Narrative:

Flight took off from ind bound for mci and all system were normal. At approximately FL190, cabin pressure altitude began climbing rapidly. First officer attempted to control cabin altitude, while I simultaneously asked center for level off at FL200. When it became apparent that we were losing pressurization, I immediately asked for and received a descent clearance to 14000 ft. We made a reasonably agressive descent to that altitude. While descending to 14000 ft, cabin altitude exceeded 14000 ft, so all the passenger oxygen masks deployed. Since we were at a 'breathable altitude,' I instructed the passenger not to don the oxygen masks. All applicable checklists were run and the decision was made to return to ind in an unpressurized condition. At that point, I requested 10000 ft from center and received clearance to descend. Since there was no apparent structural problems and center was accommodating all of our requests, I did not declare an emergency. Return to ind and subsequent landing were both normal. We returned to gate and 'write up' the airplane. When we finally arrived in ind, mechanics showed us that we had 'blown' a pneumatic/air conditioning duct behind the rear pressure bulkhead.

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Original NASA ASRS Text

Title: FLC OF ACR MLG ACFT LOST CABIN PRESSURIZATION DURING CLBOUT AND RETURNED TO LAND.

Narrative: FLT TOOK OFF FROM IND BOUND FOR MCI AND ALL SYS WERE NORMAL. AT APPROX FL190, CABIN PRESSURE ALT BEGAN CLBING RAPIDLY. FO ATTEMPTED TO CTL CABIN ALT, WHILE I SIMULTANEOUSLY ASKED CTR FOR LEVEL OFF AT FL200. WHEN IT BECAME APPARENT THAT WE WERE LOSING PRESSURIZATION, I IMMEDIATELY ASKED FOR AND RECEIVED A DSCNT CLRNC TO 14000 FT. WE MADE A REASONABLY AGRESSIVE DSCNT TO THAT ALT. WHILE DSNDING TO 14000 FT, CABIN ALT EXCEEDED 14000 FT, SO ALL THE PAX OXYGEN MASKS DEPLOYED. SINCE WE WERE AT A 'BREATHABLE ALT,' I INSTRUCTED THE PAX NOT TO DON THE OXYGEN MASKS. ALL APPLICABLE CHKLISTS WERE RUN AND THE DECISION WAS MADE TO RETURN TO IND IN AN UNPRESSURIZED CONDITION. AT THAT POINT, I REQUESTED 10000 FT FROM CTR AND RECEIVED CLRNC TO DSND. SINCE THERE WAS NO APPARENT STRUCTURAL PROBS AND CTR WAS ACCOMMODATING ALL OF OUR REQUESTS, I DID NOT DECLARE AN EMER. RETURN TO IND AND SUBSEQUENT LNDG WERE BOTH NORMAL. WE RETURNED TO GATE AND 'WRITE UP' THE AIRPLANE. WHEN WE FINALLY ARRIVED IN IND, MECHS SHOWED US THAT WE HAD 'BLOWN' A PNEUMATIC/AIR CONDITIONING DUCT BEHIND THE REAR PRESSURE BULKHEAD.

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.