A B767 OVER THE ATLANTIC RECEIVED A TCAS RA AND DSNDED TO AVOID CONFLICT. A 4 ENG JET; BELIEVED TO BE MIL; PASSED 400 FT OVERHEAD.

Narrative

AT POS 5005N 2720W AT FL300 WE RECEIVED A TA FOLLOWED SHORTLY AFTERWARD WITH AN RA TO DSND. THE RA STARTED WITH A 1500 FPM DSCNT. RELIEF PLT DISCONNECTED THE AUTOPLT AND BEGAN A DSCNT. THE RA QUICKLY INCREASED TO 2500 FPM DSCNT WHICH HE MAINTAINED UNTIL REACHING AN ALT OF FL285 AT WHICH POINT THE OPPOSITE DIRECTION ACFT PASSED DIRECTLY OVERHEAD 400 FT ABOVE US. DURING THE EVENT THE AURAL WARNING SAID 'TFC; DSND' FOLLOWED BY 'INCREASE DSCNT.' WE THEN INFORMED SHANWICK ATC OF AN NMAC AND CLBED BACK TO OUR ASSIGNED ALT OF FL300. I WENT ON BREAK AND RELIEF PLT TOOK COMMAND OF THE ACFT. I TURNED ON MY COMPUTER AND CAMERA TO DOWNLOAD SOME PICTURES I HAD TAKEN DURING MY TRIP. MY OTHER FO SAID TO ME THAT THERE WAS APCHING TFC AT 12 O'CLOCK AND 20 MI OUT AND 1000 FT ABOVE US AND I MIGHT WANT TO TAKE A PICTURE AS IT PASSED. AS THE ACFT APCHED THE 10 MI ARC ON OUR TCAS WE RECEIVED A TA AND THE ACFT SHOWED TO BE 600 FT ABOVE OUR ALT. WE THEN RECEIVED THE RA AND STARTED OUR DSCNT. WHEN THE TFC PASSED OVER US IT WAS AT AN ALT INDICATED BY OUR TCAS AS ABOUT FL289. SINCE I HAD MY CAMERA OUT AND WAS ON A BREAK; I TOOK A PICTURE TO IDENT THE ACFT AS IT PASSED OVERHEAD. FROM THE PICTURE IT APPEARED TO BE A HIGH WING 4 ENG MIL ACFT.