ACR X HAD LTSS FROM ACR Y UNDER OCEANIC CTL. EVASIVE ACTION TAKEN. SYS ERROR.

Narrative

ACR X RTE OF FLT WAS FROM EFHK DCT VTI UG5 RUS DCT SUN DCT OSD DCT TRM DCT 65N000W RANDOM DCT 65N010W DCT 66N020W DCT 67N030W DCT 67N040W DCT 66N050W DCT 63N060W DCT FASSA NA362 MT J574 YUL DCT ALB J37 IGN IGN6 JFK. WE WERE CLRED TO MAINTAIN FL350. PRIOR TO 65N000W; TRM RADIO ASKED IF COULD MAINTAIN FL370. WE ANSWERED WE WERE TOO HVY. WE WERE THEN TOLD TO DSND TO FL330. WE ACKNOWLEDGED AND DSNDED TO FL330. WE WERE THEN SELCALED BY ICELAND RADIO ON HF AND ASKED TO CONFIRM WE WERE AT FL330. WE CONFIRMED WE WERE LEVEL AT FL330. WE THEN PASSED 65N000W. A FEW MINS PRIOR TO XING 65N010W (CROSSED AT XA25Z) WE RECEIVED A RPT ON ICELAND RADIO FREQ 127.85. ACR Y WAS RPTING A NEAR MISS WITH ACR ACFT AT FL330. DURING THE DISCUSSION WITH ACR Y WE DISCOVERED THE NEAR MISS WAS WITH US. ACR Y DEPARTED DUSSELDORF AND WAS PRECEDING TO EDMONTON; CA; AND THEN ON TO LAX. HIS RTE OF FLT THAT CONFLICTED WITH OURS WAS FROM LIRKI (61N00151W) TO 66N010W. HE RPTED HE SAW US AT HIS 1 O'CLOCK POS. HE TURNED TO HIS R TO PASS BEHIND US. HE RPTED PASSING 500 METERS BEHIND US. THE NEAR MISS OCCURRED AT N6504/W0814. THIS OCCURRENCE APPEARS TO HAVE BEEN CAUSED BY MIS-COM BTWN 2 ATC FACILITIES THAT ALLOWED 2 ACFT TO DEPART THEIR AIRSPACE AT THE SAME FL ON CONVERGENT FLT PATHS.