GPS are computer based systems.
• More capable, but much more complex. They differ from model to model. The TSO’d units have standardized functions,
but the user interfaces differ...
• Most readily used for flying over a sequence of defined fixes stored in a “flight plan”. The GPS auto-sequences to fly to the next fix as the previous one is crossed.
• Pilot input may be required to interrupt this sequence – to hold or make a procedure turn, or to skip fixes – as in “vectors-to-final”.
• Flying overlay approaches is more complex than flying those designed for GPS.