Robinson Helicopter Company R44 II N74496 accident near Wainwright, Alaska

Probable cause

The failure of ground personnel to ensure the helicopter was serviced with the proper fuel. Contributing to the accident was the pilot's failure to monitor the fueling process.

NTSB analysis

After landing at the airport, the pilot asked ground personnel to fuel the helicopter while he prepared a sling load for his next flight. The pilot said that while he was weighing the sling load cargo on a nearby scale, the ground crew finished fueling the helicopter. The pilot then signed the fuel delivery manifest for the 25.4 gallons of aviation fuel. Shortly thereafter, the pilot boarded the helicopter and started the engine. He said that after liftoff, he picked up the 775-pound sling load and then departed toward his destination. About 10 to 15 seconds after takeoff, the engine began to run rough and lose power, so the pilot elected to land, but while attempting to set the sling load on the ground, all engine power was lost. The low rotor warning horn sounded, the pilot entered a low-altitude emergency autorotation and attempted to cushion the landing, but the helicopter landed hard. The helicopter sustained substantial damage to the fuselage and tail rotor drive system.

A postaccident examination revealed that the reciprocating engine helicopter had been inadvertently serviced with Jet A turbine fuel. In a written statement, the ground personnel who fueled the helicopter stated that they thought they were fueling the helicopter with aviation gas, but they were using the same trailer that they used to fuel larger (turbine-powered) helicopters.

Text from the NTSB. Open the NTSB docket for ANC12CA082 for the full record.