What happened
During a climb through 20,500 feet, the aircraft began maneuvering to avoid low-intensity weather cells. During this phase, the plane lost controlled flight and entered a right-hand spiral. The descent was rapid, with descent rates surpassing 16,600 feet per minute as the aircraft dropped from 18,300 feet to 3,900 feet.
Eyewitnesses reported seeing the plane emerge from the clouds in a right flap spin. Upon impact, the empennage had broken into multiple pieces, with debris scattered up to 1.5 miles from the main crash site. While both wings remained attached to the fuselage, the right engine had experienced a flameout, and the propeller was in a feathered position at the time of the crash. No mechanical cause for the engine failure was identified, and the pilot had not communicated any difficulties prior to the accident.
Findings
Investigations into the accident highlighted several contributing factors. An NTSB weather analysis confirmed the presence of moderate turbulence in the vicinity at the time of the event. Additionally, toxicology results for the pilot revealed a concentration of 0.15-micrograms per milliliter of chlorpheniramine in the blood, which is significantly higher than the standard therapeutic range of 0.01 to 0.04. The elevated level of this medication can lead to symptoms such as sedation and reduced mental alertness. The pilot, who was the only person on board, was killed in the accident.