Mooney M20E N9224M accident near San Antonio, Texas

Probable cause

The pilot's inadvertent overboost of the turbocharged engine during initial climb, which resulted in detonation and a partial loss of engine power followed by the pilot's failure to maintain airspeed and the instructor's delayed remedial action, which resulted in an aerodynamic stall. Contributing to the accident was the instructor's improper judgment in acting as a pilot with disqualifying medical conditions and while taking impairing medications.

NTSB analysis

After takeoff, when the airplane was about 200 feet above ground level, the tower controller noticed the airplane in a right turn and instructed the pilot to make a left turn to the northeast. An incomplete radio call from the pilot indicated he was turning back. The controller saw the airplane flying southwest at a low altitude and shortly thereafter saw a cloud of black smoke about 1/2 mile south of the airport. Two other witnesses saw the airplane suddenly roll to the right and enter a nose-down dive, indicative of a stall. Evidence at the scene showed that the airplane impacted terrain in a nose-down attitude and came to rest inverted. There was a postimpact explosion and fire.

Based on the pilot's lack of previous experience in flying an airplane with a turbocharged engine, and the evidence of detonation found in the postaccident examination of the engine, it is likely that the pilot inadvertently overboosted the engine during takeoff and initial climb, which resulted in a partial loss of engine power. Based on the sudden change of flight direction, it is likely that the pilot became preoccupied with the partial loss of engine power and lost control of the airplane. The instructor should have been able to successfully complete an emergency off-field landing, but it does not appear that he attempted one.

This instructor had been using a series of psychotropic medications, culminating in his use of paroxetine, which would have been disqualifying for him to act as a required flight crewmember. Major depression itself is associated with significant cognitive degradation, particularly in executive functioning. While the exact degree of impairment from the instructor's incompletely controlled depression and his use of impairing medications at the time of the accident is impossible to determine, it is likely that there was some impairment in cognitive functioning as a result of his uncontrolled depression. Further, the instructor had sleep apnea, and that, combined with his recent use of sedating medications, chronic pain, and depression may well have contributed to his failure to take control of the airplane and conduct an emergency of-field landing after the partial loss of engine power.

Text from the NTSB. Open the NTSB docket for CEN12FA170 for the full record.