TM 1-1510-224-10 NOTE The control wheel must be held at mid-travel due  to  ballast  in  the  elevator.    The  autopilot will disconnect during pitch wheel check due to  the  heavy  nose  down  force  if  the  control wheel is not off the forward stop. d. Control wheel - Move to mid-travel. e. AP ENGAGE switch-indicator (autopilot   controller)      -   Depress   to engage  autopilot  and  yaw  damper. Check  that    AP   ENGAGE   and    YD ENGAGE switch-indicators on autopilot controller and remote annunciators    on    instrument    panel are illuminated. 4. Autopilot  overpower  check  -  Check  as follows: a. Rudder pedals - Overpower slowly. b. Control wheel - Overpower slowly in both directions. WARNING If  the  autopilot  or  yaw  damper  disengages during   the   overpower   test,   the   system   is considered  non-operative  and  should  not  be used.  The elevator trim system must not be forced beyond the limits which are indicated on the elevator trim indicator. 5. Elevator    trim    follow-up    -    Check    as follows: a. Control   wheel   -   Move   aft   of   mid- travel.    Trim  wheel  should  run  nose down after approximately 3 seconds.        TRIM    DN    annunciator (autopilot controller) should illuminate  after  approximately  6  to  8 seconds, and  AP  TRIM  annunciator (instrument panel)  should illuminate after approximately 15 seconds. b. Cont rol   wheel   -   Move   forward   of mid-travel.      Trim   wheel   should   run nose up after approximately 3 seconds.        TRIM    UP    annunciator (autopilot controller) check illuminated  after  approximately  6  to 8  seconds.    AP  TRIM  annunciators (instrument panel) check illuminated    after    approximately    15 seconds. 6. AP   &   YD/TRIM   DISC   switch   (control wheel)    -  Depress  to  first  level.    Check that autopilot and yaw damper disengage, AP ENGAGE and YD ENGAGE switch-indicators on the autopilot controller and remote annunciators  above  the  EADI's  flash  5 times. 7. Control wheel - Hold to mid-travel. 8. AP ENGAGE switch - Re-engage. 9. Turn  knob  -  Check  that  elevator  control trim     wheel     follows     in     each     applied direction, then center. 10.   Pitch  wheel  -  Check  that  trim  responds to  pitch  wheel  movements.    (UP  TRIM and DN TRIM annunciators may illuminate.) 11.   Heading   marker   -   Center   and   engage HDG.    Check  that  control  wheel  follows a turn in each direction. 12.   GO AROUND button (left power lever)  - Depress.    Check  that    AP   disengages and   FD   commands   a   wings   level,   7 degrees   nose   up   attitude.      Check   GA annunciator  on  EADI  illuminates.    Yaw damper    should    automatically    engage and    YD    ENGAGE    switch-annunciator should   be   illuminated   on   the   autopilot controller  and  the  remote  annunciators above the EADI's should be illuminated. 13.   RUDDER BOOST/YAW CONTROL TEST   switch    (pedestal    extension)       - TEST.      Check   the   RUDDER   BOOST annunciator above the EADI's illuminates,    yaw    damper    disengages, YD   ENGAGE   switch-indicator    on    the autopilot controller extinguishes, and the YD ENGAGE remote annunciators above the EADI's flash 5 times. WARNING If  the  SBY  annunciator  on  the  flight  director mode  selector  does  not  illuminate  within  10 seconds  after  the  avionics  master  switch  is turned  on,  the  autopilot  has  failed  self-test and is considered inoperative and should not be used. CAUTION Do not force the elevator trim system beyond the     limits     which     are     indicated     on     the ELEVATOR trim tab indicator. 14.   YD ENGAGE pushbutton switch- indicator  (autopilot  controller)  -  Depress while   holding   rudder   boost/yaw   control test    switch    in    TEST.        Yaw    damper should not engage. 3-50