What happened
On a scheduled domestic flight operating as Flight 55, a Fairchild F-27B, registration N4905, was traveling from Anchorage International Airport toward Iliamna Airport with planned stops at Big Mountain, Iliamna, and King Salmon. The aircraft departed Anchorage at 08:46 under an instrument flight plan, cleared to an altitude of 16,000 feet. While the weather at the destination was reported as clear with 15 miles of visibility, the flight disappeared from communications after the first officer requested approach clearance for Iliamna at 09:25.
Witnesses near Pedro Bay observed a large cloud of black smoke and a fireball trailing behind the aircraft's wing. Following this observation, the aircraft began shedding debris and entered a spinning descent. The wreckage was recovered on the southern shore of Foxies Lake at an elevation of roughly 220 feet. The accident resulted in 39 fatalities, including all 36 passengers and three crew members, and the total destruction of the airframe.
Findings
The investigation concluded that the aircraft suffered an in-flight structural failure after encountering unforecasted severe to extreme turbulence. This encounter led to a breakdown of the wing structure. The failure specifically occurred in a section of the right wing that had been compromised by pre-existing fatigue cracks.