A CLBING LEAR 31 HAS A VERY CLOSE POTENTIAL CONFLICT WITH A CARGO 727 IN CRUISE THAT WAS OPPOSITE DIRECTION TFC; AT THE ASSIGNED ALT OF THE LEARJET.

Narrative

WE WERE CLBING OUT OF ATLANTA AREA (DEPARTED FTY; DEST TPA); ASSIGNED HDG 190 DEGS BY AN EARLIER SECTOR. WE CHKED ON WITH ZTL WITH OUR ASSIGNED HDG AND WERE ASSIGNED FL310. MY FO WAS COMMUNICATING AND SET FL310 IN ALT PRESELECT. I HEARD FL310 AND CONFIRMED IT WITH HIM. AUTOPLT WAS FLYING; HDG MODE; ALT SELECT ENGAGED; HALF BANK MODE; 1500 FPM VERT SPD. OUT OF ABOUT FL295; CTR CALLED TFC AT 12 O'CLOCK; 3 MI NBOUND; BUT NO ALT WAS GIVEN. WE HAD ALREADY SWITCHED OUR MFD OFF OF TCASII DISPLAY TO A MAP MODE. AT FL298; CTR GAVE US 'R TURN 20 DEGS.' WE READ IT BACK AND DIALED IN THE NEW HDG. AT THE SAME TIME I ACQUIRED THE TFC AND KICKED OFF HALF BANK MODE. I JUST MADE THE COMMENT THAT THIS WASN'T GOING TO WORK (TO MY FO) AND REACHED TO DISCONNECT THE AUTOPLT. AT FL300 WE GOT AN RA. WE NEVER DID GET A TA; BUT THE HDG CHANGE PUT US ON A MORE DIRECT COLLISION COURSE. SIMULTANEOUSLY WITH THE 'DSND; DSND' RA; CTR CALLED 'ACR YYY; TURN L HDG 270 DEGS IMMEDIATELY -- BREAK -- LEARJET XX STOP CLB IMMEDIATELY!' WE TOPPED OUT AT FL302 AND PASSED UNDER THE B727'S R WING CLOSE ENOUGH TO CLRLY READ THEIR LOGO! AFTER WE PASSED; THE CARGO FLT COMMENTED THAT THEY 'SAW THE LITTLE GUY GO UNDER OUR R WING.' CTR APOLOGIZED A LITTLE LATER. THERE WERE SEVERAL MOMENTS OF CONFUSION IMMEDIATELY AFTER WE COMPLIED WITH THE RA REGARDING WHAT ALT AND HDG CTR WANTED US ON. I DON'T BELIEVE THE ERROR WAS OURS; BUT IT WOULD HAVE RUINED OUR WHOLE DAY. IN THE FUTURE; I WILL PAY MORE ATTN TO LOOKING OUTSIDE; EVEN IN THE FLT LEVELS. ALSO; IT WOULD HAVE HELPED IF CTR HAD CALLED OUT AN ALT ON OUR TFC.