NTSB investigators either traveled in support of this investigation or conducted a significant amount of investigative work without any travel, and used data obtained from various sources to prepare this aircraft accident report.
The flight was intended for the dispersal of the passenger's deceased husband's ashes, which took place over a river. The dispersal procedure called for the ashes to be placed in a bag that was cinched at the top and tethered to the airframe inside the cabin. The pilot was required to slow the airplane and fly it in a banking maneuver, and the passenger in the aft cockpit would then throw the bag out through the opened aft canopy and retrieve the bag once the ashes had been released into the slipstream.
Witnesses described the airplane flying low and slow over the river channel and then rolling left and nose-diving into the water.
Examination of the wreckage revealed that the rear sliding canopy was most likely open at the time of impact. The ash dispersal bag was not located. Therefore, based on the accident location, the observed maneuver, and the open rear canopy, the accident likely occurred at some point during the ash dispersal sequence.
Postaccident examination did not reveal any anomalies with the airframe or engine that would have precluded normal operation. Several maintenance discrepancies were found; however, none would have resulted in the flight maneuver observed. Although the airplane was required to have undergone an inspection on an annual basis, the last inspection had occurred 22 months before the accident. Additionally, the pilot's last flight review had occurred 29 months before the accident, rather than the 24 months required.
The airplane was equipped with dual controls and a swiveling rear seat; the seat was found in the forward and locked position, and the rear control stick appeared to have been removed and stowed. Therefore, passenger interference with the flight controls was unlikely.
The pilot's autopsy revealed significant coronary artery disease, which review of his medical records indicated was apparently undiagnosed. Therefore, he was susceptible to an acute cardiac event or stroke (although the degree of blunt force injury prevented the evaluation of his brain.)
Toxicology testing on the pilot identified sertraline, its metabolite desmethylsertraline, and trazodone in urine and cavity blood. According to his medical records, the pilot had insufficiently treated sleep disorders and had been taking trazodone as a sleep aid. Trazodone can increase the potential for arrhythmias in patients with pre-existing cardiac disease. In addition, the pilot had longstanding depression, and he had sufficient neurocognitive symptoms the preceding year from a series of concussions that he had stopped flying, driving, and working for several months. While the pilot's depression and symptoms related to his concussion were described as in remission, he had not undergone formal psychometric testing to evaluate these issues, and he had been self-medicating with sertraline, which he had been obtaining from another country out of concern about Federal Aviation Administration (FAA) regulations. He did not report the use of sertraline and trazodone to his FAA medical examiner.
Chronically insufficient sleep can lead to chronic fatigue, which results in impaired attentiveness and slowed hazard detection and response times. The use of sleep aids such as trazodone in patients with inadequately treated sleep apnea may worsen the effects of sleep apnea and both directly and indirectly increase the degree of fatigue. The pilot's failure to have obtained the required condition inspection of the airplane or his required flight review may indicate some difficulty in attention and organization.
Thus, the pilot had a number of medical conditions which could have contributed to him becoming inattentive, distracted, or debilitated during flight. He could have had a stroke or sudden cardiac event leading to a loss of control. Further, the negative cognitive effects from chronic fatigue resulting from his inadequately treated sleep disorders, chronic depression, and neurocognitive deficits from postconcussive syndrome would have increased the likelihood of the pilot failing to effectively manage airplane control while either setting up for, or during performance of the ash dispersal maneuvers.