TM 55-1510-219-10 d. Normal Operation. (1) To align. 1.    Compass    GYRO        SLAVE/FREE switch SLAVE. 2.    Compass  INCREASE/  DECREASE switch   Hold   switch   momentarily   in the     direction     desired,     and     then release.    This  will  place  system  in fast erect mode.  The gyro will then erect  at  approximately  30  degrees per minute.  While in the fast erect mode, the HEADING flag (HSI) will be  in  view.    When  the  HEADING flag retracts from view, the heading displayed     will     be     the     magnetic heading. (2) To determine magnetic heading. 1.    Compass    GYRO/SLAVE        FREE switch SLAVE. 2.    RMI rotating heading dial (compass card) Read heading. (3) To determine directional gyro heading. 1.       Compass   GYRO/SLAVE      FREE switch-FREE. 2.    Compass  INCREASE/  DECREASE switch  Hold  until  the  RMI  compass card aligns with the magnetic heading, then release. 3.    Read   heading.      The   heading   will agree with the appropriate HSI. e. Shutdown.      Both   compass   systems   are   shut down  when  the  inverter  switch  is  turned  off.    (If  either system is ON, both compass sets will be energized.) 3-23.  VOR/LOC NAVIGATION SYSTEM. a. Description.    The  aircraft  is  equipped  with  two VOR systems which are controlled by the NAV-I NAV-2 control panel located in the pedestal (fig.  2-11). Either   VOR   can   direct   input   signals   to   the   flight director indicator.  Controls are shown in figure 315. Each   VOR   system   includes   independent   receiver units  for  VOR/LOC  and  glideslope  (GS).    Each  VOR receiver   provides   a   VOR   input   to   a   respective   RMI indicator   and   VOR   and   localizer   data   to   the   flight director.    Each  glideslope  receiver  sends  GS  flag  and pointer deviation information to the flight director. VOR/LOC   indicators   may   be   used   for   navigation during  manual  control  of  the  aircraft,  or  the  autopilot may  be  coupled  to  the  VOR  system,  accepting  VOR inputs to the autopilot computer. The pilot's unit (VOR 1) is a navigation radio system which    receives    and    interprets    VHF    Omnidirectional Radio   Range   (VOR)   signals,   localizer   (LOC)   signals, glideslope   signals,   and   marker   beacon   signals.      The system   operates   in   a   VOR/LOC   frequency   range   of 108.00 to 117.95 Mhz.  Glideslope frequencies (329.15 to  335.00  Mhz)  are  paired  with  LOC  frequencies,  and are  automatically  selected  when  LOC  frequencies  are selected.        LOC    frequencies    are    those    frequencies between 108.00 and 112.00 Mhz that end in odd tenths (108.1, 109.3, 109.5, etc.).  The marker beacon receiver operates at 75 Mhz and is not tuneable. VOR  2  is  similar  to  VOR  1  except  VOR  2  cannot receive or interpret marker beacon signals. Each  VOR  system  provides  course  deviation  and glide  path  data,  which  can  be  switched  either  to  the copilot's   HSI   or   to   the   autopilot   flight   computer   and pilot's  HSI,  or  both.    The  audio  outputs  of  VOR  1  and VOR 2 systems are supplied to the NAV control, on the audio control panels.  VOR 1 bearing data is supplied to the    single    needle    pointer    on    both    Radio    Magnetic Indicators.      VOR   2   bearing   data   is   supplied   to   the double-needle pointer on both Radio Magnetic Indicators. Both   systems   use   a   single   VOR/LOC   antenna, located on the vertical stabilizer, and a single glideslope antenna, located in the radome.  VOR 1 uses a marker beacon antenna located on the underside of the forward fuselage. The  VOR  1  system  is  protected  by  the  2-ampere VOR  #1  and  35-ampere  AVIONICS  MASTER  PWR  #1 circuit  breaker  on  the  overhead  circuit  breaker  panel (fig.    2-26).    The  VOR  2  system  is  protected  by  the  2- ampere  VOR  #2  and  35-ampere  AVIONICS  MASTER PWR #2 circuit breakers on the overhead circuit breaker panel. 3-26