TM 1-1510-225-10 3C-45 NOTE When    storing    a    frequency,    the    second actuation of the STO button must be done within 5 seconds after selecting the channel number or the first actuation of the STO    button.        If    more    than    5    seconds elapse, the control will revert to the normal modes  of  operation  and  the   second  store command  will  be  interpreted  as  the  first store command. After a frequency has been stored in memory, it will   remain   there   until   changed   by   using   the   STO button.    Memory  is  retained  even  when  the  unit  is turned off for an extended period of time. d.    Normal Operation. (1)   Function  Selection.     Position  the  power and mode switch to ANT, ADF, or TONE (BFO). (2)   Frequency Selection. Using the preceding frequency select procedures, tune the ADF until  the  desired  frequency  is  indicated  in  the  active frequency display and verify the station identifier. (a)  ANT   Function.    Position  the  power and  mode  switch  to   ANT.  The   RMI  pointer  will  park horizontally.    Select   ADF  on  the  audio  system  and adjust the volume. (b)  ADF   Function.    Position  the  power and   mode   switch   to    ADF.      The   RMI   pointer   will indicate relative bearing to the turned station. NOTE When  the  ADF  system  is  not  receiving  a reliable signal, the RMI pointer will remain parked  in  the  ADF  mode.    The  ADF  may momentarily park during station crossings because   of   signal   loss.      If   the   bearing pointer  fails  to  respond  as  indicated  or  ID is lost in ANT position, the ADF should be considered unreliable and will not be used for navigation or approaches.  (c)  TONE  Function.    Position  the  power and mode switch to TONE (BFO).  A 1000-Hz tone will identify keyed CW stations. e.     Self-Test. NOTE If  the  signal  received  is  weak  or  of  poor quality, the bearing pointer rotation will be slow. 1.   Position   the   power   and   mode   switch   to ADF    and    tune    a    nearby    NDB,    outer marker, or broadcast station and press the TEST  button.    The  RMI  pointer  will  rotate 90° from the previous valid indication. 2.   Release the   TEST  button  and  verify  that the  RMI  pointer  returns  to  that  indication.   Select   ANT   on   the   ADF   control   panel.   Bearing  pointer  should  point  horizontally, and   a   valid   aural   navaid   identifier   (ID) should continue. 3.   Select   ADF   on   the   control   panel.      The bearing pointer should return to the proper relative bearing. 3C-25.  RADIO MAGNETIC INDICATOR. Two identical Radio Magnetic Indicators (RMI’s) are installed, one on each side of the instrument panel.   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  ADF and  #1 VOR or ADF and TACAN for single   needle   display.      The   double   needle   always points to the ADF or #2 VOR bearing as selected by the double needle switch. NOTE Aircraft   RMI   circuitry   modified   by   Beech Service     Instruction     No.    C-12-0118,     will operate    as    follows:    In    addition    to    the standard    warning    flag    conditions,    if    a TACAN   circuitry   26   Vac   electrical   power loss   occurs   and   TACAN   is   selected,   the RMI  single-needle  pointer  will  drive  to  the three o'clock PARK position. 3C-26.  GLOBAL POSITIONING S YSTEM (KLN 90B). Refer to Chapter 3D for detailed information. 3C-27.  ALTIMETERS. a.     Pilot’s Servoed Altimeter. (1)   General.    The  pilot’s  altimeter  provides  a servoed counter drum/pointer display of barometrically corrected  pressure  altitude,  derived  from  the  air  data computer system.  For proper operation, the 2-ampere AIR  DATA  ENCODER  circuit  breaker  located  in  the avionics  section  of  the  right  sidewall  circuit  breaker panel must be set.  The altimeter is 26 Vac powered, and   is   protected   by   the   12-ampere   PILOT   ALTM circuit breaker also located on the right wall panel.