Yakovlev YAK 52 N27YK accident near Palmyra, Illinois

Probable cause

A loss of control during a low-altitude aerobatic maneuver.

NTSB analysis

Witnesses saw the airplane approach the airport and perform a low-altitude pass 20 to 30 ft above the runway. The airplane then pitched up, climbed about 200 feet, and entered a roll. During the roll, the airplane’s nose dropped, and the airplane descended and impacted the ground in a steep, nose-down attitude.

One of the witnesses was familiar with the pilot and had seen the pilot perform similar maneuvers previously. A review of the pilot’s logbooks revealed one entry about three years before the accident flight that suggested some aerobatic training in the accident airplane; however, the extent of the pilot’s aerobatic training could not be determined.

Postaccident examination of the airplane revealed no evidence of anomalies; however, impact damage prevented complete examination of the flight control system.

Based on autopsy findings, the pilot did not appear to have any natural disease that would be a factor in this accident; however, his toxicology was positive for the anticoagulant warfarin. This medication, while non-impairing, is used to prevent complications of atrial fibrillation or prevent several cardiovascular conditions, such as heart attack and stroke, which can cause sudden incapacitation. This would be especially true for aerial maneuvers that would result in changes in gravitational forces that could trigger heart arrhythmias. The pilot’s FAA third-class medical certificate expired 10 years before this accident, and his current medical status and the reason he was taking warfarin are unknown. Given the operational findings of this accident, the pilot’s use of the medication warfarin and the possible medical conditions for which warfarin was prescribed were unlikely factors in the accident.

Ethanol detected in the pilot’s vitreous fluid was likely from sources other than ingestion and did not contribute to the accident.

Based on the available information, the circumstances of the accident are consistent with a loss of control during a low-altitude aerobatic maneuver.

Text from the NTSB. Open the NTSB docket for CEN20LA168 for the full record.