Aug 18, 2012
Accident
Substantial Sunburst, MT
InjuriesNone
Phase of Flight-
ConditionsVMC
OperationFAR PUBU
Probable Cause
The improper installation of the engine-to-main gearbox flex coupling, which resulted in the failure of the flex coupling and a loss of power to the rotor system during takeoff.
NTSB WPR12TA364