Accident Overview
A helicopter experienced a loss of power during initial climb immediately after takeoff. The pilot maneuvered to reach a clear area but struck trees during the descent.
Post-Crash Examination
Post-crash examination revealed no mechanical malfunction with either the engine or carburetor. However, the carburetor had been subjected to a post-crash fire, and its fuel metering orifices could not be bench tested.
Fuel Sample Analysis
Fuel samples were taken from the helicopter's fuel tank prior to the accident, and from the fueling hose of a portable fuel truck. A fuels testing lab examined the samples and found they contained 1,2-Benzenedicarboxylic acid, bis(2-ethylhexyl) ester. The pre-accident aircraft fuel sample contained a submersed glob of clear substance similar to that observed by the pilot seeping from the cut ends of the fueling hose. Testing revealed that the 'soluble gum' consisted of the same compound and that nearly 100% of the gum was soluble in the fuel.
Fueling Hose Information
The operator was advised by the local distributor of the 'Versicon' hose that the hose was acceptable for use with aviation fuels. Specifications provided by the manufacturer, HBD Industries, included a note stating 'Not recommended for the variety of unleaded gas existing presently.'