For Training Purposes Only
Sept 04
2-25
P I L O T T R A I N I N G G U I D E
AUTOMATIC FLIGHT CONTROL SYSTEM
FMS Lateral Navigation (LNAV) Mode
The FMS lateral steering command is a roll command which aligns the airplane with
the flight plan in the FMS. The FGC limits the FMS roll commands to 30° and roll rate
to 5.5°/sec.
As LNAV moves from ARMED to ACTIVE, the LNAV will flash for approximately 5
seconds, when active.
LNAV capture will also occur when the airplane is within 2.5 miles of the desired
track, and moving away from it.
LNAV capture will occur when the airplane is at a calculated point, as a function of
track record and groundspeed, if the airplane is flying towards the desired track.
The FD will transition automatically (NAV to NAV transfer) from FMS navigation to a
LOC or VOR approach via the APR, or BC button. The selected NAV source
must be
FMS
, NAV radio must be tuned to the approach frequency and preview mode selected,
to allow a NAV transfer to occur.
The previewed approach is armed by pushing the APR or BC switch on guidance
panel. When LOC or BC captures, it replaces LNAV.
If the active vertical mode was not VNAV prior to capture, the vertical mode remains
unchanged. If the active vertical mode was VNAV prior to capture, then ALT mode
will replace the vertical mode.
If armed approach mode was APR (ILS), then GS is armed with LOC capture and GS
will capture when GS criteria is met.
DESIRED TRACK
LNAV capture will occur when the airplane
is within 2.5 miles of the desired track, and
moving away from it.
GX_02_021
DESIRED TRACK
LNAV capture will occur when the airplane is at
a calculated point, as a function of track error and
groundspeed, if the airplane is flying towards the
desired track.
GX_02_022
