ERA18FA064 · Vans Aircraft Inc RV-12

The sport pilot departed on the visual flight rules (VFR) cross-country flight under day visual meteorological conditions and climbed the airplane to 2,500 ft. While on the ground and during the climb and cruise portions of the flight, the pilot missed or did not respond to numerous radio calls from air traffic controllers, deviated from assigned altitudes, and used improper radio terminology. Data from onboard the airplane indicated that, throughout the flight, the pilot operated the airplane within the yellow airspeed caution range in excess of its maximum structural cruise speed of 108 knots. About 4 minutes before the accident, he began a descent toward the destination airport. When the controller advised the pilot of nearby traffic, the pilot responded that he was looking. The airplane's pitch then increased slightly nose-up, followed by a significant pitch change to 45° nose-down and a right roll of 37°. The pilot transmitted "mayday, mayday." The roll continued through inverted and the airspeed eventually increased to 169 knots, which was 33 knots in excess of the airplane's never-exceed (redline) speed. During the final 10 seconds of recorded data, the engine speed varied between 4,550 and 5,950 rpm (redline rpm was 5,800).

The wreckage debris path and fracture signatures on the left wing indicated that it failed in-flight in a positive (wing up) direction, striking the airplane's canopy while departing the airplane. The wing spar fracture surfaces were consistent with overload with no evidence of preexisting corrosion or fatigue. It is likely that the wing failure occurred as the airplane descended and exceeded its redline speed. Although the airplane did not have a current condition inspection, there was no evidence of any preexisting mechanical malfunction or anomaly with the airplane or engine.

The pilot did not possess a Federal Aviation Administration (FAA) medical certificate, nor was he required to in order to exercise the privileges of a sport pilot. According to personal medical records, he had been diagnosed with hypertension, high cholesterol, obstructive sleep apnea, neurogenic bladder, cataracts, peripheral neuropathy, depression, and post-traumatic stress disorder. It would have been the pilot's responsibility to report any medical deficiency that would interfere with the safe performance of sport pilot operations to the FAA; however, he did not do so. An autopsy of the pilot revealed an enlarged and thickened heart and significant coronary artery disease with about 50% to 75% narrowing of both the left main and left anterior descending coronary arteries. While possible, it could not be determined if the pilot experienced an acute cardiac event that may have affected his ability to control the airplane. Toxicology testing identified three different potentially impairing psychoactive medications in specimens of the pilot. What effects the pilot may have experienced from the use of this combination of medications could not be determined; additionally, the pilot's mental state at the time of the accident could not be established.

Overall, the pilot's coronary artery and significant psychiatric disease put him at risk for distraction and inattention that could have led to the accident circumstances. His unreported psychiatric disease, if not well-controlled, could have led to intentionally unsafe maneuvering. Whether the effects from multiple psychoactive medications contributed to the accident could not be determined, but it was evident that, based on his interaction with air traffic controllers, the pilot was not performing at a competent level. While the exact cause of the pilot's behavior could not be determined, given the lack of mechanical anomalies or weather phenomena that could explain the accident sequence, it is likely that his underlying physiologic or psychiatric disease resulted in his exceedance of the airplane's operating limitations, which led to an in-flight failure of the left wing while maneuvering.

Verbatim NTSB analysis and probable cause from the NTSB dataset