A B737-300 suffered a slow pressurization leak at cruise altitude and descended in a timely fashion ...

Attributes
ACN	882944
Time
Date	201004
Local Time Of Day	1801-2400
Place
Locale Reference	ZZZ.ARTCC
State Reference	US
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Make Model Name	B737-300
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Flight Plan	IFR
Component
Aircraft Component	Pressurization System
Person 1
Function	First Officer Pilot Not Flying
Experience	Flight Crew Last 90 Days 194 Flight Crew Type 4800
Person 2
Function	Pilot Flying Captain
Experience	Flight Crew Last 90 Days 106
Events
Anomaly	Aircraft Equipment Problem Critical

Narrative:

Our aircraft experienced a slow leak loss of cabin pressurization at FL340. Upon hearing the cabin altitude warning horn; the captain (pilot flying) began an emergency descent while I accomplished the [associated] checklist. The emergency descent was uneventful all the way down to 10;000 MSL. The cabin altitude rose as high as 12;000'. This was not high enough to deploy the passenger oxygen masks. The cabin pressurization started to indicate normal around FL180. An uneventful approach and landing was accomplished at our scheduled destination. Maintenance said it was an APU duct seal clamp that came loose in the left main wheel well.

Original NASA ASRS Text

Title: A B737-300 suffered a slow pressurization leak at cruise altitude and descended in a timely fashion when the Cabin Altitude Warning was activated. Cabin altitude did not reach that which deploys the passenger oxygen masks.

Narrative: Our aircraft experienced a slow leak loss of cabin pressurization at FL340. Upon hearing the Cabin Altitude Warning horn; the Captain (pilot flying) began an emergency descent while I accomplished the [associated] checklist. The emergency descent was uneventful all the way down to 10;000 MSL. The cabin altitude rose as high as 12;000'. This was not high enough to deploy the Passenger Oxygen masks. The cabin pressurization started to indicate normal around FL180. An uneventful approach and landing was accomplished at our scheduled destination. Maintenance said it was an APU duct seal clamp that came loose in the left main wheel well.

Data retrieved from NASA's ASRS site as of April 2012 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.

A B737-300 suffered a slow pressurization leak at cruise altitude and descended in a timely fashion when the cabin altitude warning was activated. Cabin altitude did not reach that which deploys the passenger oxygen masks.