A306 crew experienced loss of cabin pressure at FL350.

Attributes
ACN	508111
Time
Date	200104
Day	Fri
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : zmp.artcc
State Reference	MN
Altitude	msl single value : 35000
Aircraft 1
Controlling Facilities	artcc : zmp.artcc
Operator	common carrier : air carrier
Make Model Name	B737-300
Operating Under FAR Part	Part 121
Navigation In Use	other other vortac
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	508111
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	aircraft equipment problem : critical maintenance problem : improper maintenance other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : cabin alt warning horn
Resolutory Action	controller : provided flight assist flight crew : diverted to another airport flight crew : landed as precaution other
Consequence	other
Supplementary
Problem Areas	Aircraft Flight Crew Human Performance Maintenance Human Performance
Primary Problem	Maintenance Human Performance

Narrative:

Ord-smf. Approximately XA15Z, 130 NM southeast of bis at FL350. First officer was out of seat using facilities. Captain had mask on. Cabin altitude warning horn started beeping. Cabin altitude was above 10000 ft and climbing. Asked for and received clearance for descent. First officer came to cockpit immediately and donned mask. Ran qrc checklist in descent. Could not control cabin altitude. Cabin climbed past 12000 ft with packs on high and outflow valve fully closed. At approximately 13000 ft aircraft altitude, cabin altitude started to respond. Leveled off 12000 ft aircraft altitude with cabin below 10000 ft. (During descent, coordinated with ATC numerous times for terrain avoidance.) once cabin under control, called maintenance and dispatch through commercial radio (conference call). Elected to divert to gfk. WX, runway and monitored ILS major reason for gfk. Uneventful landing. No injuries, no masks deployed and no overweight landing. Discovered silver cloth jammed and exiting the aircraft from the outflow valve during postflt inspection. Depressurization very gradual -- horn was first indication. Nothing felt in ears.

Original NASA ASRS Text

Title: A306 CREW EXPERIENCED LOSS OF CABIN PRESSURE AT FL350.

Narrative: ORD-SMF. APPROX XA15Z, 130 NM SE OF BIS AT FL350. FO WAS OUT OF SEAT USING FACILITIES. CAPT HAD MASK ON. CABIN ALT WARNING HORN STARTED BEEPING. CABIN ALT WAS ABOVE 10000 FT AND CLBING. ASKED FOR AND RECEIVED CLRNC FOR DSCNT. FO CAME TO COCKPIT IMMEDIATELY AND DONNED MASK. RAN QRC CHKLIST IN DSCNT. COULD NOT CTL CABIN ALT. CABIN CLBED PAST 12000 FT WITH PACKS ON HIGH AND OUTFLOW VALVE FULLY CLOSED. AT APPROX 13000 FT ACFT ALT, CABIN ALT STARTED TO RESPOND. LEVELED OFF 12000 FT ACFT ALT WITH CABIN BELOW 10000 FT. (DURING DSCNT, COORDINATED WITH ATC NUMEROUS TIMES FOR TERRAIN AVOIDANCE.) ONCE CABIN UNDER CTL, CALLED MAINT AND DISPATCH THROUGH COMMERCIAL RADIO (CONFERENCE CALL). ELECTED TO DIVERT TO GFK. WX, RWY AND MONITORED ILS MAJOR REASON FOR GFK. UNEVENTFUL LNDG. NO INJURIES, NO MASKS DEPLOYED AND NO OVERWT LNDG. DISCOVERED SILVER CLOTH JAMMED AND EXITING THE ACFT FROM THE OUTFLOW VALVE DURING POSTFLT INSPECTION. DEPRESSURIZATION VERY GRADUAL -- HORN WAS FIRST INDICATION. NOTHING FELT IN EARS.

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.