TM 1-1510-218-10 8-14 e.   Horizontal Situation Indicator (HSI) heading   marker   under   lubber   line   and vertical needle centered – Set. f.    Engage autopilot and check controls stiff – Check. g.   Move  HSI  heading  marker  10°  left  and right    and    verify    that    FD    and    control wheels respond in the appropriate direction – Check. h.   Press   AP/YD  disengage  switch   to   first detent and verify that autopilot disengages and flight controls are free – Check. i.    Elevator Trim – Check on. j.    Engage autopilot – Check. k.   Command   5°   trim   UP   with   AP   pitch wheel  and  verify  that  manual  trim  wheel moves    nose    UP    and    AP    trim    light indicates UP trim – Check. l.    Press   PITCH   TRIM   switch   NOSE   DN and  verify  that  autopilot  disengages  and AUTO  PILOT  TRIM  FAIL  and  MASTER WARNING lights illuminate – Check. NOTE The AP TRIM FAIL annunciator will extinguish by pressing the AP/YD disconnect  button  on  the  control  wheel  to the first detent. m. Engage autopilot – Check. n.   Move HSI heading marker to command a bank on FD – Check. o.   Press  go-around  switch  and  verify  that GA light illuminates, autopilot disengages,  and  that  FD  commands  a wings level, 7° nose-up attitude – Check. p.   Press    TEST    switch    (pilot's    HSI)    and verify  that  attitude  display   indicates  an additional 10° pitch up and 20° right bank – Check. H 8.   Autopilot trim fail system C D1 – Check as follows: a.   Engage  autopilot  command  DN  with  AP pitch  wheel  and  engage   AUTO  PILOT TRIM  TEST  switch   when   elevator   trim wheel starts to rotate. b.   Verify  that  autopilot  disengages  and  AP TRIM   FAIL   and   MASTER   WARNING lights illuminate within 10 seconds. H 9.   Automatic flight control system D2  – When the PC determines that an autopilot check is required, check as follows: a.   Altitude alert. NOTE Pause  a  few  seconds  after   each   step   to allow time for the proper indications. (1)   Set alert controller more than 1000 feet above altitude indicated on pilot's altimeter.  The pilot's altimeter alert light should be extinguished. (2)   Decrease the alert controller to within 1000    feet    of    the    pilot's    altimeter setting.          The     alert     light     should illuminate. (3)   Decrease  the  controller  to  less  than 250  feet  above  the  pilot's  altimeter setting.          The     alert     light     should extinguish. (4)   Increase    the    controller    to    300    ± 50 feet   above   the    pilot's    altimeter indication   and   check   that   the   alert light illuminates. (5)   Set the desired altitude. b.   Autopilot. (1)   Autopilot   controller    UP   TRIM,   DN TRIM    annunciators    –    Check    not illuminated. CAUTION A  steady  illumination  of  UP  TRIM  or  DN TRIM annunciator indicates that the automatic synchronization is not functioning and the autopilot should not be engaged. (2)   Turn knob – Center. (3)   Elevator trim control switch – ON. (4)   Control wheel – Hold to mid travel. (5)   AP  button  –  Press.     AP  ENGAGE and   YD   ENGAGE   annunciators   on autopilot  controller  will  flash.    Servo clutches will engage.  FD flag on ADI should be in view. (6)   Control movement – Check. (a)   Rudder pedals – Overpower slowly.  YD ENGAGE annunciator stops flashing.