TM 1-1510-225-10 3B-200 Figure 3B-159.  Navaid Setup – Select To place the item into one of the six positions on the screen, press the  PLACE  button.  This  places  the data item in the upper left position in the legend area.   To move the item to another position, press the MOVE button.    Each  additional  press  of  the   MOVE  button advances the item counterclockwise.  Refer to Figure 3B-160. Figure 3B-160.  Navaid Setup – Move To set the display position of a highlighted item, press the SET button.  This establishes the position of the  data  item  display  on  the  weather  screens.    After pressing the SET button, the highlight will return to the next data item on the grid.  To return the data item to the  grid  without  setting,  press  the   CANCEL  button.   This   will   return   the   data   item   highlight   to   the   grid.   Since  the  data  item  was  not  set  to  the  legend  area, any  data  item  previously  occupying  the  position  will remain  there.    To  select  additional  data  items,  repeat the sequence of  NEXT to highlight the item,  PLACE it from   the   grid   to   the   legend  area,   MOVE  it  to  the desired  position  on  the  legend  area,  and   SET  it.    To replace  a  data  item  previously  set  in  position,  follow the same sequence.  Pressing the SET button when a highlighted data item is in an occupied legend position causes the new item to replace the previous item. To  erase  an  item  from  the  legend  area,  press NEXT to highlight the blank space on the grid, PLACE it to the legend area, MOVE it in the legend area to the position to be erased, and SET it. Press the   EXIT  button  to  return  to  the  Options Menu.    The  press   MENU  to  return  the  Main  Menu including the weather options. (7)   Error   Messages.    Most  common  errors and malfunctions are indicated on the display screen.   These messages enable service personnel to diagnose    and    correct    the    problem.      If   continued operation  is  possible,  a  message  to  press  any  key  to continue    operation    will    be    displayed.        When    the LORAN  or  GPS  receiver  fails  to  acquire  a  consistent signal  and  is  not  certain  of  its  position,  the  message NAV     FLAG     will     appear     in     place     of     the     CDI.   Navigational  data  will  not  be  displayed  if  the  receiver indicates  a  flag  condition.    In  conditions  where  the LORAN  or  GPS  receiver  determines  its  position  error to be greater than 1.7 nm, a W (warning) will appear next to the affected data items. 3B-36.  GROUND COLLISION AVOIDANCE SYSTEM. The ground collision avoidance system will provide little, if any, warning for flight into precipitous   terrain   approaching   a   sheer wall if there is little gradually rising terrain before reaching the steep terrain. The ground collision avoidance system will provide  no  warning  for  stabilized  descent in  the  landing  configuration  into  terrain, unless the aircraft is following an operating electronic glideslope or a correct minimum descent  altitude  has  been  set  on  the  radio altimeter (activating mode 6). a.   Description. The Ground Collision Avoidance System (GCAS) is provided to aid the flight crew  in  terrain  avoidance.    Figure  3B-161  shows  the ground     collision     avoidance     system     controls     and indicators. WARNING