What happened
On July 13, 1988, a Sikorsky S-61N helicopter operated by British International Helicopters departed the Safe Felicia semi-submersible oil platform in the Forties oilfield. The aircraft, identified as G-BEID, was carrying two pilots and nineteen passengers on a scheduled one-hour flight to Sumburgh Airport on the Shetland mainland.
At approximately 14:28, while the co-pilot was flying, a muffled bang was heard from the area of the No. 2 engine transmission. Shortly thereafter, fire warning lights for the No. 2 engine activated. The pilot initiated a descent and issued a distress call. About forty-eight seconds after the initial noise, the No. 2 engine was shut down and its fire extinguisher discharged. Subsequently, the No. 1 engine fire warning also illuminated, and passengers observed oil leaking from the cabin ceiling.
The pilot instructed the passengers to brace for an emergency water landing and took manual control. Floats were deployed, and the helicopter executed a gentle ditching approximately three minutes after the initial incident. By this time, smoke had filled the cabin. All 21 occupants evacuated onto liferafts and were subsequently winched aboard a Search and Rescue helicopter. The floating wreckage was consumed by fire before breaking up and sinking.
Investigation
A recovery operation commenced using the diving support vessel Stena Marianos, which arrived on July 16. The aft fuselage section was raised on July 17, followed by the forward section. Operations ceased on July 19 due to vessel commitments, leaving engines and transmission components unrecovered.
Recovery resumed on August 2 using the DSV Norskald. The engines, main rotor, and transmission were successfully located and raised on August 5.
Findings
The investigation concluded that the fire originated in the main gearbox, likely caused by a bearing failure in the No. 2 engine. A contributing factor was the absence of fire detection or suppression systems within the gearbox bay. The specific cause of the bearing failure could not be definitively established. The Air Accidents Investigation Branch issued twenty-seven safety recommendations to the Civil Aviation Authority regarding maintenance, detection, escape equipment, documentation, training, and firewall integrity.