On February 15, 1985, a Hughes 369D (registration N58395) operated by Sunair Copters, Inc. was involved in an aviation accident near Hilo, HI. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
Shortly after takeoff, a helicopter's engine flamed out, leading to a forced autorotative landing that damaged the tail boom. Investigation revealed the helicopter was fueled with AVGAS instead of turbine fuel; the pilot could not recall if the fuel boost pump was on.
Incident
A helicopter experienced an engine flameout shortly after takeoff, necessitating a forced autorotative landing. The pilot reported that at an altitude of 4,500 feet MSL, the engine's N2 indication dropped to 92%. Approximately 15 seconds later, the engine flamed out. During the subsequent forced autorotative landing, the main rotor blades struck the tail boom, causing damage to that structure.
Investigation
The investigation into the incident revealed that before departure, the helicopter had been fueled with AVGAS instead of the required turbine fuel. The engine operating manual permits the substitution of AVGAS for turbine fuel in emergency situations, but it advises that the fuel boost pump must remain on when using this alternate fuel. The pilot was unable to recall whether the fuel boost pump was activated during the flight.