MD80 flight crew has pressurization problem; declares emergency and diverts for landing.

Attributes
ACN	701923
Time
Date	200607
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : zzz.airport
State Reference	US
Altitude	msl single value : 31000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zzz.artcc
Operator	common carrier : air carrier
Make Model Name	MD-80 Series (DC-9-80) Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
ASRS Report	701923
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	aircraft equipment other aircraft equipment : cabin alt other flight crewa other flight crewb
Resolutory Action	flight crew : overcame equipment problem flight crew : declared emergency
Consequence	other
Supplementary
Problem Areas	Flight Crew Human Performance Aircraft
Primary Problem	Aircraft

Narrative:

We were cruising at FL310 with our primary pressurization controller placarded inoperative. We received the 'cabin altitude' aural warning and observed that the cabin altitude and master warning lights had illuminated. We declared an emergency and executed the QRH cabin altitude warning/rapid depressurization procedure; diverting to indianapolis. We were able to control the cabin altitude using manual pressurization procedures; bringing the cabin altitude back below 10000 ft; preventing passenger oxygen mask deployment; and controling the cabin through the descent. The remainder of the flight was uneventful. Upon landing; maintenance placarded the standby controller and we were dispatched unpressurized.

Original NASA ASRS Text

Title: MD80 FLT CREW HAS PRESSURIZATION PROB; DECLARES EMER AND DIVERTS FOR LNDG.

Narrative: WE WERE CRUISING AT FL310 WITH OUR PRIMARY PRESSURIZATION CONTROLLER PLACARDED INOP. WE RECEIVED THE 'CABIN ALT' AURAL WARNING AND OBSERVED THAT THE CABIN ALT AND MASTER WARNING LIGHTS HAD ILLUMINATED. WE DECLARED AN EMER AND EXECUTED THE QRH CABIN ALT WARNING/RAPID DEPRESSURIZATION PROC; DIVERTING TO INDIANAPOLIS. WE WERE ABLE TO CTL THE CABIN ALT USING MANUAL PRESSURIZATION PROCS; BRINGING THE CABIN ALT BACK BELOW 10000 FT; PREVENTING PAX OXYGEN MASK DEPLOYMENT; AND CTLING THE CABIN THROUGH THE DSCNT. THE REMAINDER OF THE FLT WAS UNEVENTFUL. UPON LNDG; MAINT PLACARDED THE STANDBY CONTROLLER AND WE WERE DISPATCHED UNPRESSURIZED.

Data retrieved from NASA's ASRS site as of January 2009 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.