Accident Sequence
The aircraft veered off the prepared landing area and nosed over in tall weeds and rocks. The pilot had changed from a gravel runway to a dirt one due to downdrafts. On the first landing on the dirt runway, the aircraft touched down on the wheels. When the tail lowered, the pilot applied the brakes. The aircraft then veered to the left by approximately 20 degrees. The pilot attempted to correct with right rudder, but it had no effect. As the aircraft reached the runway edge, full right brake was applied. Despite this, the aircraft continued into the grass and rocks, where it nosed over.
Findings
Upon inspection, it was discovered that the left brake was stuck in the on position. When the B nut on the brake line at the left wheel cylinder was loosened, the brake released.