An Angle of GPS Navigation
O n low-level VFR flights, we typically enter the next destination airport into the GPS unit and deal with deviations forced by high towers, controlled airports, TFRs, restricted areas, and so on, with temporary deviations from the direct course. This approach forces us to track the course on the sectional chart — a good thing. If the navigation equipment ever fails, we will be well prepared for appropriate action. For the same reasons, we never let the autopilot execute the flight plan in the GPS unit. Instead, we input the GPS bearing to the destination into the autopilot, and adjust that setting manually as needed. Suppose we are approaching an obstacle forcing a course change. If we detour close to the obstacle, we add some distance — a bad thing. We avoid that through a course correction for the autopilot while we are relatively far from the obstacle. In the past, we carried out estimation of the course correction 30-60miles out as follows. We w...