Section 3 Display Symbology
3-22
IDU-450 EFIS Software Version 8.0H (Rotorcraft)
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Ed Nov 2018
3.3.14. Flight Path Marker (Velocity Vector)
Figure 3-39: Flight Path Marker
The FPM appears on the background to coincide with the aircraft’s actual
flight path as projected on the outside world. The FPM is laterally displaced
parallel to the horizon with respect to the center of the display to account
for the difference between aircraft track and heading, and is vertically
displaced perpendicular to the horizon to account for aircraft climb or
descent angle.
Because the FPM is used in conjunction with a 3-D background, the FPM
utility normally associated with a HUD is achieved. When the FPM is
displaced to the extent it interferes with heading, altitude, or airspeed
indications, it is removed from the display as in Figure 3-40.
FPM nearing airspeed tape due
to strong crosswind from the right
FPM removed due to excessive
crosswinds from the right
Figure 3-40: Flight Path Marker Views
FPM movement is dampened by reference to aircraft pitch and heading so
not to deviate from pitch or heading at a rate greater than 1°/sec.