Installation manual

Map Pages 3-23
FORWARD LOOKING TERRAIN ALERTING (FLTA)
FLTA alerting is triggered by either a projected imminent impact
with terrain or obstacle or reduced terrain and obstacle
clearance. Projected imminent impact with terrain occurs when
the aircraft flight path is projected to intersect with terrain up to
3.0nm (yellow caution) or up to 1.5nm (red warning) in front of the
aircraft flight path. By way of reference, this means an aircraft
traveling at 180 knots of ground speed will have 60 seconds of
notice for a caution and 30 seconds for a warning. Reduced
terrain or obstacle clearance occurs when the aircraft flight path is
not projected to impact the terrain but the projected clearance
between the aircraft flight path and nearby terrain or obstacles
falls below a designated safe vertical distance. The reduced
terrain and obstacle clearance distance varies with phase of flight
and aircraft dynamics per TAWS TSO C-151b but generally
ranges from 300’ to 1000’.
Either terrain or obstacles can trigger FLTA alerts and they are
distinguished via the CAS messaging and aural alerting. The
difference between FLTA warnings and cautions is exclusively
based on distance-to-go to projected impact points or reduced
clearance areas.
The projected imminent impact location or the projected reduced
terrain and obstacle clearance area is depicted on the maps with
a solid yellow (caution) or red (warning) “flashlight” elliptical
depiction. Depending on aircraft dynamics, it may be possible
for a solid red FLTA “flashlight” projected terrain impact point to
appear on top of a larger hatched yellow TA depiction.
FLTA Depiction