Aviation Accident Summaries

Aviation Accident Summary LAX98LA089

CHICO, CA, USA

Aircraft #1

N4027Z

Hiller UH-12E

Analysis

During an aerial application flight over an orchard at 40 feet above ground level, the pilot experienced a total loss of engine power. Unable to enter an autorotation due to the low altitude, the pilot landed hard in an open field, and the helicopter was substantially damaged. An examination of the helicopter revealed it was out of fuel. According to the pilot, prior to the mishap the fuel quantity gage had indicated 12 gallons remained in the tank, and evidently the fuel float had become stuck in the tank. The FAA coordinator reported that the conditions which may have produced the discrepancy could not be duplicated during the postimpact testing. However, during the examination when the fuel quantity sender arm was manipulated the float could be induced to hang up vertically. Then, when lowered to the bottom of the tank, the fuel quantity would read 12 gallons. All other system circuitry and component tests were negative. No specific mechanical defect was established.

Factual Information

On February 13, 1998, at 1130 hours Pacific standard time, a Hiller UH-12E, N4027Z, owned and operated by Chico Aerial Applicators, Chico, California, experienced a total loss of engine power during an aerial application flight. The pilot reported that he was too low to enter an autorotation, and the helicopter touched down hard in an open field a few miles from the Chico Airport. The helicopter was substantially damaged, and the commercial pilot was not injured. Visual meteorological conditions prevailed. The flight originated from Chico at 1100. The pilot verbally stated that seconds prior to experiencing the loss of engine power he heard two loud "bang" sounds and then the engine failed. In the pilot's completed report, he reported that the engine lost power at 40 feet above ground level while he was spraying an orchard. The pilot further reported that an examination of the helicopter revealed it was out of fuel. According to the pilot, prior to and following the mishap, the fuel quantity gage indicated 12 gallons remained in the tank and evidently the fuel float had become stuck in the tank. According to the Federal Aviation Administration (FAA) coordinator, the fuel tank quantity gage and its associated erroneous reading was examined and the discrepancy that the pilot reportedly observed could not be duplicated during the postimpact examination. The FAA reported that, however, during the examination when the fuel quantity sender arm was manipulated the float could be induced to hang up vertically. Then, when lowered to the bottom of the tank, the fuel quantity would read 12 gallons. All other system circuitry and component tests were negative. No specific mechanical defect was established.

Probable Cause and Findings

Fuel exhaustion due to the pilot's failure to ensure that an adequate fuel supply was onboard. A contributing factor was related to the fuel quantity gage's erroneous indication of fuel.

 

Source: NTSB Aviation Accident Database

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