Aviation Accident Summaries

Aviation Accident Summary ERA13LA127

Merritt Island, FL, USA

Aircraft #1

N5072R

HILLER UH-12B

Analysis

The pilot reported that, during the initial climb, when the helicopter was about 75 feet above ground level, he heard a "pop" noise, and the engine then lost total power. The pilot performed an autorotation, and the helicopter subsequently landed hard on a taxiway. A postaccident examination of the helicopter revealed that the fuel supply line from the gascolator to the mechanical fuel pump was not attached and that the fuel supply line and fitting were broken where they attached to the gascolator. Examination determined that the fuel fitting separated due to overstress. It is likely that, when the fuel supply line fitting broke off of the gascolator, it resulted in a loss of fuel supply to the engine, subsequent fuel starvation, and a total loss of engine power.

Factual Information

On February 6, 2013, about 1810 eastern standard time, a Hiller UH-12B, N5072R, impacted a taxiway after the helicopter experienced a total loss of engine power after takeoff from the Merritt Island Airport (COI), Merritt Island, Florida. One passenger sustained minor injuries, and the commercial pilot and another passenger were not injured. The helicopter was owned by a corporation and operated by Florida Biplanes under Title 14 Code of Federal Regulations Part 91 as a sightseeing flight. Visual meteorological conditions prevailed and no flight plan was filed for the local flight. According to the pilot, he performed a preflight and engine run up with no anomalies noted. In addition, he performed five sightseeing flights prior to the accident flight. On the sixth flight, during the initial climb, about 75 feet above ground level, the pilot heard a "pop" noise just prior to the loss of engine power. He performed an autorotation and the helicopter impacted a taxiway. A postaccident examination of the wreckage by a Federal Aviation Administration inspector revealed that the helicopter incurred substantial damage to the engine mounts, main rotor blades, tail rotor, and tail boom. The inspector disconnected the fuel supply line from the electric fuel pump to the carburetor and operated the fuel pump; however, no fuel was observed in the fuel line. He disconnected the fuel supply line from the gascolator to the electric fuel pump and noted no fuel in the supply line and removed the fuel filter and examined it with no debris or obstructions noted. He verified fuel was in the gascolator drain. The inspector then discovered the fuel supply line from the gascolator to the mechanical fuel pump was not attached and that the fuel supply line and fitting was broken where it attached to the gascolator. The fuel fitting was inspected by the NTSB materials laboratory in Washington, D. C. Microscopic analysis of the part revealed that both ends of the fitting failed due to overstress. According to the helicopter maintenance records, the most recent annual inspection was performed on May 1, 2012. At that time, the helicopter had a total tachometer time of 75.2 hours. At the time of the accident, the tachometer indicated 114.6 hours. According to the Hiller Helicopters Model UH-12B Flight Manual, the fuel system consists of a fuel tank, an engine-driven fuel pump, an electrical auxiliary fuel pump, a fuel quantity gauge, strainer, shut-off valve, and the necessary lines and fittings.

Probable Cause and Findings

A total loss of engine power due to fuel starvation, which resulted from an overstress failure of a fitting on the fuel supply line and led to an autorotation and hard landing.

 

Source: NTSB Aviation Accident Database

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