Contribution
The investigation of the crash of a DC-8 on approach to Portland on 28 December 1978, which killed eight passengers, the flight engineer and a flight attendant. It establishes that the aircraft and its fuel gauges worked, that the fuel burned at the planned rate, and that the crew had the fuel quantity available; the failure was in relating fuel to time and in the crew’s management. Its last recommendation, X-79-17, is one of the earliest official calls for what became Crew Resource Management.
Key insight
The crew knew how much fuel there was and did not act on what it meant. “While there is evidence to indicate that the crew was aware of the amount of fuel remaining at various times, there is no evidence that the onboard quantity was monitored, in relation to time remaining during the final 30 min of flight” (p. 25, image). The Board’s explanation is organizational: “apparently no one was specifically delegated the responsibility of monitoring fuel state” (p. 26), and the captain’s “stature” and “management style may exert subtle pressure on his crew to conform to his way of thinking” (p. 27).
Assumptions
- The reconstruction rests on the CVR and FDR, ATC and company radio recordings, crew interviews and the captain’s deposition, and fuel-burn studies by Douglas and United, which agreed with each other and with the CVR’s fuel readings within their stated errors.
- The Board adopts Douglas’s figure for the burn in the hold (13,209 lb per hour) and so reconstructs the fuel state at each moment; its judgement that “Fuel exhaustion was predictable” depends on that.
- It considered and rejected two alternative accounts: misreading of the newly installed fuel gauges as the cause, and a deliberate burn-down to reduce fire risk (no evidence; the captain would have told the crew).
Key results
- Probable cause (p. 29). “the failure of the captain to monitor properly the aircraft’s fuel state and to properly respond to the low fuel state and the crew-member’s advisories regarding fuel state.” His “inattention resulted from preoccupation with a landing gear malfunction and preparations for a possible landing emergency.”
- Contributing (p. 29). “the failure of the other two flight crewmembers either to fully comprehend the criticality of the fuel state or to successfully communicate their concern to the captain.”
- The machine was not the cause. The gear fell because of a corroded retract-cylinder rod end; the gear checks were done; the fuel-quantity system “accurately indicated fuel quantity to the crew” (Finding 11). The company’s procedures for gear failure were “adequate to permit the safest possible operation” (p. 23).
- Predictability. Finding 8 (image): “Fuel exhaustion was predictable. The crew failed to equate the fuel remaining with time and distance from the airport.” The captain told the company he would land about 1805 with about 4,000 lb, minutes after learning 5,000 lb remained, which the hold would have consumed (p. 25).
- What the others said. The flight engineer warned that fifteen more minutes would run them low; the first officer asked about fuel several times. “The other two flight crewmembers, although they made several comments regarding the aircraft’s fuel state, did not express direct concern regarding the amount of time remaining to total fuel exhaustion” (p. 25, image). Of the first officer: “If the first officer recognized the criticality of the situation, he failed to convey these thoughts to the captain in a timely manner” (p. 27). Finding 15 (image): “Neither the first officer nor the flight engineer conveyed any concern about fuel exhaustion to the captain until the accident was inevitable.”
- The general problem. “a breakdown in cockpit management and teamwork during a situation involving malfunctions of aircraft systems in flight”, which the Board calls recurring. “To combat this problem, responsibilities must be divided among members of the flightcrew while a malfunction is being resolved” (p. 26).
- Redundancy. “The first officer’s and the flight engineer’s inputs on the flight deck are important because they provide redundancy”; and “assertiveness training should be a part of the standard curricula” (p. 27).
- Recommendations (p. 30). Three on the fuel gauges and their certification. And X-79-17 (image): “Issue an operations bulletin to all air carrier operations inspectors directing them to urge their assigned operators to ensure that their flightcrews are indoctrinated in principles of flightdeck resource management, with particular emphasis on the merits of participative management for captains and assertiveness training for other cockpit crewmembers.”
