Pressurization system malfunctions during descent.

Attributes
ACN	265748
Time
Date	199403
Day	Mon
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : ott
State Reference	MD
Altitude	msl bound lower : 24000 msl bound upper : 27000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zdc tracon : tpa
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Phase	descent other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 150 flight time total : 10000 flight time type : 7000
ASRS Report	265748
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : instrument pilot : cfi pilot : atp pilot : commercial
Experience	flight time last 90 days : 100 flight time total : 16000 flight time type : 90
ASRS Report	265758
Events
Anomaly	aircraft equipment problem : less severe altitude deviation : excursion from assigned altitude non adherence : clearance
Independent Detector	aircraft equipment other aircraft equipment : unspecified
Resolutory Action	flight crew : overcame equipment problem flight crew : declared emergency
Consequence	Other Other
Supplementary
Primary Problem	Aircraft

Narrative:

Aircraft had previous write-ups on pressurization system. During descent from FL270 to FL240, captain -- whom at the time was in cockpit alone (first officer was in lavatory) -- got a cabin altitude warning horn that meant cabin was exceeding 10000 ft. After an unsuccessful attempt to get cabin altitude under control, the captain initiated an emergency descent, notified ATC and then gave a 6 bell signal to inform all crewmembers of an emergency. As I arrived back into the cockpit I donned my oxygen mask and captain called for checklist. Within a matter of mins, 2-3 mins, cabin was brought under control. We then told ATC we wanted to continue to our destination.

Original NASA ASRS Text

Title: PRESSURIZATION SYS MALFUNCTIONS DURING DSCNT.

Narrative: ACFT HAD PREVIOUS WRITE-UPS ON PRESSURIZATION SYS. DURING DSCNT FROM FL270 TO FL240, CAPT -- WHOM AT THE TIME WAS IN COCKPIT ALONE (FO WAS IN LAVATORY) -- GOT A CABIN ALT WARNING HORN THAT MEANT CABIN WAS EXCEEDING 10000 FT. AFTER AN UNSUCCESSFUL ATTEMPT TO GET CABIN ALT UNDER CTL, THE CAPT INITIATED AN EMER DSCNT, NOTIFIED ATC AND THEN GAVE A 6 BELL SIGNAL TO INFORM ALL CREWMEMBERS OF AN EMER. AS I ARRIVED BACK INTO THE COCKPIT I DONNED MY OXYGEN MASK AND CAPT CALLED FOR CHKLIST. WITHIN A MATTER OF MINS, 2-3 MINS, CABIN WAS BROUGHT UNDER CTL. WE THEN TOLD ATC WE WANTED TO CONTINUE TO OUR DEST.

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.