What happened
During a fire retardant delivery flight, the pilot was operating approximately 60 feet above the terrain with 30 degrees of flaps extended. The aircraft passed over the drop site at a speed between 95 and 100 mph. Following the release of the retardant, the pilot applied full power and retracted the flaps to 10 degrees; engine indications remained normal during this process.
However, the aircraft was unable to climb without a loss of airspeed. The pilot determined that the flight path would not allow for clearing the upcoming ridgeline. In an attempt to manage the situation, the pilot slowed the aircraft as much as possible before the impact occurred.
Findings
Weather observations from a nearby airport and reports from ground personnel near the accident site indicated high and gusty wind conditions. Wind velocities were recorded as high as 40 knots at the time of the accident. These conditions would have resulted in a tailwind for the aircraft during its retardant drop, contributing to the encounter with tailwind and downdraft conditions that led to the impact.