Vans RV-12 — Niceville, FL

What happened

The owner of the airplane, who was a flight instructor, completed a 100-hour inspection on the light sport airplane before another flight instructor departed in the airplane on an instructional flight. That instructor reported that, during takeoff, the engine was not producing full power and experienced a momentary loss of power. He returned to the airport and landed uneventfully. The owner examined the airplane and concluded that the loss of power was likely due to vapor lock. They left the engine cowl open to cool the engine, and about 2 hours later, the owner/flight instructor departed with a student on the accident flight. The student stated that, after takeoff, the engine sputtered and the flight instructor took control. He had no recollection of the accident other than that the altimeter indicated 240 ft.

Recorded data revealed that the airplane experienced a significant reduction in engine rpm for unknown reasons about 35 seconds after the takeoff. The throttle was reduced, and the airplane reached a maximum altitude of about 250 ft at an airspeed of 44 knots. Vertical acceleration began to oscillate, the airplane was banking to the left and reached a 68° left wing down bank angle. It then began to descend rapidly; the throttle was advanced and engine speed increased; however, shortly thereafter, the airplane impacted the ground. Examination of the airframe and engine did not reveal any preimpact anomalies. The airplane's flight track and recorded data were consistent with it entering a stall during a left turn back toward the airport.

An editorial "what led to it / how to avoid it" analysis for this accident is generated separately and will appear here.