Two pilots and 14 oil workers died when the Super Puma aircraft suffered a catastrophic gearbox failure on April 1 2009.
The chopper was returning from an offshore installation when it plunged into the sea off the Aberdeenshire coast with the death of all on board.
The helicopter's flight safety monitoring system flagged up potentially serious problems on two occasions a few days before it crashed.
But a communication error between the aircraft manufacturer and the maintenance team resulted in the wrong part being checked.
Yesterday Worcestershire county coroner Geraint Williams returned a narrative verdict on the death of co-pilot Richard Menzies, 24, of Droitwich Spa.
He ruled the accident could have been avoided if proper maintenance procedures had been followed.