A B737-700's pressurization control panel failed completely at FL400. An emergency was declared; the...

Narrative:

During cruise at FL400; we got a master caution indicating a pressure controller failure. We had the amber auto fail and the green altitude lights on. We started the QRH procedure A-11. Just as I was finishing the QRH procedure; the green altitude light went out and the amber auto fail light re-illuminated and the cabin altitude started to rise rapidly. In a matter of a second or two; the cabin altitude horn sounded and we both completed the memory items for this procedure and I started the QRH procedure. While [we were] in manual pressurization with the outflow valve closed; the cabin was still losing pressure but at a much slower rate. We then declared an emergency and diverted.

Original NASA ASRS Text

Title: A B737-700's pressurization control panel failed completely at FL400. An emergency was declared; the QRH procedure completed; an emergency descent begun and the cabin stopped at 14;000 FT. The flight diverted to an enroute airport.

Narrative: During cruise at FL400; we got a Master Caution indicating a pressure controller failure. We had the amber Auto Fail and the green Altitude lights on. We started the QRH procedure A-11. Just as I was finishing the QRH procedure; the green Altitude light went out and the amber Auto Fail light re-illuminated and the cabin altitude started to rise rapidly. In a matter of a second or two; the Cabin Altitude horn sounded and we both completed the memory items for this procedure and I started the QRH procedure. While [we were] in manual pressurization with the outflow valve closed; the cabin was still losing pressure but at a much slower rate. We then declared an emergency and diverted.

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.

Attributes
ACN	930780
Time
Date	201102
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.ARTCC
State Reference	US
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Make Model Name	B737-700
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Flight Plan	IFR
Component
Aircraft Component	Pressurization Control System
Person 1
Function	First Officer Pilot Not Flying
Experience	Flight Crew Last 90 Days 329 Flight Crew Type 3000
Events
Anomaly	Aircraft Equipment Problem Critical

A B737-700's pressurization control panel failed completely at FL400. An emergency was declared; the QRH procedure completed; an emergency descent begun and the cabin stopped at 14;000 ft. The flight diverted to an enroute airport.