Accident Overview
On the night of the accident, a medical transport flight departed under an instrument flight rules (IFR) flight plan in night instrument meteorological conditions (IMC). The aircraft was occupied by the pilot, two medical crew members, and two passengers. Approximately 11 minutes after takeoff, the aircraft deviated from the published departure procedure, entering an uncontrolled descent that ended in a crash.
Flight Sequence
Data from onboard recorders and ADS-B tracking indicated that between 1 and 3 minutes after takeoff, the autopilot disengaged and then reengaged; however, the aircraft continued to follow the departure procedure course. About 11 minutes after takeoff, the aircraft turned approximately 90° right, away from the next waypoint, and held that heading for about 47 seconds. Around this time, the autopilot disengaged again and was not reengaged for the remainder of the flight. Simultaneously, the aircraft's previously consistent climb rate stopped, and it maintained an altitude of about 18,300 ft mean sea level (msl) for about 20 seconds, despite the pilot being cleared to climb to 25,000 ft msl. The aircraft then turned left to a northeasterly heading and climbed to about 19,400 ft msl before entering a descending right turn. Shortly after entering the right turn, the rate of descent increased from about 1,800 ft per minute (fpm) to about 13,000 fpm, and the turn rate increased. ADS-B tracking was lost at an altitude of about 11,100 ft msl, near the accident site.
Final Events
The aircraft crashed in a snow-covered area 32 km southeast of Reno-Tahoe Airport. The aircraft was destroyed, and all five occupants were killed.
Investigation Findings
The official investigation determined the probable cause of the accident to be the pilot's loss of control due to spatial disorientation while operating in night instrument meteorological conditions, which resulted in an in-flight breakup. Contributing to the accident were the disengagement of the autopilot for undetermined reasons, as well as the operator’s insufficient flight risk assessment process and lack of organizational oversight.