ERA21LA020 · Aero Commander 100

The student pilot took off from an unlit grass airstrip at dusk. The moon (in the waning crescent phase) was well below the horizon at -29° altitude, so dark conditions existed shortly into the flight. About 15 minutes after takeoff, he contacted his sister stating he was low on fuel, trying to land, and he could not see the airstrip. He asked her to light up the airstrip with her car headlights. The pilot called a second time during which he sounded panicked and exclaimed “get out there!” Neighbors arrived and attempted to illuminate the airstrip with their vehicle headlights. Still unable to see the airstrip, the pilot flew on an easterly heading away from the airstrip where the airplane ultimately impacted a marsh in a nose-down attitude. A postaccident examination of the airframe and engine could not be accomplished due to hazardous conditions at the wreckage site. The student pilot’s autopsy findings included moderate coronary atherosclerosis and dilated cardiomyopathy. There was no operational or medical evidence to suggest that an acute cardiac event occurred; thus, it is unlikely that such an occurrence was a factor in the accident. Toxicology testing of the pilot’s specimens revealed evidence of cannabis usage that may have occurred sometime earlier on the day of the accident. However, blood concentrations do not correlate well with impairment and cannot be used to prove that the user was experiencing the effects of cannabis at the time of testing. Metabolism and elimination depend on the means of ingestion, potency of the product, frequency of use, and user characteristics; none of this information was available to evaluate concerning the pilot’s cannabis usage. Thus, based on the information provided, while the pilot was found to have cannabis in his system, it could not be determined if the pilot’s use of cannabis contributed to the accident. Toxicology testing of the pilot’s specimens also revealed ethanol in blood, vitreous fluid, and urine. The concentration of ethanol detected in his blood is associated with impairment. The pilot’s use of alcohol would affect his ability to assess the airworthiness of his airplane, limit his self-control in choosing to fly while under the influence, and impact his ability to safely manage his flight. Since vitreous fluid does not suffer from postmortem microbial production to any significant extent, the ethanol concentration in vitreous fluid suggests that ingestion was the major source of ethanol in the blood. The description of the sequence of events as reported by the pilot’s sister further supports that the pilot’s judgment, behavior, and motor skills were influenced by the effects of ethanol. Given the pilot’s impairment from ethanol (alcohol), he likely performed an inadequate preflight inspection and departed with an inadequate fuel supply. Additionally, he failed to perceive the risk of departing from an unlit grass airstrip in increasingly dark conditions. It is likely that, once airborne and after the sky became dark, the pilot could not find nor see the airstrip. With the airplane’s dwindling fuel supply, the pilot continued to look for the airstrip but proceeded in the wrong direction. During his search, the engine likely lost power due to fuel exhaustion and the airplane subsequently impacted the marsh.

Verbatim NTSB analysis and probable cause from the NTSB dataset