TM 1-1510-225-10 3B-58 In  addition  to  the  annunciations  and  scratchpad messages   listed   in   Table   3B-9,   the   FMS-800  will provide  the  additional  alerts  listed  in  Table  3B-11 to inform   the   flight   crew   of   various   flight   conditions.   These   alerts   may   appear   either   on   electronic   flight instrument displays or on annunciator light displays. c.   Power Control. (1)   FMS -800  System  Power.      All   FMS-800 units operate from 28 Vdc aircraft essential bus power.   Power  is  provided  through  a  5-ampere  CB  placarded FMSI on the right side circuit breaker panel. (2)   CDU Power Control of Associated Subsystems.  Using the CDU, the crew can control the power on/off state of the avionic subsystems managed by the FMS-800.  Whenever a unit is powered off, the CDU shows dashes for the data normally supplied by that  unit.    Attempts  by  the  flight  crew  to  control  that subsystem   is   inhibited   and   results   in   a    POWER message in the scratchpad. (3)   CDU    Power    Control    Procedures.       On Index  1  page,  pressing  the    POWER  line  select  key displays   the   Master   Power   page.    Refer  to  Figure 3B-20   and   Table   3B-12.      This   page   permits   on/off control    of    individual    communication    or    navigation radios.    It  also  provides a  RADIO MASTER selection which turns the controlled radio on or off. Table 3B-11.  Additional Alerts TYPE OF ALERT INITIATING CONDITION Waypoint Within waypoint alert prior to waypoint sequence when in EN ROUTE and OCEANIC  sensitivity  modes.    Ten  seconds  prior  to  waypoint  sequence when in TERMINAL and APPROACH sensitivity modes. Terminal FMS in Terminal Mode. Approach FMS in Transition or Approach Mode. RAIM Alert GPS RAIM function detects error (RAIM Warn). Parallel Track Parallel offset has been applied to  the active flight plan. CDU MSG Alert Light The   MSG   Alert   column   in   this   table   lists   which   annunciations   are accompanied by a message alert. No     INPUT     (with     a     blank screen) A  bus  terminal  has  taken  control  of  the  MIL-STD -1553  bus,  but  is  not responding   as  a  bus  controller.    Activate  the  bus -split  switch  to  split operations and isolate the faulty device on the 1553 bus. Or CDU  has  experienced  a  catastrophic  failure  of  the  CDU  chip  or  a  flash memory  fault  and  should  not  be  used  for  navigation  because  navigation data   may   be   corrupted   and   extremely   unreliable.      Switch   to   backup navigation means immediately. NOTE A  power  reset  of  the  CDU  may  restore  full  operation  if  the failure   was   caused   by   the   CDU’s   misreading   its   terminal address   during   cyclic   power   fluctuations.    If  this  occurs, cross check all navigation data until you are ensured that the primary FMS-800 system is operating properly.