CEN21LA084

The pilot and passenger departed on a flight to herd cattle via helicopter. There were no witnesses to the accident. Examination of the wreckage and debris pattern was consistent with an inflight break-up at low altitude. Main rotor blade contact marks were found on the cabin section of the fuselage and likely occurred before ground impact. No preimpact anomalies were found with helicopter or engine. Toxicology of the pilot identified high levels of delta-9-tetrahydrocannabinol (THC, the active compound in cannabis), as well as its active and inactive metabolites. Even accounting for postmortem redistribution, the levels of THC detected indicated recent use of cannabis and a very high likelihood of impairment. Given that gastric and liver levels were very high while lung levels were much lower, it is likely that the pilot used an edible form of the drug. Based on the available information, it is likely that the pilot lost control and exceeded the performance and/or structural limitations of the helicopter while flying at low-level, resulting in an inflight breakup. It is likely that the pilot’s impairment from his recent use of cannabis contributed to the accident.

The helicopter’s maintenance history could not be determined, as no logbooks were available for review. On December 10, 2020, about 0930 central standard time, a Robinson R44 helicopter, N7085Z, was destroyed when it was involved in an accident near Colorado City, Texas. The pilot and passenger sustained fatal injuries. The personal flight was conducted under the provisions of Title 14 Code of Federal Regulations Part 91. According to a family member, the intent of the flight was to herd cattle on a ranch. The flight originated from the pilot’s home helicopter pad about 0900. There were no reported radio or distress calls from the pilot, and there were no witnesses. Visual flight rules conditions prevailed in the area around the time of the accident. There were no witnesses to the accident, which was reported to local authorities about 1400. The pilot’s certificate was revoked in 2011 for flying while intoxicated. It was reinstated in 2014. According to the autopsy performed by the Southwestern Institute of Forensic Sciences at Dallas, the cause of death was blunt force injuries, and the manner of death was accident. No significant natural disease was identified. Toxicology testing performed by the Laboratory at the Southwestern Institute of Forensic Sciences at Dallas identified delta-9-tetrahydrocannabinol (THC, the psychoactive compound in cannabis) at 132 ng/ml and its inactive metabolite, carboxy-delta-9-THC at 329.5 ng/ml in chest cavity blood. Toxicology testing performed by the FAA’s Forensic Sciences Laboratory identified delta-9-THC at 81.7 ng/ml in cavity blood as well as at 2,664.5 ng/ml in gastric contents, 29.5 ng/g in liver tissue, 914.4 ng/g in lung, and 94.8 ng/g in brain. In addition, its psychoactive metabolite, 11-hydroxy-delta-9-THC, was identified at 96 ng/ml in cavity blood,171.1 ng/g in liver tissue, 46.7 ng/g in lung, and 44.1 in brain. Finally, the inactive metabolite, carboxy-delta-9-THC was found at 356.6 ng/ml in cavity blood, 3749.5 ng/g in liver, 190.9 ng/g in lung, and 94 ng/g in the brain. The pilot’s logbooks were not available for review. Estimates of his flight time were provided by a family member. The wreckage was located on relatively flat rural terrain, and the debris field was about 400 yards long. The first pieces of wreckage were identified as fragments of the left landing skid and forward skid strut. About 30 yards forward of the strut, fragments of a main rotor blade skin were found. The main wreckage, consisting of the cabin, main rotor assembly, and tail boom and rotor assembly were found about 400 yards from the left landing gear skid and strut fragments. There was no evidence of an in-flight collision with fixed obstacles. The wreckage debris pattern was consistent with an inflight break-up at low altitude. A tail rotor driveshaft segment was found twisted and fractured forward of the aft flex coupling. The fracture and twist were consistent with a sudden stoppage. The tail rotor gearbox rotatedby hand more than 360° with no anomalies. The tail rotor blades exhibited minor dents on the outer skins, with no damage to the leading edges. The tail rotor pitch control operated properly. The main rotor blades exhibited impact damage near mid-span and damage to the leading edge of the spars, which separated sections of skin and honeycomb. The nose of the cabin showed impact damage consistent with main rotor blade contact before ground impact. Paint transfer marks on the damaged portions of the main rotor blades and the left side of the landing gear strut were consistent with the shape of a main rotor blade spar. There was paint transfer in the damaged areas of both main rotor blades. The main and tail rotor flight controls displayed several fractures. The surfaces of the fractures were angular and jagged, consistent with overload. The tail rotor pedals were found jammed with the left pedal forward. Other than impact damages and separations, flight control continuity was established from the cockpit throughout all flight controls to the main rotor head and tail rotor assembly. The main rotor blade fragments were examined and there was no evidence of pre-impact delamination. All main rotor blade damage was consistent with impact forces. The tail rotor blade damage was consistent with impact forces. No pre-impact anomalies were found with the engine. Rotational continuity was established from the engine to the main and tail rotor gearboxes. Rotational signatures were present on the engine crankshaft. No pre-impact structural anomalies were found.