How do pilots get confused by their GPS? Over the 15 years of teaching classes on a half dozen different GPS navigators I hear comments like "what happened, and why", followed by "what do I do now"? I discovered there were a number of specific topics that led to this confusion -- the same topics over and over again. A number of them deal with the concept of a flight leg, and issues associated with them. Many pilots think of a flight plan as a sequence of waypoints they will follow to their destination; only a few know a flight plan is actually a sequence of legs that you fly, usually in the order they appear in your flight plan.
But sequencing through the list is not automatic, and sequencing (and suspended legs) are issues to be dealt with. Which legs sequence, and which have autopilot signals generated when they are active? Are those analog signals from the deviation of your CDI or are they pitch and/or roll signals from your GPS direct to your autopilot? Are there vertical components to a flight leg, and what are the 3 ways those can be generated? How are flight legs that represent a procedure inserted into your flight plan, and where? What problems does that create, and what tools are at your disposal to solve them? These issues are explored with examples taken from the GNS 430W/530W, 480, GTN 650/750, and G1000, and from the Chelton and Avidyne 440/540. The use of autopilots and GPSS convertors are illustrated as well, using the DFC90, KFC225, Sorcerer, S-Tec 55x, and G700. Using this variety of GPS/Autopilot combinations exposes the pilot to a number of different looks at the same problems. It should be especially useful to flight instructors, but even if you only use one specific unit this broader look will help you understand your device better.