B767 ACFT CLRED TO DSND FROM FL370 TO FL330 BY FOREIGN CTLR AND WHEN RPTR ACFT WAS IN DSCNT; SAW ANOTHER ACFT ON THEIR RADAR AND CONFIRMED THEY WERE AT FL350. BOTH ACFT HAD TO TAKE EVASIVE ACTION.

Narrative

WE WERE LEVEL FL370 AND MANAUS CLRED US TO CROSS NANDA AT FL370 AND THEN DSND TO FL330. THE CLRNC WAS CONFIRMED TWICE. PASSING NANDA WE RPTED OUT OF FL370 IN THE DSCNT I NOTICED A RADAR RETURN INSIDE 10 MI DIRECTLY AHEAD. I LOOKED AHEAD; TURNED ON THE LNDG LIGHTS AND XCHKED THE TCASII. NO TCASII WARNING BUT THERE WAS AN ACFT; A B747; LEVEL AT FL350 ON AN INTERCEPT COURSE. I TURNED R TO AVOID THE TFC AND WE PASSED APPROX 500 FT FROM THE B747. THE B747 ALSO TURNED ON HIS LIGHT. THEY RPTED THAT THEY DID HAVE A MODE C XPONDER BUT NO TCASII. MANAUS DID NOT RESPOND TO NUMEROUS CALLS. SUPPLEMENTAL INFO FROM ACN 392239: ACR X WAS CLRED TO DSND FROM FL370 TO FL330 FLYING SBOUND ON UW9; CLRED BY MANAUS CTR. WE WERE FLYING N ON UW9 AT FL350. WE WERE 3 MINS S OF NANDA INTXN. ACR X WAS CLRED TO BEGIN THEIR DSCNT AT NANDA INTXN. ACR X DSNDED THROUGH OUR FLT PATH AND WAS 500 FT BELOW US AT INTERCEPT AND 100 FT L OF OUR COURSE HORIZLY. MANAUS CTR IS AT FAULT FOR CLRING ACR X TO DSND TO FL330 PRIOR TO OUR PASSING NANDA INTXN. ACR X TOOK EVASIVE ACTION TO ATTAIN 100 FT OF HORIZ SEPARATION AND 500 FT VERTLY (ESTIMATED). WE SAW ACR X AHEAD OF US BUT SINCE THERE WAS NO HORIZON WE DIDN'T KNOW IF THEY WERE ABOVE OR BELOW US.