May 13, 1991
Accident
Destroyed GRAND CANYON, AZ
Injuries7 fatal
Phase of Flight-
ConditionsVMC
OperationFAR 135
Probable Cause
DETONATION (OR PRE-IGNITION) IN THE NUMBER 1 CYLINDER, WHICH RESULTED IN EROSION (BURNING) OF THE NUMBER 1 PISTON AND SUBSEQUENT LOSS OF ENGINE POWER. A FACTOR RELATED TO THE ACCIDENT WAS: THE LACK OF SUITABLE TERRAIN FOR AN EMERGENCY LANDING.
NTSB LAX91FA213