ERA20FA022 · Beech 58 Undesignat

After experiencing an issue with a fluctuating fuel transducer on the right engine, the pilot hired a mechanic, who removed the fuel flow transducers from both engines and reinstalled them on the opposite engine to determine if there was an instrument indication problem or a fuel flow sensor issue. After performing the maintenance, the pilot and mechanic performed several ground runs of the engines without incident. They then departed on a local flight. Review of air traffic control communications revealed that the pilot initially taxied to the wrong runway, and after takeoff, failed to acknowledge multiple calls from the controller, did not follow the controller’s instructions, and thought that he was flying west when he was flying toward the east. About 2 minutes after takeoff, a transmission was received from the accident airplane requesting to return to the airport. The airplane impacted a four-lane divided highway and was consumed by a postcrash fire. Examination of the airplane, both engines, and their respective fuel transducers revealed no mechanical discrepancies that would have precluded normal operation. Autopsy of the pilot revealed severe abdominal aortic atherosclerotic disease, which increased his risk for an extra-cardiovascular event such as a stroke. Toxicology testing detected the impairing medication diazepam and its metabolite at the lower end of its therapeutic range in the pilot’s chest blood. Toxicology testing also revealed that the primary psychoactive compound of marijuana, THC, was detected in the pilot’s blood just above the laboratory’s detection limit. The THC concentration did not suggest recent use and it is unlikely that the pilot’s use of marijuana contributed to the accident. The circumstances of the accident indicate that the pilot did not perform in a manner consistent with his level of skill and experience, and it is likely that his loss of control was the result of physiological impairment; however, whether his impairment was the result of an acute medical event and/or his use of impairing medications could not be determined based on the available information.

Verbatim NTSB analysis and probable cause from the NTSB dataset