TM 1-1510-224-10 indicated airspeed to be selected with either the autopilot pitch wheel or by using the touch control steering switch on the control wheel.  When operating in the   IAS  mode the ON indicator located on the face of the switch will be illuminated  and  the  target  airspeed  will  be  displayed  on the EADI. (8)   Vertical speed hold mode switch- indicator.      Depressing   the   vertical   speed   hold   mode switch-indicator, placarded VS, will command the system to  maintain  the  current  vertical  speed  or  to  allow  a  new vertical   speed   to   be   selected   with   either   the   autopilot pitch wheel or by using the touch control steering switch on  the  control  wheel.    When  operating  in  the   VS  mode the ON indicator located on the face of the switch will be illuminated     and     the     target     vertical     speed     will     be displayed on the EADI. (9)   Altitude preselect mode switch-indicator. Depressing  the  altitude  preselect  mode  switch-indicator, placarded   ALT   SEL,   will   command   the   flight   control computer  to  arm  and  capture  and  maintain  the  altitude displayed  on  the  altitude  preselector  (fig.  3-23).    When operating   in   the   ALT   SEL   mode   the   ARM   or    CAP indicators  located  on  the  switch  face  will  be  illuminated as appropriate. (10)Altitude hold     m ode switch-indicator. Depressing    the    altitude    hold    mode    switch-indicator, placarded ALT, commands the flight control computer to hold   the   current   altitude,   and   will   illuminate   the   ON indicator located on the face of the switch.  Capturing the altitude   displayed   on   the   altitude   preselector   will   also cause the system to maintain that altitude. i. Control-Wheel Mounted Autopilot Disconnection   Switches.        A    bi-level    autopilot/electric trim/yaw  damper  disconnect  switch,  placarded    DISC   - AP & YD - TRIM, is mounted on each control wheel (fig. 2-24).      Depressing   the   switch   to   the   first   level   will disconnect the autopilot and the yaw damper. Depressing   the   switch   to   the   second   level   will   also disconnect the electric elevator trim. j. Touch  Control  Steering  (TCS).    A  control- wheel  mounted  touch  control  steering  switch  (fig.  2-24), placarded   TCS,   allows   the   pilot   to   manually   change aircraft   attitude,   altitude,   vertical   speed,   or   airspeed without  disengaging  the  autopilot.    The    TCS  switch  is held  depressed  while  the  aircraft  is  maneuvered  to  the new attitude, altitude, vertical speed, or airspeed.  When the   switch   is   released,   the   autopilot   will   automatically synchronize  to  the  vertical  mode.    If  an  air  data  mode (IAS or  VS)    has  been  selected,  the  selected  value  will be  synchronized  to  the  current  value  when  the  switch  is released. 1. Heading Mode Switch-Indicator 2. Navigation Mode Switch-Indicator 3. Approach Mode Switch-Indicator 4. Back Course Mode Switch-Indicator 5. VOR Approach Mode Switch-Indicator 6. Standby Mode Switch-Indicator 7. Indicated Airspeed Hold Mode Switch-Indicator 8. Vertical Speed Hold Switch-Indicator 9. Altitude Preselect Mode Switch-Indicator 10. Attitude Hold Mode Switch-Indicator A93FE00D106 C Figure 3-22.  Flight Director Mode Selector 3-47