TM 1-1510-224-10 1. Set    selected    altitude    on    altitude preselector. 2. Select  pitch  hold,  VS, or  IAS  mode descend  or  ascend  toward  selected altitude. 3. Depress ALT SEL pushbutton switch-indicator     on     flight     director mode   selector   panel.      ALT   SEL mode is now armed. The   altitude   flare   point  ( ALT   SEL   CAP)   is   a nonlinear  function,  dependent  upon  vertical  speed  and distance to the selected altitude. 4. ALT   SEL   capture   is   dropped   and ALT HOLD is automatically engaged. The ALT SEL capture submode is cancelled by: Moving   the    ALT   SET    knob    on    the    altitude preselector. Moving     the     pitch     wheel     on     the     autopilot controller. Selecting    on    or    captured    any    other    vertical mode. Coupling to the cross-side EFIS. Selecting an alternate ATT source on the display controller. (17)Go-around mode (wings level).  The go- around   mode   is   normally   used   to   transition   from   an approach   to   a   climb   when   a   missed   approach   has occurred.    Go-around  mode  is  selected  by  depressing the  go-around  switch  located  on  the  left  power  lever. With  go-around  selected,  all  flight  director  modes  are cancelled, and the autopilot is disengaged.  The pilot will see a wings level command and a 7-degree climb angle will   be   presented   on   the   EADI.      When   go-around   is selected,  the  autopilot  will  automatically  disengage,  and the yaw damper will automatically engage. 3-24. VHF NAVIGATION RECEIVERS (VIR-32). a. Introduction.    The  VHF  navigation  receivers (fig.   3-24),   provide   200   50-kHz   spaced   VOR/localizer channels   from   108.00   through   117.95   MHz,   40   glide slope     channels     automatically     paired     with     localizer channels,  and  a  marker  beacon  receiver.    The  digital navigation    receiver    provides    VOR,    LOC,    and    GS deviation    outputs,    high    and    low    level    flag    signals, magnetic   bearing   to   the   station,   to/from   information, marker   beacon   lamp   signals,   and   VOR   and   marker beacon   audio   outputs.      The   navigation   receivers   are powered  through  the  2-ampere   VOR  #1 and   VOR   #2 circuit  breakers,  located  on  the  overhead  circuit  breaker panel (fig. 2-9). b. VHF Navigation Receiver Control Unit Controls  and  Functions.      All  operating  controls  for  the navigation receiver are located on the CTL-32 navigation receiver   control   unit   (fig.   3-24).      The   VHF   navigation receiver  control  unit  also  controls  the  DME  function  of the TACAN when it is operated in DME mode. (1)    Active   frequency   display.      The   active frequency (frequency to which the receiver is tuned)  and diagnostic messages are displayed in the upper window. (2)   Transfer/memory  switch.    This  switch  is a    3-position    spring-loaded    toggle    switch    placarded XFR/MEM,   which,   when   held   to   the    XFR    position, causes  the  preset  frequency  to  be  transferred  up  to  the active   display   and   the   receiver   to   be   retuned.      The previously  active  frequency  will  become  the  new  preset frequency  and  will  be  displayed  in  the  lower  window. When this switch is held to the  MEM position, one of the four stacked memory frequencies will be loaded into the preset  display.    Successive  pushes  will  cycle  the  four memory frequencies through the display. (3)    Store   switch.      This   switch,   placarded STO, allows up to four preset frequencies to be selected and    entered    into    the    control    unit's    memory.        After presetting  the  frequency  to  be  stored,  the   STO  switch should   be   pushed.      The   upper   window   displays   the channel   number   of   available   memory   channel   (CH   1 though   CH   4)   while   the   lower   window   continues   to display the frequency to be stored.  For approximately 5 seconds,   the   MEM   switch   may   be   used   to   advance through   the   channel   numbers   without   changing   the preset display.  The STO switch is pushed a second time to    commit    the    preset    frequency    to    memory    in    the selected  location.    After  approximately  5  seconds,  the control will return to normal operation. (4)    Tuning   knobs.      Two   concentric   tuning knobs  control  the  preset  or  active  frequency  displays. The larger knob changes the three digits to the left of the decimal point in I-MHz steps.  The smaller knob changes the  two  digits  to  the  right  of  the  decimal  point  in  0.05 MHz   steps.      The   two   frequency   select   switches   are independent  of  each  other  so  that  the  upper  and  lower rollover  of  the  0.1  MHz  digit  will  not  cause  the  1.0  MHz digit to change. (5)    Active switch. The     active     switch, placarded ACT, enables the tuning knobs to directly tune the  receiver  when  depressed  and  held  for  two  seconds. The  bottom  window  will  display  dashes  and  the  upper window   will   continue   to   display   the   active   frequency. Pushing the   ACT  switch  a  second  time  will  return  the control unit to the normal 2-display mode. (6)    Test    switch.        This    switch,    placarded TEST,  initiates  the  receiver  self-test  diagnostic  routine. (Self-test    is    active    only    when    the    TEST    switch    is pressed.) 3-57