I also don't really know if Appendix J was meticulously followed or not but there is no evidence it was. They claim they photographed one FDR and published the photo but they never showed that the serial number matched the parts log for the aircraft. IMO, if they really conducted a forensic examination of the parts, they would have proudly showed the match so that there would be no controversy about what actually hit the Pentagon. But they did all sorts of deliberate things to hide as much as possible (confiscating all the videos and showing 4 poor quality frames that show nothing, compromising the crime scene, classifying everything, etc.). Maybe a plane hit the Pentagon, maybe not. Maybe it was AA77, maybe it wasn't. We have no physical confirmation, despite that the NTSB guy said that the serial number on the recovered part would be used to confirm the aircraft. Just like with everything about 9/11, all the so-called investigations were a farce and a coverup.