Yes, it has been discussed many times on the forum.
- Someone suggested we could do a non-functioning apu, just for show, but this is not what we generally like to do: if a vehicle that has a purpose in real life exists, it should do something to the simulation.
- A functional vehicle would maybe help with battery draining on airplanes that use default subsystems, but it would become very complex to support 3rd party airplanes with their own implementations made with custom code, because many of them might have found alternatives in code to the problem of the FSX too fast battery drain.
- FSUIPC also has a feature that helps with that.
- The most complex 3rd party add-ons that most people uses, have entirely custom subsystems, and they have their own APU/Air cart anyway.
So yes, it's a potentially interesting addition, but it has a lot of issues that must be considered. In any case, it's something probably reserved for GSX 2...
