I worked a TWA TriStar tail strike at JFK, where the leading edge slat asymmetery brake experienced an overspeed trip and the crew continued to to carry out a full flap no slat landing. The first part of the aircraft to contact the runway was the translating cowl of the No. 2 engine. The deck angle in that case was in excess of 15 degrees. My experience of this, and several other tail strikes, is that the retractable tail skid (bumper) actually causes addtional damage rather than protecting the aft body.