Background
The aircraft, registered as N84UM, departed on a flight. During a preflight briefing, the pilot was advised of turbulence and icing conditions, with expectations of light to moderate rime icing in clouds up to 15,000 feet. The aircraft was reported to be equipped for flight in icing conditions.
Flight Events
Approximately two minutes after climbing and leveling at flight level 290 (FL290), the air route traffic control center (ARTCC) controller observed no transponder return from the aircraft. The controller transmitted an advisory but received no reply. Several more radio calls were made, and two replies were received. A review of the radio transcript indicated the pilot's first reply referenced 'ice.' In response to the controller's inquiry about reception quality, the pilot replied 'good.' No further radio contact was established.
Wreckage and Findings
Wreckage was scattered over a six-mile area, indicating an in-flight breakup. Pieces from the horizontal stabilizers were located two to six miles from the main wreckage. The right wing was found two miles from the main wreckage, and the left outboard wing panel was found approximately one mile from the right wing.
Toxicological Report
A toxicological test of the pilot's liver fluid revealed a benzoylecgonine (cocaine metabolite) level of 0.136 mg/l. Both occupants were killed.
Probable Cause
The official probable cause findings include: an in-flight encounter with weather (dark night, clouds, icing conditions); loss of control in flight due to aircraft control not being maintained and impairment (drugs) by the pilot; airframe failure when design stress limits were exceeded, resulting in horizontal stabilizer and wing overload and separation; and an in-flight collision with terrain.