B737-300 crew lost cabin pressurization, and made an emergency descent.

Attributes
ACN	606774
Time
Date	200401
Day	Sat
Local Time Of Day	0601 To 1200
Place
Locale Reference	intersection : fuzzy
State Reference	NV
Altitude	msl single value : 33000
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	B737-300
Operating Under FAR Part	Part 121
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Experience	flight time last 90 days : 150 flight time total : 13000 flight time type : 1000
ASRS Report	606774
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	aircraft equipment other aircraft equipment : master caution light other flight crewa other flight crewb
Resolutory Action	flight crew : declared emergency
Consequence	other other
Supplementary
Problem Areas	Aircraft
Primary Problem	Aircraft

Narrative:

We were at cruise at FL330 for approximately 20 mins. Master caution air conditioning came on, at same time felt ears pop. Cabin climbing off the scale. Pressure controller automatic switched to standby mode, no help. Manually selected standby, no help. Switched to manual AC, outflow valve, indicated full closed. Declared emergency, squawked 7700, started emergency descent. Completed qrc for rapid decompression at about 15000 ft. Cabin started to stabilize at 13000 ft. Cabin stayed at 6000 ft. Switched to standby mode and cabin held at 6000 ft. Landed at las. Standby mode descended the cabin normal from 13000 ft to land at las.

Original NASA ASRS Text

Title: B737-300 CREW LOST CABIN PRESSURIZATION, AND MADE AN EMER DSCNT.

Narrative: WE WERE AT CRUISE AT FL330 FOR APPROX 20 MINS. MASTER CAUTION AIR CONDITIONING CAME ON, AT SAME TIME FELT EARS POP. CABIN CLBING OFF THE SCALE. PRESSURE CTLR AUTO SWITCHED TO STANDBY MODE, NO HELP. MANUALLY SELECTED STANDBY, NO HELP. SWITCHED TO MANUAL AC, OUTFLOW VALVE, INDICATED FULL CLOSED. DECLARED EMER, SQUAWKED 7700, STARTED EMER DSCNT. COMPLETED QRC FOR RAPID DECOMPRESSION AT ABOUT 15000 FT. CABIN STARTED TO STABILIZE AT 13000 FT. CABIN STAYED AT 6000 FT. SWITCHED TO STANDBY MODE AND CABIN HELD AT 6000 FT. LANDED AT LAS. STANDBY MODE DSNDED THE CABIN NORMAL FROM 13000 FT TO LAND AT LAS.

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.