B757-200 crew lost control of cabin pressurization in skec class a airspace.

Attributes
ACN	569899
Time
Date	200101
Day	Fri
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : skec.artcc
State Reference	FO
Altitude	msl single value : 35000
Environment
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : skec.artcc
Operator	common carrier : air carrier
Make Model Name	B757 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Phase	cruise : enroute altitude change descent : vacating altitude
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	569899
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : multi engine pilot : commercial
ASRS Report	569778
Events
Anomaly	aircraft equipment problem : critical other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : cabin altimeter, rate of clb. altitude warning horn other flight crewa other flight crewb
Resolutory Action	controller : issued new clearance controller : provided flight assist flight crew : diverted to another airport flight crew : declared emergency none taken : detected after the fact other
Consequence	other other
Supplementary
Problem Areas	Aircraft
Primary Problem	Aircraft

Narrative:

Rapid depressurization. Proceeding at cruise altitude, first officer noticed unusually high cabin altitude and a slight cabin climb. Switched automatic controllers as per QRH. Condition remained the same with increasing cabin altitude. Switched to manual control and attempted to regain control and lower cabin altitude. Cabin continued to climb. As cabin approached approximately 9000 ft started rapid descent after declaring emergency. Unable to descend cabin and cabin altitude warning sounded. Began emergency descent. Was able to gain control of cabin at 16000 ft. Leveled aircraft at 14000 ft and requested diversion to kingston once situation was under control and emergency terminated. Proceeding to kingston uneventfully. Supplemental information from acn 569778: switched to manual controller as per QRH. Attempted to manually descend cabin, however, outflow valve froze short of full closed position as per the cabin outflow valve indicator. Initiated rapid descent. Soon after that cabin altitude alert sounded and cabin masks deployed.

Original NASA ASRS Text

Title: B757-200 CREW LOST CTL OF CABIN PRESSURIZATION IN SKEC CLASS A AIRSPACE.

Narrative: RAPID DEPRESSURIZATION. PROCEEDING AT CRUISE ALT, FO NOTICED UNUSUALLY HIGH CABIN ALT AND A SLIGHT CABIN CLB. SWITCHED AUTO CONTROLLERS AS PER QRH. CONDITION REMAINED THE SAME WITH INCREASING CABIN ALT. SWITCHED TO MANUAL CTL AND ATTEMPTED TO REGAIN CTL AND LOWER CABIN ALT. CABIN CONTINUED TO CLB. AS CABIN APCHED APPROX 9000 FT STARTED RAPID DSCNT AFTER DECLARING EMER. UNABLE TO DSND CABIN AND CABIN ALT WARNING SOUNDED. BEGAN EMER DSCNT. WAS ABLE TO GAIN CTL OF CABIN AT 16000 FT. LEVELED ACFT AT 14000 FT AND REQUESTED DIVERSION TO KINGSTON ONCE SIT WAS UNDER CTL AND EMER TERMINATED. PROCEEDING TO KINGSTON UNEVENTFULLY. SUPPLEMENTAL INFO FROM ACN 569778: SWITCHED TO MANUAL CONTROLLER AS PER QRH. ATTEMPTED TO MANUALLY DSND CABIN, HOWEVER, OUTFLOW VALVE FROZE SHORT OF FULL CLOSED POS AS PER THE CABIN OUTFLOW VALVE INDICATOR. INITIATED RAPID DSCNT. SOON AFTER THAT CABIN ALT ALERT SOUNDED AND CABIN MASKS DEPLOYED.

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.