Large transport return land dfw when they are unable to maintain cabin pressurization.

Attributes
ACN	160599
Time
Date	199010
Day	Thu
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : adm
State Reference	OK
Altitude	msl bound lower : 10000 msl bound upper : 24000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	cruise other
Route In Use	enroute airway : j52
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : flight engineer pilot : commercial pilot : atp pilot : instrument
Experience	flight time last 90 days : 160 flight time total : 8500 flight time type : 6000
ASRS Report	160599
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	aircraft equipment problem : critical altitude deviation : excursion from assigned altitude non adherence : clearance
Independent Detector	aircraft equipment other aircraft equipment : unspecified
Resolutory Action	other
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation other

Narrative:

Flight from dfw to den was dispatched to FL240 due to single pack operation. At cruising altitude of FL240 we had just passed adm and were proceeding out the 300 degree right on J52 when we developed a pressurization problem and the cabin altitude exceeded 10000'. We requested an immediate descent and ATC told us they would check on the request and that the airspace below was clear if we needed to start the descent. The cabin altitude was still climbing and so I started a descent and just as we started to descend, we received clearance. We made a rapid descent to 10000' with speed brakes extended and the gear up. The cabin altitude never went about 12800'. No O2 masks were deployed in the cabin. We diverted to dfw and flew the short return trip to dfw at 10000' unpressurized. Even though we were slightly closer to oklahoma city at the time, I elected to return to dfw since no emergency existed and dfw could provide more maintenance, substitute aircraft and better capability of accommodating passenger needs.

Original NASA ASRS Text

Title: LGT RETURN LAND DFW WHEN THEY ARE UNABLE TO MAINTAIN CABIN PRESSURIZATION.

Narrative: FLT FROM DFW TO DEN WAS DISPATCHED TO FL240 DUE TO SINGLE PACK OPERATION. AT CRUISING ALT OF FL240 WE HAD JUST PASSED ADM AND WERE PROCEEDING OUT THE 300 DEG R ON J52 WHEN WE DEVELOPED A PRESSURIZATION PROB AND THE CABIN ALT EXCEEDED 10000'. WE REQUESTED AN IMMEDIATE DSNT AND ATC TOLD US THEY WOULD CHK ON THE REQUEST AND THAT THE AIRSPACE BELOW WAS CLR IF WE NEEDED TO START THE DSNT. THE CABIN ALT WAS STILL CLBING AND SO I STARTED A DSNT AND JUST AS WE STARTED TO DSND, WE RECEIVED CLRNC. WE MADE A RAPID DSNT TO 10000' WITH SPD BRAKES EXTENDED AND THE GEAR UP. THE CABIN ALT NEVER WENT ABOUT 12800'. NO O2 MASKS WERE DEPLOYED IN THE CABIN. WE DIVERTED TO DFW AND FLEW THE SHORT RETURN TRIP TO DFW AT 10000' UNPRESSURIZED. EVEN THOUGH WE WERE SLIGHTLY CLOSER TO OKLAHOMA CITY AT THE TIME, I ELECTED TO RETURN TO DFW SINCE NO EMER EXISTED AND DFW COULD PROVIDE MORE MAINT, SUBSTITUTE ACFT AND BETTER CAPABILITY OF ACCOMMODATING PAX NEEDS.

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.