CEN23FA183

The non-certificated pilot’s failure to ensure the collective friction control was adequately engaged during an on-ground engine run, which resulted in the helicopter inadvertently becoming airborne. Contributing to the crash were the pilot’s various physical and mental conditions and his use of potentially impairing medications.

Although there were no witnesses to the crash, it is likely that the non-certificated pilot was conducting an engine ground run when the helicopter inadvertently became airborne. The helicopter impacted the terrain about 70 ft from the concrete pad used during ground operations. After the crash, the collective friction control was found off, which likely resulted in an unintended increase of the collective control to a point where the helicopter became airborne. The pilot’s logbook contained a student pilot certificate; however, it expired more than 50 years before the crash. A review of the pilot’s logbook did not reveal any flights after he received a 90-day solo endorsement for a single-engine airplane in 1971, nor did it reveal any flights completed in a helicopter. The pilot had served in the US Army but in a non-pilot role. The pilot purchased the helicopter in March 2016 as an investment and family members could not recall the last time he flew the helicopter. One of the pilot’s daughters reported that he would occasionally bring the helicopter out of the shed to perform an engine run and, on multiple occasions, he forgot to engage the collective friction control, which resulted in unintended movement of the helicopter on the ground while the engine was running. The 93-year-old pilot’s medical history was significant for impairing physical and mental conditions. There was documentation of a previous stroke and Parkinson’s disease that impacted the strength and function of his left and right upper extremities. During his last hospital admission, about 4 months before the crash, the pilot was diagnosed with moderate senile dementia. The pilot’s postmortem toxicology results detected central nervous system depressant medications, including gabapentin and cyclobenzaprine, both of which can adversely interact with one another and worsen impairment, especially in older adults. The pilot’s baseline ability to operate the helicopter is uncertain. Regardless, it is likely that some combination of the pilot’s various physical and mental conditions and his use of potentially impairing medications contributed to the circumstances of the crash. Ethanol was detected in blood, but not in vitreous fluid or urine. Other volatiles, n-butanol and n-propanol were also detected. It is likely that some, or all, of the detected ethanol was from postmortem production. Thus, it is unlikely that ethanol contributed to the crash.

