A lineman who spoke with the pilot/owner of the Beech E90 before its departure from Casa Grande Airport in Arizona reported that the pilot stated that he and a flight instructor were going out to practice for about an hour.
The owner had a multiengine certificate and approximately 663 hours in multiengine airplanes, including 112 in the Beech E90.
The flight instructor, who had 8,552 hours, including 325 in the Beech E90, had given the owner his initial instruction in the airplane and flew with him regularly.
There were several witnesses to the accident. One reported seeing the airplane pull up into vertical flight, bank left, rotate nose down, and then crash and burst into flames.
Another witness reported observing the airplane go from east to west, turn sharply, and then go north of the runway before it crashed.
A third witness, who was a pilot, said the plane banked to the left, then entered a nose-down attitude of about 75° at an altitude of about 300 feet above ground level, which was too low to recover.
Both the owner and CFI were killed in the crash.
Investigators speculated that the pilot was attempting a go-around and pitched up excessively and subsequently lost control, which resulted in the airplane hitting flat desert terrain about 100 feet north of the runway at about the midfield point in a steep nose-down, left-wing-low attitude.
The post-accident examination of the airframe and both engines revealed no anomalies that would have precluded normal operation. Additionally, an examination of both propellers revealed rotational scoring and twisting of the blades consistent with there being power during the impact sequence.
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 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 that he had a number of medical conditions that would have been grounds for denying his medical certificate. The ongoing treatment of his conditions with more than one sedating benzodiazepine, including oxazepam, hours and possibly several days before the accident indicate that he likely did not experience any impairment from the medication itself, however, the cognitive effects from the underlying mood disturbance could not be determined.
The NTSB determined the probable cause was the pilot’s loss of control after pitching it excessively nose up during a go-around, which resulted in a subsequent aerodynamic stall/spin.
NTSB Identification: WPR13FA115
This February 2013 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.