Engine Failure and Forced Landing
Shortly after takeoff, the pilot felt a shudder in the aircraft and noticed a rise in the turbine outlet temperature. A low-pitched whine was heard from the engine, followed by the illumination of the engine chip detector light. Subsequently, the engine out light, horn, and oil pressure warning light activated. The pilot executed an autorotation to a clearing at the bottom of a canyon. During touchdown, the helicopter slid forward in approximately 1 foot of snow, causing the right skid to collapse and the helicopter to roll over onto its right side.
Post-Accident Inspection Findings
Inspection of the engine revealed evidence of oil starvation in both the turbine and compressor sections. The turbine bearings had failed, and the gearbox bearings showed signs of high heat distortion. Oil starvation was also evident in the compressor bearings. The lubrication system components were checked and found to function normally. However, a 1 1/8-inch disk of gasket-like material was discovered in the oil reservoir. This disk was similar to those found on the caps of quart-sized oil containers. It matched the size of the opening leading to the oil pump and engine. When the disk was placed over this opening, it blocked the flow of oil from the tank to the engine.
Oil Supply and Pilot Procedures
Extra quarts of oil were often kept on board the aircraft, allowing the pilot to add oil as needed. The presence of the disk in the reservoir suggests that it may have entered during a previous oil change or maintenance action, though the source does not specify how it got there.