Schweizer SGS 1-35 N2878H accident near Wurtsboro, New York

Probable cause

The pilot’s low-altitude release from tow for reasons that could not be determined, and his subsequent exceedance of the glider’s critical angle of attack while returning to the runway, which resulted in an aerodynamic stall and impact with terrain.

NTSB analysis

The accident flight was the pilot’s first flight in the glider make/model, and he indicated to the wing runner that he was “hesitant” about the flight. Witness statements and recorded data indicated that, just after takeoff, the glider released from the tow plane about 170 ft above ground level, while in a 25° right turn over the runway departure end. The glider continued the right turn and stalled about 1.4 seconds later, impacting airport property 13 seconds after the stall. Examination of the wreckage did not reveal any preimpact mechanical malfunctions.

Toxicology testing revealed the presence of the sedating antihistamine diphenhydramine in cardiac blood and urine, indicating that the pilot had taken some allergy, cold, or sleep-aid medication before the accident. Even considering two-to-three-fold postmortem redistribution of diphenhydramine, the concentration in the pilot’s blood appeared to be at therapeutic levels. Compared to other antihistamines, diphenhydramine causes marked sedation; impaired cognitive and psychomotor performance may also be observed. While the impairing medication diphenhydramine was detected, it is unlikely that the effects from the pilot’s use of diphenhydramine contributed to this accident.

Although the reason for the pilot’s release from tow at low altitude could not be determined, the accident is consistent with his failure to maintain airspeed during the turn back to the runway, which resulted in an aerodynamic stall and impact with terrain.

Text from the NTSB. Open the NTSB docket for ERA21FA239 for the full record.