TM 1-1510-218-10 3A-37 wings   level   and   7   nose   up   climb attitude. NOTE Go-around  mode  can  be  selected  any  time after selecting APPR mode. 2.   HDG selector switch  – Press, after aircraft cleanup,   go-around  power  settings,  and airspeed are established. m.   Back-Course Approach. 1.   VOR receiver – Tune appropriate frequency. 2.   COURSE knob  – Set front course inbound runway heading in  COURSE window. 3.   HDG    knob    –    Set    heading    marker    to desired intercept angle. 4.   HDG  selector  switch   –  Press.    Observe that  HDG  lamp  illuminates  autopilot/flight director annunciator panel. 5.   B/C selector switch – Press.  Observe that BACK  LOC and   NAV   ARM   annunciator lamps    illuminate    autopilot/flight    director annunciator  panel,  indicating  that  system is  armed  for  back  localizer  capture.    Any previously    selected    vertical    mode    will cancel. 6.   NAV CAP annunciator lamp will illuminate when  system  has  captured  back  localizer course. 7.   PITCH   control    –   Use   to   establish   and maintain desired rate of descent. n.  Yaw Damper Operation. (1)   The  rudder  channel  of  the  autopilot  may be  selected  separately  for  yaw  damping  by  pressing the  YAW  DAMP  switch  on  the  pedestal.    The  switch face will illuminate when the yaw damper is engaged. (2)   To disengage the yaw damper, press the disconnect   button   on   the   pilot's   or   copilot's   control wheel   to   the   first   detent   or   press   the   YAW   DAMP switch on the pedestal. (3)   Refer to Emergency Procedures for other means of disconnecting the yaw damper. o.  Disconnecting Autopilot.  The autopilot may be disconnected by any of the following actions. 1.   Pressing DISC TRIM/AP YD switch located   on   the   outboard   horn   of   either control wheel to the first detent. 2.   Placing   the    ENG   /   DIS   switch   on   the autopilot  mode  selector  panel  to  the   DIS position. Section IV.  RADAR AND TRANSPONDER 3A-28.  DESCRIPTION. The    radar    and    transponder    group    provides identification,   position,   emergency   tracking   system, and radar system to locate weather areas. 3A-29.  DIGITAL    WEATHER    RADAR    (RDR   2000) SYSTEM. a.   Description.    The  RDR  2000  color  weather radar   not   only   displays   in-flight   weather,   but   also permits  incorporation  of  the  KGR-358  radar  graphics unit.      The   color   weather   radar   is   used   to   detect significant   enroute   weather   formations   to   preclude undesirable    penetration    of    heavy    weather    and    its usually   associated   turbulence.      The   weather   radar system   provides   a   320   nm   display,   with   a   240 nm weather   avoidance   range   plus   weather   penetration advantages.  With the radar graphics unit in the NAV mode,   navigation   information   is   integrated   with   the weather   display.      The   phased   array   antenna   (flat plate),   located   in   the   nose   of   the   aircraft,   is   fully stabilized to compensate for aircraft pitch and roll.  The antenna provides a full 90° scan angle, ±15° tilt, and a 4-microsecond pulse width in both weather and ground mapping modes. Extended Sensitivity Time Control (STC) increases the displayed intensity of storms outside the normal  STC  range.    Extended  STC  relates  the  storm intensity  to  its  distance  and  assigns  a  corresponding color.      As   a   result,   the   display   presents   a   more accurate picture of storm intensity. Weather   systems   are   displayed   as   5   colors, including black, depicting rainfall intensity overlaid with range rings.  Bearing marks at dead ahead and 20° on either   side,   aids   the   pilot   in   judging   the   bearing   of storms and necessary heading changes. With  radar  graphics  interfaced,  activate  a  circle mode by pressing the page button located on the radar graphics  control  panel.    Functional  operation  in  this mode is the same as in the standard display mode and