Pressurization problems force large transport to divert land.

Attributes
ACN	251200
Time
Date	199309
Day	Wed
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : stl
State Reference	MO
Altitude	msl bound lower : 10000 msl bound upper : 35000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	cruise other ground : preflight
Route In Use	enroute : on vectors enroute airway : zkc
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : flight engineer pilot : commercial pilot : atp
Experience	flight time last 90 days : 220 flight time total : 11000 flight time type : 5500
ASRS Report	251200
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : flight engineer pilot : atp
Experience	flight time last 90 days : 300 flight time total : 12000
ASRS Report	251103
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 other
Consequence	Other
Supplementary
Primary Problem	Aircraft

Narrative:

While in cruise at 35000 ft, cabin started climbing uncontrollably. Switching to standby and manual modes no help. Declared emergency and received clearance to 10000 ft. During descent, control of cabin was regained by standby control. Continued descent to 10000 ft with normal control of cabin maintained by standby controller and no abnormalities noted. Consulted dispatch about options and tried higher altitudes with cabin control now operating normally. After some time, problems developed with cabin control again and decision was made to divert to dfw at 10000 ft. Nearing dfw, priority handling was requested to conserve fuel even though we landed with approximately 43 mins fuel. No medical problems or unusual discomfort noted of any passenger.

Original NASA ASRS Text

Title: PRESSURIZATION PROBS FORCE LGT TO DIVERT LAND.

Narrative: WHILE IN CRUISE AT 35000 FT, CABIN STARTED CLBING UNCONTROLLABLY. SWITCHING TO STANDBY AND MANUAL MODES NO HELP. DECLARED EMER AND RECEIVED CLRNC TO 10000 FT. DURING DSCNT, CTL OF CABIN WAS REGAINED BY STANDBY CTL. CONTINUED DSCNT TO 10000 FT WITH NORMAL CTL OF CABIN MAINTAINED BY STANDBY CTLR AND NO ABNORMALITIES NOTED. CONSULTED DISPATCH ABOUT OPTIONS AND TRIED HIGHER ALTS WITH CABIN CTL NOW OPERATING NORMALLY. AFTER SOME TIME, PROBS DEVELOPED WITH CABIN CTL AGAIN AND DECISION WAS MADE TO DIVERT TO DFW AT 10000 FT. NEARING DFW, PRIORITY HANDLING WAS REQUESTED TO CONSERVE FUEL EVEN THOUGH WE LANDED WITH APPROX 43 MINS FUEL. NO MEDICAL PROBS OR UNUSUAL DISCOMFORT NOTED OF ANY PAX.

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.