The Flight
A commercial pilot was conducting an instrument flight rules (IFR) cross-country flight at night in a multi-engine airplane. After takeoff, the pilot checked in with air traffic control (ATC) while cruising at an altitude of about 10,000 ft mean sea level (msl).
Weather Reports
Approximately 31 minutes into the flight, the pilot reported seeing lightning off the airplane's left wing. The controller responded that the weather appeared to be about 35 to 40 miles away and that the airplane should remain clear of it. The pilot acknowledged, stating that he had onboard weather radar and agreed that they would fly clear of the weather. The pilot then provided no further communications.
Loss of Radar Contact
About 4 minutes after the pilot’s last transmission, radar showed the airplane at 10,400 ft msl. Roughly 1 minute later, radar indicated the airplane in a descending right turn at 9,400 ft. Shortly thereafter, radar contact was lost entirely.
Wreckage and Examination
The wreckage was scattered across an area with a radius of about one-quarter mile, consistent with an in-flight breakup. The left horizontal stabilizer, significant portions of both left and right elevators, and their respective trim tabs were not located among the wreckage. Examination of the recovered airframe components revealed no pre-impact structural anomalies. The engines and turbochargers showed no pre-impact issues, and the propellers exhibited evidence of rotation at impact with no pre-impact anomalies found.
Pilot and Weather Factors
Autopsy and toxicology testing showed no evidence of pilot impairment or incapacitation. A review of weather information indicated that no convection or thunderstorms were coincident with or near the airplane's route of flight; the nearest convective activity was located about 25 miles west of the accident site.
Analysis
Given the lack of radar data after the airplane descended through 9,400 ft, it is likely that it entered a rapid descent during which it exceeded its design stress limitations, resulting in the in-flight breakup. However, based on the available information, the event that precipitated the descent and loss of control could not be determined.