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.

This article about an aviation accident is a stub.