TM  55-1510-221-10 NOTE Pause  a  few  seconds  between  each  step  to allow time for the proper indications. (1) (2) (3) (4) (5) Set  alert  controller  more  than  1000 feet   above   altitude   indicated   on pilot’s  altimeter.  The  pilot’s  altimeter alert light should be extinguished. (a) (b) Decrease   the   alert   controller   to within  1000  feet  of  the  pilot’s altimeter  setting.  The  alert  light should  illuminate. Decrease  the  controller  to  less  than 250  feet  above  the  pilot’s  altimeter setting.   The   alert   light   should extinguish. Increase the controller to 300 ±50 feet  above  the  pilot’s  altimeter indication and check that the alert light  illuminates. 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. (6)   Deleted. (a) Deleted. (b)  Deleted. (7) Elevator trim follow-up - Check. Control wheel - Hold aft of mid travel.  Trim  wheel  should  run nose down after approximately 3 seconds. Trim down annunciator should illuminate after approximately  8  seconds. Control wheel - Hold forward of mid travel. Trim wheel should run nose up after approximately 3 seconds,  trim  up  annunciator should illuminate after approximately  8  seconds,  and  AP TRIM  FAIL  annunciator  and MASTER   WARNING   lights s h o u l d    i l l u m i n a t e    a f t er approximately  15  seconds. The  elevator  trim  system  must  not  be  forced beyond the limits which are indicated on the elevator trim tab indicator. (8)    AP/YD  &  TRIM  DISC  Button  - Depress   through   second   level. Autopilot and yaw damper  should disengage  and  ELECT  TRIM  O F F annunciator should illuminate. AP ENG and YD ENG annunciators on instrument  panel  should  flash  5 times. (9) Elevator trim control switch - OFF, then  ON. (ELEC  TRIM  OFF annunciator  should  extinguish). (10)  AP  -  Re-engage. (11) Turn controller - Check that control wheel   follows   in   each   applied direction,  then  center. 8-14   Change   4