Incident Overview
After landing at an airport, a pilot requested ground personnel to refuel the helicopter while he prepared a sling load for the next flight. The pilot was weighing the cargo on a nearby scale when the ground crew completed fueling. He then signed the fuel delivery manifest for 25.4 gallons of "avgas" aviation fuel.
Sequence of Events
Shortly thereafter, the pilot boarded the helicopter and started the engine. After liftoff, he picked up a 775-pound sling load and departed toward his destination. About 10 to 15 seconds after takeoff, the engine began to run rough and lose power. 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, and the pilot entered a low altitude emergency autorotation, attempting to cushion the landing. However, the helicopter landed hard.
Damage and Findings
The helicopter sustained substantial damage to the fuselage and tail rotor drive system. A postaccident inspection by a Federal Aviation Administration (FAA) inspector 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 it with avgas, but they had used the same trailer they used to fuel larger (turbine powered) helicopters.