Task Management - University of Oregon



Task Management

I. Examples of task management problems

a. Northwest 255

i. Flight 255 departed Saginaw for a flight to Detroit, Phoenix and Santa Ana, arriving at Detroit at 19.42h. Pushback for departure was accomplished at 20.34 and the crew received taxi instructions for runway 3C.

ii. During the taxi out, the captain missed the turnoff at taxiway C and new taxi instructions were given. At 20.42 Flight 255 was told to taxi into position on runway 3C and hold, followed by a takeoff clearance two minutes later.

iii. Shortly after rotation the stick shaker (stall warning) activated. The aircraft rolled left and right and the left wing struck a light pole in a car rental lot. Flight 255 continued to roll to the left, continued across the car lot, struck a light pole in a second rental car lot and struck the side wall of the roof in a 90 degree left wing down attitude. The plane was still rolling to the left when it impacted the ground on a road outside the airport boundary and continued to slide along the road, striking a railroad embankment, disintegrating and bursting into flames.

iv. Probable Cause:

1. "The flight crew's failure to use the taxi checklist to ensure that the flaps and slats were extended for take-off.

2. Contributing to the accident was the absence of electrical power to the airplane take-off warning system which thus did not warn the flight crew that the airplane was not configured properly for take-off. The reason for the absence of electrical power could not be determined."

b. Delta 1141

i. Flight DL1141 (Jackson - Dallas - Salt Lake City) left Gate 15 at 08.30h and was instructed to taxi to runway 18L. When first in line for take-off (at 08.59h) the flight was cleared for takeoff.

ii. The takeoff was uneventful until the airplane reached the rotation phase (at 154kts, 6017ft down the runway). As the main gear wheels left the ground, the airplane began to roll violently, causing the right wingtip to contact the runway (1033 ft after lift-off), followed by compressor surges. The plane continued and struck the ILS localizer antenna array 1000 ft past the end of runway 18L. After impacting the antenna installation, the airplane remained airborne for an additional 400 ft, then struck the ground, traversed a ground depression and slid sideways until it came to rest near the airport perimeter fence, 3200 ft from the runway end. Parts of the aircraft had separated in the slide and a fire had erupted in the right wing area, quickly engulfing the rear, right side of the airplane after it came to rest.

iii. [RM Note: Fuel distraction and unusual T/O position]

c. Probable Cause:

i. "(1) The captain and first officer's inadequate cockpit discipline which resulted in the flight crew's attempt to takeoff without the wing flaps and slats properly configured; and

ii. (2) the failure of the takeoff configuration warning system to alert the crew that the airplane was not properly configured for the takeoff.

iii. Contributing to the accident was Delta's slow implementation of necessary modifications to its operating procedures, manuals, checklists, training and crew checking programs which were necessitated by significant changes in the airline following rapid growth and merger.

iv. Also contributing to the accident was the lack of sufficiently aggressive action by the FAA to have known deficiencies corrected by Delta and the lack of sufficient accountability within the FAA's air carrier inspection process."

d. Flap configuration accidents

|Date |Type |Operator |Fatalities |Country |

|21-MAR-1968 | Boeing 727 |United Air Lines |0 |USA |

|26-DEC-1968 | Boeing 707 |Pan Am |3 |USA |

|04-MAR-1975 | Falcon 20 |LTV Aerospace |0 |USA |

|11-JAN-1983 | DC-8 |United |3 |USA |

|18-SEP-1984 | DC-8 |AECA |4 |Ecuador |

|16-AUG-1987 | MD-80 |Northwest Airlines |154 |USA |

|20-JUL-1988 | DHC-6 Twin Otter |Fairways Corp |1 |USA |

|31-AUG-1988 | Boeing 727 |Delta Air Lines |14 |USA |

|31-AUG-1999 | Boeing 737-200 |LAPA |63 |Argentina |

II. Why?

a. Prospective Memory Errors

b. Interruptions

c. Lack of procedure for recovering from disruption

d. Failure to train for contingency

e. Failure to supervise training

f. Types of Work to be Managed

i. Single task

ii. Multiple sequential tasks

iii. Multiple concurrent tasks

iv. Common

v. Abnormal

vi. Emergency

III. Task Constraints

a. Operation

i. What needs to be done

b. Equipment

i. How the equipment must be operated

c. Operator

i. What the humans can do

d. Environment

i. What the physical and social environment require

IV. Task Management Strategies

a. Ad hoc

i. Each individual decides how to perform task

ii. Problems

1. Learning curve for each individual

2. Inefficient: Satisfactory performance may be suboptimal

3. Error Prone: There are more ways to do most things than ways to them right

b. Standard Operating Procedures

i. All operators perform tasks the same way

ii. Reduces individual learning time

iii. Potential for greater efficiency

iv. Potential for reduced error rate

v. Individual performance

vi. Crew performance

vii. Enhances scheduling flexibility because different individuals in the same role will do it the same way.

V. SOP Techniques

a. Flow patterns

i. One philosophy: “Every change in phase of flight is performed with a flow pattern and confirmed with a checklist.”

ii. Method of Loci

1. System used by ancient Greeks for memorizing long speeches

iii. Sequential cueing

1. Each item provides a physical cue for the next item to be accomplished.

b. Checklists & Do Lists

i. Detailed written SOP

ii. Checklist

1. Perform task from memory

2. Check performance with written aid

iii. Do-list

1. Perform task using written aid

c. Checklist Variations

i. Roles of pilots

1. Who initiates (“calls for”) checklist

2. Who completes the item (self/other)

3. Who confirms completion

ii. Challenge and response system

1. One pilot reads item

2. Other pilot confirms completion

iii. Acknowledgement

1. Verbal

2. Silent

d. Problems

i. Items missed

ii. Items performed incorrectly

iii. Proximal Causes

1. Prospective Memory failures

2. Poor checklist design

iv. Contributing Factors

1. Interruptions

a. E.g., ATC, ground ops, flight attendant

2. Items deferred

a. Completion of item deferred due to external demand

3. Items waived

a. Incorrectly decide item does not need to be accomplished (“as required”)

VI. Abnormal Situations

a. Problem

i. Lack of practice with SOP if it exists

ii. Lack of SOP

b. Intervention

i. Design SOP that:

1. Assists in identification of type of abnormal situation

2. Guides problem solving

3. Guides post-implementation monitoring

VII. Emergency Procedures

a. Problem

i. Abnormal situation with additional stress

ii. Operators cognitive capacity will be limited

iii. SOP’s may not apply (directly)

b. Intervention

i. Design SOPs that take into account operators mental state

ii. Short, clear, breakdown complex procedures into smaller chunks, eliminate need for high STM workload

iii. Train emergency SOP when possible

iv. Train emergency problem solving?

1. Results mixed

v. Select individuals resistant to stress effects

VIII. Multiple Tasks

a. Concurrent task management

i. Prioritization & Task switching

b. Intervention

i. If possible avoid concurrent tasks

ii. When tasks must be accomplished concurrently, avoid concurrent tasks that utilize same cognitive functions

iii. Establish prioritization scheme

iv. Avoid task confusable messages

1. Use dissimilar signals

2. Use signals that differ from noise

3. Avoid concurrent transmission

v. Avoid interruptions

vi. Develop procedures for mitigating and recovering from the effects of interruptions

c. Design Issues

i. Avoid interruptions

ii. Develop procedures for reducing the effects of interruptions

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