NTSB Identification: ERA11LA197
14 CFR Part 91: General Aviation
Accident occurred Saturday, March 19, 2011 in Lincoln, AL
Probable Cause Approval Date: 10/03/2011
Aircraft: BURR ANDREW E XIV ROTORWAY EXEC 162F, registration: N192AB
Injuries: 2 Uninjured.

NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

The experimental helicopter was equipped with a modified kit engine. After completing 1.7 hours of instruction, the instructor and pilot landed uneventfully and fueled the helicopter. Shortly after departure for a nearby airport, about 600 feet above ground level, the helicopter experienced a total loss of engine power. The instructor took control of the helicopter and performed an autorotation to a field; however, the helicopter rolled during touchdown and sustained substantial damage.

The experimental engine used the engine case and crankshaft of the kit engine, but an additional 40 horsepower was achieved with the use of modified cylinders, valves, and two digital engine control units (DECUs). If the DECUs sensed a fuel flow disruption, they would reduce engine power to idle. Examination of the wreckage revealed that there was adequate fuel on board. The fuel and fuel filter were absent of contamination. The engine was started and ran continuously for approximately 10 minutes.

According to the pilot, who was also the owner of the helicopter, the fuel line was routed next to a hot water line, and a radiator hose was used to separate the two lines. During the accident flight, just prior to the loss of engine power, the pilot noted that the engine was hot, the water temperature was 210 degrees Fahrenheit (F), and the oil temperature was 165 degrees F. The pilot added that the water temperature should only usually be about 10 degrees F hotter than the oil temperature. He believed that heat from the water line caused a vapor lock in the fuel line. Subsequently, when the DECUs sensed a disruption of fuel flow, they reduced engine power to idle; however, that theory could not be verified during a postaccident wreckage examination or an engine test run. The ambient temperature at the time of the accident was 81 degrees F.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

A total loss of engine power during cruise flight for undetermined reasons.

Full narrative available

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