Date: 201502
Local time of day: 1801-2400
Location: ZZZ.Airport, US
Aircraft: A319
Operator: Air Carrier
Operating under: Part 91
Flight phase: Parked
ATC / advisory: Ramp ZZZ
Aircraft component: Exterior Pax/Crew Door
Component problem: Improperly Operated
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Second reporter function: First Officer; Pilot Not Flying
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: Aircraft In Service At Gate
Result: General Maintenance Action
Contributing factors: Human Factors
Primary problem: Human Factors

Narrative: After a [very late night] gate return and flight cancellation the First Officer and I were waiting for our hotel confirmation and the hotel shuttle. The station manager asked us to move the aircraft because there was another inbound flight that would require the gate our aircraft was currently at. Later scheduling called me with an official request to do so. They asked us to call back to adjust our rest times. The aircraft was going to be under tow to a remote location. We made our way towards the aircraft but my FO was the first to enter and sit at his station. I entered last and upon closing the cabin door I proceeded to arm L1 and L2 doors and call out that I had done that so; in the event of an emergency; we could exit the aircraft. I sat down at my station and we began to discuss our plan of action since we had previously gone through the securing checklist shutting everything down. At this point we knew that we may have to tow the plane with the batteries as the only source of power. I then called maintenance control for guidance on this procedure. The maintenance controller agreed that we might have to do just that because he did not believe that the ground crew was qualified to tow with one engine running. In the meantime my FO tried to contact Ops with no luck. While I was still on the phone with the maintenance controller he got up and went to the back. In a split second I realized he was heading towards the door and shouted to warn him that the doors were armed. Unfortunately it was too late and he opened the door and the slide started to deploy but was stopped by the jetway and just started to unravel. Luckily a mechanic was able to pin the bottle and stop the deploying sequence. My first officer is a capable; professional; and determined team player. He was of much assistance to me throughout the time we were together. Unfortunately even the best of us are susceptible to human error. He accidentally opened the armed door and I assumed that he was aware of the door's armed status. He should have waited until I was done on the phone so we could be on the same page; not just go off by himself. Also the situation we were in was a challenging one because it was cold dark airplane; we were off duty and in a different mindset and there was no checklist for this type of situation. To avoid something like this a checklist for similar situations would be invaluable so that pilots can avoid unnecessary mishaps. Another suggestion would be that no matter what the circumstance; pilots should consider every door as if it was armed and handle them with the proper care.


Second narrative: We were approached by the Airport ZZZ station manager who informed us that there were no qualified personnel available and requested that we assist the ground crew with moving the aircraft. The Captain and I had a brief discussion about [the aircraft's] condition; specifically the fact that our APU was deferred and that we would need to conduct the pushback in a batteries-only configuration. I noticed the [station manager] returning the aircraft and walking up the jet bridge stairs. I left my seat to meet him at the door and discuss with him the possibility that we would not be assisting with moving the aircraft if we did not receive an OK from maintenance. As I approached the main cabin door; the Captain attempted to inform me of its armed condition but; unfortunately; I opened it and the emergency slide began its deployment process.


Synopsis: When asked to help relocate their inbound aircraft to make the gate available for a later inbound flight; the flight crew of an A319 inadvertently deployed the main cabin door slide. The First Officer went aft to confer with the station manager about technical problems with respect to towing the aircraft with only battery power available and was unaware that door had been armed by the Captain after they boarded.