On August 4, 1984, a Hiller UH-12ET (registration N5359V) was involved in an aviation accident near Delano, CA. Investigators recorded the probable cause as: Fuel exhaustion due to the pilot's failure to monitor fuel quantity, contributed by an inoperative fuel quantity gauge. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A Hiller helicopter lost power and crashed into trees while conducting an agricultural spray run because the fuel quantity gauge was inoperative, leaving only ounces of fuel.
What happened
The Hiller helicopter, equipped with a Soloy conversion, was engaged in an agricultural spray operation. During one of the spray runs, the engine began to lose power. The pilot attempted to navigate toward an open area within the trees to land safely. However, all engine power was lost before a safe landing could be achieved. The aircraft subsequently collided with almond trees.
The investigation
Post-accident examination revealed that only 15 to 18 ounces of fuel remained in the fuel tanks. The pilot stated that he believed approximately 20 minutes of fuel remained at the time of the incident. The investigation found that the fuel quantity gauge was inoperative, which likely contributed to the miscalculation of available fuel.
Findings
The primary factor leading to the accident was fuel exhaustion. The inoperative fuel quantity gauge prevented the pilot from accurately monitoring fuel levels. The aircraft involved was a Hiller helicopter with a Soloy conversion. The phase of flight was agricultural operation. The location was an almond orchard.
Probable cause
Fuel exhaustion due to the pilot's failure to monitor fuel quantity, contributed by an inoperative fuel quantity gauge.