Large Transport; Low Wing; 2 Turbojet Eng
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 120; Flight Crew Total 21000; Flight Crew Type 8400
Communication Breakdown; Confusion
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy
General Maintenance Action
Aircraft; Human Factors
Just after we parked at gate in DEN; the lead flight attendant called us and advised us the seat belt sign was still on; I looked up and saw the switch was in auto and not off and corrected it. After running our checklist I emerged from the cockpit and heard a hissing sound that I recognized from our EVAC simulator; the sound of a slide deploying. I peered around the corner of my doorway and saw door 1R open; with the red tape still across the viewport and the slide pack flopped out onto the deck of a catering truck. The slide luckily had not inflated. I immediately told the caterer; who had stepped into the cabin over the slide into the galley and the flight attendants in the area; to get away from the area in case the slide was still able to inflate. On debriefing; it turned out the caterer had opened the door without getting the ok; with the red tape still across the viewport; indicating the door was still armed.When the mechanics arrived and secured the slide; we discussed how the door; when opened from outside; is supposed to disarm. It had not. Also; that the position of the slide as it landed; it should have deployed and inflated; it also had not. On further investigation; the mechanic found that the slide had a date on it of 1994. I don't know what the required inspection intervals for the slides are; but 21 years seems excessive. Today; we were in fact very lucky these failures occurred.
A flight crew on arrival at the gate noted that a caterer opened up an armed door with the red tape still across the viewport and the slide pack flopped out onto the deck of a catering truck. The slide did not inflate.  Mechanics were called.  The slide was long overdue for inspection.