TM 1-1510-225-10 3C-24 director/air  data  system  that  has  a  full  complement  of horizontal  and  vertical  flight  guidance  modes.    These include all radio guidance modes, and air data oriented vertical modes. When engaged and coupled to the flight director commands,  the  system  will  control  the  aircraft  using the same commands displayed on the attitude director indicator.      When   engaged   and   uncoupled   from   the flight    director    commands,    manual    pitch    and    roll commands  may  be  inserted  using  the  Touch  Control Steering   (TCS)   or   the   pitch   wheel   and   turn   knob.   System limits are shown in Table 3C-1. When the autopilot is coupled, the flight director instruments act as a means to monitor the performance of the autopilot.  When the autopilot is not engaged,  the  same  modes  of  operation  are  available for flight director only.  The pilot maneuvers the aircraft to  satisfy  the  FD  commands,  as  does  the  autopilot when it is engaged. NOTE The autopilot will disengage when transferring  between  the  pilot  and  copilot flight directors.  b.    Autopilot  Flight  Director  Transfer  Panel.   Refer to Figure 3C-11.  A panel containing an alternate action    autopilot    and    flight    director    transfer    switch, placarded  AP  FD  1 and   AP  FD  2,  is  located  on  the pedestal   extension.      This   switch   is   used   to   select which   autopilot   flight   director   computer   controls   the aircraft   flight   servos.      If   AP   FD   2  is  selected,  the annunciators placarded   AP  FLT  DIR  NO.  2, located above  the  pilot's  and  copilot's  ADI's,  will  illuminate  to alert  both  pilots  that  the  No.  2  autopilot  flight  director computer is controlling the aircraft.  The  NO. 1 AP FD is not annunciated. NOTE If  VOR  is  selected  on  both  the  pilot  and copilot  HSI's,  the  DME  readout  and  Radar NAV  display  will  accompany  the  selected autopilot flight director. c.     Air    Data    Computer.        A    digital    air    data computer, located in the forward avionics compartment, provides the altitude information for the pilots'   servoed   altimeter,   altitude   alerter,   flight   data recorder,     and     transponder.          The     computer     also provides altitude and airspeed hold function data to the flight  control  computers,  generates  and  provides  total airspeed, static/total air temperature to the  TAS / SAT /TAT indicator with inputs from the airspeed/ temperature probe.  The air data computer receives 28 Vdc  power  through,  and  is  protected  by,  a  2-ampere circuit    breaker,    placarded    AIR    DATA    ENCODER, located  in  the  avionics  section  of  the  circuit  breaker panel.  All air data computer functions are automatic in nature and require no flight crew action. 1.  Pilot’s CDI Failure Warning Test Switch 2.  AP Flight Director Transfer Switch 3.  Crash Data Recorder Fail Light 4.  Copilot’s CDI Failure Warning Test Switch Figure 3C-11.  Autopilot/Flight Director Transfer Panel