Narrative:

Prior to reaching 5000', we were cleared to 12,000'. Shortly after 10,000' a bright red warning light came on and the overhead annunciator panel stated cabin altitude in red letters. This light meant that the cabin altitude was at least 10,000' or greater. The noise level was greatly increased and your ears noticed odd feelings. Looking at the pressurization panel I noticed everything normal (packs switches on, no lights on controller selector, etc). Then, the big find was that by the manual wheel, to control the main outflow valve, the valve indicator showed full open and the automatic manual knob was full down (manual). I asked copilot to get clearance for 10,000', while I worked on manually controling the cabin altitude. After many mins, I was able to get the cabin altitude on schedule and reinstate the automatic controller. Rest of flight was normal. Conclusions: we had the aircraft on previous leg and had performed complete before starting engines checklist. On this leg only a short checklist was performed. This list does not call for up and automatic on pressurization knob before takeoff calls for checking pack switches on. Then sometime after takeoff you check pressurization. On 2-MAN cockpit you are busy. This proves that before takeoff there may be other knobs that should be looked at. This problem could have been worse operating pressurization manually is not too enjoyable.

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Original NASA ASRS Text

Title: ACR MLG UNABLE TO PRESSURIZE CABIN AFTER TKOF DUE TO PRESSURIZATION CONTROL VALVE IN MANUAL FULL OPEN. UNABLE CALLBACK.

Narrative: PRIOR TO REACHING 5000', WE WERE CLRED TO 12,000'. SHORTLY AFTER 10,000' A BRIGHT RED WARNING LIGHT CAME ON AND THE OVERHEAD ANNUNCIATOR PANEL STATED CABIN ALT IN RED LETTERS. THIS LIGHT MEANT THAT THE CABIN ALT WAS AT LEAST 10,000' OR GREATER. THE NOISE LEVEL WAS GREATLY INCREASED AND YOUR EARS NOTICED ODD FEELINGS. LOOKING AT THE PRESSURIZATION PANEL I NOTICED EVERYTHING NORMAL (PACKS SWITCHES ON, NO LIGHTS ON CTLR SELECTOR, ETC). THEN, THE BIG FIND WAS THAT BY THE MANUAL WHEEL, TO CONTROL THE MAIN OUTFLOW VALVE, THE VALVE INDICATOR SHOWED FULL OPEN AND THE AUTO MANUAL KNOB WAS FULL DOWN (MANUAL). I ASKED COPLT TO GET CLRNC FOR 10,000', WHILE I WORKED ON MANUALLY CTLING THE CABIN ALT. AFTER MANY MINS, I WAS ABLE TO GET THE CABIN ALT ON SCHEDULE AND REINSTATE THE AUTO CTLR. REST OF FLT WAS NORMAL. CONCLUSIONS: WE HAD THE ACFT ON PREVIOUS LEG AND HAD PERFORMED COMPLETE BEFORE STARTING ENGINES CHECKLIST. ON THIS LEG ONLY A SHORT CHECKLIST WAS PERFORMED. THIS LIST DOES NOT CALL FOR UP AND AUTO ON PRESSURIZATION KNOB BEFORE TKOF CALLS FOR CHECKING PACK SWITCHES ON. THEN SOMETIME AFTER TKOF YOU CHECK PRESSURIZATION. ON 2-MAN COCKPIT YOU ARE BUSY. THIS PROVES THAT BEFORE TKOF THERE MAY BE OTHER KNOBS THAT SHOULD BE LOOKED AT. THIS PROBLEM COULD HAVE BEEN WORSE OPERATING PRESSURIZATION MANUALLY IS NOT TOO ENJOYABLE.

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.