TM 1-1510-225-10 3B-145 the current orbital characteristics of the GPS constellation.    It  does  not  provide  an  actual  integrity determination at the desired location. (d)   Selective Availability/Antispoofing Control  Page.      The   FMS-800  provides  access  to  a GPS  Selective  Availability/Antispoofing  control  page.   From   the   IDX   page,   select   SA/AS   to   access   the SA/AS  control.   From  this  page,  the  current  status  of GPS receiver keying is displayed,  with  two  selections for mission duration and SA/AS mode selection.  GPS mission  duration  is  entered  in  days  and  defines  the expected  length  of  an  aircraft  mission  requiring  GPS keys.  If more keys are loaded into the GPS receiver than  are  needed,  the  entry of duration will zeroize the excess  keys.    If  duration  exceeds  the  availability  of keys,   the   FMS   will   annunciate   the   need   to   load additional keys.  The duration displayed on the page is the  current  duration  of  the  keys  loaded  into  the  GPS receiver. NOTE When the GPS receiver is configured for Y- Only mode and no keys are loaded into the GPS     receiver     to     decrypt     the     satellite telemetry, RAIM processing is disabled and RAIM protection will be unavailable. The  SA/AS  mode  selection  allows  the  operator to select between a MIXED mode satellite constellation   with   both   keyed   and   unkeyed   satellite transmissions, or restrict the receiver to Y-only keyed satellites,  excluding  the  use  of  satellites  not  currently keyed for P(Y) code encryption. s.    Navigation Radio Information. (1)   Navigation   Radio   Information   Overview.   The   FMS-800  provides  navigation  radio  information upon valid entry of an airport identifier.  The crew may access  the  Navigation  Information  Radio  page  via  the NAV function key on the CDU.  Refer to Figure 3B-117 and Table 3B -80. Selection   of   the   airport   identifier,   with   a   valid airport  ID  in  the  scratchpad  and  loaded  on  the  data cartridge, will load the airport navigation information of that airport from the data cartridge.  The entered ID will also be entered on the Communications Radio page. Figure 3B-117.  Navigation Radio Information Page Table 3B-80.  Navigation Radio Information Page NO. DESCRIPTION/FUNCTION 1 Pressing   the   function   key   NAV   will access the Navigation Radio Information page. 2 Indicates the frequency of the recommended airport navigation aid. 3 Indicates page 1 of 4. 4 The NDB frequency. 5 The frequency of the navigation aid. 6 The runway ID. 7 Type of navigation aid. 8 When    a    valid    airport    ID    is    in    the scratchpad, LS1 retrieves the navigation  information  for  that  ID  from the data cartridge. 9 The airport ID. (2)   Navigation Radio Information Page Functionality.    Data  lines,  2  through  4,  displays  the following data: 1.   The    name    of    the    approach    which includes  the  type  of  nav  aid  and  the runway.    The  possible  types  of  nav aids are ILS, LOC, BC (Back Course) for  an  LOC,  BC,  LDA  (Localizer  type Directional   Aid),   or   SDF   (Simplified Directional Facility). 2.   The frequency of the nav aid.