Accident Sequence
A lineman who spoke with the pilot/owner before departure reported that the pilot stated he and the flight instructor were going to practice for about an hour. The flight instructor had provided initial instruction to the pilot/owner in the accident airplane and flew with him regularly, including about 58 hours of dual instruction in that specific aircraft. The pilot/owner had logged approximately 51 hours of pilot-in-command time in the airplane make and model, and it is likely he was the pilot flying.
Several witnesses observed the accident sequence. One witness reported seeing the airplane pull up into vertical flight, bank left, rotate nose down, and then impact the ground. Another witness observed the airplane traveling from east to west, turn sharply, and then go north of the runway before hitting the ground. A third witness, who was a pilot, stated that he saw the airplane enter a left bank and then a nose-down attitude of about 75 degrees at an altitude of approximately 300 feet above ground level, which was too low to recover.
It is likely that the pilot was attempting a go-around and pitched the airplane up excessively, subsequently losing control. The airplane impacted flat desert terrain about 100 feet north of the active runway at about the midfield point in a steep nose-down, left-wing-low attitude.
Aircraft Examination
The airplane was destroyed by postimpact forces and thermal damage. All components necessary for flight were accounted for at the accident site. A postaccident examination of the airframe and both engines revealed no anomalies that would have precluded normal operation. Examination of both propellers showed rotational scoring and twisting of the blades consistent with power being applied during the impact sequence. No anomalies were noted with either propeller that would have precluded normal operation.
Toxicological Findings
Toxicological testing of the pilot was negative for drugs and alcohol. The flight instructor’s toxicology report revealed the presence of tetrahydrocannabinol (THC). Given the elevated levels of metabolite in the urine and kidney, the absence of quantifiable THC in the urine, and the low level of THC in the kidney and liver, it is likely that the flight instructor most recently used marijuana at least several hours before the accident. However, the effects of marijuana use on the flight instructor’s judgment and performance at the time of the accident could not be determined.
A review of the flight instructor’s personal medical records indicated several medical conditions that would have been grounds for denying his airman medical certificate. The ongoing treatment of his conditions with more than one sedating benzodiazepine, including oxazepam, simultaneously would also likely not have been allowed. However, none of the prescribed, actively sedating medications were found in the flight instructor’s tissues, and oxazepam was only found in the urine, suggesting that the flight instructor used the medication many hours and possibly several days before the accident. The toxicology findings indicate that the flight instructor likely did not experience any impairment from the benzodiazepine medication itself; however, the cognitive effects from the underlying mood disturbance could not be determined.