Narrative:

Cabin altitude pressurization failure at FL370. The cabin altitude intermittent horn came on. We checked the cabin altitude and it was indicating 10;500 ft and climbing at 500 FPM. We immediately went to oxygen masks on and communication established; then checklist. The cabin altitude continued to climb despite our running the checklist. We requested an immediate descent and were only given FL350. We then declared an emergency and were given 10;000 ft. We quickly descended to 10;000 ft and diverted to ZZZ. During the initial stages of this problem; I could not hear the first officer because my headset earpiece tubing had come apart. We used the overhead speaker to communicate. No further problems noted. After landing we entered the discrepancy in the logbook and called dispatch and maintenance. Supplemental information from acn 828358: during the initial phases of the event; we had difficulty communicating with the oxygen masks on. The initial delay was the required use of the captain's volume knob on the speaker itself to be powered on when communicating via the mask-mike/speak combination and the use of the intercommunication push-to-talk switch on the first officer control column.

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Original NASA ASRS Text

Title: A B737-300 flight crew reported losing pressurization. They ran the procedure; declared an emergency; and descended to a safe altitude while they diverted to the nearest suitable airport.

Narrative: Cabin altitude pressurization failure at FL370. The cabin altitude intermittent horn came on. We checked the cabin altitude and it was indicating 10;500 FT and climbing at 500 FPM. We immediately went to oxygen masks on and communication established; then checklist. The cabin altitude continued to climb despite our running the checklist. We requested an immediate descent and were only given FL350. We then declared an emergency and were given 10;000 FT. We quickly descended to 10;000 FT and diverted to ZZZ. During the initial stages of this problem; I could not hear the First Officer because my headset earpiece tubing had come apart. We used the overhead speaker to communicate. No further problems noted. After landing we entered the discrepancy in the logbook and called dispatch and maintenance. Supplemental information from ACN 828358: During the initial phases of the event; we had difficulty communicating with the oxygen masks on. The initial delay was the required use of the Captain's volume knob on the speaker itself to be powered on when communicating via the mask-mike/speak combination and the use of the intercommunication push-to-talk switch on the First Officer control column.

Data retrieved from NASA's ASRS site as of April 2012 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.