ERA10LA026 · Fuji LM1

In the 2 years prior the accident, the Japanese military airplane was flown less than 30 hours because the owner had had surrendered his Federal Aviation Administration medical certificate and had moved to another state. A pilot-rated acquaintance agreed to assist the owner by flying him to the airplane and then accompanying him back home in it. The retrieval flight was filed as an instrument flight rules flight. Visual flight rules conditions prevailed at the departure airport. After takeoff, as the airplane turned onto the crosswind leg, it was observed to cease its climb and then roll into a stall/spin until impact with the ground.

Witnesses reported that the propeller was not rotating, but physical evidence was inconclusive. The airplane was not equipped with a stall warning system. Examination of the wreckage did not reveal any preimpact mechanical failures, but both the ignition switch and the fuel selector valve were found in their respective "off" positions. While it is clear that the airplane stalled and impacted the ground in uncontrolled flight, the precipitating event(s) could not be determined. Equal cases could be made that the positions of the ignition switch and the fuel selector valve were causal to the stall (through inadvertent manipulation, and resulting distraction), or that they were reactions to the stall and imminent ground impact (to reduce the fire hazard).

Toxicological testing detected Donepezil and another medication in the owner's liver and kidney tissue. Donepezil (also known by the trade name "Aricept") was used almost exclusively to help treat the cognitive decline associated with Alzheimer’s disease. Neither medication would normally be expected to result in significant impairment, but the cognitive decline associated with Alzheimer’s disease would be expected to result in impairment. The investigation was unable to determine when or why the Donepezil was prescribed, or the cognitive condition of the owner. The available evidence suggested that his cognitive condition, if it was in fact diminished, was not apparent to others.

The specific roles and actions of the two pilots during the accident flight could not be determined, but the evidence suggested that the owner acted as pilot in command and that he operated the controls. The investigation was unable to determine the extent of the acquaintance's knowledge of the owner's cognitive abilities and limitations or whether he was aware that the owner no longer held a valid FAA medical certificate. Evidence suggested that the acquaintance had little to no knowledge about the airplane’s operation or performance characteristics. The effect of the owner's extensive aviation experience on the acquaintance's judgment and decision-making could not be determined.

Verbatim NTSB analysis and probable cause from the NTSB dataset