TM 1-1510-218-10 3C-132 (4)   Immediate   Present   Position   Hold.    If  it becomes    necessary    to    hold    the    present    position, access  the  Hold  page.    Press  the   HOLD  PPSN line select   key   and   confirm   the   selection   by   pressing   it again.  Refer to Figure 3C–77  and  Table  3C-56.  The aircraft's  present  position  is  immediately  inserted  into the  flight  plan  as  the  active  waypoint,  interrupting  the current flight plan leg and activates a holding pattern at that fix with either the entered or default parameters on the  Hold  page.    This  pattern,  and  its  holding  fix,  is treated the same as a preplanned hold at a flight plan waypoint.    All  parameters  may  be  edited.    Any  user– defined  holding  patterns  defined  at  future  waypoints will    be    deleted    when    a    present    position    hold    is activated. (5)   Holding    Course    Edits.        If    no    holding pattern inbound course has been inserted, the inbound course  to  the  fix  is  used  when  holding  guidance  is activated.  If an inbound course has been inserted, the inbound holding course is fixed but may be edited. The  holding  course  is  entered  by  two  different methods.  Default to the current inbound course to the fix  or  enter  the  desired  course  by  the  crew  via  the scratchpad.      In   either   method   the   course   can   be modified as needed. To restore the inbound course to the fix waypoint as  the  holding  course,  enter  a   –  and  select  the   CRS  line select key. (6)   Holding  Pattern  Length.    The  length  of the  holding  pattern  can  be  defined  by  either  defining an inbound leg length or inbound leg duration.  Before execution of the pattern, only the entered value will be displayed  for  the  hold  definition  and  will  be  identified with an  *.  After the aircraft passes the holding fix, the FMS  will  calculate  the  length  or  duration  that  was  not entered  based  upon  the  current  groundspeed  at  the pattern   fix.      Default   values   for   pattern   length   are 4.0 nm or 1 minute duration. (7)   Holding Pattern Activation and Execution.   When  the  holding  fix  is  passed  for  the  first  time,  the holding  guidance  computations  are  activated.   At  this time, the following  changes  will  take  place  in  the  flight plan operation and page displays. (a)   The automatic leg advance is suspended. (b)   Course edits on the Flight Plan page may no longer be made.  Inbound holding course edits may be made on the Hold page. (c)   All   displays   reference   the   inbound course displayed on the Hold page. (d)   Holding fix cannot be edited. To  edit  a  user–defined  holding  pattern  once  it  is in the flight plan, press the line select key on the Flight Plan Waypoint page adjacent to the  H attribute or use the EDIT key and select HOLD. If the inbound course is changed, the FMS–800 commands  an  immediate  turn  to  the  current  inbound course  and  upon  passing  the  holding  fix,  performs  a holding   pattern   entry   procedure.      If   the   direction   is changed, the action commanded is similar to a course change.  The FMS–800 commands an immediate turn to  the  inbound  leg  and,  upon  passing  the  holding  fix, turns onto the outbound leg in the new turn direction.   If    the    leg    length    is    changed,    it    will    take    effect immediately.  The effect will depend on the position of the aircraft in the holding pattern at the time the length was changed.  If the aircraft is outbound, the FMS–800 will  command  an  immediate  turn  or  maintain  course depending on whether the new turning point is behind or in front of the aircraft.  If the aircraft is in a turn, it will  continue  the  turn  and  intercept  the  leg  based  on the old length.  Upon completion of the turn, the new length  will  be  active.    The  length  and  width  of  the holding    pattern    is    recomputed,    using    the    inbound groundspeed,    each    time    the    aircraft    passes    the holding fix. When  the  holding  guidance  has  been  activated, all course and lateral deviation displays will reference the   inbound   holding   course.      The   inbound   holding course   is   referenced   whether   the   aircraft   is   on   the inbound  or  outbound  leg  of  the  holding  pattern.    The 10-second turn alert will be computed on the outbound leg   to   alert   the   crew   of   the   upcoming   turn   to   the inbound leg.