CL65 DEPARTING DFW VARIES FROM ASSIGNED CLRNC TRACK.

Narrative

DURING OUR CLBOUT FROM DFW; WE WERE BEING VECTORED TO INTERCEPT THE 085 DEG RADIAL FROM MAVERICK VOR; WHICH IS PART OF THE DALLAS 7 DEP PROC. WE ARMED THE NAV MODE ON THE FMS. AS THE FMS CAPTURED THE COURSE AND THE ACFT BEGAN TO TURN R; WE NOTICED THAT THE FMS WAS IN 'FMS DR' MODE; WHICH IT WAS NOT DURING THE TKOF AND INITIAL CLB. WE STOPPED THE TURN BY GOING TO HDG MODE AND TRIED TO UPDATE THE POS ON THE FMS WITH AN OPERATIONAL AND VALID VOR (MAVERICK TTT). THE FMS WOULD NOT EXCEPT IT. WE THEN WENT TO VHF NAV (GREEN NEEDLES). NOTICING THAT WE WERE R OF COURSE; WE BEGAN A L TURN TO INTERCEPT THE ASSIGNED RADIAL. AT THIS TIME ATC STOPPED OUR CLB AND QUESTIONED OUR CLRNC. ATC GAVE US A NEW HDG TO INTERCEPT OUR COURSE; AND THEN CONTINUED OUR CLB. AFTER DISCUSSING THIS EXPERIENCE TOGETHER; WE FEEL WE HAVE LEARNED FROM THIS EXPERIENCE. WHAT WE WOULD DO DIFFERENTLY IN THE FUTURE IS; NEVER ARM THE ANV MODE UNTIL SE VERIFY THAT THE FMS IS NOT IN 'FMS DR' MODE. THEN WE WOULD KEEP OUR PRIORITIES IN ORDER; IF THE FMS IS IN 'DR' MODE; FIRST GO TO GREEN NEEDLES; NAV THE ACFT; AND THEN TRY AND UPDATE THE FMS POS.