Rainboe - actually the first touchdown looks very violent as if recovering desperately from wind shear - his tail strikes something leaving a small visible puff, well beyond the threshold and it appears near the roadway underpass at that end of 16L, before the main hard touchdown with its large debris cloud. The initial contact could be the left wing contacting a light standard or part of the landing light structure. In any case there is contact with something at the very end of the runway a good 1.5 seconds before the first major impact, indicating his altitude was rapidly decaying - his pitched up nose indicates a GA attempt just as in Dallas - that L1011 at least had the same flight dynamic issues as the MD-11 if not the same specific handling peculiarities.
-drl