|Date||26 June 1978|
|Site||North Sea, Norway |
|Aircraft type||Sikorsky S-61|
|Flight origin||Bergen Airport, Flesland, Bergen, Norway|
|Destination||Statfjord A, North Sea, Norway|
Helikopter Service Flight 165 was a crash of a Sikorsky S-61 helicopter into the North Sea, 78 nautical miles (144 km; 90 mi) northwest of Bergen, Norway, on 26 June 1978. The aircraft was en route from Bergen Airport, Flesland to Statfjord A, an offshore oil platform. The accident was caused by a fatigue crack in a knuckle joint, causing one of the rotor blades to loosen. All eighteen people on board were killed in the crash.