A B727-200 in climb at 10000 ft declared an emergency and diverted due to unable to pressurize the cabin caused by a failed pneumatic valve.

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Attributes
ACN	448415
Time
Date	199909
Day	Tue
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : dfw.airport
State Reference	TX
Altitude	msl single value : 10000
Environment
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zfw.artcc
Operator	common carrier : air carrier
Make Model Name	B727-200
Operating Under FAR Part	Part 121
Navigation In Use	other vortac
Flight Phase	climbout : intermediate altitude
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	448415
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : multi engine pilot : instrument
Events
Anomaly	aircraft equipment problem : critical maintenance problem : improper maintenance maintenance problem : non compliance with mel non adherence : published procedure
Independent Detector	aircraft equipment other aircraft equipment : cabin pressure indication
Resolutory Action	flight crew : declared emergency
Consequence	other
Factors
Maintenance	contributing factor : schedule pressure performance deficiency : repair performance deficiency : fault isolation
Supplementary
Problem Areas	Maintenance Human Performance Aircraft
Primary Problem	Maintenance Human Performance

Narrative:

Departed dfw with 13TH stage mod valve placarded inoperative. MEL requires #1 pack and bleed be closed for takeoff and reinstated with #2 bleed after 10000 ft. We did that and cabin became uncontrollable. It fluctuated up and down 2000 ft. We leveled at 12000 ft and began to troubleshoot system. No combination of bleeds or packs would stabilize cabin. After consulting maintenance technician we decided to return to dfw. We were 15000 pounds over our landing weight. We advised ATC received a vector and began to dump fuel to our landing weight. We returned to dfw without further problems. Callback conversation with reporter revealed the following information: the reporter stated the aircraft was dispatched with the #1 pneumatic bleed system inoperative and deferred per the MEL. The reporter said the #3 pneumatic bleed system had a previous history of pneumatic problems and had just been repaired. The reporter said the #3 bleed system failed in climb and resulted in a return to the field.

Original NASA ASRS Text

Title: A B727-200 IN CLB AT 10000 FT DECLARED AN EMER AND DIVERTED DUE TO UNABLE TO PRESSURIZE THE CABIN CAUSED BY A FAILED PNEUMATIC VALVE.

Narrative: DEPARTED DFW WITH 13TH STAGE MOD VALVE PLACARDED INOP. MEL REQUIRES #1 PACK AND BLEED BE CLOSED FOR TKOF AND REINSTATED WITH #2 BLEED AFTER 10000 FT. WE DID THAT AND CABIN BECAME UNCONTROLLABLE. IT FLUCTUATED UP AND DOWN 2000 FT. WE LEVELED AT 12000 FT AND BEGAN TO TROUBLESHOOT SYS. NO COMBINATION OF BLEEDS OR PACKS WOULD STABILIZE CABIN. AFTER CONSULTING MAINT TECHNICIAN WE DECIDED TO RETURN TO DFW. WE WERE 15000 LBS OVER OUR LNDG WT. WE ADVISED ATC RECEIVED A VECTOR AND BEGAN TO DUMP FUEL TO OUR LNDG WT. WE RETURNED TO DFW WITHOUT FURTHER PROBS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE ACFT WAS DISPATCHED WITH THE #1 PNEUMATIC BLEED SYS INOP AND DEFERRED PER THE MEL. THE RPTR SAID THE #3 PNEUMATIC BLEED SYS HAD A PREVIOUS HISTORY OF PNEUMATIC PROBS AND HAD JUST BEEN REPAIRED. THE RPTR SAID THE #3 BLEED SYS FAILED IN CLB AND RESULTED IN A RETURN TO THE FIELD.

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.