There was a very interesting reconstruction and reporter investigation conducted by National Geographic Channel. They interviewed many people, including French technical staff who were eye witnesses. What came out was far from conclusive that it was caused by 'that single piece of metal' puncturing the wing. These guys claimed to have seen other things, but were not listened too. Where's Michael Moore when you need him? I'm not trying to trivialise the issue, but the program did raise some question which, in the aftermath, do not appear to have been answered. It may not have been such a simple stright forward matter. I stand to be corrected in the final report.