Please excuse the poor wording of the first sentence of my previous post.
Vd/Md are design speeds which don't have to be demonstrated in flight. Vdf/Mdf are determined during flight test - high speed testing is done at speeds up to Vdf/Mdf (by definition these cannot exceed Vd/Md).
Typically the manufacturers that I have flown with use the -7.5 degree flight path for twenty seconds from Vmo/Mmo, with maximum cruise power, to simulate a type of upset required by FAR 25.253. The justification being that this is a method of establishing Vd/Md (by test or analysis), already written in the certification standards (FAR 25.335) so should be accepted by the regulatory authority during the determination of Vdf/Mdf.
Whatever method of upset simulation used (and accepted by the certification authority) the aircraft will be flown to, and recovered from, speeds significantly greater than Vmo/Mmo
Last edited by zzuf; 22nd May 2012 at 14:38.
Reason: typo