I just installed the David Bushell/Vanessa Leightower SR-71 (an FS2000 model) and it refuses to hold the set altitude in autopilot.
The autopilot section of aircraft.cfg appears normal and I tried a different autopilot gauge - still no good. It just ignores the set altitude and climbs like a bat out of hell. Every other part of the autopilot works - speed, heading, etc.
Has anyone else experienced and overcome this problem?