Narrative:

We departed sna on a planned flight to phx. Departure was on the back bay 2 departure (an FMS procedure) which included a maximum thrust takeoff and power cutback at 1000 ft for noise abatement. My first officer was making his first flight out of sna and had only seen this departure in the simulator. The takeoff is planned to be accomplished bleeds off, and we then need to reconfigure the pressurization after clearing the noise sensitive area. At approximately the same time this would have been accomplished by the checklist. We were given an FMS rerte and the first officer's attention was diverted. He neglected to complete the checklist and reconfigure the bleed air system. At approximately 13000 ft we shut down the APU and at approximately FL180 the automatic fail light illuminated indicating pressurization was being lost. After complying with prescribed procedure we initiated a descent. Once stabilized in the descent, a re-evaluate of the overhead panel indicated that the bleed valves had not been repositioned to provide engine bleed air for pressurization. We turned the bleed valves on and the system operated normally. During the descent the oxygen masks deployed in the rear of the aircraft. After advising the flight attendants that they could discontinue use of oxygen we climbed to FL330 and continued to phx. Human performance factors: 1) last leg of a 3-DAY trip late at night on a 9 1/2 hour duty day. 2) first departure for a new first officer out of sna. 3) 3 days of back side of the clock flying. 4) predisposition of crew to assume problem was caused by loss of pressure due to pressure vessel failure rather than considering both supply problem and pressurization failure. 5) crew neglected to consider ramifications of returning to cruise altitude after masks (and canisters) had been activated. This incident began with a new first officer being distraction during a highly demanding procedure and neglecting to configure the pressurization system for its proper operation. The captain then did not notice this oversight when he shut down the APU. These are both understandable errors which were probably exacerbated by some degree of fatigue due to the schedule as well as the first officer being somewhat overwhelmed by a new, complex procedure and normal distrs. Returning to cruise altitude after the problem was an oversight by the captain, probably caused by a combination of all of the above.

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Original NASA ASRS Text

Title: B737-300 CLBED TO FL180 WITH PRESSURIZATION INOP. CABIN GOT TO 14000 FT.

Narrative: WE DEPARTED SNA ON A PLANNED FLT TO PHX. DEP WAS ON THE BACK BAY 2 DEP (AN FMS PROC) WHICH INCLUDED A MAX THRUST TKOF AND PWR CUTBACK AT 1000 FT FOR NOISE ABATEMENT. MY FO WAS MAKING HIS FIRST FLT OUT OF SNA AND HAD ONLY SEEN THIS DEP IN THE SIMULATOR. THE TKOF IS PLANNED TO BE ACCOMPLISHED BLEEDS OFF, AND WE THEN NEED TO RECONFIGURE THE PRESSURIZATION AFTER CLRING THE NOISE SENSITIVE AREA. AT APPROX THE SAME TIME THIS WOULD HAVE BEEN ACCOMPLISHED BY THE CHKLIST. WE WERE GIVEN AN FMS RERTE AND THE FO'S ATTN WAS DIVERTED. HE NEGLECTED TO COMPLETE THE CHKLIST AND RECONFIGURE THE BLEED AIR SYS. AT APPROX 13000 FT WE SHUT DOWN THE APU AND AT APPROX FL180 THE AUTO FAIL LIGHT ILLUMINATED INDICATING PRESSURIZATION WAS BEING LOST. AFTER COMPLYING WITH PRESCRIBED PROC WE INITIATED A DSCNT. ONCE STABILIZED IN THE DSCNT, A RE-EVAL OF THE OVERHEAD PANEL INDICATED THAT THE BLEED VALVES HAD NOT BEEN REPOSITIONED TO PROVIDE ENG BLEED AIR FOR PRESSURIZATION. WE TURNED THE BLEED VALVES ON AND THE SYS OPERATED NORMALLY. DURING THE DSCNT THE OXYGEN MASKS DEPLOYED IN THE REAR OF THE ACFT. AFTER ADVISING THE FLT ATTENDANTS THAT THEY COULD DISCONTINUE USE OF OXYGEN WE CLBED TO FL330 AND CONTINUED TO PHX. HUMAN PERFORMANCE FACTORS: 1) LAST LEG OF A 3-DAY TRIP LATE AT NIGHT ON A 9 1/2 HR DUTY DAY. 2) FIRST DEP FOR A NEW FO OUT OF SNA. 3) 3 DAYS OF BACK SIDE OF THE CLOCK FLYING. 4) PREDISPOSITION OF CREW TO ASSUME PROB WAS CAUSED BY LOSS OF PRESSURE DUE TO PRESSURE VESSEL FAILURE RATHER THAN CONSIDERING BOTH SUPPLY PROB AND PRESSURIZATION FAILURE. 5) CREW NEGLECTED TO CONSIDER RAMIFICATIONS OF RETURNING TO CRUISE ALT AFTER MASKS (AND CANISTERS) HAD BEEN ACTIVATED. THIS INCIDENT BEGAN WITH A NEW FO BEING DISTR DURING A HIGHLY DEMANDING PROC AND NEGLECTING TO CONFIGURE THE PRESSURIZATION SYS FOR ITS PROPER OP. THE CAPT THEN DID NOT NOTICE THIS OVERSIGHT WHEN HE SHUT DOWN THE APU. THESE ARE BOTH UNDERSTANDABLE ERRORS WHICH WERE PROBABLY EXACERBATED BY SOME DEG OF FATIGUE DUE TO THE SCHEDULE AS WELL AS THE FO BEING SOMEWHAT OVERWHELMED BY A NEW, COMPLEX PROC AND NORMAL DISTRS. RETURNING TO CRUISE ALT AFTER THE PROB WAS AN OVERSIGHT BY THE CAPT, PROBABLY CAUSED BY A COMBINATION OF ALL OF THE ABOVE.

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.