Installation manual

5-17 Navigation
approach remains a non-precision approach and does not
consider any step-down limitations. The Nav Mode datablock will
display “LNAV+V” for the approach type.
LNAV/VNAV (Lateral Navigation with Vertical Navigation)
In this mode, the GPS provides lateral navigation, providing more
accurate guidance than regular LNAV but easier to follow
indications than a localizer. The vertical navigation is driven by
GPS signals. LNAV/VNAV approaches are operationally different
from LNAV+V in that the glide path is protected from obstructions
but attention still must be applied to step down fixes. Also, the
minimum altitude presented is a decision altitude/height (DA/DH)
– DA being what is on the altimeter, and DH being the height of
the DA above the touchdown zone elevation. This is not a MDA,
thus, fly it just as though it were an ILS approach: follow the glide
slope all the way to the DA before initiating a missed approach, if
appropriate. The Nav Mode datablock will display “LNAV/VNAV”
for the approach type.
LPV (Localizer Precision with Vertical Guidance)
The lateral guidance is significantly more precise than LNAV, and
equivalent to that of a localizer. Vertical guidance is provided to
minimums as low as 200’ AGL above the touchdown zone.
Lateral tolerance starts out at 0.3 NM full-scale (slightly tighter
than a localizer at the FAF), transitioning to 350 feet either side at
the runway threshold (slightly looser than a localizer). The
steering remains linear all the way without the difficult to follow
swings of a VHF localizer. The vertical guidance is precise and
has a DA/DH (shown as “DA(H)” on approach charts) rather than
a MDA. The Nav Mode datablock will display “LPV” for the
approach type.
LP (Localizer Performance)
These approaches have localizer performance but no vertical
guidance associated with them. Use the published “LP”
minimums. The Nav Mode datablock will display “LP” for the
approach type.