Narrative:

Aircraft #1, B767, an overseas departure off of iad, climbed to 17000 ft, informed of traffic at FL180 (a king air, aircraft #2, sbound at FL180). Traffic exchanged. King air sees B767. King air is turned away from traffic so to allow B767 to climb sooner. Aircraft #3 was on a STAR to phl, was issued a descent clearance that aircraft #1 mistook for a climb clearance. Controller did not catch the aircraft #1 climb readback and issued other clrncs. Aircraft #3 came back and informed controller that someone else took his clearance and was it for him. A descent clearance was reissued to aircraft #3 in which aircraft #1 responded roger, climbing to FL200. Aircraft #1 told negative, maintain 17000 ft for traffic. Asked to verify his altitude, aircraft #1 said 17800 ft descending. King air aircraft #2 asked if he had traffic in sight. The king air responded yes and that traffic was no factor. Situation arose from a pilot who was in a hurry to climb and possibly from a controller issuing a clearance that could not be misunderstood and didn't listen to readback as closely as possible. Supplemental information from acn 413811: the B767 took another aircraft's clearance and climbed into the king air causing a loss of separation. Supplemental information from acn 414254: on climb out from iad at 17000 ft, ZDC had given a climb clearance. Captain read back that climbing to FL200 and then set altitude window. First officer began climb. Another aircraft on frequency to ZDC stated that another aircraft has mistaken the climb clearance. At that time captain asked ZDC about altitude clearance. ZDC returned us 17000 ft. On descent to 17000 ft, captain and first officer had received a TA on TCASII. Aircraft was approximately 1 mi horizontal separation. Aircraft had us in sight. There were no further comments from ZDC. In retrospect, I realize that at the time of the confusion, I was not fully listening to center communications. I was beginning my first officer relief duties and heard the captain read back the climb clearance, but did not fully hear the climb clearance being given. I should have questioned it immediately.

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Original NASA ASRS Text

Title: ACR B767 FLC ACKNOWLEDGED A CLRNC FOR ANOTHER ACR AND CAME INTO CONFLICT WITH A BE90 ABOVE THE B767. THE B767 THOUGHT A DSCNT CLRNC TO THE ACR ACFT WAS A CLB CLRNC FOR ITSELF.

Narrative: ACFT #1, B767, AN OVERSEAS DEP OFF OF IAD, CLBED TO 17000 FT, INFORMED OF TFC AT FL180 (A KING AIR, ACFT #2, SBOUND AT FL180). TFC EXCHANGED. KING AIR SEES B767. KING AIR IS TURNED AWAY FROM TFC SO TO ALLOW B767 TO CLB SOONER. ACFT #3 WAS ON A STAR TO PHL, WAS ISSUED A DSCNT CLRNC THAT ACFT #1 MISTOOK FOR A CLB CLRNC. CTLR DID NOT CATCH THE ACFT #1 CLB READBACK AND ISSUED OTHER CLRNCS. ACFT #3 CAME BACK AND INFORMED CTLR THAT SOMEONE ELSE TOOK HIS CLRNC AND WAS IT FOR HIM. A DSCNT CLRNC WAS REISSUED TO ACFT #3 IN WHICH ACFT #1 RESPONDED ROGER, CLBING TO FL200. ACFT #1 TOLD NEGATIVE, MAINTAIN 17000 FT FOR TFC. ASKED TO VERIFY HIS ALT, ACFT #1 SAID 17800 FT DSNDING. KING AIR ACFT #2 ASKED IF HE HAD TFC IN SIGHT. THE KING AIR RESPONDED YES AND THAT TFC WAS NO FACTOR. SIT AROSE FROM A PLT WHO WAS IN A HURRY TO CLB AND POSSIBLY FROM A CTLR ISSUING A CLRNC THAT COULD NOT BE MISUNDERSTOOD AND DIDN'T LISTEN TO READBACK AS CLOSELY AS POSSIBLE. SUPPLEMENTAL INFO FROM ACN 413811: THE B767 TOOK ANOTHER ACFT'S CLRNC AND CLBED INTO THE KING AIR CAUSING A LOSS OF SEPARATION. SUPPLEMENTAL INFO FROM ACN 414254: ON CLBOUT FROM IAD AT 17000 FT, ZDC HAD GIVEN A CLB CLRNC. CAPT READ BACK THAT CLBING TO FL200 AND THEN SET ALT WINDOW. FO BEGAN CLB. ANOTHER ACFT ON FREQ TO ZDC STATED THAT ANOTHER ACFT HAS MISTAKEN THE CLB CLRNC. AT THAT TIME CAPT ASKED ZDC ABOUT ALT CLRNC. ZDC RETURNED US 17000 FT. ON DSCNT TO 17000 FT, CAPT AND FO HAD RECEIVED A TA ON TCASII. ACFT WAS APPROX 1 MI HORIZ SEPARATION. ACFT HAD US IN SIGHT. THERE WERE NO FURTHER COMMENTS FROM ZDC. IN RETROSPECT, I REALIZE THAT AT THE TIME OF THE CONFUSION, I WAS NOT FULLY LISTENING TO CTR COMS. I WAS BEGINNING MY FO RELIEF DUTIES AND HEARD THE CAPT READ BACK THE CLB CLRNC, BUT DID NOT FULLY HEAR THE CLB CLRNC BEING GIVEN. I SHOULD HAVE QUESTIONED IT IMMEDIATELY.

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.