THE WRONG COURSE SET IN THE FMC CAUSED A TCASII RA.

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CLRNC WAS DALLAS 9 TXK TRANSITION. LOADED VIA CDU. CHKING LEGS PAGE THE FIRST FIX WAS DFW AND THE SECOND TXK; A NORMAL DEP RTE. I WAS HAND FLYING THE DEP. THROUGH APPROX 12000 FT; WE WERE GIVEN A TURN TO INTERCEPT THE DFW 067 DEG RADIAL (WHICH WAS THE SID THAT WE HAD PROGRAMMED AT THE GATE) AND CLB TO 17000 FT. I NOTICED THAT THE CAPT WAS MAKING ENTRIES ON HIS CDU. I FOUND THIS SOMEWHAT STRANGE BECAUSE; IF LEFT ALONE; THE ACFT WOULD CAPTURE THE RTE WE HAD PROGRAMMED. THERE ARE MANY WAYS TO MAKE THIS ACFT CAPTURE A SPECIFIC COURSE. AS I GLANCED DOWN APPROX 30 SECONDS LATER; I NOTICED THAT THERE WAS A WHITE DASHED LINE SUPERIMPOSED ON WHAT I THOUGHT WAS THE ORIGINAL RTE MAGENTA LINE (I THOUGHT WRONG). AT THE TIME I FELT THAT WHATEVER THE CAPT HAD DONE WAS CORRECT; WHAT I DID NOT KNOW AT THE TIME WAS THAT IT WAS THE SECOND TIME HE PUT ERRONEOUS DATA IN THE CDU AND THE MAGENTA LINE I THOUGHT WAS THE ORIGINAL COURSE; DFW 067 DEG RADIAL; WAS ACTUALLY THE TXK 247 DEG RADIAL (HE PUT TXK IN THE INTERCEPT LEG BOX WITH AN INTERCEPT COURSE OF 067 DEGS). BUT; AS I SAID BEFORE; IT LOOKED OK TO ME. I SAW A MAGENTA LINE LEADING STRAIGHT TO TXK. AS LNAV TURNED TO CAPTURE TO WRONG COURSE; I WAS ALSO LEVELING THE ACFT AT 17000 FT. WE THEN GOT A TA FROM TCASII WHICH WAS FOLLOWED BY AN RA COMMANDING A CLB. AT FIRST I THOUGHT THE RA MIGHT BE FALSE FOR WE WERE ON COURSE (NOT!) AT OUR ASSIGNED ALT. HOW DARE ANYONE INVADE OUR AIRSPACE! 2 SECONDS LATER WE LEFT 17000 FT WITH A VERT SPD OF 1200 FPM AS COMMANDED BY THE ILLUMINATED VSI. AS I CLBED; I LOOKED OUT THE R WINDOW TO SEE AN MD-80 IN A DSCNT. (HE RECEIVED A DSND RA.) CTR CAME ON TO TELL WE WERE TRACKING THE WRONG RADIAL; TURN 40 DEGS L AND REINTERCEPT THE DFW 067 DEG RADIAL. IN THE TURN; I PUT THE ACFT ON AUTOPLT AS THE CAPT WAS MAKING INPUTS ON THE CDU. I STILL HAD NO IDEA WHAT HAD HAPPENED TO OUR ORIGINAL RTE. AS HE FINISHED THE INPUTS; I SAW ON MY HSI MAP THE RTE WHICH I THOUGHT WAS OUR ORIGINAL SHIFT ABOUT 6 MI N. HE HAD CORRECTED THE PROB WITH HIS INPUTS. WE CONTINUED TO BOS WITHOUT ANY FURTHER INCIDENT. WHAT HAD HAPPENED WAS WHEN HE USED THE 067 DEG RADIAL TO TXK RATHER THAN THE CORRECT 069 DEG RADIAL; OUR COURSE INTERSECTED THE DFW 078 DEG RADIAL WHERE THE MD-80 WAS TURNING TO INTERCEPT THE 078 DEG RADIAL DFW. WE WERE NOT TRACKING THE DFW 078 DEG RADIAL; JUST PASSING THROUGH IT. STILL WRONG. THIS PROB AROSE BECAUSE: 1) THE CAPT FELT THAT HE HAD TO DO ADDITIONAL CDU ENTRIES IN ORDER TO COMPLY WITH ATC'S INSTRUCTIONS TO INTERCEPT; HE DID NOT. THE FMC WOULD HAVE CAPTURED THE DFW 067 DEG RADIAL WITHOUT ANY ADDITIONAL INPUTS. 2) HE HAD HIS SCALE SET TOO HIGH TO NOTICE THAT WHEN HE CHANGED THE ORIGINAL RTE; HE DID NOT SEE THE SEEMINGLY INSIGNIFICANT RTE CHANGE WHEN HE PUT THE WRONG RADIAL IN. 3) NOT HAVING RAW DATA DISPLAYED TO DOUBLE-CHK THE FMC. ALTHOUGH I FEEL THAT THESE ARE THE EVENTS THAT HAPPENED; I AM NOT FULLY SURE OF WHAT THE CAPT DID ON THE CDU FOR I WAS BUSY FLYING THE ACFT. SUPPLEMENTAL INFO FROM ACN 276519: ZFW SAID WE WERE ON THE 078 DEG RADIAL OF DFW. OUR INFO STILL SHOWED DFW-TXK WITH A 068 DEG RADIAL INBOUND COURSE; EVEN AFTER RECHKING AND REENTERING THE INFO IN THE CDU. WE MAY HAVE HAD AN UNOBSERVED MAP SHIFT; BUT NEITHER CREW MEMBER SAW ONE OCCUR. NO ABNORMAL INDICATIONS IN ANY EQUIP.