A B737-300 with the aural warning circuit breaker popped had no aural warning as the cabin climbed a...

Attributes
ACN	690400
Time
Date	200603
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : zzz.airport
State Reference	US
Altitude	msl single value : 31500
Environment
Flight Conditions	VMC
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	climbout : intermediate altitude
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Experience	flight time last 90 days : 160 flight time total : 5000 flight time type : 1100
ASRS Report	690400
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Events
Anomaly	aircraft equipment problem : critical other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : master caution/air cond other flight crewa other flight crewb
Resolutory Action	flight crew : overcame equipment problem flight crew : regained aircraft control
Consequence	other
Supplementary
Problem Areas	Aircraft Maintenance Human Performance
Primary Problem	Aircraft

Narrative:

During climb to FL320; automatic fail light and stby light on pressurization panel with associated master caution and air conditioning lights illuminated. Cabin altitude indicated 13500 ft. We performed the qrc for cabin altitude warning and began descent to FL240. We regained control in the stby mode. We also ran the automatic fail irregular procedure. The automatic mode was not regained. Once the cabin altitude was under control; we continued to ZZZ. The aural warning circuit breaker on the first officer's circuit breaker panel was found popped resulting in no aural warning of the cabin above 10000 ft. The captain suspects the circuit breaker was pulled and not reset during maintenance actions on the 'a' autoplt prior to departure. The cabin crew attempted to contact the cockpit crew several times but was unable due to the aural waning circuit breaker being popped. The crew was unaware that the cabin chime was wired through this circuit breaker. The combination of the aural warning circuit breaker out and the pressurization failure could have had serious consequences had we not donned the oxygen masks as directed in the qrc. I believe the qrc should be renamed to include the cabin altitude above 10000 ft since we did not have the cabin altitude warning nor was it a rapid depressurization.

Original NASA ASRS Text

Title: A B737-300 WITH THE AURAL WARNING CB POPPED HAD NO AURAL WARNING AS THE CABIN CLBED ABOVE 10000 FT. THE MASTER CAUTION LIGHT ILLUMINATED WITH THE PRESSURE CTLR AUTO FAIL LIGHT ILLUMINATED.

Narrative: DURING CLB TO FL320; AUTO FAIL LIGHT AND STBY LIGHT ON PRESSURIZATION PANEL WITH ASSOCIATED MASTER CAUTION AND AIR CONDITIONING LIGHTS ILLUMINATED. CABIN ALT INDICATED 13500 FT. WE PERFORMED THE QRC FOR CABIN ALT WARNING AND BEGAN DSCNT TO FL240. WE REGAINED CTL IN THE STBY MODE. WE ALSO RAN THE AUTO FAIL IRREGULAR PROC. THE AUTO MODE WAS NOT REGAINED. ONCE THE CABIN ALT WAS UNDER CTL; WE CONTINUED TO ZZZ. THE AURAL WARNING CB ON THE FO'S CB PANEL WAS FOUND POPPED RESULTING IN NO AURAL WARNING OF THE CABIN ABOVE 10000 FT. THE CAPT SUSPECTS THE CB WAS PULLED AND NOT RESET DURING MAINT ACTIONS ON THE 'A' AUTOPLT PRIOR TO DEP. THE CABIN CREW ATTEMPTED TO CONTACT THE COCKPIT CREW SEVERAL TIMES BUT WAS UNABLE DUE TO THE AURAL WANING CB BEING POPPED. THE CREW WAS UNAWARE THAT THE CABIN CHIME WAS WIRED THROUGH THIS CB. THE COMBINATION OF THE AURAL WARNING CB OUT AND THE PRESSURIZATION FAILURE COULD HAVE HAD SERIOUS CONSEQUENCES HAD WE NOT DONNED THE OXYGEN MASKS AS DIRECTED IN THE QRC. I BELIEVE THE QRC SHOULD BE RENAMED TO INCLUDE THE CABIN ALT ABOVE 10000 FT SINCE WE DID NOT HAVE THE CABIN ALT WARNING NOR WAS IT A RAPID DEPRESSURIZATION.

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.

A B737-300 with the aural warning circuit breaker popped had no aural warning as the cabin climbed above 10000 ft. The master caution light illuminated with the pressure controller automatic fail light illuminated.