B757-200
Flight Crew Air Transport Pilot (ATP)
Situational Awareness
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy
General Flight Cancelled / Delayed
Aircraft
At departure time #1 Flight Attendant (FA) called on intercom advising door Right Aft failed to 'Arm'. I asked 'what was problem?' FA1 stated door handle was not going into full down position thus not 'Arming'. Since #1 was a male FA (strength) I asked FA1 to cycle door and re-attempt Arming. With door disarmed; during attempted cycling of handle; door 'jammed' and FA states he heard 'hissing' and two fabricated metal hinges fell off the bottom of the door. When Maintenance arrived the AMTs stated door 'must' be rigged improperly because bottle was blown and door & evacuation slide both failed to operate. I don't believe the FA blew the bottle. I believe the door failed to Arm because the door has a mechanism to stop disarming if the door is unable to function. How the door got into this state is unknown. My guess is repeated use from catering cycling the door 4 to 5 times daily caused an internal fatigue failure.The #1FA is NOT culpable for any of this failure; FA1 was acting on my orders. If any blame must be levied it is solely mine. Ops found new aircraft and flight continued late with no further events. I don't believe the aircraft could have stayed in Service. In hindsight; if I had called maintenance to look at door first; the AMTs may have cycled door without damaging it - but unlikely.
[Report narrative contained no additional information.]
B757 pilots and a Flight Attendant reported that the aft cabin door would not arm before departure. The door assist bottle was triggered while attempting to cycle the door handle.