As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT ATTENDANT WAS ARMING SLIDE AT POSITION 2E WHEN HEARD A LOUD HISSING SOUND (NOT INTENTIONAL). THE BOTTLE DEPLETED BUT THE SLIDE DID NOT INFLATE AT ALL. THE AMT'S OPENED THE PARACHUTE PINS TO INSPECT THE SLIDE PACK AND SUSPECT THAT THE DEFLATION VALVE WAS PARTIALY OPENED, P/N 100505-201 S/N D9A011 ROUTED TO REPAIR SUPPLIER USING REPAIR PO 4800028600. SLIDE WAS REPLACED ON THE A/C.