Bell 206 N224KM accident near Bentley, Illinois

Probable cause

The pilot's failure to ensure that adequate fuel was on board for the maneuvering flight, which resulted in a total loss of engine power due to fuel starvation.

NTSB analysis

The commercial helicopter pilot indicated that, about 10 minutes after takeoff, while making a turn during an aerial application flight, he noticed the low fuel pressure light illuminate; the fuel pressure gage indicated 0 psi, and the fuel quantity gage indicated 15 gallons. The engine subsequently lost total power, and the pilot performed an autorotation in preparation for a forced landing, during which the helicopter nosed over and sustained damage to the main and tail rotors.

Postaccident examination of the helicopter revealed that the fuel quantity gage read 4 gallons, and the fuel tank contained about 9.5 gallons of fuel. Both fuel boost pumps tested normally. Examination of the airframe and engine revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation.

The helicopter's flight manual stated to land as soon as practical when fuel quantity was less than 20 gallons and contained a warning that uncoordinated turns and maneuvers were to be avoided with a fuel quantity of less than 20 gallons. The manual also stated that, due to possible fuel sloshing in unusual attitudes or out-of-trim conditions and one or both fuel boost pumps inoperative, the unusable fuel was 10 gallons.

The turn during spray operations with less than 20 gallons of fuel likely caused the fuel to unport, allowing air into the fuel line. This resulted in a total loss of engine power due to fuel starvation. The pilot did not ensure that adequate fuel was on board for the maneuvering flight.

Text from the NTSB. Open the NTSB docket for CEN18LA260 for the full record.