Narrative:

Left pack was deferred. During cruise at FL260; we received a 'rt pack temperature' caution message. QRH procedure states to turn affected pack 'off;' and the MEL procedure (for the already deferred left pack) said to comply with all QRH procedures for subsequent pack failure; and to comply with the unpressurized flight procedure. We notified ATC of our need to descend to 10;000 ft; due to the impending unpressurized flight; and were cleared to descend to 10;000 ft. We began an expedited; but not emergency descent (approximately 3;000 FPM). I; as pilot not flying; performed the 'rt pack temperature' QRH procedure. When the right pack was selected 'off;' the cabin began climbing 400 FPM.next; I began the unpressurized flight procedure QRH procedure. Knowing we had 2 infants; 3 children and a few elderly passengers on board; and the cabin was climbing very slowly; even with both packs 'off;' we carefully monitored the cabin differential; so we would not cause any unnecessary discomfort. We were subsequently cleared to 7;000 ft; and continued our descent. Leveling at 7;000 ft; the cabin differential reached 0.0 psi; so we then completed the unpressurized flight procedure. When I opened the ram-air valve; the cabin spiked; and at the exact same time; the aircraft pitched down and began to descend approximately 1;500 FPM. The autopilot was engaged; and did not disconnect; 7;000 ft was still selected in the altitude pre-select; and no vertical modes on the fcp were changed. We reversed the descent by selecting pitch mode on the fcp; and the aircraft altitudes cap'ed at 7;000 ft. We had no other abnormal functions throughout the remainder of the flight.uncommanded descent concurrent with ram-air selection.

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Original NASA ASRS Text

Title: A CRJ-700 crew descended to 7;000 FT because of a non emergency dual Pack failure and when completing the UNPRESSURIZED FLT PROCEDURE the aircraft pitched over in an uncommanded descent when RAM-AIR was selected.

Narrative: Left pack was deferred. During cruise at FL260; we received a 'RT PACK TEMP' Caution message. QRH procedure states to turn affected Pack 'OFF;' and the MEL procedure (for the already deferred left Pack) said to comply with all QRH procedures for subsequent Pack failure; AND to comply with the Unpressurized Flight Procedure. We notified ATC of our need to descend to 10;000 FT; due to the impending unpressurized flight; and were cleared to descend to 10;000 FT. We began an expedited; but not emergency descent (approximately 3;000 FPM). I; as pilot not flying; performed the 'RT PACK TEMP' QRH procedure. When the right Pack was selected 'OFF;' the cabin began climbing 400 FPM.Next; I began the Unpressurized Flight Procedure QRH procedure. Knowing we had 2 infants; 3 children and a few elderly passengers on board; and the cabin was climbing very slowly; even with both Packs 'OFF;' we carefully monitored the cabin differential; so we would not cause any unnecessary discomfort. We were subsequently cleared to 7;000 FT; and continued our descent. Leveling at 7;000 FT; the cabin differential reached 0.0 PSI; so we then completed the Unpressurized Flight Procedure. When I opened the Ram-Air Valve; the cabin spiked; and at the exact same time; the aircraft pitched down and began to descend approximately 1;500 FPM. The Autopilot was engaged; and did not disconnect; 7;000 FT was still selected in the Altitude Pre-select; and no vertical modes on the FCP were changed. We reversed the descent by selecting Pitch Mode on the FCP; and the aircraft ALTS CAP'ed at 7;000 FT. We had no other abnormal functions throughout the remainder of the flight.Uncommanded descent concurrent with Ram-Air selection.

Data retrieved from NASA's ASRS site as of July 2013 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.