Preflight and Departure
During a preflight weather briefing, the pilot was advised of thunderstorms and intense rain showers along the intended route. Despite the forecast, the pilot filed an IFR flight plan and departed.
In-Flight Events
During the flight, air traffic control (ATC) advised the pilot of a level 6 thunderstorm cell ahead and stated that they had no report on its top. The pilot responded that his radar was not displaying any returns. Attempts were made to deviate from the path. Approximately 20 minutes later, the pilot reported that the aircraft was encountering icing conditions and was losing altitude. One minute and 38 seconds after that report, the pilot transmitted, "we're going in."
Accident Sequence
Subsequently, the aircraft experienced an in-flight breakup. The wreckage was found scattered over a half-mile area. Examination revealed that the outboard wing panels had failed in flight. Witnesses on the ground reported seeing either smoke or fire emanating from the aircraft before it crashed. Evidence of an electrical discharge was found on the outboard portion of the right wing, although the pilot had not mentioned any lightning encounter during the flight. No evidence of metal fatigue was discovered.
Occupants and Damage
All three occupants were killed in the accident.
Probable Cause
The official probable cause findings were listed as multiple occurrences: Occurrence #1: in flight encounter with weather (findings: flight into known adverse weather - continued - pilot in command; weather condition - clouds, thunderstorm, rain, icing conditions; wing - ice). Occurrence #2: loss of control - in flight (findings: in-flight planning/decision - improper - pilot in command; stall - inadvertent - pilot in command). Occurrence #3: airframe/component/system failure/malfunction (findings: design stress limits of aircraft - exceeded - pilot in command; wing - overload; fuel system, tank - overload). Occurrence #4: fire/explosion. Occurrence #5: in flight collision with terrain/water.