I think in the 4-Apr-79 Hoot Gibson TWA 727-100 incident, JFK-MSP, possible uncommanded slat deployment, supersonic dive, 6g pullout, landed safely in DTW, that it was pretty well established he was supersonic. Incredible how strong those planes are, at least in the direction of intended stress.
BTW this was well told in the excellent book, Emergency! Crisis in the Cockpit by Stanley Stewart. See
http://www.amazon.com/exec/obidos/AS...587801-6869603