Mar 19, 1991
Accident
Substantial RICHVALE, CA
InjuriesNone
Phase of Flight-
ConditionsVMC
OperationFAR 137
Probable Cause
THE FAILURE OF THE ENGINE'S NUMBER 4 CYLINDER INTAKE VALVE KEEPER. TREES UNDER THE HELICOPTER AT THE TIME OF THE LOSS OF ENGINE POWER WERE FACTORS IN THE ACCIDENT.
NTSB LAX91LA137