Amateur-built Amphibious Trike N440LS accident near Lake Chelan, Washington

Probable cause

The pilot's failure to maintain adequate airspeed during the initial climb, which resulted in an inadvertent aerodynamic stall. Contributing to the accident was the pilot's lack of experience in the float-equipped, weight-shift airplane.

NTSB analysis

The pilot had transported the float-equipped weight-shift amateur-built airplane to the training facility for assistance in having it certified, as well as to receive flight instruction in the airplane. When the flight instructor informed the pilot that his flight training would be postponed for about two weeks, the pilot agreed to wait. The flight instructor cautioned the pilot not to attempt to fly the airplane until he had received adequate training, to which the pilot agreed. Subsequently, the pilot elected to fly the airplane without having received any flight instruction. During the takeoff, witnesses reported observing the airplane climb rapidly, followed by a left wing low, steep nose down attitude prior to impacting the ground with its left wing, consistent with a stall/spin. According to the flight instructor, the airplane's 19-meter wing, known for its lifting capacity, most probably caused the inexperienced pilot to think that he was airborne, when the airplane was only light on its wheels, resulting in the pilot pushing out on the control bar thinking he would climb out. However, not having enough airspeed to sustain flight, the wing stalled. No pre-impact anomalies were reported with the airplane.

Text from the NTSB. Open the NTSB docket for SEA08LA207 for the full record.