Tailwheel-Equipped Airplane Ground Loops During Landing Roll After Brake Failure (N3050B)

Accident Summary

A commercial certificated pilot was landing a tailwheel-equipped airplane on a gravel surface runway. During the landing roll at about 35 knots of airspeed, the airplane began to drift to the right. The pilot applied left brake pressure, but the pedal went to the floor without producing any braking action from the left brake. The airplane departed off the right side of the runway and ground looped to the right. The left main gear strut fractured just outboard from the fuselage, and the left wing struck the ground. The airplane received damage to the fuselage and the left wing.

Investigation Findings

An FAA inspector examined the airplane at the accident site. The actuator rod connecting the left brake pedal to the left brake master cylinder was found fractured. The point of separation had flat fracture planes oriented 90 degrees to the long axis of the rod. The separated left main landing gear strut was also examined and photographed. The point of separation was oriented perpendicular to the span of the gear strut. Visual examination of the fracture surface revealed flat fracture planes with multiple beach marks radiating in successive arc patterns from the outer edges of the strut. The landing gear on the accident airplane is a spring steel strut bolted to the fuselage at its upper end. Neither the manufacturer nor the FAA have established a life limit (hours or cycles) for the main landing gear strut. No inspection procedures other than a general visual inspection of the landing gear have been specified by the manufacturer or the FAA.