B777-200
Flight Crew Instrument; Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP)
Time Pressure; Troubleshooting; Human-Machine Interface
Aircraft Equipment Problem Critical
Aircraft; Procedure
I was the Captain on Aircraft X parked at the gate. After the agent closed the door; the number 1 FA (Flight Attendant) came to the cockpit and said she couldn't arm the 1R door. This we confirmed this on the door ECAM page. I went back to look at door and confirmed it wouldn't arm. I disarmed door and cycled it. The arming lever would not arm. I disarmed the door again and confirmed the arm light was not lit and the green disarmed indicator showed disarmed; not armed. Both FA's in galley confirmed this. I opened the door slightly and the slide deployed. My FO (First Officer) confirmed that cockpit indicated not armed at deployment. No one was injured.
B777 Captain reported a cabin door arming issue led to an inadvertent slide deployment.