Accident Summary
On September 24, 2020, at 1624 Pacific daylight time, a Great Lakes 2T-AI-2 biplane, registration N3617L, was substantially damaged when it collided with a tree and crashed in a parking lot outside the airport perimeter near San Diego, California. The aircraft was engaged in a Title 14 Code of Federal Regulations Part 91 instructional flight. The flight instructor sustained serious injuries, and the pilot receiving instruction suffered minor injuries.
Flight Narrative
The flight instructor reported that the airplane underwent a preflight inspection and was fueled before the first flight of the day. The student pilot was on the flight controls during takeoff and the airplane climbed at 70-80 mph. At about 350 ft above ground level, the student noticed a lack of climb performance. The instructor took control and began troubleshooting by verifying that the throttle, mixture, and propeller controls were full forward and the fuel shutoff valve was in the ON position. Due to obstructions ahead, he initiated a steep turn back toward the runway and established a 75-mph glide. Seeing trees in the path, he attempted to turn inside of them while maintaining controlled flight and adequate airspeed. The airplane subsequently struck a tree and crashed in a parking lot. A video surveillance camera captured the airplane in a steep descent after the impact with the tree.
Witness Account
A witness at the airport reported hearing the engine sputtering and observed the airplane during takeoff. The airplane leveled off at about 300 ft above ground level while making a right turn. The airspeed decreased dramatically, and the nose of the airplane began to pitch down. By the time the airplane completed a 180-degree turn, the nose was pitched down approximately 40 degrees. The airplane recovered enough airspeed to raise the nose, but then struck a tree.
Aircraft Examination
Post-accident examination revealed that the engine was partially torn from its mounting points and sustained significant impact damage. The exhaust system was crushed, and the fuel servo broke away from the oil sump. The propeller had separated from the crankshaft about 1 inch aft of the propeller flange; both blades were intact and straight, with no evidence of chordwise scratches or leading-edge nicks. The fuel selector valve sustained impact damage and was found in the OFF position, but fuel was present in the fuel lines and components downstream. The engine and electrically driven fuel pumps were intact. When the crankshaft was rotated, accessory gear and valve train continuity was established. All eight spark plugs were removed and displayed normal operating signatures. Magneto-to-engine timing was confirmed, and both magnetos sparked with the impulse coupling. A drill rotated the magnetos to speed, and spark was produced on each remaining undamaged ignition lead. Examination of the engine and fuel servo revealed no anomalies.