NTSB Identification: LAX99FA052 . General Aviation
Accident occurred Friday, December 18, 1998 in TUCSON, AZ
Aircraft: Parkman VARI-EZE, registration: N81EZ
Injuries: 1 Fatal.
This was the maiden flight in the aircraft, and during construction,
the pilot made numerous design modifications to the airplane which had
changed the flight and performance characteristics. Instead of the
airplane's engines recommended by the designer, the pilot had
installed a GM Geo Metro automobile engine, which the
pilot altered by the addition of a Mitsubishi turbocharger. The pilot
also altered the fuel computer chip to adjust the fuel flow,
attempting to achieve a 2-gallon-per-hour consumption rate. The pilot
told associates that the engine produced 78 hp at 4,800 rpm. Engine
technical data showed the actual power output of the unmodified engine
to be 79 hp at 6,000 rpm. Severe detonation was found in the engine
during postaccident examination and it is believed that it most likely
would produce only 55 percent of rated power. Following takeoff,
witnesses saw the aircraft in a nose high attitude and it never
achieved more than 100 feet agl. Some witnesses said the nose attitude
was as high as 15 to 20 degrees just before the crash. The pilot
radioed that he was having a problem and said he had to put
the aircraft down. The airplane collided with a tree during the
attempted forced landing and a postcrash fire consumed the wreckage.
The National Transportation Safety Board determines the probable
cause(s) of this accident as follows:
The pilot's failure to attain and maintain an adequate flying airspeed
during the aircraft's maiden flight, which resulted in a stall/mush
condition. Also causal was the pilot/builder's decision to modify the
engine and the fuel system control microchip, which resulted in
detonation and a severe reduction in power output, and led
directly to the pilot's inability to attain and maintain airspeed.
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