TM 1-1510-218-10 3B-12 If another channel is to be reset, use the smaller concentric  knob  to  select  the  channel  and  repeat  the steps. 7.     To  return  to  an  operating  mode, push the PGM button. 3B-10.  EMERGENCY LOCATOR TRANSMITTER. a.     Description.        An    automatic    or    manually activated    Emergency    Locator    Transmitter    (ELT)    is located     in     the     right     side     of     the     fuselage     at approximately  FS  340.00.    The  associated  antenna is mounted   on   top   of   the   aft   fuselage   at   the   same location,  Figure  2-1, Sheet 2.  An access hole with a spring-loaded  cover  is  located  in  the  right  fuselage skin  adjacent  to  the  transmitter,  enabling  a  downed pilot to manually initiate, terminate, or reset the ELT to an   armed   mode.      Self-contained   batteries   provide operation for a minimum of 48 hours. The transmitter contains an impact G switch that automatically activates the transmitter following a 3 to 7 G impact along the flight axis of the aircraft.  When activated, it will simultaneously radiate omni-directional RF signals on the international distress frequencies of 121.5    and    243.0    MHz.        The    radiated    signal    is modulated with an audio swept tone. b.    Controls and Functions. (1)   ON / ARM / OFF Switch. (a)   ON. Turns set on, initiating emergency signal transmissions. (b)   ARM .   Establishes a readiness state to   start   automatic   emergency   signal   transmissions when the force of impact exceeds a preset threshold. (c)   OFF.  Turns set off. Section III.  NAVIGATION 3B-11.  DESCRIPTION. The overall navigation equipment group provides the  pilot  and  copilot  with  the  instrumentation  required to establish and maintain an accurate flight course and position   and   to   make   an   approach   on   instruments under    Instrument    Meteorological    Conditions    (IMC).   The   navigation  configuration  includes  equipment  for determining  attitude,  position,  destination  range  and bearing, heading reference, and groundspeed. 3B-12.  RADIO MAGNETIC INDICATORS (RMI). a.     Description.      Two   identical   KNI-582   RMI indicators  are  installed.    Refer  to  Figure  3B-5.  Each RMI    provides    aircraft    heading    and    radio    bearing information to/from a VOR, TACAN or ADF facility.  A selector   switch   on   the   RMI   allows   the   operator   to select  either  #1  ADF  and  #1  VOR  or  #1  ADF  and TACAN  for  single  needle  display.    The  double needle always  points  to  the  #2  ADF  or  #2  VOR  bearing  as selected by the double needle switch.  The pilot's RMI is  protected  by  a  1-ampere circuit breaker, placarded #1 RMI.  The copilot's RMI is protected by a 1-ampere circuit    breaker,    placarded     #2    RMI.        Both    circuit breakers  are  located  on  the  overhead  circuit  breaker panel, Figure 2-16, Sheet 3. b.    Controls and Functions. (1)   Warning Flag.  Indicates loss of heading signal, or that bearing information is unreliable. (2)   Compass     Card.          Gyro     stabilized     to indicate aircraft heading and bearing information. 1.  Warning Flag 2.  Compass Card 3.  Heading Index 4.  Double Needle Pointer 5.  Single Needle Pointer 6.  Double Needle Switch 7.  Single Needle Switch Figure 3B-5.  Radio Magnetic Indicator (RMI) (3)   Heading    Index.        Reference    point    for aircraft heading.