B777 Undifferentiated or Other Model
Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Communication Breakdown; Distraction; Other / Unknown; Fatigue
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy; Flight Deck / Cabin / Aircraft Event Other / Unknown
Flight Crew Became Reoriented; Flight Crew Took Evasive Action
Human Factors
After arrival and shutdown at ZZZZ we went to the courier area to disarm the entry doors with [a Flight Attendant] the designated operator and myself as observer. As soon as I saw the L1 door arming panel I noticed the handle to already be in the disarmed position (green). [The Flight Attendant] reached up and lifted the cover and positioned the handle to armed (red). I immediately verbalized 'no no no' and she returned the handle to the disarmed position and verified the girt bar flags to be out of view. Turning to the right side door to find it was also disarmed already. We verified the girt bar flags and I went to cockpit and verified the doors disarmed; announced 'doors clear'. [The Flight Attendant] cracked open L1 door and no further incident. We went forward to complete the remaining items on the shutdown checklist and discussed how this could have happened. We agreed that do to last minute departure route changes just prior to departure that [the Flight Attendant] didn't arm the doors and I didn't notice that the memo message remained manual. I can see this happening and a tired crew arming already disarmed doors and then blowing a slide. Read the EICAS messages more closely.
B777 Captain reported the crew failed to arm cabin doors before departure; then almost deployed the door slide after arrival.