Incident Overview
According to the operator, the helicopter was on its first flight of the day when a ground loader crewman observed white sparks and a fire emanating from the engine area. Subsequently, the helicopter began to spin and fell to the ground, after which a fire enveloped the aircraft.
Post-Accident Examination
An FAA inspector responded to the accident site and examined the wreckage. The inspector reported that drive system continuity was established throughout the aircraft, and all rotating components of the main and tail rotor systems were accounted for in the wreckage.
Engine Inspection
The engine underwent a detailed examination. The accessory section, all accessories, carburetors, magnetos, pumps, and engine compartment fuel and oil lines were completely melted. The number two cylinder head sustained extreme heat distress, with partial melting of the head noted. The valves, valve springs, rocker arms, and valve seats for the number two cylinder head were present in the remains of the head. No evidence was found of an internal catastrophic failure.
Findings
The examination confirmed that the fire originated in the engine area, but no specific cause for the fire was identified. The absence of internal catastrophic failure suggests the fire was not due to a mechanical breakup of the engine core.