Flight crew of a widebody transport declared an emergency to descend because of a loss of cabin pres...

Attributes
ACN	288479
Time
Date	199411
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : grd
State Reference	SC
Altitude	msl bound lower : 29000 msl bound upper : 29000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : ztl
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Navigation In Use	Other
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : second officer
Qualification	pilot : cfi pilot : commercial pilot : flight engineer pilot : instrument
Experience	flight time last 90 days : 200 flight time total : 9000 flight time type : 200
ASRS Report	288479
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 100 flight time total : 15000 flight time type : 1000
ASRS Report	288694
Events
Anomaly	aircraft equipment problem : critical other anomaly other
Resolutory Action	flight crew : declared emergency other
Consequence	Other
Supplementary
Primary Problem	Aircraft

Narrative:

In climb to FL350 one air conditioning pack failed just after takeoff. At FL290 the #2 air conditioning pack blew a duct causing the cabin pressure altitude to climb at 500 FPM. The frequency with center was jammed with other aircraft talking, so decision was made to declare emergency to ensure clear altitude below. We subsequently had to descend to FL250 to maintain cabin altitude. Cabin altitude never got above 7700 ft and was restablized at approximately 5800 ft.

Original NASA ASRS Text

Title: FLC OF A WDB DECLARED AN EMER TO DSND BECAUSE OF A LOSS OF CABIN PRESSURIZATION.

Narrative: IN CLB TO FL350 ONE AIR CONDITIONING PACK FAILED JUST AFTER TKOF. AT FL290 THE #2 AIR CONDITIONING PACK BLEW A DUCT CAUSING THE CABIN PRESSURE ALT TO CLB AT 500 FPM. THE FREQ WITH CTR WAS JAMMED WITH OTHER ACFT TALKING, SO DECISION WAS MADE TO DECLARE EMER TO ENSURE CLR ALT BELOW. WE SUBSEQUENTLY HAD TO DSND TO FL250 TO MAINTAIN CABIN ALT. CABIN ALT NEVER GOT ABOVE 7700 FT AND WAS RESTABLIZED AT APPROX 5800 FT.

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.

Flight crew of a widebody transport declared an emergency to descend because of a loss of cabin pressurization.