B737-300 crew lost cabin pressurization in ZFW class a airspace.

Attributes
ACN	511731
Time
Date	200105
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	navaid : llo.vortac
State Reference	TX
Altitude	msl bound lower : 10000 msl bound upper : 33000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zfw.artcc artcc : zhu.artcc tower : alw.tower
Operator	common carrier : air carrier
Make Model Name	B737-300
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : flight engineer
Experience	flight time last 90 days : 250 flight time total : 11150 flight time type : 4400
ASRS Report	511731
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 240 flight time total : 6500 flight time type : 2000
ASRS Report	512148
Events
Anomaly	aircraft equipment problem : critical other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : cabin high altitude warning horn other flight crewa other flight crewb
Resolutory Action	controller : issued new clearance flight crew : landed in emergency condition flight crew : declared emergency other
Consequence	other
Supplementary
Problem Areas	Aircraft
Primary Problem	Aircraft

Narrative:

Flight abq-iah was level at FL330 when cabin pressurization warning horn sounded continuously. Loss of pressurization checklist was accomplished and ZFW notified with a request for immediate descent. The first officer completed a descent and a turn off course of 20 degrees as per ATC instructions. Initial clearance to FL240 then to 10000 ft MSL was completed. During the initial descent, the checklist for the abnormal was accomplished and pressurization was regained using manual operation of pressurization controller. ZFW handed us off to ZHU who notified us that an emergency had been declared for us by ZFW. I requested that the emergency handling be canceled but that we remain at 10000 ft MSL due to the proximity to destination and potential for problems with the cabin at higher altitudes. During cabin pressurization loss, cabin altitude did not exceed 11000 ft. No passenger or flight crew were injured and cabin emergency masks did not deploy. Arrival, approach and landing were normal at iah. Upon arrival at the gate, maintenance supervisor noted that pressurization controller had recently been changed.

Original NASA ASRS Text

Title: B737-300 CREW LOST CABIN PRESSURIZATION IN ZFW CLASS A AIRSPACE.

Narrative: FLT ABQ-IAH WAS LEVEL AT FL330 WHEN CABIN PRESSURIZATION WARNING HORN SOUNDED CONTINUOUSLY. LOSS OF PRESSURIZATION CHKLIST WAS ACCOMPLISHED AND ZFW NOTIFIED WITH A REQUEST FOR IMMEDIATE DSCNT. THE FO COMPLETED A DSCNT AND A TURN OFF COURSE OF 20 DEGS AS PER ATC INSTRUCTIONS. INITIAL CLRNC TO FL240 THEN TO 10000 FT MSL WAS COMPLETED. DURING THE INITIAL DSCNT, THE CHKLIST FOR THE ABNORMAL WAS ACCOMPLISHED AND PRESSURIZATION WAS REGAINED USING MANUAL OP OF PRESSURIZATION CTLR. ZFW HANDED US OFF TO ZHU WHO NOTIFIED US THAT AN EMER HAD BEEN DECLARED FOR US BY ZFW. I REQUESTED THAT THE EMER HANDLING BE CANCELED BUT THAT WE REMAIN AT 10000 FT MSL DUE TO THE PROX TO DEST AND POTENTIAL FOR PROBS WITH THE CABIN AT HIGHER ALTS. DURING CABIN PRESSURIZATION LOSS, CABIN ALT DID NOT EXCEED 11000 FT. NO PAX OR FLC WERE INJURED AND CABIN EMER MASKS DID NOT DEPLOY. ARR, APCH AND LNDG WERE NORMAL AT IAH. UPON ARR AT THE GATE, MAINT SUPVR NOTED THAT PRESSURIZATION CTLR HAD RECENTLY BEEN CHANGED.

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.