What happened
Following departure from Sitka, the aircraft proceeded generally eastward, navigating via Blue Lake and Blue Lake Pass before reaching the "Cut," a ridge oriented northeast to southwest with an elevation of approximately 3000 feet MSL. The impact site was located approximately one nautical mile southeast of the Cut on the north face of the valley. Both stall fences, situated on the upper surface of each wing, were discovered imbedded in the ground. Their position corresponded roughly to where they would have been had the aircraft fallen vertically and landed in a relatively flat attitude.
The investigation
Several pilots operating in the vicinity of the accident site and Blue Lake Pass within several hours after the incident reported turbulence and strong northwest winds. There were also multiple reports of cloud spillover to the lee side of the Cut, indicative of downdrafts.
Findings
The physical evidence and witness accounts suggest the aircraft encountered severe turbulence and strong northwest winds. The condition of the stall fences indicated a vertical descent. These factors contributed to the accident.