Narrative:

Atx X was given a restriction to cross the peter intersection at 17000 ft. Pilot read back cross peter at 10000 ft. Readback was missed by controller. Supplemental information from acn 219995: ZBW issued crossing restriction to cross peter intersection at 10000 ft. Clearance was read back and descent was initiated. Out of 17500 ft ZBW issued a frequency change. At 17000 ft new ZBW controller was contacted and we reported leaving 17000 ft for 10000 ft. Controller told us of air carrier Y at 12 O'clock and instructed us to level off at 17000 ft. At this point we were at 16500 ft and we returned to 17000 ft. TCASII then warned us of traffic with a TA then an RA to monitor vertical speed but we were already climbing back to 17000 ft. The original ZBW controller was busy and probably didn't realize he had issued a conflicting clearance and when it was read back didn't catch that it was conflicting with other traffic. Next ZBW controller realized the conflict and issued a revised clearance. Situation could be avoided by adding additional controllers to split up a sector when aircraft are deviating due to thunderstorms. Supplemental information from acn 219680: a quick look at the arrival plate for pawling 1 to jfk indicates to expect peter intersection at or below 17000 ft. I have flown this route numerous times and it is not uncommon to reach FL190 and then descend immediately to 11000 ft or 10000 ft before reaching pawling or sometimes delancey. However, in our case, we had deviated so far south around thunderstorms that we were not on the normal airway when issued the crossing restriction. Therefore, the clearance may have been issued out of habit and we would think nothing of it because it always happens.

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Original NASA ASRS Text

Title: ALTDEV ALT OVERSHOT CREATES POTENTIAL CONFLICT LTSS.

Narrative: ATX X WAS GIVEN A RESTRICTION TO CROSS THE PETER INTXN AT 17000 FT. PLT READ BACK CROSS PETER AT 10000 FT. READBACK WAS MISSED BY CTLR. SUPPLEMENTAL INFO FROM ACN 219995: ZBW ISSUED XING RESTRICTION TO CROSS PETER INTXN AT 10000 FT. CLRNC WAS READ BACK AND DSCNT WAS INITIATED. OUT OF 17500 FT ZBW ISSUED A FREQ CHANGE. AT 17000 FT NEW ZBW CTLR WAS CONTACTED AND WE RPTED LEAVING 17000 FT FOR 10000 FT. CTLR TOLD US OF ACR Y AT 12 O'CLOCK AND INSTRUCTED US TO LEVEL OFF AT 17000 FT. AT THIS POINT WE WERE AT 16500 FT AND WE RETURNED TO 17000 FT. TCASII THEN WARNED US OF TFC WITH A TA THEN AN RA TO MONITOR VERT SPD BUT WE WERE ALREADY CLBING BACK TO 17000 FT. THE ORIGINAL ZBW CTLR WAS BUSY AND PROBABLY DIDN'T REALIZE HE HAD ISSUED A CONFLICTING CLRNC AND WHEN IT WAS READ BACK DIDN'T CATCH THAT IT WAS CONFLICTING WITH OTHER TFC. NEXT ZBW CTLR REALIZED THE CONFLICT AND ISSUED A REVISED CLRNC. SIT COULD BE AVOIDED BY ADDING ADDITIONAL CTLRS TO SPLIT UP A SECTOR WHEN ACFT ARE DEVIATING DUE TO TSTMS. SUPPLEMENTAL INFO FROM ACN 219680: A QUICK LOOK AT THE ARR PLATE FOR PAWLING 1 TO JFK INDICATES TO EXPECT PETER INTXN AT OR BELOW 17000 FT. I HAVE FLOWN THIS RTE NUMEROUS TIMES AND IT IS NOT UNCOMMON TO REACH FL190 AND THEN DSND IMMEDIATELY TO 11000 FT OR 10000 FT BEFORE REACHING PAWLING OR SOMETIMES DELANCEY. HOWEVER, IN OUR CASE, WE HAD DEVIATED SO FAR S AROUND TSTMS THAT WE WERE NOT ON THE NORMAL AIRWAY WHEN ISSUED THE XING RESTRICTION. THEREFORE, THE CLRNC MAY HAVE BEEN ISSUED OUT OF HABIT AND WE WOULD THINK NOTHING OF IT BECAUSE IT ALWAYS HAPPENS.

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.