Forgive me if I chose the wrong forum but I could find no category for Scruffy Duck software.

I want to install ADE to make a few mods to a default local airport in P3Dv4. Must I install ADE to the same HD that the simulator is installed on?

Thanks

No, not at all. You can install it anywhere you want, but you will also need an FSX SDK. For FSX SE, it never really came with a full SDK, but you can use a version from the other FSX options, but as it's been well over 10 years since I've had to myself, I don't know exactly which version. It's well documented though online and shouldn't take very long at all to find out.

I have my P3Dv4 SDK. That what I will work in.