GFC 600 installed with a GDU 620 and dual Garmin GNS/GTN products are affected.
When the pilot’s PFD CDI source is selected to display VOR/LOC 2 the following may occur:
- VOR/LOC mode may appear to be armed but the autopilot may not capture and engage VOR/LOC mode when intercepting the VOR/LOC 2 course.
- If the frequency or course for VOR/LOC 1 is changed while coupled to VOR/LOC 2, the autopilot may deviate from the VOR/LOC 2 course in an attempt to couple to the VOR/LOC 1 source.
Navigation information shown on the displays is correct, and the HSI/CDI operates correctly in all cases.
Coupling to GPS 2 is not affected.
Do not use the VOR/LOC 2 source on the pilot’s PFD for coupling to the autopilot. If it is necessary to couple to VOR/LOC 2 in abnormal/emergency operations, closely monitor the autopilot modes and course deviation to ensure proper operation.
Garmin will address this issue in future software releases.