Ive flown off quite a few full scale airports during contests. Never had a problem and it would not be a violation of the AMA rules either. There are quite a few model airplane clubs that use full scale runways. Mind you these are not busy airports by any means. you should not worry about the 400 foot altitude. The important thing to remember is the full scale planes always get the right of way. NO EXCEPTIONS. Another one of the clubs i used to fly at had a small private airport across the street and the owner was not to happy with us flying there and would make low passes directly over our runway. But after about a year he figured that we always kept an eye open for him there has been no times at all in the last few years he's flown over the runway. Just watch out for those powered parachutes. They are quiet and will appear from behind the trees and are they slow. So slow in fact that just about any 40 size trainer at idle is probably three times as fast. you have to give them a wide berth.

I say go right ahead and use it. As long as you have permission. The people flying full scale planes know your there and the the guys flying model planes know there there. See one big happy family.

Dennis