CEN23FA283

The pilot’s visual flight rules flight into instrument meteorological conditions, which resulted in a loss of control during the approach to the destination airport and subsequent impact with terrain.

The airplane was enroute to the destination airport under visual flight rules and without air traffic control services; radar data showed that it made several turns before approaching the airport from the south. The turns were not consistent with a standard visual airport traffic pattern. The airplane wreckage was located about 1 mile south of the airport. Ground scarring and airplane damage was consistent with a nose-down, high-speed terrain impact with the landing gear extended. Postaccident examination of the airplane and engine revealed no mechanical anomalies that would have precluded normal operation. The accident site was located ahead of a cold front; it had rained earlier in the evening, leading to abundant surface moisture after sunset. High-Resolution Rapid Refresh (HRRR) model sounding for the approximate accident site location and time indicated a conditionally unstable environment from the surface through 200 ft above ground level (agl) then a stable environment from 200 ft agl through 4,000 ft. With a subsidence inversion of approximately 1,600 ft, it is likely fog and low clouds were beginning to form above the accident site at the accident time. Recorded weather observations indicated ceilings down to 200 ft agl and decreasing visibilities below a mile after the accident time. It is likely the accident flight likely encountered instrument meteorological conditions between 200 ft agl and 1,600 ft mean sea level east of Monroe Regional Airport, which was about 13 miles west of the accident site. Based on the variation in measured ethanol levels, the extent of the pilot’s injuries, and the presence of other alcohols, at least some of the detected ethanol likely was from sources other than alcohol consumption. The levels of ethanol in the tested tissue specimens could not be used to reliably determine the pilot’s blood ethanol level at the time of the crash, or to exclude the possibility of alcohol consumption and associated impairment. The postmortem concentrations of delta-9-THC and its metabolite indicate that the pilot had used a cannabis product. However, the precise timing of last cannabis use, and whether associated impairing effects were present at the time of the crash, could not be determined from the toxicological evidence. The toxicology results also indicate that the pilot had used phentermine, but the levels measured in tissues could not be used to establish the presence of associated impairing effects at the time of the crash. Overall, several substances were detected that may cause performance impairment alone or in combination, but no reliable conclusion could be drawn from toxicological evidence about specific effects on the pilot at the time of the crash.

