Accident Overview
A commercial pilot experienced a loss of control during the landing roll of an agricultural airplane following the failure of the right wheel brake system. The incident occurred when the pilot attempted to apply brake pressure to slow the airplane after touchdown.
Sequence of Events
According to the pilot, initial brake application was successful. However, when the pilot attempted to re-apply brake pressure, the right brake pedal dropped completely to the floorboard, indicating a loss of hydraulic pressure. The airplane subsequently began a gradual left turn. With the right brake inoperative, the pilot could not compensate for the turning moment. The left wing of the airplane struck a concrete pole located on the west side of the airstrip.
Investigation Findings
The FAA inspector determined that the right brake failure was due to the eye bolt, which connects the brake master cylinder to the top portion of the rudder pedal, pulling out from the master cylinder. The operator stated that the only plausible mechanism for the separation was the eye bolt pulling out of the threaded hole in the brake master cylinder. The operator also reported that the time in service for the failed part was unknown. Examination revealed that the bottom two or three threads of the eye bolt appeared damaged or stripped. The operator noted that this condition could have resulted in the eye bolt pulling out of the cylinder.
The airplane sustained damage to the left wing from the impact with the concrete pole. No further details were provided regarding other damage or injuries.