YD BARO ARM AP FD HDG NAV REV ALT APR A L T S E L DN UP FT OBS BS 0 9 18 27 3 33 24 21 15 12 30 6 TO N A V SET Knobs on the autopilot control panel can be used  to enter assigned altitudes and vertical speeds. The OBS knob on the  CDI is used to specify  target courses. Th CD  ta A heading knob on the direction indicator is used to specify target headings. BRT DIM 29.92" 5000 FT Range View Aux OFF Bearing GPS2 Nav GPS1 Baro Set 29.92" VSI Bug 0 FPM Alt Bug 5000 FT Hdg Bug 270° Hdg Sync Range View OAT TAS GS 7°C 143 KTS 135 KTS BDL BRG 264° 32.8 NM 00:14:34 KHPN BRG 234° 96.4nm 00:42:50 5200 5100 4900 50 40 20 00 160 150 140 130 14 4 3 2 20 10 10 20 20 10 10 20 20 10 5 0 -20 -10 -5 268 ° 332 °  / 12 Vertical speed selection Altimeter setting Altitude Alt itu de Heading Vertical speed indicator This primary flight display offers separate windows used to input course, heading, altitude, and vertical speed targets. 4-3 Figure 4-2. Entering goals on a primary flight display. Figure 4-1. A simple autopilot. Primary flight displays (PFDs)  often integrate all controls  that allow modes to be entered for the autopilot. The PFD  shown in  Figure 4-2  offers knobs that allow you to enter  modes without turning attention away from the primary flight  instruments. Modes entered using the controls on a PFD are  transferred to the autopilot. Engagement of Autopilot Function Verification of Autopilot Function Engagement Every autopilot offers a collection of buttons that allow you  to choose and engage autopilot modes and functions. Buttons  used to engage autopilot modes appear along the bottom  of the autopilot shown in  Figure 4-1.  The system shown  in  Figure 4-3  does not use a separate device for autopilot  controls; it integrates the autopilot function buttons into  another cockpit display. It is very important to verify that an autopilot mode has  engaged, and the aircraft is tracking the intended flight 