Hi
I wonder how this commercial version of a gpl x-plane plugin was done? Have a look here:
http://forums.x-plane.org/index.php?showtopic=60497

Is such possible or should I report it to gpl violations?
Thanks

If it is just a plugin for a gpl tool without using any code of the gpl tool..hmm..IMHO this would be no violations, but a lawyer could have an other option.

A GPL program can consume a non-GPL library/module/plugin (assuming the non-GPL plugin was built correctly to avoid GPL code). But I think the first reply to that post answers it pretty clearly:

You don't have to order a copy to get the sorucecode.
It's open: http://code.google.com/p/sasl/

The commercial version just adds an additional module to encrypt the scripts, and that module is of course not GPL.
[/quote]

So:
*X-plane is a commercial product
*SASL is a GPL project
*There is also a commercial version of SASL, created by the original authors of SASL.

The bold bit is the key. Normally, this commercial version of SASL would also have to be GPL licensed (which means you would be able to ask them for the source-code).
However, because the same company makes the GPL and the commercial version, this is known as dual-licensing -- they own the original copyright over the SASL code, and as long as they don't accept any public GPL-licensed contibutions, they continue to own the copyright over that code.
If they own the code, they can license it however they want. They can even release it under multiple licenses, which is what they've done. They've released a 99% complete version of their code, under the GPL license, and they've also released a 100% complete binary version under a commercial license.

Yes, I've asked the autor if he has also created the commercial version. If not, I might investigate that further and get back.