Incident Overview
An aircraft operating under instrument flight rules (IFR) was vectored by air traffic control (ATC) to avoid an active military operations area (MOA). The controller informed the pilot that deviation was only possible to the left of the course due to the active MOA.
Flight Details
The airplane was in an area of developing convective weather activity and was likely in instrument meteorological conditions. The pilot reported to ATC that he encountered freezing rain and requested a deviation to the left, which was approved.
Sequence of Events
Flight track data showed the airplane entered a descending left turn. A performance study based on the aircraft's track data indicated that during the turn, the roll angle reached 70°, the pitch angle reached -17° and then -34°, and the calibrated airspeed exceeded both the airplane's published never exceed speed (VNE) and its maximum operating maneuvering speed (VO). During the turn, the airplane's structure broke apart, and wreckage was distributed along a 3-mile path. The flight path depicted in the flight track data was consistent with a loss of airplane control.
Investigation Findings
The airplane was destroyed and the pilot was killed. The investigation determined that the flight encountered convective weather conditions, leading to a loss of control, exceedance of the airplane's never exceed speed, and subsequent structural failures.
Probable Cause
The pilot’s encounter with convective weather conditions, which resulted in a loss of airplane control, the exceedance of the airplane’s never exceed speed, and the resulting overload failure of the horizontal stabilizer and subsequent failure of the airplane’s wings.