Narrative:

Departing camrn, ATC clearance was heading 040 degrees, 6000 ft MSL. Upon reaching 6000 ft, ATC immediately called for us to climb to 7000 ft. As we reestablished our climb passing 6200 ft, ATC reclred us to 6000 ft, then 5000 ft. No explanation for the variance in altitudes. Both captain and I reconfirmed that we both had originally heard and acknowledged to ATC 6000 ft, thus the very apprehension that we busted altitude assignment. I called TRACON upon landing and they confirmed that we were assigned 6000 ft, not 7000 ft originally. Both the controller and supervisor on duty admitted that it was ATC error, in that there are new airspace procedures in place for that particular airspace, time of day, and when ILS runway 22L jfk is in use and that they were actually in a turnover or switchover (assigning 6000 ft or 7000 ft) time frame when they picked up our flight. Boy, what a window to be in at the wrong time and wrong place. All was resolved and all happy. No ATC conflict, but we did get a TCASII alert with traffic right below us at 5000 ft.

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Original NASA ASRS Text

Title: B737-300 FLT CREW IS ISSUED MULTIPLE ALT CHANGES BY N90 APCH APPARENTLY DUE TO UNTIMELY AIRSPACE COORD CONFIGN CHANGES.

Narrative: DEPARTING CAMRN, ATC CLRNC WAS HEADING 040 DEGS, 6000 FT MSL. UPON REACHING 6000 FT, ATC IMMEDIATELY CALLED FOR US TO CLB TO 7000 FT. AS WE REESTABLISHED OUR CLB PASSING 6200 FT, ATC RECLRED US TO 6000 FT, THEN 5000 FT. NO EXPLANATION FOR THE VARIANCE IN ALTS. BOTH CAPT AND I RECONFIRMED THAT WE BOTH HAD ORIGINALLY HEARD AND ACKNOWLEDGED TO ATC 6000 FT, THUS THE VERY APPREHENSION THAT WE BUSTED ALT ASSIGNMENT. I CALLED TRACON UPON LNDG AND THEY CONFIRMED THAT WE WERE ASSIGNED 6000 FT, NOT 7000 FT ORIGINALLY. BOTH THE CTLR AND SUPVR ON DUTY ADMITTED THAT IT WAS ATC ERROR, IN THAT THERE ARE NEW AIRSPACE PROCS IN PLACE FOR THAT PARTICULAR AIRSPACE, TIME OF DAY, AND WHEN ILS RWY 22L JFK IS IN USE AND THAT THEY WERE ACTUALLY IN A TURNOVER OR SWITCHOVER (ASSIGNING 6000 FT OR 7000 FT) TIME FRAME WHEN THEY PICKED UP OUR FLT. BOY, WHAT A WINDOW TO BE IN AT THE WRONG TIME AND WRONG PLACE. ALL WAS RESOLVED AND ALL HAPPY. NO ATC CONFLICT, BUT WE DID GET A TCASII ALERT WITH TFC RIGHT BELOW US AT 5000 FT.

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.