Accident Overview
A pilot reported that during a cross-country flight, the helicopter's engine ceased operation unexpectedly. The flight was estimated to last one hour and forty-five minutes, but after approximately one hour and twenty-five minutes in the air, with about 5 nautical miles remaining to the destination airport, the engine quit.
Pilot Actions and Preflight
Prior to departure, the pilot performed a preflight inspection, which included verifying that the fuel tank was full and free of water or other contaminants. Based on past performance and a lack of specific guidance from the manufacturer, the pilot calculated fuel consumption at about 13 gallons per hour. This led to an anticipated total consumption of 22.8 gallons, leaving roughly 6 gallons in the 29-gallon fuel system.
Emergency Maneuver and Impact
Following the engine failure, the pilot initiated an autorotation. During this maneuver, the tail boom struck a dirt and stone pile, resulting in substantial damage to that component.
Post-Accident Examination
A Federal Aviation Administration inspector examined the helicopter after the accident. The inspection revealed that the fuel tank was empty, and only a small amount of fuel was found in both the carburetor and the gascolator. Samples taken from these components were verified to be free of water or contaminants.
Fuel Leak Investigation
A slight indication of a blue fuel stain was observed at the fitting for the fuel line connecting the fuel tank and the carburetor. Twelve days after the accident, the helicopter’s Airframe and Powerplant maintenance technician conducted additional inspection and testing to determine the source of the fuel leak, but the results were inconclusive. Fuel stains were also noted on the carburetor around the split line of the two body halves and around the fuel strainer screen on the left side.