Claims
| id | claim | strength | support |
|---|---|---|---|
| C1 | The aircraft ran out of fuel because the crew did not relate fuel remaining to time and distance while it worked a gear problem; the systems and gauges were not at fault | strong | FDR, CVR, two fuel-burn studies, gauge tests (§§1.16, 2) |
| C2 | The captain’s preoccupation with the gear and the cabin preparation narrowed his attention; the problem had “a disorganizing effect” on his performance | moderate | CVR content, deviations from his own stated landing time; an inference about attention (§2, Finding 14) |
| C3 | The first officer and flight engineer did not press the fuel problem on the captain in time; whether they grasped it is left open | strong as a description of what they said; open on what they understood | CVR (§2, Finding 15, contributing cause) |
| C4 | The accident exemplifies a recurring breakdown in cockpit management and teamwork during malfunctions | weak here | asserted; no other accidents are analysed in the report |
| C5 | Crews should be trained in flightdeck resource management: participative management for captains, assertiveness for others | a recommendation | §4, X-79-17 |
Concepts
- Flightdeck resource management: the Board’s phrase in X-79-17, not defined in the report.
- Participative management for captains and assertiveness training for other cockpit crewmembers: the two halves of the recommended training, one for the holder of command and one for those below it.
- Redundancy (of crew inputs): the first officer and flight engineer as independent monitors of the captain.
Connections
United’s own Flight Operations Manual already required that “all crew members noting a departure from prescribed procedures and safe practices should immediately advise the captain” (§1.17.1). The report thus records a procedure that existed and was not exercised. Helmreich, Merritt and Wilhelm (LIT-1386) date the first comprehensive CRM program to United in 1981 and cite this report as singling out the captain and the flight engineer.
Bearing on the record
- CASE-127. Supported: the date, the hour of holding, ten dead, the probable cause and the contributing factor, which the case states closely. One overstatement. The case title says the crew “knew the fuel was running out and did not make the captain act”. The Board does not find that they knew it was running out. It finds that they knew the quantity at various times, made “several comments”, and either did not “fully comprehend the criticality” or did not communicate it; it leaves which open. The NASA workshop of 1979, TWA 514 and ASRS are not in this report; the case already marks them as the exchange’s.
- CLAIM-349 (access, authority, action separable). The case reads United 173 as access without authority. The report supports a finer version. Access to the number was present; access to its meaning (fuel against time) was not maintained by anyone, because no one was assigned to it. The crew’s concerns were voiced as comments, and none had the standing of a demand. So the report separates three things the claim keeps together as “access”: the signal displayed, the signal monitored as a function someone owns, and the signal pressed with standing. The middle one, an assigned monitoring function, is the Board’s main remedy (“responsibilities must be divided”).
- CLAIM-424 and CASE-127’s “authority without abolishing command”. The phrase is the exchange’s, but X-79-17 is its earliest official form: “participative management for captains and assertiveness training for other cockpit crewmembers”. The remedy leaves the captain in command and changes how command takes input. The report also names the mechanism the reform targets, the captain’s “stature” and “management style”.
- CLAIM-422 (procedure and capacity). The company manual already required crew members to advise the captain of departures from safe practice. The procedure existed; the capacity to exercise it in a stressed cockpit did not. A pre-CRM instance of the claim’s separation.
- No THEORY filed: the general claim the Board makes (a recurring breakdown in cockpit teamwork) is asserted, not shown, in this report.
- No instruction for machine-learning practice.
Limitations
- One accident; the “recurring problem” is asserted from the Board’s experience, and no other accidents are analysed.
- The inner states of the crew (what the first officer and flight engineer understood) are inferred from the CVR and left open.
- The OCR copy is incomplete in places; the analysis and findings pages were read from images.
- There was no public hearing; the captain was deposed.
Open questions
- Did the first officer and flight engineer grasp the time to exhaustion? The Board could not say, and the contributing cause is written as a disjunction to cover both.
- Would an assigned fuel monitor have been enough, without changing the captain’s style? The report recommends both and does not separate them.