B737-700
Flight Crew Air Transport Pilot (ATP)
Confusion; Distraction; Training / Qualification; Situational Awareness
Deviation / Discrepancy - Procedural Published Material / Policy; Flight Deck / Cabin / Aircraft Event Other / Unknown
General Maintenance Action
Aircraft; Human Factors; Procedure
After arrival to a very hot aircraft (because it had been closed with the ground heat on) I tried opening the galley door for airflow. It did not have a window flag; and the slide girt bars were stowed on the door. I turned the handle; did an initial push to open the door. I didn't push hard enough; so I let it come back a bit; and gave a harder push. I heard the telltale Velcro release sound; and let off the door pressure and allowed it to close. However; I pushed it far enough for the slide to deploy.When I realized what had happened; I noticed the slide bar had somehow slid to the right during the opening sequence; and in a sense 'armed' the door by catching the door frame. This allowed the slide to deploy. I told the Agent - he called Maintenance. I notified the Chief Pilots and Captain.Preventative Measures: 1. The slide bar needs to be locked into place in the latches/ locks; not just placed on top of them. 2. The person opening the door (including me) needs to pay more attention that the slide bars are in proper position before opening the door. Other than the pride hit and embarrassment of this occurring; I feel the situation is very lucky that no one was outside the door or on the ground when this happened.
An air carrier pilot reported that while opening an unarmed B737 galley door for ventilation;  the girth bar fell; caught the door frame and the slide deployed.