and the command bar vary by manufacturer. Regardless, the  object is always to fly the aircraft symbol into the command  bar symbol.  [Figure 10-114] The instrument that displays the flight director commands is  known as a flight director indicator (FDI), attitude director  indicator (ADI), or electronic attitude director indicator  (EADI). It may even be referred to as an artificial horizon  with flight director. This display element combines with  the other primary components of the flight director system.  Like an autopilot, these consist of the sensing elements, a  computer, and an interface panel. Integration of navigation features into the attitude indicator is  highly useful. The flight director contributes to this usefulness  by indicating to the pilot how to maneuver the airplane to  navigate a desired course. Selection of the VOR function  on the flight director control panel links the computer to the  omnirange receiver. The pilot selects a desired course and the  flight director displays the bank attitude necessary to intercept  and maintain this course. Allocations for wind drift and  calculation of the intercept angle is performed automatically. Flight director systems vary in complexity and features.  Many have altitude hold, altitude select, pitch hold, and other  features. But flight director systems are designed to offer the  greatest assistance during the instrument approach phase of  flight. ILS localizer and glideslope signals are transmitted  through the receivers to the computer and are presented as  command indications. This allows the pilot to fly the airplane  down the optimum approach path to the runway using the  flight director system. EADIs can be housed in a single instrument housing or  can be part of an electronic instrument display system.  One such system, the electronic flight instrument system  (EFIS), uses a cathode ray tube EADI display driven by a  The concept behind an EADI is to put all data related to the  flight situation in close proximity for easy observation by the  pilot.  [Figure 10-115]  Most EADIs can be switched between  different display screens depending on the preference of the  pilot and the phase of flight. EADIs vary from manufacturer  to manufacturer and aircraft to aircraft. However, most of  the same information is displayed. The EADI is an advanced version of attitude and electric  attitude indicators previously discussed. In addition to  displaying the aircraft’s attitude, numerous other situational  flight parameters are displayed. Most notable are those  that relate to instrument approaches and the flight director  command bars. Annunciation of active systems, such as the  AFCS and navigation systems, is typical. With the altitude hold function engaged, level flight can be  maintained during the maneuvering and procedure turn phase  of an approach. Altitude hold automatically disengages when  the glideslope is intercepted. Once inbound on the localizer,  the command signals of the flight director are maintained in  a centered or zero condition. Interception of the glideslope  causes a downward indication of the command pitch indicator.  Any deviation from the proper glideslope path causes a fly- up or fly-down command indication. The pilot needs only to  keep the airplane symbol fit into the command bar. Electronic Instruments Electronic Attitude Director Indicator (EADI) 20 20 I0 I0 I0 I0 20 20 20 20 I0 I0 I0 I0 20 20 Flight director command bars Airplane symbol Figure 10-114.  The fight director command bar signals the pilot how to steer the aircraft for a maneuver. By flying the aircraft so the  triangular airplane symbol fits into the command bar, the pilot performs the maneuver calculated by the flight director. The instrument  shown on the left is commanding a climb while the airplane is flying straight and level. The instrument on the right shows that the pilot  has accomplished the maneuver.  10-68