Flight Crew Air Transport Pilot (ATP)
Confusion
Aircraft Equipment Problem Critical
Flight Crew Returned To Gate; General Maintenance Action
Human Factors; Aircraft
Approaching the hold short for the runway at ZZZ; and waiting for one aircraft to land; I stopped the aircraft. As I set the parking brake; the right Rudder Pedal Assembly broke loose; (concurrent with a snap and clunk sound); the pedal rested in the full forward position. First Officer and I set the parking brake; he used his brake pedals; while I used my hand on the parking brake handle to set the brakes. We started the APU; shutdown the engines; and requested to be towed back to the Ramp. Prior to the decision to request tow; First Officer and I discussed (briefly) what we should do. It was very clear that we did not know what our ability to stop the aircraft would be; or even the extent of any damage that may have occurred. We concluded that our safest course was to be towed in. First Officer and I coordinated with Ground Control; Line Maintenance; Operations Control; and Maintenance Control; and the aircraft was safely returned to the Ramp where repairs could be made. Logbook entry was made. Support group dropped a plane in for the freight; our duty day expired and we dispatched to the hotel. Maintenance history [noted that] Maintenance found the bolt where the right rudder pedal pushrod attaches to the rudder pedal arm to be sheared. Somehow; this bolt sheared while I was setting the parking brake. Thankfully this did not occur during flight; or a more critical phase of flight; V1 cut; crosswind landing; etc. To clarify; the right rudder pedal broke; moved freely with no affect on flight controls. The pedals on the First Officer's side still worked; and my left pedal still worked as well. Gate return.
While taxiing for departure to the runway at ZZZ; the Captain went to set the parking brake to hold short of the runway for landing traffic. At that moment; we heard a loud bang; and the Captain's right rudder pedal appeared to completely separate from the assembly. It subsequently moved freely back and forth and he was unable to 'Set' or use brakes; and had no rudder control. I was able to set brakes from the First Officer's side; and we elected to shut down and get towed back to the Ramp. Upon inspection; Maintenance discovered that the bolt where the right rudder pedal pushrod attaches to the rudder pedal arm was sheared off.
Two pilots report about a Captain's right rudder pedal attach bolt that sheared (broke); while setting the parking brake on a B757-200 aircraft when they stopped to hold short for another aircraft to land. Aircraft towed back to gate.