Narrative:

While flying from bos to ewr, we were inbound to sax, tracking along V213. We were initially level at 12000 ft MSL. We received clearance to cross 25 mi northeast of the sax VOR at 7000 ft MSL. During our track inbound, ZBW then cleared us 'pilot's discretion' to 8000 ft MSL. As the PF, I thought we were cleared at our discretion to 8000 ft with the original clearance to cross 25 mi northeast at 7000 ft. I either misinterped the controller's clearance or missed a transmission canceling the clearance to cross at 7000 ft 25 me northeast of sax. At approximately 35 mi northeast of sax, I started to descend from 8000 ft so as to cross 25 mi northeast at 7000 ft. At about 32-33 mi out at 7600 ft approximately, we received a TCASII RA to climb, which we did back to 8000 ft. The controller then asked about our altitude and stated we were not cleared to 7000 ft MSL. I realize that the particular sector of ZBW airspace we were in is very busy at that time of day and the controller was working a great deal of traffic. It is also a busy time for our flight crew, obtaining ATIS information, talking to company for gate information, ETA, etc. I feel that a more explicit canceling of the 7000 ft crossing restr would have aided in alleviating this situation.

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Original NASA ASRS Text

Title: ACR DSNDS BELOW ASSIGNED ALT NEAR SAX AFTER RECEIVING A PLT'S DISCRETION CLRNC.

Narrative: WHILE FLYING FROM BOS TO EWR, WE WERE INBOUND TO SAX, TRACKING ALONG V213. WE WERE INITIALLY LEVEL AT 12000 FT MSL. WE RECEIVED CLRNC TO CROSS 25 MI NE OF THE SAX VOR AT 7000 FT MSL. DURING OUR TRACK INBOUND, ZBW THEN CLRED US 'PLT'S DISCRETION' TO 8000 FT MSL. AS THE PF, I THOUGHT WE WERE CLRED AT OUR DISCRETION TO 8000 FT WITH THE ORIGINAL CLRNC TO CROSS 25 MI NE AT 7000 FT. I EITHER MISINTERPED THE CTLR'S CLRNC OR MISSED A XMISSION CANCELING THE CLRNC TO CROSS AT 7000 FT 25 ME NE OF SAX. AT APPROX 35 MI NE OF SAX, I STARTED TO DSND FROM 8000 FT SO AS TO CROSS 25 MI NE AT 7000 FT. AT ABOUT 32-33 MI OUT AT 7600 FT APPROX, WE RECEIVED A TCASII RA TO CLB, WHICH WE DID BACK TO 8000 FT. THE CTLR THEN ASKED ABOUT OUR ALT AND STATED WE WERE NOT CLRED TO 7000 FT MSL. I REALIZE THAT THE PARTICULAR SECTOR OF ZBW AIRSPACE WE WERE IN IS VERY BUSY AT THAT TIME OF DAY AND THE CTLR WAS WORKING A GREAT DEAL OF TFC. IT IS ALSO A BUSY TIME FOR OUR FLC, OBTAINING ATIS INFO, TALKING TO COMPANY FOR GATE INFO, ETA, ETC. I FEEL THAT A MORE EXPLICIT CANCELING OF THE 7000 FT XING RESTR WOULD HAVE AIDED IN ALLEVIATING THIS SIT.

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.