LAX03FA135 · Beech A36

The airplane lifted off near the end of the runway, snagged the airport boundary fence, crossed a canyon, and then collided with terrain. Runway 21 was 5,132 feet long, 75 feet wide, and the airport elevation was 4,827 feet. The density altitude was calculated at 6,435 feet. Witnesses noted that the airplane did not seem to accelerate and was rolling very slowly as it passed the midfield point. The engine did not sound like it was producing much power, yet the engine tones stayed steady and the engine sounded smooth. Several of the witnesses noted that the flaps were partially down. The witnesses thought that the pilot would abort the takeoff; however, the airplane continued down the runway and was still on the ground about 80 percent of the way down the runway. Then the pilot rotated it to a takeoff attitude, and broke ground with an extremely nose high attitude. The airplane only attained an altitude of several feet. The landing gear caught the upper strands of the airport boundary fence. The airplane then collided with the far side of a canyon that bordered the airport. The operator had a form that they used for weight and balance and performance. They required pilots to complete the form prior to each flight. The form provided spaces for pilots to record pertinent data, and log computed parameters. Those parameters included takeoff weight, density altitude, runway length, rotation speed, takeoff distance, takeoff distance over a 50-foot obstacle, rate of climb, and landing distance. Calculations for the given takeoff conditions indicated that the airplane should have had a ground roll of 1,900 feet, and would clear a 50-foot obstacle at 2,100 feet. The airplane had an altitude compensating fuel pump installed. The pump would automatically lean or enrich the engine's fuel mixture as the airplane changed altitude. The before takeoff checklist in Section IV of the Pilot Operating Handbook instructed the pilot to takeoff with the mixture in the full rich position. Other instructors from the operator who had flown with the accident instructor indicated that contrary to the instructions in the POH, they all leaned the engine prior to takeoff from high density altitude airports. The spark plugs indicated operation with an excessively lean mixture. Investigators noted no other anomalies with the airframe or engine that would have precluded normal operation.

Verbatim NTSB analysis and probable cause from the NTSB dataset