A search of FAA airman certification records found no record of a pilot certificate ever being issued to the pilot. The pilot’s family provided a pilot logbook that contained a combined FAA third-class medical and student pilot certificate dated February 3, 1970. The medical/student pilot certificate was expired. The final logbook entry was a 90-day solo endorsement for a Cessna 172 airplane dated January 17, 1971. Further review of the pilot logbook did not reveal any flights completed in a helicopter. According to the pilot’s family, he had served in the US Army but in a non-pilot role. The pilot’s baseline ability to fly helicopters could not be assessed with the available documentation. The last annual inspection of the helicopter was completed on October 10, 2003, at 3,449.7 total airframe hours. The logbook documentation did not reveal any maintenance actions after the annual inspection. At the time of the crash, the airframe total time was 3,527.0 hours, and the engine total time since new and time since overhaul were 4,035.7 hours and 1,527.3 hours, respectively. The 93-year-old pilot had an extensive past medical history, including a stroke in 2019 with residual left upper extremity weakness, Parkinson’s disease resulting in a tremor of his right hand, coronary artery disease, a recent electrocardiogram with arrhythmias, high blood pressure, high cholesterol, degenerative arthritis of the spine, chronic kidney disease, and recurrent urinary tract infections resulting in hospital admissions. On January 19, 2023, during his most recent hospital admission, the pilot was diagnosed with moderate senile dementia. His medication list at that time included carbidopa/levodopa, a prescription medication commonly used to treat Parkinson’s disease; atorvastatin, a prescription medication commonly used to control cholesterol and reduce cardiovascular risk; gabapentin, a prescription medication commonly used to treat nerve pain; aspirin, an over-the-counter medication commonly used to treat pain and fever and to reduce cardiovascular risk; finasteride, a prescription medication commonly used to treat an enlarged prostate; and levothyroxine, a prescription medication commonly used to treat low thyroid hormone. The autopsy of the pilot was performed by Central Texas Autopsy, Lockhart, Texas, as authorized by a McCulloch County Judge. According to the autopsy report, the pilot’s cause of death was blunt force head and chest trauma, and the manner of death was accident. The heart was described as enlarged with severe calcific coronary artery disease, including 50-90% stenosis of the right coronary artery, 40% stenosis of the left main coronary artery, 50-80% stenosis of the left anterior descending coronary artery and 50-100% stenosis of the circumflex coronary artery. A prior myocardial infarction (heart attack) was noted. The heart was also found to have moderate to severe left ventricular hypertrophy, and severe biventricular dilatation. The aorta was noted to have severe calcific atherosclerotic disease. The kidneys were noted to have changes from severe atherosclerosis. The remainder of the autopsy including examination of the brain, heart, and lungs did not identify other significant natural disease. At the request of Central Texas Autopsy, NMS Labs completed toxicological testing of blood samples obtained during the pilot autopsy. No tested-for substances were detected. Caffeine was presumptively positive. The FAA Forensic Sciences Laboratory completed postmortem toxicological testing of specimens obtained during the pilot autopsy. Ethanol was detected in blood at 0.06 gm/dL. Ethanol was not detected in vitreous fluid or urine. N-butanol was detected in heart blood and was not detected in vitreous fluid or urine. N-propanol was detected in heart blood and was not detected in vitreous fluid or urine. Gabapentin was detected in heart blood at 1986 ng/mL and detected in urine at 102,094 ng/mL. Cyclobenzaprine was detected in heart blood, and testing for cyclobenzaprine was inconclusive in urine. Norcyclobenzaprine was detected in heart blood at 3 ng/dL and was detected in urine at 17 ng/mL. Acetaminophen was detected in urine and was not detected in heart blood. Ethanol is a type of alcohol. It 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 prohibiting pilots from flying with a blood ethanol level of 0.04 g/dL or greater. Alcohol consumption is not the only possible source of ethanol in postmortem specimens. Ethanol can sometimes be produced by microbes in a person’s body after death. Postmortem ethanol production is made more likely by extensive traumatic injury and can cause an affected toxicological specimen to test positive for ethanol while another specimen from the same person tests negative. N-propanol and particularly n-butanol are other alcohols that can be produced by microbes in a person’s body after death. Their presence in a postmortem specimen is potentially indicative of postmortem microbial activity in the specimen but does not reliably indicate that postmortem ethanol production occurred. Gabapentin is a medication that is approved by the U.S. Food and Drug Administration for seizure disorders and nerve pain caused by herpes infections. It generally carries a warning that use may cause somnolence, dizziness, and general central nervous system (CNS) depression. Precautions are advised for driving a vehicle or operating heavy machinery until the user can assess the impact of dosing on alertness and motor activities. Gabapentin is commonly prescribed for off-label uses such as insomnia, anxiety, depression, migraine, nerve pain, and fibromyalgia. Caution is advised when using gabapentin in older adults as these individuals have increased risk for somnolence, dizziness and falls with gabapentin use. Cautious dosing is also advised in chronic kidney disease to minimize CNS depression. The FAA considers gabapentin a “do not issue/do not fly” medication. Cyclobenzaprine is a prescription medication commonly used to treat muscle spasms. It generally carries a warning that use in combination with other CNS depressants may impair mental and physical abilities required for the performance of hazardous tasks such as operating a motor vehicle or operating machinery. The drug generally carries a warning that older adults may be more at risk for CNS events such as hallucinations, confusion, cardiac events, and falls. Caution is advised in using cyclobenzaprine for older adults unless strongly indicated. The FAA considers cyclobenzaprine a “do not fly” medication. Norcyclobenzaprine is a metabolite of cyclobenzaprine. Caffeine is a CNS stimulant that is commonly ingested, including in coffee, tea, soft drinks, and chocolate, and is also an ingredient in certain anti-drowsiness medications and headache medications. Caffeine is not generally considered impairing. A search of FAA medical certification records search did not locate a medical file for the pilot. The helicopter was found on its right side, facing west, about 15 ft from the north wall of the house, as shown in figure 1. The helicopter was about 70 ft southwest from a concrete pad that the pilot used during ground operations, as shown in figure 2. The helicopter’s ground handling wheels and a hand truck associated with a battery charger were found beside the concrete pad, as shown in figure 3. The battery charger and its integrated jumper cables were found about 60 ft from the concrete pad against the rear right tire of a white sedan parked beside the helicopter wreckage, as shown in figure 4. The hood and roof of the white sedan exhibited fresh dirt deposits. There was a small truck, full-sized recreational vehicle, and two steel drums located between th