NTSB Identification: LAX99FA052.
The docket is stored in the Docket Management System (DMS). Please contact Records Management Division
Accident occurred Friday, December 18, 1998 in TUCSON, AZ
Probable Cause Approval Date: 09/28/2000
Aircraft: Parkman VARI-EZE, registration: N81EZ
Injuries: 1 Fatal.
NTSB investigators either traveled in support of this investigation or conducted a significant amount of investigative work without any travel, and used data obtained from various sources to prepare this aircraft accident report.
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 to be: 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. Full narrative available
Index for Dec1998 | Index of months