The accident site was located south and on the warmer side of a cold front with low- and mid-level ridge pressure centered over the Gulf of America. Light and variable surface winds affected the region, where it had rained earlier in the evening. The High-Resolution Rapid Refresh model sounding for the approximate accident site location, at 0000, indicated a conditionally unstable environment from the surface through 200 ft agl then a stable environment from 200 ft agl through 4,000 ft. The top of a subsidence inversion was approximately 1,600 ft. Geostationary Operational Environmental Satellite imagery indicated the cloud cover above the accident site was a combination of low- and very low-level water clouds with the cloud cover expanding in area coverage with time. A surveillance camera located about 1 mile east of M79 with a west view toward the airport recorded a light consistent with the periodicity of an airport rotating beacon and sky conditions. As the recording progressed, clouds/obscuration increased, and the luminosity of the periodic light decreased over time. The Graphical Forecasts for Aviation (GFA) cloud forecast applicable to the accident site that was valid on July 6, 2023, at 2200, indicated scattered to overcast clouds with bases at 800 ft and tops at 16,000 ft and with layered clouds to flight level 400. By 0100, the GFA cloud forecast indicated few to broken cloud coverage, with bases at 700 ft and cirrus above. The Monroe Regional Airport (MLU) Automated Surface Observing System (ASOS) was located 13 miles west of the accident site. At 0116, the ASOS recorded: wind calm, visibility 4 miles, mist, scattered clouds at 200 ft agl, temperature of 23°C, dew point temperature of 22°C, and an altimeter setting of 29.98 in Hg. The Morehouse Memorial Airport (BQP) Automated Weather Observing System (AWOS) was located 18 miles north-northwest of the accident site. At 0035, the AWOS recorded: wind calm, visibility 10 miles or greater, scattered clouds at 200 ft agl, scattered clouds at 6,000 ft agl, temperature of 23°C, dew point temperature of 22°C, and an altimeter setting of 30.01 in Hg. There were no pilot reports in the national airspace system within 2 hours before and after the accident time and within 100 miles of the accident site at altitudes below 18,000 ft. Forensic Autopsy and Consulting Services, North Little Rock, Arkansas, performed the pilot’s autopsy. According to the pilot’s autopsy report, his cause of death was multiple blunt force injuries, and his manner of death was accident. The pilot’s autopsy was severely limited for evaluation of natural disease due to the extent of his injuries. The autopsy was documented as an external examination only. Within its limitations, no significant natural disease was identified. Postmortem toxicological testing by the FAA Forensic Sciences Laboratory detected ethanol at 0.057 g/hg in liver tissue, at 0.109 g/hg in lung tissue, at 0.155 g/hg in kidney tissue, and at 0.164 g/hg in muscle tissue (in tissue, concentrations in g/hg are approximately equivalent to concentrations in g/dL). N-propanol was detected in lung tissue and kidney tissue and was not detected in liver tissue or muscle tissue. Isopropanol was detected at 0.012 g/hg in muscle tissue and was not detected in liver tissue, lung tissue, or kidney tissue. FAA testing also detected delta-9-tetrahydrocannabinol (delta-9-THC) at 0.9 ng/g in lung tissue and did not detect delta-9-THC in liver tissue. Carboxy-delta-9-tetrahydrocannabinol (carboxy-delta-9-THC) was detected at 3.7 ng/g in liver tissue and was not detected in lung tissue. FAA testing detected phentermine at 352 ng/g in liver tissue and at 174 ng/g in muscle tissue. Ethanol is the intoxicating alcohol in beer, wine, and liquor, and, if consumed, can impair judgment, psychomotor performance, cognition, and vigilance. FAA regulation imposes strict limits on flying after consuming ethanol, including a prohibition on piloting a civil aircraft while having a blood ethanol level of 0.04 g/dL or greater. Ethanol absorbed into circulation after alcohol consumption distributes relatively evenly throughout body tissues with water. Alcohol consumption is not the only possible source of ethanol in postmortem specimens. Ethanol sometimes may be produced by microbes in a person’s body tissues or fluids after death, potentially elevating ethanol levels in some postmortem specimens. Postmortem ethanol production is made more likely by extensive traumatic injury. N-propanol (also known as 1-propanol) is another alcohol that can be produced by microbes in a person’s body after death. Detection of n-propanol in a postmortem specimen potentially is indicative of postmortem microbial activity in the specimen, with or without associated ethanol production. Isopropanol (also known as 2-propanol, or isopropyl alcohol) is rubbing alcohol. It is widely available for a variety of commercial and industrial uses. If ingested, it has roughly twice the central nervous system depressant potency of ethanol. However, isopropanol detected in postmortem specimens often is a result of sources other than ingestion, such as postmortem microbial production. Delta-9-THC and metabolite is the primary psychoactive chemical in cannabis, including marijuana, hashish, and other cannabis products such as extracts and edibles. Carboxy-delta-9-THC is a non-psychoactive metabolite of delta-9-THC. Cannabis may be inhaled or ingested recreationally by users seeking mind-altering effects. It may also be used to treat symptoms of various medical conditions. Psychoactive effects of cannabis vary depending on the user, dose, and route of administration, and may impair motor coordination, reaction time, decision making, problem solving, and vigilance. A person’s instantaneous blood concentration of delta-9-THC does not directly predict that person’s impairment. Additional challenges exist to interpreting delta-9-THC concentrations measured in postmortem specimens, as such concentrations may not represent antemortem concentrations in blood. Marijuana is a federal Schedule I controlled substance, and the FAA considers its use by pilots unacceptable, regardless of state laws. Phentermine is a prescription weight loss medication. It is a federal Schedule IV controlled substance, with some potential for abuse. It may sometimes be associated with adverse cardiovascular effects including increased blood pressure, rapid or irregular heartbeat, or heart attack. Side effects of phentermine may include insomnia, nervousness, and dizziness. Uncommonly, more-extreme side effects such as psychosis may occur. The drug typically carries a warning that it may impair the ability to engage in potentially hazardous activities such as operating machinery or driving a motor vehicle. The FAA considers phentermine to be a “do not issue/do not fly” medication; according to the FAA medical case review for this accident, phentermine use is disqualifying for pilot medical certification. The airplane wreckage was located about 1 mile south of M79 and was destroyed by impact forces. The airplane’s heading was about 268°. Ground scarring and airplane damage was consistent with a nose-down, high-speed impact. Ground scarring began with two main landing gear wheel impressions separated by 7 ft and immediately forward was the impression of the wing leading edges. A 3-ft deep hole followed and preceded the aircraft tail by about 8 ft. The airframe was upright. The nose wheel strut and wheel were found in the hole. Wreckage debris extended about 50 ft forward of the aircraft nose and contained windscreen pieces and avionics. All components of the airplane were at the accident site. The main landing gear was extended. The wing flaps were in the retracted position. Flight control continuity was confirmed from the control surfaces to the cockpit. The left and right elevator trim tabs were relatively neutral