Narrative:

The aircraft was accepted in msy for the flight to mdw with a MEL item which rendered the automatic cabin pressure controller inoperative, during climb out, the first officer, who was controling the cabin pressurization manually, lost control of the cabin, and the master warning light illuminated signalling 'cabin altitude'. While I was regaining control of the cabin, ATC questioned our altitude expecting 25000', since the altitude alert was set for 27000' I indicated we were climbing to FL270. However, due to the pressurization abnormality, I had no recall of the altitude assignment or readback. The problem behind these events revolves around the aircraft operation west/O automatic pressurization. The workload in this 25 yr old, 2-MAN cockpit becomes unacceptably high, during climb and descent, with manual pressurization control.

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Original NASA ASRS Text

Title: ALT DEVIATION. OVERSHOOT IN CLIMB. PRESSURIZATION DIFFICULTIES.

Narrative: THE ACFT WAS ACCEPTED IN MSY FOR THE FLT TO MDW WITH A MEL ITEM WHICH RENDERED THE AUTOMATIC CABIN PRESSURE CTLR INOP, DURING CLBOUT, THE F/O, WHO WAS CTLING THE CABIN PRESSURIZATION MANUALLY, LOST CTL OF THE CABIN, AND THE MASTER WARNING LIGHT ILLUMINATED SIGNALLING 'CABIN ALT'. WHILE I WAS REGAINING CTL OF THE CABIN, ATC QUESTIONED OUR ALT EXPECTING 25000', SINCE THE ALT ALERT WAS SET FOR 27000' I INDICATED WE WERE CLBING TO FL270. HOWEVER, DUE TO THE PRESSURIZATION ABNORMALITY, I HAD NO RECALL OF THE ALT ASSIGNMENT OR READBACK. THE PROB BEHIND THESE EVENTS REVOLVES AROUND THE ACFT OPERATION W/O AUTOMATIC PRESSURIZATION. THE WORKLOAD IN THIS 25 YR OLD, 2-MAN COCKPIT BECOMES UNACCEPTABLY HIGH, DURING CLB AND DSNT, WITH MANUAL PRESSURIZATION CTL.

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.