DC9 crew made a rapid descent after getting cabin altitude warning.

Attributes
ACN	451309
Time
Date	199910
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : zjx.artcc
State Reference	FL
Altitude	msl bound lower : 20000 msl bound upper : 35000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zjx.artcc
Operator	common carrier : air carrier
Make Model Name	DC-9 30
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
Qualification	pilot : multi engine pilot : cfi pilot : flight engineer pilot : atp
Experience	flight time last 90 days : 180 flight time total : 15000 flight time type : 4800
ASRS Report	451309
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : multi engine pilot : instrument pilot : commercial
Events
Anomaly	aircraft equipment problem : critical non adherence : company policies non adherence : far non adherence : published procedure
Independent Detector	aircraft equipment other aircraft equipment : cabin altitude warning other flight crewa other flight crewb
Resolutory Action	other
Consequence	other
Supplementary
Problem Areas	Aircraft Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance

Narrative:

Aircraft level at 35000 ft. Master warning (red) light illuminated, overheard annunciator panel showed cabin pressure. Cabin altitude was at 10000 ft, normally 8000 ft. Both packs on, outflow valve closed, automatic-shutoff in override. We started a descent down to 20000 ft, cabin stabilized at 5000 ft, then went down to 2000 ft. We followed our red bordered checklist and notified ATC.

Original NASA ASRS Text

Title: DC9 CREW MADE A RAPID DSCNT AFTER GETTING CABIN ALT WARNING.

Narrative: ACFT LEVEL AT 35000 FT. MASTER WARNING (RED) LIGHT ILLUMINATED, OVERHEARD ANNUNCIATOR PANEL SHOWED CABIN PRESSURE. CABIN ALT WAS AT 10000 FT, NORMALLY 8000 FT. BOTH PACKS ON, OUTFLOW VALVE CLOSED, AUTO-SHUTOFF IN OVERRIDE. WE STARTED A DSCNT DOWN TO 20000 FT, CABIN STABILIZED AT 5000 FT, THEN WENT DOWN TO 2000 FT. WE FOLLOWED OUR RED BORDERED CHKLIST AND NOTIFIED ATC.

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.