Airlines - Preoccupation Spells Peril

The captain’s inattention was attributable to preoccupation with the landing gear malfunction and preparations for a possible landing emergency

Crew Resource Management (CRM) training is routine in aviation circles, but it was not always so. What probably triggered formal CRM training in the airline industry was an accident in 1978 involving a McDonnell Douglas DC-8-61. A relatively minor problem experienced while lowering the undercarriage to land, was allowed to drift for an hour or more, till the aircraft ran out of fuel and the crew out of luck.

On December 28, 1978, United Airlines Flight 173 took off from Denver, Colorado-bound for Portland, Oregon, USA, with 181 passengers onboard. The crew were Captain Malburn Mc Broom, First officer Rodrick Beebe, Flight engineer Forrest Mendenhall and five cabin attendants. McBroom was a highly experienced pilot with nearly 28,000 flight hours, about 5,500 of them captaining the DC-8. The airliner had 46,700 lbs of fuel onboard when it departed the gate at Denver. This figure included the Federal Aviation Regulation requirement for fuel to destination plus fuel for 45 minutes of flight and the company contingency fuel sufficient for another 20 minutes of flight.

The expected arrival time at Portland was 1713 hours. The weather was good as Flight 173 descended for approach and landing at the destination. The aircraft was cleared by Air Traffic Controllers for a visual approach to Runway 28. The First officer, who was at the controls, requested that the wing flaps be extended to 15 degrees. Once it was done, he asked for the landing gear to be lowered. When the Captain operated the landing gear handle, there was a thump followed by a shudder which ran the length of the aircraft. Only the nose wheel green light came, while the main gear position lights indicated neither ‘down and locked’ nor ‘in transit’.

Time Slips

While the crew methodically discussed and accomplished the various emergency and precautionary actions required in such a situation, Portland Approach vectored the aircraft into a holding pattern south and east of the airport. The cockpit crew consulted the ‘Irregular Procedures’ section of the DC-8 Flight Manual, which stipulated check of the visual indicators atop both wings. These extend above the wing surface if the landing gear is down and locked. The Flight Manual specifies, “If the visual indicators indicate the gear is down, then a landing can be made at the captain’s discretion.” The flight engineer’s visual inspection of both main landing gear showed that they appeared to be down and locked, although there is an element of doubt in his observation.

At 1738, Flight 173 radioed its maintenance facility for assistance, reporting that they would orbit at the assigned altitude for another 15 to 20 minutes before attempting to land at about 1805. The maintenance facility ascertained that the crew had done everything possible to remedy the situation. It was 1745. The captain then had a discussion with the senior flight attendant concerning the imminent emergency landing and how it would be communicated to the passengers. The first officer, still at the controls, asked the flight engineer what the remaining fuel was, to which he replied 5,000 lbs. The captain then asked him to recalculate the weight for landing, saying he expected to land in approximately 15 minutes. Later, the cockpit voice recorder (CVR) revealed that the flight engineer said, “Not enough! 15 minutes is going to really run us low on fuel here.” Unfortunately, he did not stress the point at that time.

At 1757, after the crew completed final checks in preparation for landing, the captain sent the flight engineer to the cabin to check on the passengers. When he returned, he told the captain that they were down to 3,000 lbs of fuel. At 1806, the senior flight attendant entered the cockpit and reported that they were ready in the passenger cabin. At this time, the aircraft was about 17 nm south of the airport. The captain then said, “Okay. We’re going to go in now. We should be landing in about five minutes.”

Almost immediately, the first officer exclaimed to the flight engineer, “I think you’ve lost number four engine… better get some cross-feeds open there or something.” One engine had flamed out. The captain asked, “Why?” The first officer replied, “Fuel.” The flight engineer managed to get the engine restarted by opening the cross-feeds. But he soon reported that the fuel gauge was now showing 1,000 lbs, with no fuel in the number two tank. At 1813, the airliner lost number one and two engines. The crew gave a May Day call. At about 1815, the aircraft, now with all four engines gone, came down six miles short of the runway in a wooded suburb. Although it was dark by now, the crew controlled the plane till the end. At least 10 passengers, including the flight engineer and the senior flight attendant, were killed. All those who died had been seated on the right side of the cabin, which suffered extensive damage during the crash-landing.