On July 14, 1997, a Bell 47G-3B (registration N8494E) operated by Wood, Milton, H. was involved in an aviation accident near Idaho Falls, ID. Investigators recorded the probable cause as: The pilot mismanaged his fuel supply which led to fuel exhaustion and subsequent loss of engine power. Factors contributing to the accident were the lack of adequate altitude and airspeed to successfully execute an autorotation. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive; 1 related events involving the same aircraft type or operator are linked below.
A Bell 47G-3B helicopter lost engine power at low altitude while returning from a spray run due to fuel exhaustion. The aircraft was on the boundary of the autorotation envelope.
Occurrence
The pilot of a helicopter reported that during the final spray pass over a potato field, he noticed a low fuel state and initiated a return flight toward his refueling truck. While at an altitude of 10 to 15 feet above ground level and an airspeed of approximately 25 knots, the engine lost power. The pilot stated, "when it quit I did not have the time to do any auto(rotation). It stopped and I hit the ground."
Investigation Findings
An FAA inspector examined the aircraft following the accident and confirmed the absence of fuel on board. Analysis of the height-velocity diagram for the Bell 47G-3B indicates that, at the reported altitude and airspeed at the time of power loss, the helicopter was positioned on the boundary of the envelope required for a successful autorotation.