NTSB Identification: LAX99LA293.
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Accident occurred Wednesday, September 01, 1999 in DELHI, CA
Probable Cause Approval Date: 05/09/2001
Aircraft: Bell 206B, registration: N59551
Injuries: 1 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 pilot reported that the engine rpm began decreasing during the takeoff climb, about 200 to 300 feet agl, while he was over a grove of trees. He extended his autorotative glide to make it past the trees, which resulted in a further decrease of main rotor rpm. The helicopter landed hard, about 20 to 30 miles per hour of forward velocity, and rolled over. Postcrash examination by a FAA inspector revealed no evidence of mechanical malfunction; however, the fluid found in the airframe fuel filter and mechanical fuel pump screen was noted to be about 90 percent water. About 30 percent of the fluid found in the Ceco fuel system screen was also water. The FAA inspector reported that the fuel cap was loose in the opening and did not appear to seal properly; the shaft seal was worn in the cap and the cap locking mechanism was not adjusted properly. When the fuel cap was removed, the inspector noted that the bottom of the fuel filler opening was deformed from the fuel nozzles being inserted in the opening. The pilot reported that he had washed the helicopter the night before the accident. He further reported that during the preflight he had drained fuel from the airframe fuel filter and fuel sump and hadn't noted any water or contaminants.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: The loss of engine power due to the pilot's inadequate preflight, which failed to detect water contamination of the fuel system. The operator's inadequate maintenance of the loose fitting fuel cap and the deformed filler opening, which allowed water to leak into the fuel tank, were also causal. A factor in the accident was the trees along the autorotative flight path, which required the pilot to stretch the glide and resulted in a low main rotor rpm situation for the landing flare. Full narrative available
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