Aircraft
The aircraft involved was a Hawker Siddeley HS 748-105 Series 1, registration G-BEKF. It first flew in 1962 and initially served with Aerolíneas Argentinas before being operated by the Argentine state oil company YPF. Dan-Air Services Limited acquired it and six other HS 748s from YPF in 1977 for North Sea oil industry support. At the time of the accident, the aircraft had accumulated 29,007 flight hours.
Accident
Flight 0034 was a regular charter from Sumburgh to Aberdeen carrying oil industry personnel. The inbound flight from Aberdeen was uneventful, and the crew had a seven-hour layover before the return trip. At 15:59 local time, the aircraft was cleared for takeoff from runway 09. After engine acceleration against the brakes, the takeoff run began at 16:00. Flight data recorder evidence showed normal acceleration through V1 (92 kn) to V2 (99 kn), but the aircraft did not rotate, even after exceeding the rotation speed VR (113 kn). About five seconds after reaching VR, the aircraft decelerated. It crossed the perimeter road, struck the sea defenses, losing its undercarriage and port wing, and broke into two sections. The wreckage came to rest on the sea surface about 50 m from shore, sinking nose-first within two to three minutes in 10 m of water. Of the 47 on board, 15 passengers and both pilots drowned; 30 people survived, including flight attendant Elizabeth Cowe, who later received an MBE for assisting in rescuing 26 passengers. Adverse weather hampered rescue efforts by boat and helicopter.
Investigation
The Air Accidents Investigation Branch (AAIB) began its investigation the morning after the accident, notified by Sumburgh Air Traffic Control. The wreckage was salvaged and examined. Both engines were stripped and tested, with no pre-impact failure found. Propeller control units performed within specification, and no evidence of fire, smoke, or overheating existed. The compass selector was found switched to the co-pilot's instrument, but it was not determined which pilot handled the takeoff; it was possible the switch moved during evacuation or salvage.
Cause
The AAIB concluded that the accident was caused by the locked condition of the aircraft's elevators, which prevented the aircraft from rotating into a flying attitude. It was considered likely that the elevator gust lock became re-engaged during the pilots' pre-takeoff checks or taxi.