B757 FLT CREW AND CABIN CREW; DURING DEPLANING; HAVE DIFFICULTY WITH THE FORWARD EXIT DOOR. FO ATTEMPTS TO CLOSE AND OPEN THE DOOR AND THE EMER SLIDE DEPLOYS.

Narrative

ON DELAY FOR NO APU BLEED AIR AND WERE UNABLE TO GET COOLING AIR ON ACFT. WHILE WAITING A DECISION; CAPT ASKED THE FLT ATTENDANTS IF THEY WANTED THE FORWARD/AFT DOORS OPEN FOR COOLING. THE DOORS WERE OPENED; THE JETBRIDGE WAS UP AND A FLT ATTENDANT WAS STATIONED AT EACH DOOR. STATION DIRECTED AN ACFT SWAP AND THE PAX BEGAN TO DEPLANE. WE RAN THE LNDG/SHUTDOWN FLOWS AND THEN DID THE PARKING CHKLIST. ON EXIT OF THE FLT DECK; THERE WERE ABOUT 30 COACH PAX REMAINING. THE FLT ATTENDANT AT 1L WAS HAVING TROUBLE CLOSING THE OPEN DOOR. I OFFERED TO ASSIST AND SHE STEPPED BACK. AS I STARTED TO MOVE THE DOOR HANDLE; THE DOOR (PWR ASSISTED) OPENED AND THE SLIDE DEPLOYED. NO ONE WAS INJURED ON THE ACFT OR ON THE GND. SUPPLEMENTAL INFO FROM ACN 689875: WHEN IT CAME TIME TO CLOSE THE DOORS; THE FLT ATTENDANT IN THE FORWARD GALLEY WAS HAVING TROUBLE CLOSING THE DOOR. THE FO TRIED TO ASSIST HER. IN THE PROCESS; THE SLIDE DISCHARGED AS THE CUSTOMERS WERE IN THE MIDDLE OF DEPLANING TO GO TO ANOTHER PLANE.