What happened
While flying at FL290, the pilot was performing circumnavigation of isolated thunderstorms. Following information from Flight Watch regarding a SIGMET for thunderstorms forming between Colorado and New Mexico, the pilot attempted to navigate toward an alternate airport. Due to rapidly developing weather cells, the pilot was forced to continually change headings.
Because there was insufficient fuel to reach the initial alternate, the pilot elected to divert to a different alternate airport. All anti-ice equipment had been activated. During the descent through cloud layers, mixed icing began to accumulate rapidly on the aircraft. As the pilot initiated a 180-degree turn intended to exit the icing conditions, the aircraft encountered severe downdrafts. The pilot declared an emergency and successfully landed at the alternate airport in visual meteorological conditions with no injuries.
The investigation
A post-accident examination of the aircraft revealed that the inboard panels of both bonded wings were wrinkled. This damage was significant enough to necessitate the replacement of the entire wing assembly.