Accident Overview
An airplane involved in a local fire reconnaissance mission crashed during takeoff-initial climb. Witnesses observed the aircraft become airborne but fail to climb, continuing down the runway in a nose-up attitude while remaining in ground effect. It impacted terrain approximately 600 feet southeast of the departure end of the runway.
Environmental and Configuration Factors
The ambient temperature at the time was about 107 degrees Fahrenheit, resulting in a calculated density altitude of 5,878 feet above mean sea level. On-scene examination revealed that the flaps were extended to 30 degrees, as indicated by both the flap actuator position and the cockpit indicator. A subsequent bench test of the combined flap/gear selector valve showed that both the gear selector and flap selector valves were bent, though otherwise operational. The stop-pin on the flap selector lever was missing. No fluid leakage was observed during the test.
Engine and Systems Examination
Examination of both engines found no abnormalities that would have prevented normal operation. The aircraft flight manual specifies that flaps should be set to 1/4 down (10 degrees) for a normal takeoff.
Probable Cause
The official probable cause was the pilot's excessive selection of flaps prior to takeoff, which resulted in a failure to obtain or maintain an appropriate climb airspeed, and an inadvertent stall or mush during the takeoff-initial climb. A factor contributing to the accident was a high density altitude.