TM 1-1520-218-10 3C-189 Table 3C-102.  System Failure Indications  (Continued) SUBSYSTEM FAILURE INDICATION POSSIBLE EFFECTS Bit 12 Antenna Fault V/UHF   radio   receive   or   transmit   capability   may   be inoperative or have impaired capability. Bit 13 Radio Fault V/UHF   radio   may   be   inoperative   or   have   impaired capability. Bit 14 Equipment Fault V/UHF   radio   may   be   inoperative   or   have   impaired capability. Verify other faults for functional degradation. Bit 15 MIL-STD -1553 Terminal Status V/UHF  radio  may  be  unable  to  communicate  on  the 1553 bus. Bit 16 V/UHF Radio Subsystem Status V/UHF   radio   may   be   inoperative   or   have   impaired capability. BUS MIL-STD -1553B Bus Status NGO-A:  V/UHF radio is not responding on the  A bus. NGO-B:  V/UHF radio is not responding on the B bus. NGO-T:      V/UHF   radio   is   not   responding   on   either 1553 bus. w.  Miscellaneous Functions.  (1)   Miscellaneous  Functions.    The  FMS-800 also   provides   the   following   functions   that   are   not covered in the previous sections. (a)    Timers.      Three   independent   stop- watch  lap  counters  are  available  complete  with  time- out annunciations. (b)    Model  Aircraft.    The  model  aircraft inserts  heading,  altitude,  wind,  and  true  airspeed  data into the navigation equations in order to provide a flight simulation capability. (2)   Timer   Function.      Access   the   timers   by pressing the   TIMERS  line  select  key  on  the  Index  1 page.  The three timers can be used independently to display   elapsed   time   (counting   up   to   23:59:59)   or countdown  to  00:00:00.    They  can  be  stopped  at  any time.  Refer to Figure 3C-140 and Table 3C-103.