Accident Overview
A single-engine airplane crashed during a flight intended to practice commercial maneuvers. The airplane, owned by a private pilot who was also on board, had flown an earlier instructional flight with a certified flight instructor (CFI) from runway 27. On that previous flight, the crew executed a practice forced landing using a 270-degree turn back to the airport. During the accident flight, the same crew departed again from runway 27. In the vicinity where the earlier forced landing had been initiated, witnesses reported hearing the engine noise decrease. The airplane then began a turn toward the airport, entered a steep descent, and crashed.
Wreckage and Systems Examination
Post-accident examination of the wreckage revealed no evidence of preimpact failure of the engine or airframe. The airplane was equipped with a single throw-over control yoke, which was found positioned on the left side, corresponding to the private pilot's seat. According to the Pilot's Operating Handbook and Federal Aviation Regulations, dual controls are required for flight instruction.
Toxicology Results
Toxicology tests on the private pilot detected 0.003 mcg/ml of tetrahydrocannabinol (marijuana) and 0.004 mcg/ml of tetrahydrocannabinol carboxylic acid (a metabolite of marijuana) in kidney fluid, and 0.006 mcg/ml of tetrahydrocannabinol carboxylic acid in liver fluid. Toxicology tests on the CFI were negative for all substances tested.
Observations
The accident occurred during a maneuver similar to the practice forced landing performed on the previous flight. The yoke was in the private pilot's position, not in the CFI's position, despite the requirement for dual controls. The investigation did not identify a mechanical cause for the loss of engine power or the subsequent descent.