DC10 FO PF WHILE ON A CEPAC TRACK OBSERVES TFC XING 3000 FT BELOW AND BELIEVES THE ACFT IS OFF COURSE.

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I WAS FLYING THE CHARLIE TRACK FROM HNL TO SFO ON APR/XA/00 AT APPROX XA30Z. ABOUT 5 MINS EARLIER; WE HAD JUST CLBED FROM FL320 UP TO FL340 AND CALLED SFO RADIO THAT WE WERE LEVEL. WE HAD AN FAA INSPECTOR FROM OAK ON THE JUMP SEAT GIVING US A LINE CHK. I SEE A CONTRAIL AT ABOUT 2 O'CLOCK POS AND THINK 'THAT'S WEIRD; WHAT'S HE DOING WAY OVER THERE (OFF THE TRACK)?' THEN I REALIZE IT'S COMING RIGHT AT US. I CALLED THE TFC; AND EVERYBODY UP FRONT PRESSES FACE TO THE WINDOWS. TURNS OUT; IT WAS AN A340 OR B747-400 (4 ENG WITH WINGLETS) AT ABOUT FL310; PASSED RIGHT UNDERNEATH US (OUR TCASII ONLY DISPLAYS 2000 FT AND HE DIDN'T SHOW UP). WE WERE 183 DME W OF COPPI (049 DEG TRACK) WITH SEVERAL OTHER PLANES ON THE TRACK AROUND US (ABOVE AND BELOW). THIS TFC WAS ON ABOUT A 260 DEG HDG WHEN HE CROSSED UNDER US. WE TRIED RAISING HIM 2 TIMES ON 128.95; NO RESPONSE. WE THEN ALERTED EVERYBODY ON 128.95 THAT THIS GUY WAS OUT HERE CUTTING ACROSS THE TRACKS; THEN CALLED IT IN TO SFO RADIO. WHEN WE REACHED 127 MI W AND CONTACTED ZOA; WE QUERIED THEM AND WERE ADVISED THAT 'IT WAS A B747 AND IT WAS RIGHT WHERE IT WAS SUPPOSED TO BE.' SO; MY QUESTION IS; IS IT LEGAL (WITH THE CEPAC TRACKS AND RVSM; ETC) FOR SOMEONE TO BE DOING SOMETHING LIKE LAX DIRECT NRT AT FL310? I MEAN; IF ANYBODY POPS AN ENG OUT THERE ON ONE OF THE CEPAC TRACKS AND STARTS A SIDESTEP AND DSCNT RIGHT IN FRONT OF SOMEONE ELSE CUTTING ACROSS ALL THE TRACKS; THERE'S AN EXTREMELY HIGH POTENTIAL FOR AN INFLT COLLISION.