What was found
SHIIP 3569 UPON ARRIVAL AT THE GATE RED FLASHING LIGHT AT ALL EMERG EXIT DOORS. CABIN IS DEPRESSURIZED, OUTFLOW VALVES OPEN.TURNED OFF PACK 1+2, ENG BLEED 1+2 AND APU BLEED. AFTER 3 MINS RED FLASHING LIGHT GOES OUT, DOORS ARE ABLE YO OPEN TO DEPLANE. CORRECTIVE ACTION: BOTH OUTFLOWS FULLY OPENED UPON ARRIVAL,LIGHTS WERE EXTINGUISHED AFTER 2 MINS. (8578816)