
Agents have varying and different responsibilities, stressors, pressures, language
Impossible not to pressure/interrupt one another

## Challenge 2

**Pilots must often perform >1 tasks concurrently**
**(e.g., captain doing preflight flow, looking for chart, **
**	****  ****first officer asks for load sheet, **
**	****  ****flight attendant reports item in galley needing service)**

_**Observed event **_**: A request from the FO asking for the Load sheet that the CA had just finished reviewing a moment ago interrupted the CA in the process of looking through his binder for the relevant departure chart in the binder.  The chart was obviously misplaced because the CA had trouble locating it.  The CA closed the binder but used his finger as a bookmark pointing to the pages he had just looked through.  While sifting through some papers on his left in search of the Load sheet, a Flight Attendant entered the cockpit to let the CA know he had identified a problem in the galley, had placed a call to the service crew, and would be informing him upon their departure and resolution of the problem.  The CA momentarily directed his attention to the FA standing at the door behind him and acknowledged the situation.  Upon redirecting his attention inside the cockpit and to his own activities he became re-engaged with the issue of the misplaced departure chart and went back to his binder.   The FO’s second request for the Load Sheet reminded him he had neglected to locate it and he re-interrupted the search for the chart to find and hand the chart to the FO.**

## Challenge 3

**Pilots do not/cannot always initiate actions**
**circumstances may not be right for an action                                 ****(e.g., must not extend flaps if taxiing in snow/icy conditions)**
**information/tool/agent may not be available for coordination      **
**	****(e.g., cannot proceed with checking final fuel load until refueling complete)**

_**Observed event**_**: the CA reached the point on his preflight flow calling for verification of sufficient fuel on board.  The fact that he still did not have a refueling slip on board made him realize that refueling was still underway.  Rather than wait, and hoping for an on-time departure, he proceeded with the next step in the preflight flow.  He formed the intention to conduct the fuel quantity check later (he may have also relied on the ensuing checklist which would, by definition, ask for number of gallons of fuel on board).  When the Gate Agent brought the fuel slip for him to sign a few minutes later, he remembered the deferred intention and checked the fuel quantity readings.**

## Challenges are underestimated
Vulnerabilities to making errors when facing such challenges are not appreciated

**Challenges are underestimated**
**Vulnerabilities to making errors when facing such challenges are not appreciated**

## Vulnerabilities 1

_**Deferring activities (interrupted or new)**_
- Must resume/start later
*	**requires*
- Deliberate formation of an intention
- Remembering the existence of an intention
- Remembering the exact content of intention                              		(what was suspended & at which point/what needs to be done)
- Remembering at a time when it is appropriate to carry out intention
- (prospective) memory for intentions is poor
- 99% of memory errors in the cockpit involve PM (Nowinski, Holbrook, & Dismukes, 2003)
- “triggers” for sequence of activities are disrupted and lost
- intentions fade from working memory/focus of attention with time
- other events continue to flow in habitual sequence and timing

## Vulnerabilities 2

_**Interleaving activities (habitual/novel)**_
- Combine two activities in previously/never-before encountered ways
- Attend to two or more activities intermittently
*	**requires*
- Remembering each activity
- Deciding when to check on progress of each activity
- Remembering to check on progress of each activity
- Monitoring
- Essentially, a *continuous* prospective memory demand
- Monitoring schedule for own /others’ progress?
- “triggers” for sequence of activities are absent

## Countermeasures

- Acknowledge human fallibility
- Vulnerable to interruptions
- Examine procedures and checklists
- Content
- Timing
- Identify source and nature of interruptions in each phase of flight
- Apportion workload
- Provide warning signs for pilots to look for
- Establish triggers for items at risk (tie critical functions to fixed reference points)
- Set traps (strict decision criteria not to cross unless all expected activities 		fulfilled)
- Monitoring is a critical task
- Better guidance needed (Sumwalt, Thomas, Dismukes, 2002)

## ALPA Training Council

- March 2003

## “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... my FO... contacted company operations, advised them of our time of arrival and called for fuel with an order for 1900 lbs... 

...once on the ground...I went inside the terminal to call Maintenance... got the information I needed and headed back to the aircraft to complete the paperwork. The passengers were boarding the flight and the FO was at the back of the aircraft... as we both got into the cockpit the FO started the load manifest. I then completed the write-up in the Maintenance Log and during this time asked the FO if the Before Start checks were complete. He answered 'no.'  I then started the Before Start checks myself but was distracted by the events of a final baggage and passenger count for the Load manifest. 

...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... 

...Construction has been going on at this airport on the main runway and we have been using a shorter runway... we were given taxi for runway 29. After a look at the takeoff data, winds and weights, we advised (Tower) we needed runway 22. The Tower then cleared us for takeoff on runway 22 but we had not completed the checklist and so we advised Tower and took the time to complete the checklist. Once completed we departed runway 22 ... after climbing through 12000 ft MSL ... I was scanning the instruments and noticed the fuel quantity only showed 980 lbs... 

I feel there were many distractions that interrupted the flows on the checklist and items were skipped..“

**...****once on the ground...I went inside the terminal to **_**call Maintenance**_**... got the information I needed and headed back to the aircraft to complete the paperwork. The passengers were boarding the flight and the FO was at the back of the aircraft... as we both got into the cockpit the FO started the load manifest. I then completed the **_**write-up**_** in the Maintenance Log and during this time asked the FO if the Before Start checks were complete. He answered 'no.'  I then **_**started the Before Start checks**_** myself but was **_**distracted**_** by the events of a final baggage and passenger count for the Load**_** **_**manifest. **
**...****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... **
**...**_**Construction**_** has been going on at this airport on the main runway and we have been using a shorter runway... we were given taxi for runway 29. After a look at the takeoff data, winds and weights, we advised***** *****(Tower)***** *****we **_**needed**_** runway 22. The Tower then cleared us for takeoff on runway 22 but we had not completed the checklist and so we **_**advised Tower**_** and took the time to complete the checklist. Once completed we departed runway 22 ... after climbing through 12000 ft MSL ... I was scanning the instruments and noticed the fuel quantity only showed 980 lbs... **
**I feel there were many distractions that interrupted the flows on the checklist and items were skipped..“**

**PREFLIGHT - real ****(Captain’s ASRS Report # 335059)**