An unexpected type of fatigue cracking led to the sudden detachment of the main rotor from an Airbus Helicopters EC225 LP Super Puma, and the helicopter’s subsequent crash on a small North Sea island while carrying oil workers from an offshore oil platform to Bergen, Norway, the Accident Investigation Board Norway (AIBN) says.
The April 29, 2016, crash killed both pilots and all 11 passengers; the CHC Helikopter Service helicopter was destroyed.
In its final report, issued in July, the AIBN said that the accident resulted from a fatigue fracture in a second-stage planet gear in the epicyclic module of the main rotor gearbox (MGB).
The arrow points to the area of the second stage planet gear where the fatigue fracture began.
The …
