TM 1-1510-218-10 3B-58 navigation   cross-reference.      The   display   colors   are changed  in  the  MAP  mode  as  follows:  green  to  cyan, yellow  stays  the  same,  red  to  magenta,  magenta  to blue.  When using the MAP mode, the gain control is used to adjust the prominence of ground features. (2)   RANGE   Selector   Control   Knob.      The range  selector  knob  selects  for  displays,  range  at   5, 10, 20, 40, 80,  160, and   320  nm.    This  enables  the pilot to select the displayed distance for most weather conditions that exist.  There are four range calibration rings on each range setting with numerical read-out of their  range  in  nautical  miles.    In  addition  to  the  range rings, bearing markers are positioned dead ahead and 20°  to  either  side  of  the  aircraft  heading  for  use  in judging   the   storm   bearing   and   necessary   heading changes. (3)   Weather    Radar    Control    Indicator   TILT Control  Knob.    The   TILT  knob  is  used  to  adjust  the radar  antenna  angle  +  12°,  relative  to  the  horizon.   Proper  tilt  adjustment  is  one  of  the  most  important factors   in   obtaining   optimum   use   from   the   weather radar.  Too high an angle will pass the majority of the radar beam above the storm cell, particularly when the storm is a great distance away.  Too low an antenna tilt  will  clutter  the  indicator  with  ground  returns.    The maximum   distance   at   which   ground   clutter   can   be obtained will depend greatly on the terrain and aircraft altitude.    The  tilt  setting  is  displayed  in  the  top  right corner of the screen.  When the  STBY switch is in the ON position the designation is replaced by STAB. (4)   BRIGHT  /  GAIN  /  MAX  Control Knobs.   These  knobs  control  display  brightness  and  manual adjustment of gain.  Brightness of the display screen is fully  adjustable  to  compensate  for  a  range  of  ambient light    levels,    while    automatically    maintaining    equal brightness     between     the     three     colors     displayed.   Likewise, the gain control can be manually adjusted in both  weather  and  ground  mapping  modes  to  provide maximum flexibility in target interpretation.  Whenever the gain is varied from the preset maximum level, the screen will annunciate VAR to remind the pilot to reset the gain for standard intensity levels. (5)   STBY  OFF  /  ON  Selector  Switch.    The selector knob permits the pilot to select gyro-stabilized control   of   the   weather   radar   system.      In   the   ON position,  the  radar's  antenna  scan  is  kept  parallel  to the    horizon    and    at    the    same    relative    tilt    angle previously    selected.        The    displayed    view    is    kept straight and level, despite changes in aircraft pitch and roll,   thus   preventing   ground   clutter   from   wiping   out potential weather targets. c.     Weather Radar System Operation. Never operate the weather radar in the WX, WXT,  or  MAP  modes  on  the  ground  when personnel  are  forward  of  the  aircraft  wing and    within    5    feet    of    the    aircraft    nose.   Failure to observe this warning may result in permanent damage to the eyes and other body organs of those persons.  NOTE To increase the solid state circuitry reliability,    it    is    recommended    that    the aircraft engines be started before applying power to the weather radar system. (1)   Turn    On    Procedure.         Mode    selector switch – Turn clockwise past detent to SBY position. NOTE Warmup period is approximately 10  seconds.  (2)   Operating Procedure. 1.   Mode selector switch  –  TEST.  Verify that all four colors are present. NOTE If TEST mode is bypassed and WX, WXT, or MAP mode is selected, the display will light up,   and   the   warmup   annunciator   in   the lower    left    corner    will    illuminate.        The transmitter   will   become   operational   after 60  seconds.  2.   Mode   selector   switch   –   SBY   while taxiing  and  until  clear  of  personnel, then as required. (3)   Shutdown Procedure. 1.   Mode selector switch – OFF. 3B-29.  RADAR GRAPHICS. a.     Description.    The  KGR-358  radar  graphics unit  interfaces  with  the  weather  radar  system  (KWX- 58),    and    receives    navigation    data    from    the    flight management system (KNS-660).  The unit can display NAV  1  or  NAV  2   or  both  in  a  weather  overlay,  or  as navigation  information  only  display.    In  addition,  NAV information  can  be  viewed  in  a  360°  (circle)  display with   weather   in   the   top   90°   sector.      Two   checklist modes    are    also    provided    for    complete    checklist capability when utilizing the pocket terminal. WARNING