MD80 crew lost control of cabin pressurization and executed an emergency descent.

Attributes
ACN	571929
Time
Date	200301
Day	Fri
Local Time Of Day	1201 To 1800
Place
State Reference	TX
Altitude	msl single value : 35000
Environment
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zme.artcc
Operator	common carrier : air carrier
Make Model Name	MD-80 Super 80
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 : first officer
Qualification	pilot : atp
ASRS Report	571929
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Events
Anomaly	aircraft equipment problem : critical maintenance problem : improper maintenance non adherence : far non adherence : published procedure non adherence : company policies other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : alt warning light cabin altimeter other flight crewa other flight crewb other other : 2
Resolutory Action	flight crew : declared emergency flight crew : overcame equipment problem other
Consequence	other other
Factors
Maintenance	contributing factor : schedule pressure performance deficiency : repair performance deficiency : non compliance with legal requirements performance deficiency : fault isolation performance deficiency : testing
Supplementary
Problem Areas	Aircraft Company
Primary Problem	Aircraft

Narrative:

While at cruise, we got a cabin warning light. We got a clearance to descend, and the cabin was climbing and passing 10000 ft. We continued our descent to 10000 ft. During the descent, the cabin continued to climb. Approaching 14000 ft cabin altitude, we deployed the masks. We leveled off at 10000 ft and finished the checklist. The automatic controller had failed, and the standby did not pick up. We got no lights except the cabin warning light and cabin oxygen on lights after deploying the masks. While level at 10000 ft, we used manual pressurization to gain control of the cabin pressure. Once stabilized, the captain contacted dispatch and told them what had happened. We then got a clearance to climb to FL180 and climbed back up to conserve fuel, so we could make it to dfw. At that time, the cabin pressure was normal, and we were able to control it with manual pressurization. The aircraft had been written up previously for the same problem, but it had been 5 days prior. We completed all checklists for the problem, and then reviewed the manual pressurization procedure prior to descent and landing at dfw. Supplemental information from acn 572196: we were about 1 1/2 hours from landing in dfw. We had already begun to descend, when the oxygen masks dropped.

Original NASA ASRS Text

Title: MD80 CREW LOST CTL OF CABIN PRESSURIZATION AND EXECUTED AN EMER DSCNT.

Narrative: WHILE AT CRUISE, WE GOT A CABIN WARNING LIGHT. WE GOT A CLRNC TO DSND, AND THE CABIN WAS CLBING AND PASSING 10000 FT. WE CONTINUED OUR DSCNT TO 10000 FT. DURING THE DSCNT, THE CABIN CONTINUED TO CLB. APCHING 14000 FT CABIN ALT, WE DEPLOYED THE MASKS. WE LEVELED OFF AT 10000 FT AND FINISHED THE CHKLIST. THE AUTO CTLR HAD FAILED, AND THE STANDBY DID NOT PICK UP. WE GOT NO LIGHTS EXCEPT THE CABIN WARNING LIGHT AND CABIN OXYGEN ON LIGHTS AFTER DEPLOYING THE MASKS. WHILE LEVEL AT 10000 FT, WE USED MANUAL PRESSURIZATION TO GAIN CTL OF THE CABIN PRESSURE. ONCE STABILIZED, THE CAPT CONTACTED DISPATCH AND TOLD THEM WHAT HAD HAPPENED. WE THEN GOT A CLRNC TO CLB TO FL180 AND CLBED BACK UP TO CONSERVE FUEL, SO WE COULD MAKE IT TO DFW. AT THAT TIME, THE CABIN PRESSURE WAS NORMAL, AND WE WERE ABLE TO CTL IT WITH MANUAL PRESSURIZATION. THE ACFT HAD BEEN WRITTEN UP PREVIOUSLY FOR THE SAME PROB, BUT IT HAD BEEN 5 DAYS PRIOR. WE COMPLETED ALL CHKLISTS FOR THE PROB, AND THEN REVIEWED THE MANUAL PRESSURIZATION PROC PRIOR TO DSCNT AND LNDG AT DFW. SUPPLEMENTAL INFO FROM ACN 572196: WE WERE ABOUT 1 1/2 HRS FROM LNDG IN DFW. WE HAD ALREADY BEGUN TO DSND, WHEN THE OXYGEN MASKS DROPPED.

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.