Narrative:

While en route from tlh to mco at 17000' MSL, the cabin altitude began climbing. It remained unnoticed until about 13000'. The passenger O2 masks dropped at 13500'. By that time we had begun a descent down to 7000' MSL. The cabin pressurization was uncontrollable and was fluctuating. The cabin seemed to follow the aircraft's rate of descent. Could not be controled from the cockpit. After recycling the bleed switches, the aircraft cabin altitude seemed to be ctlable for a brief period, then uncontrollable again. We depressurized the aircraft and landed in mco.

Google
 

Original NASA ASRS Text

Title: ACR MLG EXPERIENCES LOSS OF CABIN PRESSURE AND METHODS OF CTL.

Narrative: WHILE ENRTE FROM TLH TO MCO AT 17000' MSL, THE CABIN ALT BEGAN CLBING. IT REMAINED UNNOTICED UNTIL ABOUT 13000'. THE PAX O2 MASKS DROPPED AT 13500'. BY THAT TIME WE HAD BEGUN A DSNT DOWN TO 7000' MSL. THE CABIN PRESSURIZATION WAS UNCTLABLE AND WAS FLUCTUATING. THE CABIN SEEMED TO FOLLOW THE ACFT'S RATE OF DSNT. COULD NOT BE CTLED FROM THE COCKPIT. AFTER RECYCLING THE BLEED SWITCHES, THE ACFT CABIN ALT SEEMED TO BE CTLABLE FOR A BRIEF PERIOD, THEN UNCTLABLE AGAIN. WE DEPRESSURIZED THE ACFT AND LANDED IN MCO.

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.