Amateur-built Quicksilver MXL-2 Sp N2942A accident near Mount Vernon, Indiana

Probable cause

The pilot’s exceedance of the airplane’s critical angle of attack during an aerobatic maneuver, which resulted in an aerodynamic stall and spin and loss of control. Contributing to the accident was the pilot’s decision to perform aerobatic maneuvers in an airplane that was not approved to do so.

NTSB analysis

The sport pilot and pilot-rated passenger were conducting a local flight in the light sport airplane, which was not approved for aerobatic flight. A witness near the accident site saw the airplane exit a loop then spiral toward the ground. The airplane impacted the ground on a southwesterly heading and came to rest about 100 ft from the initial impact point. The flight controls were intact and there were no mechanical malfunctions or anomalies with the airplane that would have precluded normal operation.

Toxicological testing detected memantine in specimens from the pilot, which is used to treat dementia. The pilot’s presumed underlying dementia could have influenced some of his decision-making but without more information about the status of his disease, its effect on the safety of his flying could not be determined. Specimens from the pilot-rated passenger detected diphenhydramine, THC, and its metabolites; however, the low levels of each substance were unlikely to have caused impairing effects. Overall, it is unlikely the pilot’s presumed dementia, or the pilot-rated passenger’s use of multiple substances contributed to the circumstances of this accident.

The circumstances of the accident are consistent with the pilot’s decision to perform aerobatic maneuvers in an airplane not approved for aerobatic flight, during which he exceeded the airplane’s critical angle of attack, resulting in an aerodynamic stall/spin and loss of control.

Text from the NTSB. Open the NTSB docket for CEN21LA008 for the full record.