Accident Overview
During an attempted takeoff, the airplane settled back to the ground and impacted a field approximately 1 mile south of the airport. The pilot reported that prior to the flight, he conducted performance calculations for the airplane to ensure it could depart from the higher altitude airport. The pilot stated that his instructor had advised him to use an airplane empty weight of 1,624 pounds in the calculations, which the instructor described as typical for the airplane type and applicable to this specific airplane.
Weight and Performance Data
The Safety Board calculated the airplane's gross weight at 2,767 pounds, which exceeded the maximum certified gross weight of 2,650 pounds by 117 pounds. Even when using the instructor's recommended empty weight, the airplane would have been 47 pounds over the maximum gross weight. Performance calculations from the Pilot Operating Handbook (POH) indicated a ground roll of 3,118 feet (3,464 feet with zero wind) and a distance to clear a 50-foot obstacle of 3,741 feet (4,157 feet with zero wind). The predicted rate of climb was 327 feet per minute.
Runway and Environmental Conditions
The runway chosen for departure was 8,999 feet long with an elevation of 6,609 feet mean sea level (msl). The density altitude was calculated to be 7,728 feet msl. The POH notes that prior to takeoff from fields above 3,000 feet elevation, the mixture should be leaned to achieve maximum power during a full throttle, static run-up. The pilot had configured the airplane with the flaps retracted and the mixture control in the full forward (rich) position.
Post-Accident Examination
Following the accident, the spark plugs were removed and found to be black and sooty, indicating the engine was running rich. The engine was subsequently test-run and no operational anomalies were noted.
Probable Cause
[Not specified in source]