Cessna 401 N401HH

Summary

On 4 October 2017 at about 21:45 local time, a Cessna 401 registered N401HH was involved in an accident near Salters, South Carolina, United States. 2 people were on board and 2 died. The aircraft was destroyed. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

4 October 2017 at 21:45

Classification

Accident

Location

Salters, South Carolina, United States

Nearest airport

Pvt (PVT)

Coordinates

33.4964, -79.9572

Aircraft

Cessna 401

Registration

N401HH

Category

Airplane

Year built

1969

Engines

2

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Personal

Phase of flight

Not recorded

Route

Salters → Salters

Aircraft damage

Destroyed

Weather

VMC

Light

Day

NTSB number

ERA18FA004

2 people died.

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.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full NTSB narrative

The commercial pilot and passenger departed on a local flight in the twin-engine airplane. According to a witness, the pilot took off from the private grass runway 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 impacting terrain. 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. Federal Aviation Administration 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 diphenhydramine in cavity blood (0.122 µg/ml, which is within or above the therapeutic range of 0.0250 to 0.1120 µg/ml; diphenhydramine undergoes postmortem redistribution, and central postmortem levels may be about two to three times higher than peripheral or antemortem levels.). Diphenhydramine is a sedating antihistamine that causes more sedation than other antihistamines; this is the rationale for its use as a sleep aid. In a driving simulator study, a single dose of diphenhydramine impaired driving ability more than a blood alcohol concentration of 0.100%. The pilot had been diagnosed with memory loss about 8 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.

Quoted verbatim from the NTSB record.