Accident Details
A private pilot was conducting a local personal flight in a helicopter. During the flight, the pilot executed a forced landing after the helicopter experienced an apparent loss of power. The helicopter subsequently collided with trees and terrain.
Witness Observations
Witnesses reported that the helicopter appeared to lose power, as if it had run out of fuel, and that it descended rapidly toward a road. The aircraft then struck trees and terrain.
Investigation Findings
An on-scene examination revealed no evidence of preimpact mechanical anomalies with either the flight controls or the engine. Fuel samples were taken from the helicopter's carburetor and fuel tanks. Laboratory analysis identified water in the carburetor fuel, while the fuel tanks showed no contamination. A fuel sample was also collected from the pilot's storage tank at his residence. This tank was located under a building without rain gutters, and the sample contained a layer of water and sediment. Detailed analysis of the water and sediment found in the carburetor fuel indicated that the contamination was consistent with runoff from a building's roof.
Engine Test
After the accident, the helicopter's engine was provided with fresh fuel and was operated successfully, confirming that the engine itself was not mechanically defective.
Additional Information
An aviation mechanic recounted that approximately two weeks prior to the accident, the pilot had lost one of the helicopter's fuel caps and had obtained a replacement cap.