Attempt at aerobatics fatal for two

The pilot and passenger departed on a local flight in the twin-engine Cessna 401.

According to a witness, the pilot took off from the private grass runway in Salters, S.C., and departed the area for about 10 minutes. The airplane then returned to the airport, where the pilot performed a low pass over the runway and entered a steep climb, followed by a roll.

The airplane entered a nose-low descent, then briefly leveled off in an upright attitude before disappearing behind trees and subsequently hitting terrain. Both the pilot and passenger died in the crash.

The pilot’s toxicology testing was positive for ethanol with 0.185 gm/dl and 0.210 gm/dl in urine and cavity blood samples, respectively. The effects of ethanol are generally well understood: It significantly impairs pilot performance, even at very low levels.

FAA regulations prohibit any person from acting or attempting to act as a crewmember of a civil aircraft while having 0.040 gm/dl or more ethanol in the blood. While the identified ethanol may have come from sources other than ingestion, such as postmortem production, the possibility that the source of some of the ethanol was from ingestion and that pilot was impaired by the effects of ethanol during the accident flight could not be ruled out.

Toxicology also identified a significant amount of diphenhydramin, a sedating antihistamine that causes more sedation than other antihistamines. In a driving simulator study, a single dose of diphenhydramine impaired driving ability more than a blood alcohol concentration of 0.100%.

The pilot also had been diagnosed with memory loss about eight months before the accident. It appears that he had some degree of mild cognitive impairment, but whether his cognitive impairment was severe enough to have contributed to the accident could not be determined from the available evidence.

However, it is likely that the pilot’s mild cognitive impairment combined with the psychoactive effects of diphenhydramine and possibly ethanol would have further decreased his cognitive functioning and contributed to his decision to attempt an aerobatic maneuver at low altitude in a non-aerobatic airplane.

Probable cause: The pilot’s decision to attempt a low-altitude aerobatic maneuver in a non-aerobatic airplane, and his subsequent failure to maintain control of the airplane during the maneuver. Contributing to the accident was the pilot’s impairment by the effects of diphenhydramine use, and his underlying mild cognitive impairment.

NTSB Identification: ERA18FA004

This October 2017 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.