Low-Altitude Maneuvering · NTSB CEN21LA008
STEPHENS WILLIAM E Quicksilver MXL-2 Sp — Mount Vernon, IN
| Date | October 6, 2020 |
| Location | Mount Vernon, IN |
| Aircraft | STEPHENS WILLIAM E Quicksilver MXL-2 Sp (amateur-built) |
| Purpose of flight | Personal |
| Conditions | Day · Visual Meteorological Cond |
| Phase / occurrence | Maneuvering-aerobatics Loss of control in flight |
| Pilot age | 75 |
| Pilot total time | Unknown |
| Time in type | Unknown |
| Fatalities | 2 |
Probable cause
NTSB findings
- Personnel issues-Task performance-Use of equip/info-Aircraft control-Pilot
- Aircraft-Aircraft oper/perf/capability-Performance/control parameters-Angle of attack-Not attained/maintained
- Personnel issues-Action/decision-Info processing/decision-Decision making/judgment-Pilot
- Aircraft-Aircraft oper/perf/capability-Aircraft capability-(general)-Incorrect use/operation
What happened
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.