Aircraft Accident/Incident Report

Chugiak, Alaska 99567
Saturday, March 13, 2010 17:00 AKD

The solo private pilot was on a personal local flight in a ski-equipped experimental light sport weight-shift-control, pusher aircraft (Trike) under Title 14, CFR Part 91. He died as a result of the accident, and was found about 10 feet from the aircraft. The accident aircraft was found near a railroad track by the crew of a passing train. According to his logbook entries, the pilot had 233 hours of powered flight experience, and logged 4.5 hours of flight in the past 15 months. According to a friend, the accident flight was his first flight of this year. No evidence of a current required aircraft annual condition inspection was discovered. The pilot had replaced the aircraft’s original engine with a more powerful 100 horsepower engine, and it was also equipped with a digital video camera mounted on the forward support strut facing forward. A review of the accident flight video showed the control tube upper support cables moving in and out of the left and right sides of the camera’s field of view. The nose of the aircraft and the single front ski could also be seen in the video. Before the accident, the aircraft was flying at a low altitude over snow-covered flats to the west of the accident site. It made a steep climbing right turn to the east and continued to climb at a very steep angle. The angle of bank approached 90 degrees relative to the horizon, the climb appeared to stop, and the nose fell through the horizon rapidly. A frame-by-frame review showed that prior to the nose falling through the horizon, the wind screen was pushed forward into the cameras field of view, and then to the left, indicating that the aircraft was descending backward. The camera recorded an event consistent with a aerodynamic tumble. During the tumble, the camera mount broke and the camera drifted away and fell alongside the tumbling aircraft, continuing to record the aircraft. The aircraft had been equipped with automotive style lap belts and shoulder harnesses, with plastic push-button receiver type buckles. The pilot's lap belt buckle came apart during the tumble, likely due to the airframe flexing between the shoulder harness mast attachment and the floor mounted lap belt attachment, which placed a tension load on the pilot's lap belt buckle. The camera attained a position below the aircraft, and showed the pilot separate from the aircraft above the treetops. The accident aircraft was originally constructed as a two-place ultralight trainer, and later transitioned to experimental light sport category aircraft. Transitioned aircraft were not subject to the construction standards of ELSA, and therefore there was no standard for occupant restraint systems.

The pilot's decision to pitch the aircraft excessively during a steep climbing maneuver, resulting in a loss of control and an aerodynamic tumble.