FLC OF MLG MISSES XING RESTR DUE TO PROGRAMMING A COURSE REVERSAL ERROR.

Narrative

CAPT INADVERTENTLY CREATED A COURSE REVERSAL BTWN 2 WAYPOINTS ALONG A STRAIGHT COURSE LINE. ALTHOUGH I CHKED MY PROGRAMMING I MISSED THE ERROR. THE COURSE REVERSAL ARTIFICIALLY ADDED DISTANCE TO TOP OF DSCNT TO CROSS 15 NM N OF BAL AT 12000 FT. CONSEQUENTLY; I STARTED DOWN LATE WITH CTLR PROMPTING; FESSED UP MY ERROR; AND WAS VECTORED FOR DSCNT. CURIOUSLY; I WAS XCHKING MY DSCNT VERSUS THE RAW DATA AND EVERYTHING SEEMED OK. I WAS WELL WITHIN THE PARAMETERS FOR A NORMAL DSCNT (FROM 20000 FT) TO LOSE 8000 FT OF ALT. I CALCULATED A 3 TO 1 DSCNT PROFILE AND FIGURED I'D NEED 24 NM TO DSND TO 12000 FT. I COULDN'T UNDERSTAND INITIALLY WHY THERE WAS A PROB. THE RAW DATA BACKED UP THE ERRONEOUS FMS COMPUTED TOUCHDOWN POINT. THEN; I REALIZED I HAD MADE 2 ERRORS SIMULTANEOUSLY. I HAD JUST CHANGED TO DCA VOR. I WAS CHKING MY DISTANCE TO DEST AND UNKNOWINGLY NEGLECTED TO RETUNE BAL. WHEN I REALIZED THE CTLR WAS CORRECT I FELT A MOMENTARY SENSE OF CONFUSION. I KNEW I HAD MADE AN ERROR BUT IT TOOK A WHILE TO FIGURE WHAT I'D DONE. I'D MADE 2 CONCURRENT ERRORS.