Figure 4-5. A flight director. Follow Route Common Error: Confusion About Autopilot  Engagement Following a Route Programmed in the FMS Common Error: Blindly Following Flight Director  Cues Using the Flight Director (FD) Flight Director Without Autopilot Flight Director With Autopilot 4-5 It is important to note that the normal navigation function  provides only lateral guidance. It does not attempt to control  the vertical path of the aircraft at any time. You must always  ensure the correct altitude or vertical speed is maintained. Figure 4-6  demonstrates how to use the navigation function to  follow a route programmed into the FMS. With the navigation  function engaged, the FD/auto-pilot steers the aircraft along  the desired course to the active waypoint. Deviations from  the desired course to the new active waypoint are displayed  on the navigation indicator. When the aircraft reaches the  active waypoint, the FMS computer automatically sequences  to the next waypoint in the route, unless waypoint sequencing  is suspended. When the aircraft includes both a flight director and an  autopilot, you may elect to use flight director cues without  engaging the autopilot. It may or may not be possible to use  the autopilot without also engaging the flight director. You  need to be familiar with the system installed. When you  engage the autopilot, it simply follows the cues generated by  the flight director to control the airplane along the selected  lateral and vertical paths. The FD and autopilot systems are designed to work together,  but it is possible to use the flight director without engaging  the autopilot, or the autopilot without the FD, depending  on the installation. Without autopilot engagement, the FD  presents all processed information to the pilot in the form of  command bar cues, but you must manually fly the airplane  to follow these cues to fly the selected flightpath. In effect,  you “tell” the FD what needs to happen and the FD command  bars “tell” you what to do. This adds to your workload, since  you must program the FD for each procedure or maneuver to  be accomplished, while actually flying the aircraft. In many  cases, you will have a decreased workload if you simply  disable the FD and fly using only the flight instruments. The FD/autopilot’s navigation function can be used to guide  the aircraft along the course selected on the navigation  indicator. Since the navigation display in most advanced  avionics cockpits can present indications from a variety of  navigation systems, you can use the autopilot’s navigation  function to follow a route programmed into the FMS using  VOR, global positioning system (GPS), inertial navigation  system (INS), or other navigation data sources. Pilots sometimes become confused about whether or not  flight director cues are being automatically carried out by  the autopilot, or left to be followed manually by the pilot.  Verification of the autopilot mode and engagement status  of the autopilot is a necessary technique for maintaining  awareness of who is flying the aircraft. inputs necessary to achieve the selected targets. To use the  flight director command bars, which are usually shaped as  inverted chevrons, or V-shaped symbols, the pilot simply flies  to the bars. Some older models use crossed bars, leading the  pilot to the selected point. In both types, you simply keep  the aircraft symbol on the attitude indicator aligned with the  command bars, or allow the autopilot to make the actual  control movements to fly the selected track and altitude. The convenience of flight director cues can invite fixation or  overreliance on the part of the pilot. As with all automated  systems, you must remain aware of the overall situation.  Never assume that flight director cues are following a route  or course that is free from error. Rather, be sure to include  navigation instruments and sources in your scan. Remember,  the equipment will usually perform exactly as programmed.  Always compare the displays to ensure that all indications  agree. If in doubt, fly the aircraft to remain on cleared track  and altitude, and reduce automation to as minimal as possible  during the problem processing period. The first priority for  a pilot always is to fly the aircraft. 20 10 20 10 10 10 880 B 050  060  070  080  090  100  110  12 0 0  0 80 8 80  090 1 100 Heading 0 2 1 0 Degrees of attitude Horizon