Narrative:

So noted a light on panel that indicated forward outflow was closing, so he was watching pressurization carefully. At approximately 26000, after trying standby and manual mode, he could not prevent cabin climb below 800 FPM rate. Cabin at this time was just below 8000. I asked ZLA for a turn to las vegas and a descent to 10000. I was given the turn and cleared to FL240. The first officer began the descent, emergency descent checklist -- slight speed brakes, power up some on #1 and #3 engines to support pressurization. I explained to center that we currently did not have an emergency, but would if unable to continue descent. He told me he had traffic blocking 190/200 ahead. I asked for a vector clear of traffic and he climbed us to 310 degrees heading and 10000 ft at approximately 17000 ft cabin was almost stabilized and never exceeded 10000 ft after 15000 ATC requested passenger onboard, fuel, etc, and I explained that we did not have an emergency. A timely descent prevented that, but that I would supply that information if necessary, we were busy calling company dispatch, ATIS, las vegas ramp, explaining to passenger, etc! Rest of flight was normal other than depressurization during last 2000-3000 ft on final. I found it useful to be not flying, to insure the proper calls and notification were made. First officer flying extremely smooth, passenger would not have known anything was wrong except for the turn. So's early reaction, execution of checklist, troubleshooting and company calls were outstanding.

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Original NASA ASRS Text

Title: FLC OF LGT MADE TIMELY DSCNT FROM HIGH ALT CLB AFTER UNABLE TO PROPERLY PRESSURIZE ACFT RESULTING IN DIVERTING TO LAND.

Narrative: SO NOTED A LIGHT ON PANEL THAT INDICATED FORWARD OUTFLOW WAS CLOSING, SO HE WAS WATCHING PRESSURIZATION CAREFULLY. AT APPROX 26000, AFTER TRYING STANDBY AND MANUAL MODE, HE COULD NOT PREVENT CABIN CLB BELOW 800 FPM RATE. CABIN AT THIS TIME WAS JUST BELOW 8000. I ASKED ZLA FOR A TURN TO LAS VEGAS AND A DSCNT TO 10000. I WAS GIVEN THE TURN AND CLRED TO FL240. THE FO BEGAN THE DSCNT, EMER DSCNT CHKLIST -- SLIGHT SPD BRAKES, PWR UP SOME ON #1 AND #3 ENGS TO SUPPORT PRESSURIZATION. I EXPLAINED TO CTR THAT WE CURRENTLY DID NOT HAVE AN EMER, BUT WOULD IF UNABLE TO CONTINUE DSCNT. HE TOLD ME HE HAD TFC BLOCKING 190/200 AHEAD. I ASKED FOR A VECTOR CLR OF TFC AND HE CLBED US TO 310 DEGS HDG AND 10000 FT AT APPROX 17000 FT CABIN WAS ALMOST STABILIZED AND NEVER EXCEEDED 10000 FT AFTER 15000 ATC REQUESTED PAX ONBOARD, FUEL, ETC, AND I EXPLAINED THAT WE DID NOT HAVE AN EMER. A TIMELY DSCNT PREVENTED THAT, BUT THAT I WOULD SUPPLY THAT INFO IF NECESSARY, WE WERE BUSY CALLING COMPANY DISPATCH, ATIS, LAS VEGAS RAMP, EXPLAINING TO PAX, ETC! REST OF FLT WAS NORMAL OTHER THAN DEPRESSURIZATION DURING LAST 2000-3000 FT ON FINAL. I FOUND IT USEFUL TO BE NOT FLYING, TO INSURE THE PROPER CALLS AND NOTIFICATION WERE MADE. FO FLYING EXTREMELY SMOOTH, PAX WOULD NOT HAVE KNOWN ANYTHING WAS WRONG EXCEPT FOR THE TURN. SO'S EARLY REACTION, EXECUTION OF CHKLIST, TROUBLESHOOTING AND COMPANY CALLS WERE OUTSTANDING.

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.