Air-crash investigations in the United States are normally carried out by the NTSB's air accident investigation division, and there are several documentary television series featuring this government agency's painstaking approach when investigating the causes of air crashes. During many such investigations, serial numbers from recovered parts are cross checked with the airline-in-question's purchase and maintenance records, to try and identify the reason for an accident, when it is suspected that mechanical failure may have been the cause.
However the NTSB has confirmed that—apparently for the first time from its inception, in 1967, since when it has investigated more than 124,000 other aviation accidents—it took no part in investigating any of the air crashes which occurred on September 11, 2001. So the world has been asked to take it on faith and hearsay that the four planes involved were normal scheduled flights which were hijacked by Arab terrorists, some of whom, are, allegedly, still alive.
Even more disturbing is the fact that documentation exists, and is available on the Internet, which indicates that the FBI, backed up by a separate letter from the Justice Department has refused to release any information, under the Freedom of Information Act, about any debris recovered from the crash sites, including the serial number of the "Black Box" Cockpit Flight Data Recorder allegedly found near the alleged crash site of United Airlines Flight 93. It may be recalled that a transcript taken from this recorder formed the basis for several TV dramas and one Academy-Award winning feature film.
http://www.salem-news.com/articles/marc ... nes-al.php
I knew there were reasons to suspect that the plane which hit the south tower had been switched and might not be what was claimed but this is the first I heard of this.