WPR19FA266 · American Aviation AA5 A

The pilot and passenger completed a cross-country flight across an area of mountainous terrain. After departing on the return flight, the pilot flew into a box canyon within a nearby mountain range. Flight track data showed the airplane at 400 ft above ground level as it entered the mountain range just before the track ended. An alert from the airplane's emergency locator transmitter indicated that the airplane impacted a mountain slope 26 minutes after departure at an elevation of about 10,300 ft mean sea level. The airplane was mostly consumed by a postcrash fire, which precluded an examination of the flight controls, magnetos, fuel pump, and other fuel system components. Examination of the remaining flight control systems and the engine did not reveal any anomalies that could have precluded normal operation, and signatures on the propeller blades indicated that the propeller was turning at the time of the impact. Performance calculations showed that the airplane likely exceeded its maximum gross takeoff weight at the time of the accident. The combination of high gross weight and high-density altitude conditions likely resulted in degraded climb performance and increased the time required to reach a suitable altitude to maintain clearance from surrounding terrain. Based on the airplane’s estimated weight, the airplane would have required about 28 minutes at a maximum airspeed of 75 kts to climb to an altitude of 500 ft above the approaching terrain. The circumstances of the accident are consistent with the pilot's failure to maintain clearance from trees and terrain and his decision to fly into terrain that required climb performance that exceeded the airplane’s performance capabilities. Impact signatures at the accident site indicated that the airplane collided with trees over a mountain slope. The steep impact angle suggests that the airplane was either slow when it collided with the trees or contacted the trees following an aerodynamic stall. Due to a lack of evidence, the investigation was unable to determine if the pilot had intended to overfly the mountain slope as part of his route of flight or if he was repositioning the airplane to execute a turn in search of lower terrain when the accident occurred. Although the pilot's autopsy showed evidence of severe premature coronary artery disease, the airplane's known final movements were not consistent with the loss of control more typical of sudden severe impairment/incapacitation associated with acute cardiac events. Thus, it is unlikely that the pilot's coronary artery disease contributed to this accident.

Verbatim NTSB analysis and probable cause from the NTSB dataset