ALERT TRACON APCH CTLR; WHILE RADAR MONITORING ARR TFC; ADVISES FLC OF HDG TRACK DEV ON A RADAR VECTOR TO AN IAP ILS.

Narrative

WE WERE APCHING THE ARPT FROM THE SW (CLT 052 DEG INBOUND). OUR VOR RECEIVERS HAVE 2 HEADS WITH A TOGGLE SWITCH IN BTWN TO CHANGE FREQ. I HAD THE VOR FREQ ON THE L; THE LOC FREQ ON THE R. THE FRONT COURSE FOR THE APCH IS 053 DEG. AFTER OUR FIRST VECTOR FOR THE APCH I SET IN THE COURSE (ONLY 1 DEG CHANGE) AND CHKED TO SEE THE CORRECT FREQ WAS SET; HOWEVER I FORGOT TO THROW THE TOGGLE SWITCH. APPROX 10 MI FROM THE RWY; APCH CTL ASKED IF WE SHOWED OURSELVES ON THE LOC. THAT'S WHEN WE DISCOVERED MY MISTAKE. I STARTED A R TURN TO JOIN THE LOC AND WHEN I DID I SAW THE RWY SLIGHTLY TO THE R (ABOUT 8-9 MI OUT). AT THIS POINT WE WERE STILL OUTSIDE THE FINAL APCH FIX AT 2300 AGL. THE BIGGEST CONTRIBUTING FACTOR TO THIS SITUATION WAS FATIGUE. THIS HAPPENED ON THE LAST LEG OF A 4 DAY TRIP. THE PRECEDING OVERNIGHT HAD BEEN A MIN REST. MY SCHEDULE BEFORE THIS TRIP WAS 2 DAYS OF GND SCHOOL; 1 DAY OFF; ANOTHER 4 DAY TRIP. ALSO THE CAPT DIDN'T IDENT THE LOC SIGNAL FOR THE APCH. AGAIN FATIGUE AS HIS SCHEDULE WAS THE SAME THAT MONTH EXCEPT FOR THE GND SCHOOL. THERE WASN'T ANY TFC OR TERRAIN CONFLICT; HOWEVER; IF IT HAD BEEN LOW IFR AT A NON RADAR FACILITY; IT MIGHT HAVE BEEN A FAR DIFFERENT ENDING.