Copyright © 2015  Grand Rapids Technologies, Inc.

Electronic Flight Instrumentation for Experimental Aircraft Since 1991

Flight Path Marker

GRT has had a Flight Path Marker feature since the first EFIS was shipped 10 years ago. In fact, it’s got a place of honor as the “little airplane symbol” in our logo.




What is it?

In the simplest of terms, it shows where the aircraft will go if all conditions of motion and wind stay the same. Shown as a circle with three spikes on the primary flight display, it is a projection of the aircraft’s flight path. It combines many data factors including attitude, airspeed, and wind vectors calculated from GPS ground track, ground speed, airspeed and magnetic heading. The Flight Path Marker will appear to float about the display as the aircraft pitches and rolls. This movement is most evident in strong crosswind or unusual attitudes. For example, during a properly-flown crabbed crosswind approach, the heading (nose) will point to the upwind side, but the Flight Path Marker (center of mass) will be superimposed on the virtual runway because that is where the airplane is going at that particular instant in time.

How do I turn it on?

Turn the Flight Path Marker “ON” in the Setup Menu > Primary Flight Display page. Save your settings before exiting the Setup Menu and it will reappear each time you turn on the EFIS system.

How do I use it?

The Flight Path Marker is displayed whenever it’s turned on in the Setup Menu. It’s useful for adjusting crab angles and approach glide paths. During Enroute operations, try parking it on a Waypoint Balloon for effortless crab angles along your course. What in Michigan is a Waypoint Balloon, you ask? That sounds like a good subject for next week’s featured feature.

What if it turns red?

If the wind or unusual attitude is so great that the actual flight path of the aircraft would place the Flight Path Marker off the edge of the screen, the Marker will stay on the closest edge of the screen and turn red, indicating a “display limited” position.

Any limitations?

For the Flight Path Marker to be accurate, it must have GPS signal and accurate magnetic heading and airspeed data for the wind vector calculations.



The Flight Path Marker is slightly right of the aircraft centerline because of the crosswind from the left, indicated by the Wind Vector.