Accident Overview
A pilot reported an accident during takeoff from a taxiway at an airport where a NOTAM had closed the sole runway, permitting takeoffs and landings from the parallel taxiway. During the takeoff roll, the airplane struck a dip in the pavement and became airborne unintentionally. The pilot heard the stall warning horn and pitched the nose forward, but the airplane drifted left into a ditch, causing the nose and main landing gear to collapse. Both wings sustained substantial damage.
Pilot Actions and Conditions
The pilot indicated no mechanical malfunctions or failures that would have prevented normal operation. The takeoff weight was approximately 1 pound below the maximum allowable takeoff weight, and the pilot attempted a short-field takeoff technique. Density altitude at departure time was 3,168 feet, with a pressure altitude of 579 feet and a temperature of 93°F (34°C).
Video Evidence
Airport surveillance video showed the airplane's takeoff roll. About 2,050 feet into the roll, the airplane pitched up, lifting the nose and left main landing gear off the ground, but it did not climb. It touched back down and attempted to become airborne again approximately 300 feet later. The nose and main landing gear momentarily left the ground, but the airplane quickly settled back and moved out of camera view.
Performance Considerations
The Federal Aviation Administration provides guidance on how density altitude affects aircraft performance. According to the FAA Koch Chart, the airplane likely experienced a 35% increase in normal takeoff distance and a 25% decrease in normal climb rate. The FAA Airplane Flying Handbook notes that reduced drag in ground effect may allow an airplane to become airborne below recommended airspeed, but climbing out of ground effect with insufficient airspeed can result in marginal climb performance, especially under high-density altitude, high temperature, or maximum gross weight conditions.
Probable Cause
It is likely that the pilot exceeded the critical angle of attack during the two initial climbs, and the airplane did not exit ground effect due to insufficient airspeed at rotation.