On July 22, 1993, a Bell 47G-3B-1 (registration N9010C) operated by Central Wisconsin Helicopter was involved in an aviation accident near Elderon, WI. Investigators recorded the probable cause as: The pilot's failure to ensure adequate fuel for the flight, resulting in fuel exhaustion. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A helicopter experienced an engine failure shortly after completing agricultural spraying operations. Investigation confirmed fuel exhaustion was the cause, as no usable fuel remained in the system despite the pilot's belief that sufficient fuel was available.
What happened
The pilot reported completing an agricultural spraying mission and departing the field at 7:30 PM. After checking a stop clock, he determined that adequate fuel remained on board. However, the engine quit at 7:37 PM.
The investigation
A postaccident examination of the helicopter revealed no evidence of usable fuel in the aircraft's fuel system. To verify mechanical integrity, the engine was supplied with fresh fuel and operated normally during an engine runup, confirming that the failure was not due to a mechanical malfunction but rather a lack of fuel supply.
Findings
The primary factor contributing to this incident was fuel exhaustion. The pilot's assessment of remaining fuel based on elapsed time proved inaccurate. The engine itself functioned correctly when provided with fuel, indicating that the cessation of power was solely due to the depletion of the onboard fuel supply.
Probable cause
The pilot's failure to ensure adequate fuel for the flight, resulting in fuel exhaustion.