On Monday, January 7, 2013 10:20:53 AM UTC-6, son_of_flubber wrote:
A standalone PNA relies solely on GPS position and stored map data.



What does a standalone PNA do poorly without flight instrument data?



What information does a PNA obtain from flight instruments?



What does a PNA do better because it has flight instrument data? To what extent do these improvements enhance performance and/or safety? Is the improvement relevant to recreational flying, or is the degree of improvement small and only relevant to competition and record-setting?

Flight computers can calculate wind more accurately from flight instrument data than just GPS track -- or get those better wind calculations from the instrument. This can be slightly useful in wave, ridge, or on final glides.

In competitions, it's nice to have a clear display somewhere of exactly what altitude is being recorded by the logger. Sometimes it's easier to see that on the flight computer.

That's about all I can think of

John Cochrane