TM 1-1510-225-10 3A-72 – Press and hold the   BRT key to dim the display.  Release the   BRT key.  – Press  and  hold  again  to  brighten  the display. NOTE The display may be changed instantaneously   to   full   bright   from   any brightness  level  by  momentarily  pressing the ON key 3.   Parallax – If the line select keys do not align  with  the  line  select  prompts  on the CRT, adjust as follows. a.     Press   the   BRT   key.      If   the screen  begins  to  dim,  release the   BRT   key.      Press   again and    hold    while    momentarily pressing the D key, then the P  key. b.     Using the  U (up) or   D (down) key,  adjust  the  display  to  the desired alignment. c. Press any key when alignment is complete. 4.   ON key – Press and hold for 3 seconds to turn system off. (2)   Initialization Page.   The Initialization page gives the pilot access to the required initialization data (date,  GMT,  and  position).    Following  confirmation  or entry of this data, the page disappears and cannot be retrieved  unless  system  power  is  removed  and  then restored.    GMT  and  date  are  available  for  display in the PLAN section and position is available in the NAV section. (a)   DATE and GMT. 1.   DATE   –   Insert,   if   required   (day/ month/year digits only). NOTE DATE  and  GMT  are  continuously  updated while the system is off.  When the system is   turned   on,   the   DATE   and   GMT   will appear   on   the   Initialization   page.      If   the DATE  is  incorrect,  move  the  cursor  to  the DATE field to update manually. Enter    a    leading    0    for    months    with    a numerical value of less than 10. 2.     ENTER    key    –    Press    to    verify display. 3.     GMT   –   Insert   if   required  (hours and minutes). 4.     IDENT   –    Verify    position.        The appropriate airport ICAO identifier or  latitude  and  longitude  may  be inserted at this point NOTE After  a  brief  delay,  this  field  normally  pre- fills with the identifier of the airport closest to the aircraft's  present  position  at  power- up, provided the aircraft's real position and system  position  were  the  same  at  system shutdown. 5.     ENTER    key    –    Press    to    verify display. 6.     MSG key – Press to verify database  expiration  date  and  to review   other   system   messages.   Continue   pressing    MSG   key   to review  sensor  messages  and  to return to Initialization page. (3)   Departure     Position.      The departure position    should    be    the    runway    threshold.        The departure  position  may  be  entered  using  either  the field identifier or the latitude and  longitude in the POS field. (4)   Entering  Departure  Position  Using  ICAO Identifier Field. 1.   Line  select  key    –   Press   to   position cursor over desired field (if required). 2.   Desired    number    and    letter    keys   – Press  until  desired  identifier  appears in display. 3.   ENTER key – Press. 4.   Airport Reference Point (ARP) coordinates  –  Will  be  displayed  with continuation records listed below. 5.   Airport    continuation    records     –     To access,  position  the  cursor  over  the departure  runway  identifier.    This  will automatically   result   in   the   display  of the departure runway threshold in the waypoint   field,   the   departure   airport will  replace  the  ARP  field,  and  POS