Narrative:

Upon leveling off at FL390 the first officer pointed to the ECAM pressure page. We noticed that the cabin was climbing slowly through 9000 ft. Cabin reached 10000 ft. Alarm went off. Donned oxygen masks. Started emergency descent after coordination with ATC. Checklist was accomplished. Noticed at the beginning of the descent that the cabin started to stabilize. Leveled at FL270 initially. Pressure system appeared to be working normally. Assessed situation with purser. She indicated everything was fine and no masks had dropped, passenger were ok and flight attendants were ok. Decided to return to lax. Declared emergency. Informed dispatch. Made PA announcement to passenger indicating the nature of the problem and the fact that we were returning to lax. Called purser again and asked about the condition of the passenger and flight attendants and indicated time to landing 17 mins. She said all was normal in the cabin. Made an uneventful approach and landing to runway 25L at lax. Secured the emergency equipment. Supplemental information from acn 596396: during the descent cabin pressure began to descend. By FL270 cabin pressure returned to normal indicating approximately 6500 ft.

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Original NASA ASRS Text

Title: AN A319 FLT CREW EXPERIENCE A LOSS OF CABIN PRESSURE WHICH LEADS TO AN EMER LNDG AT LAX.

Narrative: UPON LEVELING OFF AT FL390 THE FO POINTED TO THE ECAM PRESSURE PAGE. WE NOTICED THAT THE CABIN WAS CLBING SLOWLY THROUGH 9000 FT. CABIN REACHED 10000 FT. ALARM WENT OFF. DONNED OXYGEN MASKS. STARTED EMER DSCNT AFTER COORD WITH ATC. CHKLIST WAS ACCOMPLISHED. NOTICED AT THE BEGINNING OF THE DSCNT THAT THE CABIN STARTED TO STABILIZE. LEVELED AT FL270 INITIALLY. PRESSURE SYS APPEARED TO BE WORKING NORMALLY. ASSESSED SIT WITH PURSER. SHE INDICATED EVERYTHING WAS FINE AND NO MASKS HAD DROPPED, PAX WERE OK AND FLT ATTENDANTS WERE OK. DECIDED TO RETURN TO LAX. DECLARED EMER. INFORMED DISPATCH. MADE PA ANNOUNCEMENT TO PAX INDICATING THE NATURE OF THE PROB AND THE FACT THAT WE WERE RETURNING TO LAX. CALLED PURSER AGAIN AND ASKED ABOUT THE CONDITION OF THE PAX AND FLT ATTENDANTS AND INDICATED TIME TO LNDG 17 MINS. SHE SAID ALL WAS NORMAL IN THE CABIN. MADE AN UNEVENTFUL APCH AND LNDG TO RWY 25L AT LAX. SECURED THE EMER EQUIP. SUPPLEMENTAL INFO FROM ACN 596396: DURING THE DSCNT CABIN PRESSURE BEGAN TO DSND. BY FL270 CABIN PRESSURE RETURNED TO NORMAL INDICATING APPROX 6500 FT.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.