What was found
WHEN A DISCREPENCY BETWEEN THE NAVDATA DATABASE & ACTUAL IMPLEMENTATION OF A LOCALIZER NAVAID, GFC700 WILL NOT INTERCEPT & TRACK LOCALIZER SIGNAL CORRECTLY. IT EITHER FLIES THROUGH COURSE OR WILL ACTIVATE LOC MODE & IMMEDIATELY TURN OFF COURSE. AFCS APPEARS TO REFERENCE LOCALIZER COURSE FROM DATABASE RATHER THAN SELECTED COURSE ON HSI. FIRST DISCOVERED ON ASE LOC DME A APPROACH LAST APRIL. NAVDATA HAD INCORRECT COURSE OF 120 FOR I-PKN LOCALIZER. I-PKN TUNED, HSI WOULD AUTO-SET COURSE TO 120. THE PILOT CAN TURN THE NEEDLE TO THE CORRECT COURSE OF 300, AND THE HSI WILL PROVIDE CORRECT SENSING. AUTOPILOT WILL NOT CAPTURE THAT COURSE & WILL FLY RIGHT THROUGH LOCALIZER TOWARD TERRAIN. MANUFACTURERS AND FAA/NFDC WERE NOTIFIED, & NFDC CORRECTED ENTRY IN LOCALIZER DATABASE. NEXT DISCOVERED ON EUG ILS 16R APPROACH. FREQUENCY FOR LOCALIZER RECENTLY CHANGED TO 110.1 WITH NEW FREQUENCY PUBLISHED BY NOTAM. TUNING 110.1, HSI AUTO-SETS COURSE WESTWARD. PILOT CAN MANUALLY SET HSI COURSE TO 160 TO GET CORRECT SENSING. ATTEMPTING TO INTERCEPT COURSE FROM NORTHEAST, AFCS WILL ENTER LOC MODE & THEN TURN WEST. WHEN ATTEMPTING TO INTERCEPT FROM NORTHWEST, THE AFCS WILL FLY THROUGH LOCALIZER COURSE.