Heading Sync Mode is activated when the AP/FD is laterally coupled to a Navigation or Approach Mode and the pilot pushes the HDG/TRK Knob. When activated, ‘SYNC’ will be displayed in the HDG Indicator Button on the PFW.

In Heading Sync Mode the Selected Heading Bug will remain continuously synchronized to aircraft heading as it changes due to winds or course changes, eliminating the need to sync the bug any time a turn is completed. Should the flight director lateral mode uncouple due to a fault or user change, the bug will already be set to continue along the current heading, if desired (i.e., by pressing the HDG Key to select HDG Mode).

If Heading Sync Mode is active and the NAV source changes, the system will remain in Heading Sync Mode. Heading Sync Mode is canceled if any of the following occur: