AFTER FLC READ BACK CLRNC; SET THE NEW ALT CAPTURE TO FL260 WITH CONFIRMATION BY CAPT; RPTR CAPT COMMENCED DSCNT TO CROSS KERNO AT FL260; AS CLRED. FLC CALLED LEAVING FL370 AND CTR RESPONDED WITH; MAINTAIN FL370; ASKED WHAT THE ALT CLRNC WAS AND WHEN WAS THAT CLRNC RECEIVED. CTLR THEN VECTORED ACFT AND EXPEDITED THEIR DSCNT.

Narrative

I WAS THE FO DURING THIS INCIDENT AND WAS OPERATING THE RADIO. OUR FLT PLAN INCLUDED THE NANCI 5 ARR INTO LGA. WHILE IN RADAR AND RADIO CONTACT WITH ZDC; WE RECEIVED CLRNC TO CROSS KERNO INTXN AT FL260. I READ BACK THE CLRNC; SET FL260 IN ALT WINDOW AND CAPT VERBALLY ACKNOWLEDGED. AFTER SETTING THE RESTR IN THE FMC; THE CAPT BEGAN HIS DSCNT AND WE CALLED CTR OUT OF FL370. CTR CALLED BACK ASKING WHY WE WERE DSNDING AND HOW LONG AGO WE RECEIVED THE CLRNC. THE CAPT DISCONNECTED THE AUTOPLT AND STOPPED THE DSCNT AT FL360. WE THEN TOLD CTLR THAT WE HAD BEEN CLRED TO CROSS KERNO AT FL260 3 MINS AGO ON THIS FREQ. CTLR THEN GAVE US AN OFF COURSE HDG TO 010 DEGS AND IMMEDIATE DSCNT TO FL260. CAPT AND I ARE BOTH CONFIDENT THAT WE HEARD; READ BACK; AND VERIFIED THE PROPER CLRNC. SUPPLEMENTAL INFO FROM ACN 325264: ESTABLISHED AT FL370 ON THE NANCI 5 ARR INTO NEW YORK'S LGA ARPT; ZDC GAVE US CLRNC TO CROSS KERNO INTXN AT FL260. THE FO WAS WORKING THE RADIOS AND READ BACK THE ENTIRE CLRNC. HE THEN RESET THE ALT CAPTURE TO FL260 AND I VERBALLY CONFIRMED FL260 WAS SET. I THEN RECHKED THE FMC TO CONFIRM IT WAS PROGRAMMED FOR KERNO AT FL260. ABOUT 3 MINS AFTER RECEIVING THE CLRNC I STARTED OUT OF FL370 AND WE CALLED 'LEAVING FL370.' ZDC RESPONDED WITH 'MAINTAIN FL370.' THE ACFT HAD ALREADY BEGUN AN AUTOPLT DSCNT SO I DISCONNECTED THE AUTOPLT AND ABRUPTLY STOPPED THE DSCNT AT FL366 AND RETURNED TO FL370. HE THEN CLRED US TO TURN L HDG 010 DEGS; DSND TO FL260; EXPEDITE THE DSCNT AND WE COMPLIED. THROUGH ABOUT FL330 WE WERE CLRED BACK DIRECT KERNO INTXN. WE DO NOT KNOW IF A CONFLICT EXISTED. AT THE TIME WE WERE NOT ADVISED OF ONE. I BELIEVE THE ONLY PROB TO BE A MISCOM ON THE PART OF ZDC.