POS HDG TRACK DEV DURING RADAR VECTORING TO INTERCEPT IAP ILS APCH.

Narrative

DURING RADAR VECTORS TO ILS-1 RWY 17L AT DFW; APCH CTLR TURNED US TO 220 DEGS AND CLRED US FOR APCH WITH A RESTRICTION TO CROSS PENNY AT 4000 FT AND CONTACT TWR ON 126.55 MHZ. FO WAS FLYING AND HIS LOC WAS TUNED PROPERLY TO 109.1. I WAS STILL ON DFW VOR 117.0. AS I WAS SWITCHING TO TWR FREQ THE FO QUESTIONED THE CLRNC FOR ILS BECAUSE HIS INSTS INDICATED THAT HE WAS ALREADY THROUGH THE LOC ON THE 220 DEGS HDG. I IMMEDIATELY TUNED MY LOC TO 109.1 TO CONFIRM THE INDICATION. BOTH OF OUR INSTS AGREED; SO I CALLED TWR TO ASK FOR A TURN TO RE-INTERCEPT. SOME OTHER VOICE ANSWERED SAYING 'ACR Y; I THINK YOU WANT 126.55.' THEN I SAW THAT I HAD NOT COMPLETED SETTING TWR FREQ OF 126.55 AND WAS ON 125.55. AS SOON AS I REACHED TWR; THEY SAID I WAS ON THE WRONG LOC (SIMULTANEOUS APCHS WERE IN PROGRESS TO RWY 18R) AND GAVE US A L TURN TO THE E AND SENT US BACK TO APCH CTL FOR RE-SEQUENCING. THIS WAS A LOC OVERSHOOT WITH A POTENTIAL FOR DISASTER! I BELIEVE THIS WAS PARTIALLY CAUSED BY THE CTLRS HDOF TO TWR FREQ BEFORE LOC INTERCEPT; AND PARTIALLY CAUSED BY NOT HAVING MY LOC TUNED BEFORE THE INTERCEPT VECTOR. WE HAD BRIEFED TO KEEP MY NAV ON DFW VORTAC BETTER NAV AWARENESS UNTIL ON FINAL; THEN SWITCH TO LOC. SUPPLEMENTAL INFO FROM ACN 199901: APCH CTLR TURNED US TO 220 DEGS WITH INSTRUCTIONS TO INTERCEPT LOC CROSS 'PENNY' AT 4000 FT; CLRED FOR APCH AND CONTACT TWR ON 126.55. I WAS FLYING WITH AUTOPLT ENGAGED. I IMMEDIATELY DIALED IN COURSE OF 220 DEGS WITH HDG SELECT ENGAGED AT 25 DEGS ANGLE OF BANK. I THEN QUESTIONED THE ALT OF 4000 FT VICE 3000 FT PUBLISHED GS INTERCEPT) TO THE CAPT. WHILE ACFT WAS STILL IN TURN I SELECTED 'VOR/LOC' ON AUTOPLT AND HAD CONFIRMED 4000 FT ALT UNTIL 'PENNY'. THE ACFT MUST HAVE ALREADY FLOWN THROUGH LOC AT THIS TIME OR IT WOULD HAVE CAPTURED. AS ACFT ROLLED OUT ON INTERCEPT HDG I NOTICED WE WERE WELL THROUGH THE LOC AND NEEDED TO COME FURTHER SE TO INTERCEPT. ALSO; APCH (IN THIS SAME TIME FRAME) QUESTIONED ANOTHER ACFT IF HE SHOWED HIMSELF ON LOC (WHICH HE DID) BECAUSE THEY HAD HIM 'A DOT AND 1/2 OFF'. I DON'T KNOW IF APCH EQUIP WAS 'OFF' ENOUGH TO SET UP A LATE TURN TO INTERCEPT WHICH I FAILED TO RECOGNIZE IN TIME AND AUTOPLT FAILED TO CAPTURE. A LOT OF SMALL THINGS ADDED UP TO A POTENTIALLY VERY DANGEROUS OVERSHOOT. TIGHT TURN. I DIDN'T RECOGNIZE OVERSHOOT AS IT OCCURRED. AUTOPLT DIDN'T CAPTURE. CAPT WAS JUST TUNING IN HIS ILS.