TM 1-1510-225-10 3A-21 Table 3A-1.  Vertical Trim Command VS Flight Director Operations TRIM COMMAND EFFECTS DISCRETE TRIM Pitch Attitude Hold 0.5° per click Altitude Hold 20 feet per click Indicated Air Speed Hold 2 knots per click Vertical Speed Hold 100 fpm per click CONTINUOUS TRIM Pitch Attitude Hold Maintains constant g profile until release. Altitude Hold Maintains 500 fpm climb or descent until release. Indicated Airspeed Hold One knot per second until release. Vertical Speed Hold 100 fpm per second until release. (i)    Pilot/copilot Roll, Pitch, and Yaw Axis Failure Annunciators.   Pilot/copilot roll, pitch, and yaw axis   failure   annunciators,   placarded   R,   P,   and   Y,  indicate autopilot axis decoupling. System  integrity  is  ensured  by  automatic  self- monitoring   tests   conducted   by   the   autopilot   during autopilot operation.  In the event of autopilot or servo motor malfunction, the flight control system automatically  disengages  the  servo  motor  clutch  and drive   power   to   the   affected   axis.      The   R,   P,   or   Y indicator lights on the autopilot controller will illuminate to alert the crew of axis decoupling and   AP FAIL will flash for 2 seconds, then remain illuminated. (j)    Soft Ride Mode Annunciator.   Illumination     of     the     soft     ride     mode     annunciator, placarded  SR,  indicates  that  the  soft  ride  mode  has been selected and is engaged. (k)   Soft Ride Mode Push-Button Selector Switch.      Pressing   the   soft   ride   mode   push-button selector  switch,  placarded  SOFT  RIDE,  engages  the soft ride mode.  With the soft ride mode engaged, the flight    director    reacts    more    slowly    than    normal    to deviations   from   the   planned   flight   track   or   aircraft attitude.    Although  soft  ride  is  most  useful  to  reduce command  activity  in  turbulent  air,  it  may  be  engaged any time a generally smoother flight is more desirable. Soft ride may be engaged with any mode as long as   the   autopilot   is   engaged,   with   the   exception   of approach.    Soft  ride  may  be  employed  at  the  same time  as  approach  arm,  but  will  cancel  automatically upon initiation of the approach capture sequence. (l)    Yaw Damper Engage/Disengage Push-Button    Selector    Switch.        The    yaw    damper engage/ disengage push-button selector switch, placarded   YD,  alternately  engages  and  disengages yaw   damper   function   independently   of   autopilot   or flight   director   operation.      If   the   yaw   damper   was previously engaged through autopilot activation, pressing   the   key   cancels   the   function.      The   yaw damper     augments     aircraft     stability     by     opposing uncommanded    motion    about    the    yaw    axis    and provides turn coordination. (m) Yaw  Damper  Engaged  Annunciator.   Illumination   of   the   yaw   damper   mode   annunciator, placarded  YD,  indicates  that  the  yaw  damper  mode has been selected and is engaged. g.  Autopilot Monitors (KAM 432). The autopilot  monitors  monitor  aircraft  movements  during autopilot  operations.    Aircraft  accelerations  and  pitch and  roll  attitudes  and  rates  are  monitored  to  detect values exceeding the maximum allowable limits.  The autopilot  monitors  also  receive  signals  from  primary and  trim  servos  that  enable  it  to  detect  trim  system malfunctions.      If   the   autopilot   is   shut   down   by   the autopilot  monitor,  the  system  cannot  be  re-engaged without  first  successfully  completing  the  flight  control system's   automatic   pre-flight  test  routine.    The  test may be initiated by cycling power to the flight computer with the autopilot power switch or circuit breaker. h.  Gyro     Adapters     (KDA     430).          The    gyro adapters     convert     information     from     the     aircraft's vertical,    directional,    and    rate    gyros    and    internal accelerometers  to  digital  format  for  use  by  the  digital flight control system. i.     Vertical  Gyros  (KVG  350).      Roll   and   pitch attitude  information  from  the  vertical  gyros  provides line of sight stabilization to the weather radar antenna and vertical reference to the autopilot and EFIS.