TM 1-1510-223-10 Change 3          8-7 CAUTION Do not force the elevator trim system beyond the limits which are indicator. n.   YD ENGAGE push-button switch-indica- tor (autopilot controller) — Depress while holding rudder boost/yaw control switch in TEST. Yaw damper should not engage. o.   RUDDER BOOST/YAW CONTROL TEST switch — RUDDER BOOST. Check RUD- DER BOOST annunciator extinguished. p.   Electric elevator trim — Check. (1)   ELEV TRIM switch — ON. WARNING Operation of the electric trim system should oc- cur only by movement of pairs of switches. Any movement of the elevator trim wheel while de- pressing  only  one  switch  element  indicates  a trim  system  malfunction.  The  electric  elevator trim control switch must then be turned OFF and flight conducted by operating the elevator trim wheel manually. Do not use autopilot. (2)   Pilot   and   copilot   trim   switches   — Check    individual    element    for    no movement of trim, then check proper operation of both elements. (3)   Pilot trim switches — Check that pilot switches   override   copilot   switches while trimming in the opposite direc- tions, and trim moves in the direction commanded by the pilot. (4)   Pilot or copilot trim switches — Check trim disconnects while activating pilot or copilot trim disconnect switches. (5)   ELEV TRIM switch — OFF, then ON (ELEV TRIM OFF annunciator extin- guishes). 24.   ASE/ACS BIT checks — Perform as required. a.   UTIL on MFD — Depress. b.   SYSTEM BIT (R1) — Depress. NOTE Before conducting the INS BIT ensure mode se- lector is in ALIGN and align state 8 or lower, but before mode selector is placed in NAV. c.   INS BIT — Perform as follows: (1)   INS — Select on EHSI by depressing INS/TCN on display controller. (2)   INS — Select on single needle bear- ing source selector switch on display controller. (3)   INS BIT (R2) — Depress. (4)   Check indications as follows: (a) MFD — INS BATT, INS FAIL, and WAYPOINT   ALERT   CWA   an- nunciators (3) illuminate. (b) EHSI — INS needle 30 degrees right  of  lubber  line  and  course deviation bar displaced right fol- lowed  by  INS  needle  centering and   course   deviation   bar   dis- placed left. Check WPT alert an- nunciator illuminated. (c) Aircraft caution/advisory annun- ciator  panel  —  Amber  INS  an- nunciator light illuminated. (d) INS  mode  controller  —  Green READY light and red BATT light illuminated. (e) Mission   annunciator   panel   — Green INS UPDATE annunciator and amber NO INS UPDATE an- nunciator light illuminated. (f) After 15 seconds the text COM- PLETE or any active  ACTION  or MALFUNCTION   codes   will   be displayed.  If  any  action  or  mal- function  code  is  displayed  they may  have  been  cleared  by  the BIT test. The only way to ensure they  are  cleared  is  to  conduct another BIT and the text COM- PLETE appears. 25.   ASE/ACS  Programming  —  Program  as  re- quired. a.   Waypoint list — build as follows: (1)   Mode switch B — Depress to select FPLN page.