Flight and Weather Conditions
The aircraft was on a leg from Hagerstown, Maryland, to Pueblo, Colorado. During the flight, the crew encountered very bad weather conditions characterized by thunderstorm activity, turbulence, and icing. These conditions were reported as heavy icing, with a line of thunderstorms to the west. The crew did not obtain a weather update at Saint Louis.
Loss of Control and Structural Failure
Control of the aircraft was lost, and it entered a dive. During the dive, the elevators and stabilizers detached from the aircraft. The separation of these flight control surfaces exceeded the designed stress limits of the aircraft. The crew failed to maintain flying speed and improperly operated the anti-icing/deicing equipment, leading to airframe ice accumulation.
Crash and Fatalities
The aircraft subsequently crashed in the Clark National Forest and was destroyed on impact. All five occupants were killed.
Probable Cause
The official probable cause was an uncontrolled descent following improper in-flight decisions or planning. Factors reported included improper operation of anti-icing/deicing equipment, airframe ice, failure to maintain flying speed, exceeded designed stress limits, separation of flight control surfaces such as horizontal stabilizers and elevators, icing conditions, thunderstorm activity and turbulence, no weather update at Saint Louis, and a line of thunderstorms west.