Incident Overview
A pressurized airplane operating at an altitude of 25,000 feet (with a cabin altitude of 10,000 feet) experienced a loss of control approximately 43 minutes after air traffic control began calling the pilot to correct his altitude. Over that period, about six calls were made to the pilot. Two transmissions between 2305 and 2311 were described as "slurred, and unclear speech." Subsequently, a two-minute span included over 30 hot microphone transmissions, with heavy breathing audible in some instances.
Last Transmission
The pilot's final transmission occurred at 2318:20: "ah Charlie Hotel, we, we've a little bit of a problem here. We're in a descent, we'll straighten it out in a minute." Witnesses then observed the airplane descending in a spin and impacting the ground.
Pilot Medical Condition
An autopsy of the pilot revealed moderate emphysema in his lungs with the presence of air-filled bullae measuring up to 3 cm. The owner of the aircraft reported that on the two flights preceding the accident flight, the pilot slept for 2 hours out of the 4.5-hour flight duration. Several friends reported that the pilot was observed to "easily doze" off while on the ground, and that he did so more regularly and for longer periods while flying.
Circumstances
The aircraft was operating in controlled airspace under air traffic control guidance. Multiple altitude deviations were noted by ARTCC, leading to repeated communications. The pilot's deteriorating speech and subsequent heavy breathing, combined with his known sleeping tendencies and medical findings, suggest a possible incapacitation or medical event, though no formal conclusions are drawn from this report.