B737-300 has problem with automatic pressurization resulting in emergency descent.

Attributes
ACN	472553
Time
Date	200005
Day	Thu
Local Time Of Day	0001 To 0600
Place
Locale Reference	atc facility : zbw.artcc
State Reference	NH
Altitude	msl single value : 29000
Environment
Flight Conditions	IMC
Light	Night
Aircraft 1
Controlling Facilities	artcc : zbw.artcc
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 : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 210 flight time total : 12000 flight time type : 2000
ASRS Report	472553
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	aircraft equipment other aircraft equipment : cab ait warning other flight crewa
Resolutory Action	flight crew : overcame equipment problem flight crew : declared emergency
Consequence	other
Supplementary
Problem Areas	Aircraft
Primary Problem	Aircraft

Narrative:

Shortly after leveling off at FL290, cabin altitude warning horn started to sound. Cabin was at 11000 ft and climbing at 500 FPM. We accomplished QRH procedures and advised ATC. Unable to control the cabin, we started an emergency descent to 10000 ft. While descending to 10000 ft, we were able to regain control of cabin in the stand-by mode. Oxygen masks never dropped in the main cabin because cabin never reached 14000 ft. Normal landing at bdl airport. Aircraft had previous write-up a few days before (different crew lost cabin at FL320).

Original NASA ASRS Text

Title: B737-300 HAS PROB WITH AUTO PRESSURIZATION RESULTING IN EMER DSCNT.

Narrative: SHORTLY AFTER LEVELING OFF AT FL290, CABIN ALT WARNING HORN STARTED TO SOUND. CABIN WAS AT 11000 FT AND CLBING AT 500 FPM. WE ACCOMPLISHED QRH PROCS AND ADVISED ATC. UNABLE TO CTL THE CABIN, WE STARTED AN EMER DSCNT TO 10000 FT. WHILE DSNDING TO 10000 FT, WE WERE ABLE TO REGAIN CTL OF CABIN IN THE STAND-BY MODE. OXYGEN MASKS NEVER DROPPED IN THE MAIN CABIN BECAUSE CABIN NEVER REACHED 14000 FT. NORMAL LNDG AT BDL ARPT. ACFT HAD PREVIOUS WRITE-UP A FEW DAYS BEFORE (DIFFERENT CREW LOST CABIN AT FL320).

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.