B757 pilots and a flight attendant reported that the aft cabin door would not arm before departure. ...

Narrative:

At departure time #1 flight attendant (flight attendant) 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 flight attendant (strength) I asked FA1 to cycle door and re-attempt arming. With door disarmed; during attempted cycling of handle; door 'jammed' and flight attendant 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 flight attendant 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.

Original NASA ASRS Text

Title: 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.

Narrative: 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.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

Attributes
ACN	1348437
Time
Date	201604
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.Airport
State Reference	US
Aircraft 1
Make Model Name	B757-200
Operating Under FAR Part	Part 121
Flight Phase	Parked
Flight Plan	IFR
Component
Aircraft Component	Escape Slide
Person 1
Function	Captain
Qualification	Flight Crew Air Transport Pilot (ATP)
Person 2
Function	Other / Unknown First Officer
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural FAR Deviation - Procedural Published Material / Policy

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.