Hiller UH-12E N138HA accident near Lost Hills, California

Probable cause

The failure of the engine-driven fuel pump, resulting in the loss of all engine power and the pilot's failure to correctly execute an autorotational landing.

NTSB analysis

During a helicopter agricultural spray operation, the pilot ascended to about 100 feet above ground level (agl) to make a downwind turn. During that sequence of events, the engine-driven fuel pump failed, resulting in the loss of all engine power. The pilot immediately entered autorotation, and attempted a power-off landing in a field of alfalfa. During landing, the pilot applied up collective too early, and the main rotor blade ran out of autorotational energy while the helicopter was still about 10 feet above the ground. The helicopter landed hard which resulted in substantial damage to the airframe. A postaccident teardown inspection of the helicopter's fuel system determined that the engine driven fuel pump could not be turned by hand, that its internal metallic surfaces were galled, and that it was contaminated with loose metal particles. The inspection also determined that the 24 volt electrically-powered auxiliary fuel pump was internally seized and could not be turned by hand.

Text from the NTSB. Open the NTSB docket for WPR11LA267 for the full record.