1. Remote, Panel-Mounted Annunciator. Provides complete information on all modes of operation, including failure warnings. Annunciates 3-level gain scheduling for enroute course intercept and tracking; NAV/CAP indicates max. sensitivity for course capture, NAV/CAP and SOFT for medium sensitivity to establish track and crosswind correction, and NAV/SOFT for lowest level for smooth enroute trackiing and station passage.
2. HDG (heading) Mode-Heading Preselect and Hold. When HDG and NAV activated simultaneously, enables dual mode intercept - autopilot operates in heading mode to automatically intercept and track selected course or localizer; at this point HDG extinguishes. *
3. NAV (coupled navigation) mode. Intercept and track VOR/GPS enroute and LOC/VOR/GPS approach signals. System automatically selects APR (approach) mode when using a localizer signal. Flashing NAV or REV annunciates course deviation of 50% or more.
4. Mode Selector Buttons. To enable or disable FD (if equipped) and AP/HDG (heading), NAV (coupled tracking VOR/LOC/GPS, enroute or approach), REV (LOC back courses), VS (vertical speed) command, ALT (altitude) hold, YD (yaw damper, if equipped), and UP or DOWN vertical speed command buttons. Display annunciates button activation. TRIM used in manual pitch trim mode; UP/DN annunciates out-of-trim conditions.
5. Pitch Modes. Include; VS, indicating vertical speed command has been selected; ALT, indicating altitude hold is engaged, capturing existing altitude; and GS, indicating glideslope coupling is armed and/or active.
6. Up/Down Buttons. Used to command vertical speed changes - 160 FPM change for every second the button is depressed. In altitude hold mode, altitude can be adjusted (trimmed in increments using the UP/DN commands).

* Operational if heading system is installed and active.