TM 55-1510-219-10 2.    RMI    select    switch    (side    panels) TACAN. 3.    Pilot's Course indicator switch TACAN. 4.    Mode switch (X/Y) As required. 5.    TACAN control panel Select desired channel. 6.    Wait 5 seconds for signal acquisition and lock-on. 7.    Insure that audio station identification signal is correct for the ground station selected. 8.    Bearing    pointer    on    RMI        Read bearing heading to station. 9.    COURSE    knob    (pilot's    HSI)    Set course desired. 10.    Course         deviation         bar      (pilot's HSI)Read   deviation   from   selected course.      Course   arrow   will   show wind    correction    angle    when    the course deviation bar is centered and the  aircraft  is  tracking  the  selected course. 11.    TACAN  indicator Read range (NM). 12.    To      determine    course    TO      or course    FROM    a    TACAN    station, rotate course knob (pilot's HSI) until course deviation bar is centered and the   TO/FROM   flag   reads   TO   or FROM. 13.    To      use      TACAN      during      pilot- controlled  flight,  control  aircraft  by manual controls, responding to information  displayed  on  the  flight director,   RMI,   TACAN,   and   other instruments. 14.    To  use  TACAN  with  the  autopilot, depress  A/P  ENGAGE  and  monitor autopilot performance on flight director, RMI, and TACAN indicators.        Verify    adherence    to preset    heading    and    course,    and confirm the execution of displayed steering commands. NOTE The TACAN ground speed reading will   be   accurate   only   when   the aircraft  is  on  a  course  directly  to or from the TACAN station.  When headed away from the station, the TACAN  indicator  minutes  reading will be in error. (3) System test. 1.    TEST  pushbutton  Press  and hold. 2.    Range indicator Check for an indication    of    0.0   ± 0.1    nautical miles. 3.    Pilot's     COURSE     selector     switch Select TACAN. 4.    Pilot's   RMI   selector   switch   Select TACAN. 5.    RMI   double   needle   Check   for   an indication of 180°  ± 2°. 6.    HSI   course   selector   Turn   to   180° and   adjust   slowly   until   the   course deviation  bar  is  centered.    The  bar should   center   between   a   selected course of 178°  to 182°. 7.    HSI course selector Turn the selector    +    10° from    the    setting achieved  in  step  6,  and  check  that course deviation bar is located over the far left 10°  dot. 8.    HSI course selector Turn the selector  -10°  from  setting  achieved in   step   6,   and   check   that   course deviation bar is located over the far right 10°  dot. 9.    TO-FROM  indicator  Check  that  TO is indicated. 10.    TEST pushbutton Release. (4) Shutdown.  Turn ON/OFF switch OFF. 3-27.  AUTOMATIC FLIGHT CONTROL SYSTEM. a. Description.        The    AP-106    is    an    integrated autopilot/flight director system that provides the following: Heading mode Navigation mode Approach     mode     with     automatic     glideslope capture and track Altitude hold mode Back course localizer mode Go-around mode 3-33