Mxsmanic wrote:
Wolfgang Schwanke writes:

http://www.flightstore.co.uk/images/...rop_1_1241.jpg

Thanks. Still looks a bit awkward to use in flight. I mean, you have
to manipulate the device and the chart at the same time, and you have
no table, and you still have to fly the plane. It looks very awkward.

You do your flight planning before take-off.

But what if the plan must change during the flight?

That's part of the PTS requirement for a private pilot checkride before
they get their certificate. You start out with a great plan to go
somewhere and after they get past their 3rd checkpoint or so, you
change their destination. The applicant is required to give you
1)heading to new destiation 2) ETA (not time enroute) 3) fuel required.
-Robert, CFII