>> [...] In most of the flight envelope the aircraft is stable. >> At high alpha the aircraft has pitch problems. > I believe the airplane is aerodynamically

>> [...] In most of the flight envelope the aircraft is stable. >> At high alpha the aircraft has pitch problems. > I believe the airplane is aerodynamically stable even at high alpha. [...] This is not a flying wing or intentionally unstable airplane (as the F-16). In some ways that's likely worse news than an airplane that's inherently unstable in general, no? A corner case, and one that evidently isn't actually all that uncommon. If you're building something like an F-16 you know that you absolutely have to make the fly-by-wire correct and robust, and the ground crews similarly know that if anything affects its performance the plane isn't fit to fly.