Aviation Accident Summaries

Aviation Accident Summary LAX05LA112

Thermal, CA, USA

Aircraft #1

N5311V

Hiller UH-12B

Analysis

The helicopter landed hard and the main rotor blades severed the tail boom following a loss of engine power and an autorotation to the runway surface. The helicopter had just undergone an annual inspection. The pilot said the fuel gauge was reading less than 1/2 full, and that a full fuel tank, approximately 25 gallons, provides about 2 hours of flight. The pilot was supposed to fly the helicopter for a post maintenance flight check to the end of the runway and then return. The pilot continued to fly the helicopter for about 1 hour until the power loss occurred. Post accident examination by the aviation maintenance technician did not reveal any fuel in the fuel tanks. Fixed base operator personnel that assisted following the accident did not see any fuel spill on the ground surrounding the helicopter. The pilot reported refueling the helicopter about 2 1/2 months prior at his local airport. There were no fueling records on file to indicate that the helicopter had been refueled. Post accident examination of the helicopter by a Federal Aviation Administration inspector did not reveal any mechanical anomalies or breeches in the fuel system.

Factual Information

On March 12, 2005, at 1250 Pacific standard time, a Hiller UH-12B, N5311V, lost engine power and made a forced landing at the Jacqueline Cochran Regional Airport, Thermal, California. The private pilot, who was also the registered owner of the helicopter, was operating it under the provisions of 14 CFR Part 91. The pilot and one passenger were not injured. The helicopter sustained substantial damage. The helicopter departed from Bermuda Dunes Airport, Bermuda Dunes, California, located about 9 miles from the accident airport, at 1200. Visual meteorological conditions prevailed, and no flight plan had been filed. The pilot reported that the helicopter had a fuel capacity of 25 usable gallons, a duration of about 2 hours. Prior to his departure from Bermuda Dunes, he did not check the fuel level, but had his mechanic check it. According to the pilot, his mechanic reported that the fuel level was just below the filler neck. The fuel gauge was reading less than 1/2 full. The last time the pilot had flown the helicopter was on January 1, 2005. Following that flight, he topped off the helicopter at Bermuda Dunes Airport and had not flown it until the accident flight. He was doing touch-and-go takeoffs and landings. The accident occurred during the second landing. While on final, approximately 100 feet above ground level, the engine lost power. The pilot performed an autorotation and during the touchdown, the tailboom struck the runway surface. The main rotor blades severed the tailboom. Prior to the power loss, there were no warnings or sounds to indicate a problem, the engine sound, "just went quiet." The accident flight was the first flight following the annual inspection of the helicopter. The aviation maintenance technician (AMT) with inspection authorization had just completed an annual on the helicopter. The pilot was going to fly the helicopter to the end of the runway at Bermuda Dunes and then return. Instead, the pilot departed the airport for the local flight. The fuel gauges were indicating about 1/4-tank. The AMT had looked in the tanks prior to the helicopter lifting off, but was uncertain of the fuel quantity in the fuel tanks. No fuel was drained from the helicopter following the accident. The passenger, the AMT's maintenance helper and relative, reported that the fuel gauges were reading about 1/4 full prior to their departure. A Federal Aviation Administration inspector examined the helicopter in a secure storage location in Porterville, California. The fuel system was intact and about 1 cup of fuel was in the fuel tank. There was no evidence of a mechanical malfunction with the airframe or engine. According to Thermal Fixed Base Operator personnel, there was no fuel spill following the accident, and no fuel was drained from the helicopter prior to its removal from the airport. The FBO employee was not able to verify the fuel quantity in the fuel tank. Fueling records obtained from Bermuda Dunes airport indicated that the helicopter was not refueled since November 2004. Fueling records prior to that date were not retained at the airport.

Probable Cause and Findings

the pilot's inadequate in-flight planning and failure to refuel the helicopter, which resulted in fuel exhaustion.

 

Source: NTSB Aviation Accident Database

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