CEN21LA223

The pilot’s loss of airplane control resulting in an aerodynamic stall while executing a steep turnaround during an aerial application flight.

On the day of the accident, the pilot had already completed several aerial application flights and was in the process of spraying product on a target field. Witnesses stated that the airplane had just completed a spray pass and was turning around. During the turn, the airplane pitched up and rolled left into a steep bank. One witness stated that it looked like the pilot, “didn’t pull out of a barrel roll.” The airplane “fell out of the sky” and impacted the ground inverted. Data extracted from the airplane’s GPS failed to record the last 30 seconds of the flight, likely as a result of a recording latency. Postaccident examination of the wreckage did not revealed any preimpact mechanical malfunctions or anomalies that would have precluded normal operation. The circumstances of the accident are consistent with the pilot failing to maintain airplane control while maneuvering in the turn at low altitude, which resulted in an aerodynamic stall and loss of control. Although toxicology testing detected diphenhydramine, a sedating antihistamine, in the pilot’s urine, operational evidence of any impairment is inconclusive. Therefore, whether the pilot’s use of diphenhydramine contributed to the accident could not be determined from the available evidence.

Toxicology testing performed by the FAA’s Forensic Sciences Laboratory detected diphenhydramine at 205 nanograms per milliliter in chest cavity blood. Diphenhydramine was also present in urine. Diphenhydramine is a sedating antihistamine available over-the-counter in multiple cold and allergy products as well as sleep aids. Diphenhydramine can cause cognitive and psychomotor slowing and drowsiness. It typically carries a warning that it may impair performance of tasks like driving and operating heavy machinery. The Federal Aviation Administration states that pilots should not fly within 60 hours of using diphenhydramine, to allow time for it to be eliminated from their systems. A postaccident examination revealed ground impact marks from the outline of the wings, as the airplane impacted the ground in a wings-level, inverted attitude. The wing fuel tanks were found breached, and a significant amount of fuel was noted in the dirt under the airplane. The propeller blades were twisted and bent and partially buried in the ground. Flight control continuity was established to the extent possible by the condition of the wreckage; all observed separations were consistent with overstress. The flaps were extended 25.4°, which corresponded to near full extension. Examination of the airplane did not reveal any preimpact mechanical malfunctions or anomalies that would have precluded normal operation. On May 18, 2021, about 1325 central daylight time, an Air Tractor AT-502A airplane, N887LA, was substantially damaged when it was involved in an accident near Clayton, Louisiana. The pilot was fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 137 aerial application flight. The operator stated that the pilot had already completed several aerial application flights and was in the process of spraying product on a field when the accident happened. Witnesses stated that the airplane had just completed a spray pass and was in the process of turning around. During the turn, the airplane pitched up and rolled left into a steep bank so that the wings were almost upside down. One witness stated that it looked like the pilot, “didn’t pull out of a barrel roll.” The airplane “fell out of the sky” and impacted the ground inverted oriented on a southeast heading. Data was extracted from the airplane’s SatLoc GPS, which revealed most of the accident flight, except for the last approximately 30 seconds, which was likely not recorded due to the unit’s recording latency. The data showed that the airplane completed several spray passes over the target field and did not reveal any anomalies.