B737-300 crew was not able to pressurize the aircraft for a third time.

Attributes
ACN	574632
Time
Date	200302
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : mmex.artcc
State Reference	FO
Altitude	msl single value : 12000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : mmex.artcc
Operator	common carrier : air carrier
Make Model Name	B737-300
Operating Under FAR Part	Part 121
Flight Phase	climbout : intermediate altitude
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : multi engine pilot : atp pilot : commercial pilot : flight engineer pilot : instrument
Experience	flight time last 90 days : 200 flight time total : 20000 flight time type : 10000
ASRS Report	574632
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	aircraft equipment problem : critical maintenance problem : improper maintenance non adherence : company policies non adherence : far non adherence : published procedure
Independent Detector	aircraft equipment other aircraft equipment : outflo valve position indicator, cabin diff, press, indicator other flight crewa other flight crewb
Resolutory Action	flight crew : diverted to another airport flight crew : landed as precaution
Consequence	other other
Factors
Maintenance	contributing factor : schedule pressure performance deficiency : inspection performance deficiency : non compliance with legal requirements performance deficiency : repair performance deficiency : testing performance deficiency : fault isolation
Supplementary
Problem Areas	Flight Crew Human Performance Company Maintenance Human Performance Aircraft
Primary Problem	Flight Crew Human Performance

Narrative:

Previous 2 revenue flts on this aircraft. Involved inability to pressurize, despite attempts to use each of the 4 modes of the pressure controller to assure closure of the outflow valve (valve indicated closed). We returned to the airport and both times maintenance thoroughly checked system and returned aircraft to service with no malfunctions observed. (Second time I personally witnessed the maintenance trouble-shooting procedures.) then we were directed to ferry the aircraft to our maintenance base if possible. Again, on takeoff, we were unable to pressurize via any pressurization mode selection as called for in our 'automatic fail or unscheduled pressurization change' non-normal checklist. We then selected the hi mode on both aircraft packs, the aircraft pressurized, and we continued to destination. I found out today that maintenance replaced the pressure controller. Test flew the aircraft and returned it to revenue service. Also, today I reviewed my manual and saw that the 'cabin altitude warning or rapid decompression/emergency descent' checklist called for the additional step of placing the left and right pack switches to hi. We used the wrong checklist for the situation! (I am just discovering this now -- the late NASA report.) I feel so badly about this -- the inconvenience to 2 planeloads of passenger, the expense, and inconvenience for my company, because we didn't use proper procedures. All involved are still stymied as to why the aircraft could be pressurized fully on the ground by maintenance in mex, and also why changing the pressure controller would fix the problem when the previous one checked out properly by maintenance procedures. Bottom line for me -- the aircraft had a problem, and I had a chance to mitigate that problem expeditiously. Yet despite our concerted best aircrew efforts, we blew it. I'll certainly make every effort, more of an effort, in the future, to use the right checklist.

Original NASA ASRS Text

Title: B737-300 CREW WAS NOT ABLE TO PRESSURIZE THE ACFT FOR A THIRD TIME.

Narrative: PREVIOUS 2 REVENUE FLTS ON THIS ACFT. INVOLVED INABILITY TO PRESSURIZE, DESPITE ATTEMPTS TO USE EACH OF THE 4 MODES OF THE PRESSURE CTLR TO ASSURE CLOSURE OF THE OUTFLOW VALVE (VALVE INDICATED CLOSED). WE RETURNED TO THE ARPT AND BOTH TIMES MAINT THOROUGHLY CHKED SYS AND RETURNED ACFT TO SVC WITH NO MALFUNCTIONS OBSERVED. (SECOND TIME I PERSONALLY WITNESSED THE MAINT TROUBLE-SHOOTING PROCS.) THEN WE WERE DIRECTED TO FERRY THE ACFT TO OUR MAINT BASE IF POSSIBLE. AGAIN, ON TKOF, WE WERE UNABLE TO PRESSURIZE VIA ANY PRESSURIZATION MODE SELECTION AS CALLED FOR IN OUR 'AUTO FAIL OR UNSCHEDULED PRESSURIZATION CHANGE' NON-NORMAL CHKLIST. WE THEN SELECTED THE HI MODE ON BOTH ACFT PACKS, THE ACFT PRESSURIZED, AND WE CONTINUED TO DEST. I FOUND OUT TODAY THAT MAINT REPLACED THE PRESSURE CTLR. TEST FLEW THE ACFT AND RETURNED IT TO REVENUE SVC. ALSO, TODAY I REVIEWED MY MANUAL AND SAW THAT THE 'CABIN ALT WARNING OR RAPID DECOMPRESSION/EMER DSCNT' CHKLIST CALLED FOR THE ADDITIONAL STEP OF PLACING THE LEFT AND RIGHT PACK SWITCHES TO HI. WE USED THE WRONG CHKLIST FOR THE SIT! (I AM JUST DISCOVERING THIS NOW -- THE LATE NASA RPT.) I FEEL SO BADLY ABOUT THIS -- THE INCONVENIENCE TO 2 PLANELOADS OF PAX, THE EXPENSE, AND INCONVENIENCE FOR MY COMPANY, BECAUSE WE DIDN'T USE PROPER PROCS. ALL INVOLVED ARE STILL STYMIED AS TO WHY THE ACFT COULD BE PRESSURIZED FULLY ON THE GND BY MAINT IN MEX, AND ALSO WHY CHANGING THE PRESSURE CTLR WOULD FIX THE PROB WHEN THE PREVIOUS ONE CHKED OUT PROPERLY BY MAINT PROCS. BOTTOM LINE FOR ME -- THE ACFT HAD A PROB, AND I HAD A CHANCE TO MITIGATE THAT PROB EXPEDITIOUSLY. YET DESPITE OUR CONCERTED BEST AIRCREW EFFORTS, WE BLEW IT. I'LL CERTAINLY MAKE EVERY EFFORT, MORE OF AN EFFORT, IN THE FUTURE, TO USE THE RIGHT CHKLIST.

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.