UK investigators call for FAA to issue drug warning and for changes to de-icing advice
Fatigue and use by the pilots of over-the-counter drugs to aid sleep have been cited as contributory factors in the 4 January 2002 Bombardier Challenger 604 take-off crash at Birmingham airport, UK, which killed all five on board (Flight International, 24-30 August).
The UK Air Accidents Investigation Branch (AAIB) has recommended that the US Federal Aviation Administration ensure that pilots are warned about use of the drug diphenhydramine, and has also called for changes to FAA advice about pre-flight airframe icing.
Frost on the wing of the aircraft - which had been parked on the ramp overnight at Birmingham airport - had been noted by the pilots, but ignored as a potential danger. But the AAIB says the crash, which resulted from a left wing stall immediately after lift-off, happened because frost caused the wing to stall at such a low angle of attack that the stall warning system did not even detect danger.
One of the AAIB recommendations is that the FAA immediately remove from its FAR Part 135.227 advice that "take-offs may be made with frost adhering to the wings or stabilising or control surfaces if the frost has been polished to make it smooth". All frost and ice must be removed by de-icing, says the AAIB.
Fatigue was cited because of the schedule the crew had worked and the number of time zones they had crossed in the previous 24h period. The trip had begun the day before the accident in the USA at Dekalb-Peachtree airport in Atlanta, where the crew started duty at 04:00 local time. They flew to Fort Myers, then West Palm Beach, from where they flew the transatlantic leg to Birmingham and left for their hotel at 21:30 GMT/local time after a 12.5h duty day. The report notes that the co-pilot, the handling pilot in the accident, had little sleep both nights before the fatal flight. "Detectable amounts" of the sleep-aid drug diphenhydramine were found in the bodies of both pilots after the accident, but "no alcohol or drugs of abuse" were detected.
After arrival at the aircraft at about 10:40 the next day (4 January), both pilots were seen to conduct independent external checks of the airframe. Later in the cockpit the commander was helping the handling pilot to programme the flight management system because "he had some difficulties which resulted in the process being re-started", according to the report. Shortly after this the pilots exchanged words:
Commander: "Got a frost on the leading edge, on there, did you see it?"
Handling pilot: "Huh?"
Commander: "D'you [see] that frost on the leading edge - wings?"
Handling pilot: "Did I feel 'em?"
Commander: "Yeah, did you-all check that out?"
Handling pilot: "Yuh".
The commander did not ask the handling pilot to be more specific.
The AAIB report says that the crew calculated the take-off weight and speeds correctly, and called them correctly during the take-off run, but the aircraft left wing stalled immediately after unstick despite quick appropriate reaction by the handling pilot. The wingtip hit the ground and the aircraft cartwheeled. It was destroyed and all five people on board were killed.
DAVID LEARMOUNT / LONDON
Source: Flight International
