Thanks George, I've dappled with the Aircraft speed in the aircraft txt file and as long as its not above approx 350 all works well. Still like to know the reason but thats usually how IT systems work.

Personally I feel 23 parking spaces is not enough, unless you are saying there are 23 large enough for this aircraft. Ive put 80 minimum at all fields where I create AFCADS, and most of the time at least 50% are filled. This leaves a good deal of empty spaces for incoming aircraft.