In my experience, limitations are often there simply because the manufacturer's test pilots have not had the time or resources allocated to take the aircraft beyond the limitation in question. On a military type I used to fly it was common to get expansions to the flight envelope as test pilots continued to completed flight test schedules for various fits and configurations. I doubt that -70C is a structural limitation. I suspect it is simply the coldest SAT experienced on any test flights.
EDJ, why don't you pop this one onto the Test Pilot forum? Somebody there might be able to give you a more informed opinion.
Last edited by Wingswinger; 9th February 2008 at 07:29.