was a Sikorsky S-61N
helicopter of British International Helicopters
which made a controlled ditching in the sea northeast of Shetland
on 12 July 1988
following an engine fire. There were no fatalities.
The helicopter left the Safe Felicia semi-submersible
oil rig in the Forties oilfield
at 13:45 with 2 pilots and a full load of 19 passengers for the one hour flight to Sumburgh Airport
on the Mainland
At 14:28 the co-pilot (who was flying) reported hearing a muffled bang which was also heard by some of the passengers, from the area of the No. 2 engine transmission. Shortly after, the No. 2 engine's fire warning lights came on. The pilot immediately began a descent and transmitted a distress call.
About 48 seconds after the noise, the No. 2 engine was shut down and the fire extinguisher triggered. The No. 1 engine fire warning then also illuminated, while passengers saw oil leaking from the cabin ceiling.
The pilot advised the passengers to prepare for an emergency ditching and took control of the aircraft. The floats were deployed and a gentle ditching was made about 3 minutes after the initial noise had been heard heard, by which time the helicopter's cabin had filled with smoke. All 21 occupants evacuated on to liferafts and were then winched up into a Search and Rescue helicopter. After a strong fire consumed most of the floating helicopter, the remains broke up and sank.
A recovery operation was mounted using the DSV (diving support vessel
) Stella Marianos
which arrived on site on 16 July 1988. The aft fuselage section was raised the following day and the forward section shortly after. The recovery operation had to be ended on 19 July before finding the engines or transmission components due to the Stella Marianos
having other commitments.
The recovery continued on 2 August using the DSV Norskald, and the engines, main rotor, and transmission were located and raised on 5 August.
It was concluded that the fire had occurred in the helicopter's main gearbox, probably resulting from the effects of a bearing failure in the No. 2 engine. A further factor was the lack of fire detection or suppression capability within the gearbox bay. The cause of the bearing failure could not be definitely established.