Departure and Witness Observations
The float-equipped airplane departed from water into gusting winds that were blowing downwind of high, steep terrain. Witnesses reported that the airplane did not climb above 200 feet above ground level, an altitude insufficient to clear the terrain at the upwind end of the lake.
Maneuver and Impact
According to witnesses, the airplane entered a steep left bank and turned within the confines of the upwind end of the lake. This turn was made in a downwind direction, directly downwind of a 2,600-foot-high peak. The airplane then abruptly pitched nose down, impacted the water in a vertical attitude, and immediately sank.
Postaccident Examination
Postaccident inspection of the wreckage disclosed that the flaps were extended to 25 degrees. The propeller had separated from its mounting studs, with metal deposited in the majority of the threads. No evidence of preimpact mechanical anomalies was discovered with the airplane.
Weather Conditions
An air taxi pilot who arrived at the lake immediately after the accident reported that gusts and turbulence were too strong to attempt a landing. He reported winds at the lake as 30 knots, with stronger winds above, and noted gusts visible on the water.