ERA21FA142 · Luscombe 8E

A witness reported that the engine sounded “strong” when the pilot and pilot-rated passenger took off from the 2,700-ft paved runway. Video of the takeoff showed a normal takeoff near the midpoint of the runway followed by a level-off about 30 ft above the ground. About that time the sound produced by the engine reduced in what appeared to be an attempt to land on the remaining runway. As the airplane passed in front of the camera, the front left engine cowl could be seen open and flapping. As the airplane proceeded to fly down the runway, the engine power increased, and the airplane began to climb. The airplane’s wings rocked left and right as the airplane climbed over the end of the runway and turned left before disappearing out of the camera’s view toward nearby trees. The airplane subsequently impacted trees and terrain about 700 ft beyond and to the left of the departure end of the runway. A postaccident examination of the airplane and test run of the engine revealed no evidence of any preimpact mechanical malfunctions or failures that would have precluded normal operation. The airplane’s engine cowling fasteners were unlatched, but otherwise intact and undamaged. A performance study based on video and ADS-B data revealed that, after departure, the airplane entered a climbing left turn during which it slowed to a calculated calibrated airspeed near its published stall speed. The turn, combined with the low speed, likely resulted in an exceedance of the airplane’s critical angle of attack and an aerodynamic stall. It is also likely that the engine cowling was not fully secured before the flight. Based on available information, it is likely that the pilot became distracted when the cowling opened during takeoff and did not maintain control of the airplane. The pilot’s post-mortem toxicology results indicated that at some point prior to the flight he had used cannabis. However, the absence of any active parent drug (delta-9-THC) or active metabolite (11-hydroxy-delta-9-THC) indicated that it was very unlikely that he was impaired by any effects from his use at the time of the accident. The detected level of cetirizine (a sedating antihistamine) in the pilot’s specimens was below the blood level thought to cause symptoms, though because the specimens were from cavity blood, they may not accurately reflect antemortem levels. Therefore, whether the pilot was impaired by effects from cetirizine and whether those effects contributed to his failure to secure the cowling and his distraction during the takeoff could not be determined.

Verbatim NTSB analysis and probable cause from the NTSB dataset