TM 1-1510-225-10 3B-144 signal,  frequency  and  code  types  being  tracked,  and the current state of receiver tracking. (c)   GPS  Receiver  Autonomous  Integrity Monitoring  (RAIM).    The  FMS-800  provides  the  crew access to a page providing the RAIM control/predictive RAIM for the active GPS receiver.  Selecting the RAIM line  key  on  the  GPS  INAV  page,  Figure  3B -116 and Table 3B -79 accesses these pages. Figure 3B-116.  GPS RAIM  Table 3B-79.  GPS RAIM  NO. DESCRIPTION/FUNCTION 1 Indicates    the    current    state    of    active RAIM solution. 2 Pressing     line     select     key RAIM    will access the RAIM/prediction page. 3 Expected   state   of   RAIM   availability   at destination. 4 Select to disable nuisance RAIM annunciations. 5 Indicates   Estimated   Time   of   Arrival   at destination. 6 Destination of interest for RAIM. The  FMS-800  provides  an  active  RAIM  solution at present position.  By tracking GPS satellite state-of- health  and  orbital  geometry,  the  FMS-800  is  capable of  determining  when  the   GPS  navigation  solution  is degraded  or  suspect  due  to  satellite  failures.  If  the GPS receiver is unable to provide a RAIM solution due to   satellite   tracking   problems   or   problems   with   the satellite constellation geometry, a No RAIM annunciation   is   shown   to   inform   the   crew   of   the absence   of   RAIM   protection.      During   a   NO   RAIM period, the GPS navigation solution may be acceptable   but   the   integrity   of   that   solution   will   be indeterminate.  During normal GPS navigation with an active  RAIM  solution,  if  the  GPS  receiver  determines that  there  is  an  inconsistency  in  the  GPS  navigation solution,  a  RAIM  alert  will  be  provided  to  inform  the crew  of  a  degraded  GPS  navigation  solution.    When an   alert   is   indicated,   the   crew   should   compare   the GPS   based   navigation   solution   with  other  available sensors  (INU,  TACAN,  and  VOR/DME)  to  ensure  the GPS navigational accuracy is acceptable. If unacceptable,   select   a   non-GPS   based   navigation solution on the lateral steer page, Figure 3B-116, until the integrity of the GPS navigation solution is restored. The  current  state  of  the  GPS  RAIM  solution  is provided on the Primary GPS INAV page as follows: 1.   NO  RAIM  when  RAIM  processing is unavailable. 2.   RAIM ACT when RAIM processing is actively performing integrity checks. 3.   RAIM WRN when RAIM has detected an inconsistency. The    line    select    key    next    to    RAIM    on    the RAIM/prediction  page  will  enable  or  disable  the  RAIM annunciations.          When OFF    is     selected,     RAIM annunciations   are   inhibited   and   the   pilot   advisories regarding    GPS    integrity    performance    will    be   only available on the GPS INAV page.  RAIM annunciations should only be disabled if a failure is suspected in the GPS receiver causing nuisance annunciations.   Annunciations will be automatically re-enabled whenever   the   FMS   is   powered   on   or   enters   the terminal area. To request the availability of approach RAIM at a destination airport, first enter the identifier of the airport in the top line of the RAIM/PREDICTION page.  Then enter   the   Expected   Time   of   Arrival   (ETA)   in   UTC.   After  performing  the  predicted  calculation,  the  FMS- 800  will  display  the  availability  of  approach  RAIM  on the page information line.  This availability applies to a period  from  15  minutes  prior  to  the  entered  ETA  until 15 minutes after the ETA.  A predictive RAIM solution only provides  an  indication  of  the  availability  of  RAIM protection that is expected at the destination based on