B737-300 flight crew has pressurization problem at FL270.

Attributes
ACN	699765
Time
Date	200606
Local Time Of Day	0001 To 0600
Place
Locale Reference	airport : zzz.airport
State Reference	US
Altitude	msl single value : 27000
Environment
Flight Conditions	Marginal
Aircraft 1
Controlling Facilities	artcc : zzz.artcc
Operator	common carrier : air carrier
Make Model Name	B737-300
Operating Under FAR Part	Part 121
Flight Phase	descent : intermediate altitude
Route In Use	arrival star : n/s
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Experience	flight time last 90 days : 75 flight time total : 12000 flight time type : 4537
ASRS Report	699765
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Experience	flight time last 90 days : 150 flight time total : 4500 flight time type : 1493
ASRS Report	699767
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	other flight crewa other flight crewb
Resolutory Action	flight crew : declared emergency
Supplementary
Problem Areas	Aircraft
Primary Problem	Aircraft

Narrative:

At FL270 cabin altitude horn sounded. Cabin indicated just above 10000 ft. Pressurization panel appeared normal with no abnormal indications. Put on oxygen masks and established communications. Asked ATC for lower. Ran all appropriate checklists. Declared emergency. Maximum cabin altitude was 13000 ft at 13000 ft. Descended to 8000 ft. All checklists. Complete. At 17000 ft did have automatic-pressurization fail light on and psi automatic-switched to standby. Normal landing.

Original NASA ASRS Text

Title: B737-300 FLT CREW HAS PRESSURIZATION PROB AT FL270.

Narrative: AT FL270 CABIN ALT HORN SOUNDED. CABIN INDICATED JUST ABOVE 10000 FT. PRESSURIZATION PANEL APPEARED NORMAL WITH NO ABNORMAL INDICATIONS. PUT ON OXYGEN MASKS AND ESTABLISHED COMS. ASKED ATC FOR LOWER. RAN ALL APPROPRIATE CHKLISTS. DECLARED EMER. MAX CABIN ALT WAS 13000 FT AT 13000 FT. DSNDED TO 8000 FT. ALL CHKLISTS. COMPLETE. AT 17000 FT DID HAVE AUTO-PRESSURIZATION FAIL LIGHT ON AND PSI AUTO-SWITCHED TO STANDBY. NORMAL LNDG.

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.