Narrative:

Aircraft had the auto pressurization controllers deferred; requiring that we operate unpressurized. This limited us to 10000' maximum altitude. While cruising at 10000' assigned; we received a TCAS TA for traffic at our 3 o'clock; 300' below us. We were sitting just on top of a cloud layer; and we could not see the traffic. I contacted ATC to see if they had the traffic on their scope since they had not warned us. ATC did not respond & before I could ask again we received a TCAS RA with a climb command. The captain climbed the aircraft to 10500' before we received a clear of conflict. I immediately notified ATC that we were responding to a TCAS RA. The [cleveland] controller was surprised; stated that the traffic was VFR at 9500 and that we should be talking to ny center. I told the controller that we had never been given a frequency change; at which time he instructed us to descend back to 10000' and contact ny center. When I contacted ny center I informed the controller that we were descending back to 10000' after having responded to an RA. He asked if we had notified the previous controller; I told him yes & that the controller indicated we should have been talking to him [ny center]; but that we had never been issued a freq change prior to the event. Also; when we swapped from cleveland to ny center we were given a new altimeter setting of 29.94. The previous setting (during the RA event) had been 30.04 which had been given to us when we checked on with cleveland.cleveland center thought they had swapped us to ny center; but had not. This meant neither controller was keeping us clear of traffic. The delayed hand off meant that we were still on cleveland's altimeter setting; while I would guess the other aircraft was on ny center's setting - effectively reducing the separation between the aircraft. The cloud layer between the two aircraft meant that neither crew could see the other aircraft. The aircraft's deferred pressurization system requiring us to operate at an unusual altitude for our aircraft (10000'). The two aircraft having assigned altitudes only 500' apart [contributed].

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Original NASA ASRS Text

Title: CRJ200 First Officer reports TCAS RA at 10000 feet and evasive climb. A frequency change had been missed or not issued resulting in the altimeter setting not being current.

Narrative: Aircraft had the auto pressurization controllers deferred; requiring that we operate unpressurized. This limited us to 10000' maximum altitude. While cruising at 10000' assigned; we received a TCAS TA for traffic at our 3 o'clock; 300' below us. We were sitting just on top of a cloud layer; and we could not see the traffic. I contacted ATC to see if they had the traffic on their scope since they had not warned us. ATC did not respond & before I could ask again we received a TCAS RA with a climb command. The Captain climbed the aircraft to 10500' before we received a clear of conflict. I immediately notified ATC that we were responding to a TCAS RA. The [Cleveland] Controller was surprised; stated that the traffic was VFR at 9500 and that we should be talking to NY Center. I told the Controller that we had never been given a frequency change; at which time he instructed us to descend back to 10000' and contact NY Center. When I contacted NY Center I informed the Controller that we were descending back to 10000' after having responded to an RA. He asked if we had notified the previous Controller; I told him yes & that the Controller indicated we should have been talking to him [NY Center]; but that we had never been issued a freq change prior to the event. Also; when we swapped from Cleveland to NY Center we were given a new altimeter setting of 29.94. The previous setting (during the RA event) had been 30.04 which had been given to us when we checked on with Cleveland.Cleveland Center thought they had swapped us to NY Center; but had not. This meant neither controller was keeping us clear of traffic. The delayed hand off meant that we were still on Cleveland's altimeter setting; while I would guess the other aircraft was on NY Center's setting - effectively reducing the separation between the aircraft. The cloud layer between the two aircraft meant that neither crew could see the other aircraft. The aircraft's deferred pressurization system requiring us to operate at an unusual altitude for our aircraft (10000'). The two aircraft having assigned altitudes only 500' apart [contributed].

Data retrieved from NASA's ASRS site as of April 2012 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.