Narrative:

Flight from cdg to iad. Reported 'porgy' (our landfall fix after crossing atlantic) at FL330 to moncton center and were asked if a higher altitude was desired. We responded with a request for FL350. A clearance was shortly issued to FL350. Just after climb was initiated a TA was received and a level off was made at FL340. A flight who had not reported 'porgy' but was apparently behind us notified moncton that we were climbing to their altitude. After a pause moncton reclred us back to FL330. In an overheard transmission, air carrier commented that they were trying to contact moncton for several minutes. We were on that frequency and did not hear any prior xmissions (they could not have been attempted on HF or a different VHF frequency). When oth flight and moncton became aware of the situation there seemed to be some confusion on the part of moncton center as to air carrier Y's position. Thank god for TCASII! Supplemental information from acn 263283: I noted a congested frequency with apparent messages to aircraft on other frequencys from controller. I heard an aircraft report porgy and noted his time same as ours, altitude FL330. I then made 2 attempts to give position and was told to 'stand by' by ATC. While waiting I happened to hear another air carrier jet cleared to our FL350. The relief copilot at that point remarked that there was a jet visible directly below his side. I looked at the TCASII and noted 1900 ft separation and slowly closing. Moncton asked our position report then responded he thought we were at foxxe intersection, one track south. We had filed for that track but had been cleared via track golf. Apparently some confusion is possible between radio service ctrs and ATC ctrs. TCASII, situational awareness by ears and eyes is critical at such times.

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Original NASA ASRS Text

Title: TCASII RA PREVENTS ACR X FROM PERFORMING CLB TO OCCUPIED ALT INTO ACR Y. POTENTIAL CONFLICT ENSUES.

Narrative: FLT FROM CDG TO IAD. REPORTED 'PORGY' (OUR LANDFALL FIX AFTER CROSSING ATLANTIC) AT FL330 TO MONCTON CTR AND WERE ASKED IF A HIGHER ALT WAS DESIRED. WE RESPONDED WITH A REQUEST FOR FL350. A CLRNC WAS SHORTLY ISSUED TO FL350. JUST AFTER CLB WAS INITIATED A TA WAS RECEIVED AND A LEVEL OFF WAS MADE AT FL340. A FLT WHO HAD NOT RPTED 'PORGY' BUT WAS APPARENTLY BEHIND US NOTIFIED MONCTON THAT WE WERE CLBING TO THEIR ALT. AFTER A PAUSE MONCTON RECLRED US BACK TO FL330. IN AN OVERHEARD XMISSION, ACR COMMENTED THAT THEY WERE TRYING TO CONTACT MONCTON FOR SEVERAL MINUTES. WE WERE ON THAT FREQ AND DID NOT HEAR ANY PRIOR XMISSIONS (THEY COULD NOT HAVE BEEN ATTEMPTED ON HF OR A DIFFERENT VHF FREQ). WHEN OTH FLT AND MONCTON BECAME AWARE OF THE SIT THERE SEEMED TO BE SOME CONFUSION ON THE PART OF MONCTON CTR AS TO ACR Y'S POS. THANK GOD FOR TCASII! SUPPLEMENTAL INFO FROM ACN 263283: I NOTED A CONGESTED FREQ WITH APPARENT MESSAGES TO ACFT ON OTHER FREQS FROM CTLR. I HEARD AN ACFT RPT PORGY AND NOTED HIS TIME SAME AS OURS, ALT FL330. I THEN MADE 2 ATTEMPTS TO GIVE POS AND WAS TOLD TO 'STAND BY' BY ATC. WHILE WAITING I HAPPENED TO HEAR ANOTHER ACR JET CLRED TO OUR FL350. THE RELIEF COPLT AT THAT POINT REMARKED THAT THERE WAS A JET VISIBLE DIRECTLY BELOW HIS SIDE. I LOOKED AT THE TCASII AND NOTED 1900 FT SEPARATION AND SLOWLY CLOSING. MONCTON ASKED OUR POS RPT THEN RESPONDED HE THOUGHT WE WERE AT FOXXE INTXN, ONE TRACK S. WE HAD FILED FOR THAT TRACK BUT HAD BEEN CLRED VIA TRACK GOLF. APPARENTLY SOME CONFUSION IS POSSIBLE BTWN RADIO SERVICE CTRS AND ATC CTRS. TCASII, SITUATIONAL AWARENESS BY EARS AND EYES IS CRITICAL AT SUCH TIMES.

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.