Narrative:

While in a smooth ride at cruise; FL380; we all heard a muffled sound followed by pressure change in the ears. We looked at cabin pressure and saw that cabin altitude was starting to climb; slowly at first (250-500 FPM) and increasing to near 2;000 FPM. I called center; declared an emergency and asked for an immediate descent to 10;000 ft. Center acknowledged the emergency and cleared us to a lower altitude. We initiated an emergency descent; followed the ECAM procedure and followed that up with the QRH. When we leveled at 10;000 feet we noticed that the cabin altitude had peaked at about 14;150 feet but had partially re-pressurized to about a 7;000 foot cabin altitude. The second officer advised the passengers they could take off the O2 masks and explained what had happened. We could see no evidence of aircraft damage or system problems on ECAM; only that the number 2 engine hp bleed was open and number 1 engine hp bleed was closed. We conferred with the dispatcher and maintenance control on the sat phone and determined; with their concurrence; we would continue to destination as; at that time; we were about 85 NM from landing. ATC gave us priority handling and we landed uneventfully. The flight attendants did an excellent job and got several compliments from the passengers.we made appropriate logbook write-ups--including that not all of the masks in the cabin dropped; even though we had pushed the manual O2 mask pushbutton. We split the duties among the 3 cockpit crew members; and felt we were very well trained to do this procedure.you will have to ask maintenance what the cause of this incident was. They thought it might have been a ruptured duct or bleed issue. We did check the outflow valves and they were closed. Maintenance had checked the exterior of the aircraft before we opened any doors and found no apparent damage.

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Original NASA ASRS Text

Title: An A330 flight crew heard a muffled sound; felt a pressure change and noted the cabin altitude begin to climb rapidly. They declared an emergency; descended to a safe altitude where stable pressurization was regained and continued the short remaining distance to their destination.

Narrative: While in a smooth ride at cruise; FL380; we all heard a muffled sound followed by pressure change in the ears. We looked at cabin pressure and saw that cabin altitude was starting to climb; slowly at first (250-500 FPM) and increasing to near 2;000 FPM. I called Center; declared an emergency and asked for an immediate descent to 10;000 FT. Center acknowledged the emergency and cleared us to a lower altitude. We initiated an emergency descent; followed the ECAM procedure and followed that up with the QRH. When we leveled at 10;000 feet we noticed that the cabin altitude had peaked at about 14;150 feet but had partially re-pressurized to about a 7;000 foot cabin altitude. The Second Officer advised the passengers they could take off the O2 masks and explained what had happened. We could see no evidence of aircraft damage or system problems on ECAM; only that the Number 2 engine HP bleed was open and Number 1 engine HP bleed was closed. We conferred with the Dispatcher and Maintenance Control on the SAT phone and determined; with their concurrence; we would continue to destination as; at that time; we were about 85 NM from landing. ATC gave us priority handling and we landed uneventfully. The flight attendants did an excellent job and got several compliments from the passengers.We made appropriate logbook write-ups--including that not all of the masks in the cabin dropped; even though we had pushed the manual O2 mask pushbutton. We split the duties among the 3 cockpit crew members; and felt we were very well trained to do this procedure.You will have to ask Maintenance what the cause of this incident was. They thought it might have been a ruptured duct or bleed issue. We did check the outflow valves and they were closed. Maintenance had checked the exterior of the aircraft before we opened any doors and found no apparent damage.

Data retrieved from NASA's ASRS site as of July 2013 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.