AN MD80 DEVELOPED A HYD LEAK INTO THE AIR CONDITIONING SYS. AS THE HYD VAPOR LOOKED LIKE SMOKE; THE RPTR ORDERED THE ACFT TO BE EVACED. EMER SIT DECLARED.

Narrative

WHILE WAITING FOR ALLEY TO CLR TO TAXI INTO GATE X; CABIN ATTENDANT OPENS DOOR AND SAYS FIRE IN CABIN. VERY HVY SMOKE PRESENT. ACCOMPLISHED GND EVAC CHKLIST. I EXITED REAR OF ACFT AFTER ENSURING NO ONE LEFT ON BOARD. NO RPTED INJURIES FROM GND EVAC. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THERE WAS NO FIRE; THE 'SMOKE' WAS HYD OIL VAPOR. THE L HYD SYS DEVELOPED A LEAK AND PUMPED 12 QUARTS OF NON FLAMMABLE OIL INTO THE AIR CONDITIONING SYS. AS THERE WAS NO GATE AVAILABLE; THE CAPT ELECTED TO EVAC ON THE RAMP. THE FORWARD ENTRY DOOR SLIDE DID NOT INFLATE AUTOMATICALLY; IT HAD TO BE MANUALLY OPERATED. THE RPTING CAPT WROTE THIS UP IN THE ACFT LOGBOOK; AND HIS ACR IS PURSUING THIS. THE RPTR HAS HEARD OF OTHER EVAC SITS WHERE THE SLIDE DID NOT DEPLOY AUTOMATICALLY. THERE WERE NO INJURIES AND THERE WAS NO ACFT DAMAGE AS THERE WAS NO FIRE. THE ACFT WAS BACK IN THE AIR WITHIN 4 HRS. BOTH THE FAA AND THE NTSB WERE INVOLVED WITH THIS INCIDENT AND 'WERE QUITE NICE.' ABOUT THE ONLY QUESTION THAT THEY HAD WAS; 'DID YOU USE THE CHKLIST?'