Medium large transport lost cabin pressurization control necessitating an emergency descent.

Attributes
ACN	82754
Time
Date	198802
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : mob
State Reference	AL
Altitude	msl bound lower : 13000 msl bound upper : 33000
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zhq
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 220 flight time total : 3500 flight time type : 1500
ASRS Report	82754
Person 2
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	aircraft equipment problem : critical other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	flight crew : declared emergency flight crew : overcame equipment problem
Consequence	Other
Supplementary
Primary Problem	Aircraft

Narrative:

Partial loss of cabin pressure. Received clearance to descended to 13000'. Masks dropped as cabin climbed through 10000'. Cabin altitude never went above 12000'. Regained control of cabin altitude in the manual mode. Climbed back to 27000' and landed in fll. Callback conversation with reporter revealed the following: it was not necessary to declare an emergency as ARTCC promptly gave them clearance for descent. The descent itself was an emergency descent. According to cabin attendant, the passenger reaction was good, no panic in the cabin. The press system was repaired in orlando, but the problem recurred on the next leg. The problem was fixed properly at the next stop. It was not an explosive decompression, there was time to take measured action rather than rely on an all out emergency descent.

Original NASA ASRS Text

Title: MLG LOST CABIN PRESSURIZATION CTL NECESSITATING AN EMERGENCY DESCENT.

Narrative: PARTIAL LOSS OF CABIN PRESSURE. RECEIVED CLRNC TO DESCENDED TO 13000'. MASKS DROPPED AS CABIN CLBED THROUGH 10000'. CABIN ALT NEVER WENT ABOVE 12000'. REGAINED CTL OF CABIN ALT IN THE MANUAL MODE. CLBED BACK TO 27000' AND LANDED IN FLL. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING: IT WAS NOT NECESSARY TO DECLARE AN EMER AS ARTCC PROMPTLY GAVE THEM CLRNC FOR DSCNT. THE DSCNT ITSELF WAS AN EMER DSCNT. ACCORDING TO CABIN ATTENDANT, THE PAX REACTION WAS GOOD, NO PANIC IN THE CABIN. THE PRESS SYS WAS REPAIRED IN ORLANDO, BUT THE PROB RECURRED ON THE NEXT LEG. THE PROB WAS FIXED PROPERLY AT THE NEXT STOP. IT WAS NOT AN EXPLOSIVE DECOMPRESSION, THERE WAS TIME TO TAKE MEASURED ACTION RATHER THAN RELY ON AN ALL OUT EMER DSCNT.

Data retrieved from NASA's ASRS site as of August 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.