Is it a user fee when I purchase an aviation chart or approach plates?
IF it were illegal to reuse charts, yes. But it's not. So no.
What does that have to do with whether it's a user fee or not?

Call it what you wish; what you call it is more semantics than anything
else. The difference I am bringing up is that when you purchase a
chart, you are not purchasing "the right to use the chart for a
specified time". It is like purchasing a book. You can read it any
time you want, you can lend it out, you can share it with friends. If
you download a tune on some services, you are most emphatically =not=
allowed to listen to it anywhere you want. You may not share it with
friends, and after you've played it a certain number of times, it
evaporates. You are paying for the "use" of the tune, but you are
paying for the =book= itself.

This is a non-trivial difference in the music world.

Something similar operates here simply due to the timeliness of the data
being used. A radar picture is not very useful a day later, so you
really are essentially paying for the =use= of the image. And,
impractical as it may be, you are probably not allowed to re-transmit
the data to the plane behind you. A similar issue exists with (say) the
Jepp subscription. You can hand your paper approach plates to another
pilot, who can use it in another plane. However, you can't do the same
with the subscription data in your GPS. And you can buy plates a state
at a time, but if you want to update your GPS, it's the whole country or
nothing. These are also non-trivial differences.

Jose
--
The monkey turns the crank and thinks he's making the music.
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