The last successful hijacking prior to the 9/11 hijackings of a U.S. commercial aircraft happened in 1991. Philippines police officials reportedly said after the 9/11 terrorist attacks that they had passed information along to the U.S. authorities from one of the terrorists in the Bojinka plot. While under Philippine police interrogation the terrorist is reported to have said that he planed to crash an airplane into the CIA building. He was reportedly a pilot but it is unclear how he intended to obtain an aircraft to carry out his stated intentions.
A suicide hijacking was one of the possibilities considered by the FAA in 1999. "In early August 1999, the FAA's Civil Aviation Security intelligence office summarized the Bin Laden hijacking threat. After a solid recitation of all the information available on this topic, the paper identified a few principal scenarios, one of which was a ?suicide hijacking operation.' The FAA analysts judged such an operation unlikely, because ?it does not offer an opportunity for dialogue to achieve the key goal of obtaining Rahman41 and other key captive extremists. ?A suicide hijacking is assessed to be an option of last resort."42
Apparently there was sufficient data regarding the possibility of terrorist attack against U.S. aviation for the FAA to send Information Bulletins to the U.S. airlines in the weeks and months prior to the 9/11 attacks. Why then weren't more deliberate security actions taken by the FAA and/or the U.S. airlines?
FAA and Airlines' Permissive Rules and Practices Concerning Carry-on Edged Weapons
The 9/11 Commission notes that "While FAA rules did not expressly prohibit knives with blades under 4 inches long, the airline's checkpoint operations guide (which was developed in cooperation with the FAA) explicitly permitted43 them." The checkpoint operations guide (COG) did indeed permit knives with blades 4 inches and less except those considered to "pose a potential danger." The COG provides the following guidance in a section labeled "Restricted":44
"Guidelines for items that may not pass into the sterile area: Restricted articles items are things or substances that pose a potential danger. Even though they are not firearms or explosives, they are not permitted in the passenger cabin of an aircraft, i.e. (i.e. toy or replica gun, martial arts devices, swords, sabers or hunting knives, etc.) The supervisor must be notified if an item in this category is found."45
The 9/11 Commission also states in the same paragraph "A proposal to ban knives altogether in 1993 had been rejected because small cutting implements were difficult to detect and the number of innocent "alarms" would have increased significantly, exacerbating congestion problems at checkpoints." This last quote is footnoted46 and the reference is even more damning as it indicates that the FAA officials were fully cognizant of the danger these edged weapons posed to the safety of flight as early as the mid-1990s.
To the FAA's credit the Associate Administrator for Aviation Security convened the Aviation Security Advisory Committee and selected other persons into a Security Baseline Working Group to review the Government's aviation security measures. The Baseline Working Group had its first meeting on July 17, 1996, in Washington ? ironically the same day that TWA Flight 800 exploded over the ocean south of Long Island a few hours later. Unfortunately the Baseline Working Group never addressed the vulnerability of allowing knives with four inches or less onto commercial aircraft.
It is well known among security professionals that small knives are extremely difficult to find under normal X-ray examination, both in 1993 and today. All knives have been banned since 9/11 and new walk-through metal detectors have been purchased and deployed by the FAA/TSA47.
Apparently the Air Transport Association of America (ATA) considered the 1996 FAA Baseline Working Group an important endeavor because the ATA President and CEO, along with other ATA representatives, attended the first session on July 17, 1996. The FAA Baseline Working Group overlapped the start of the Gore Commission. The work, findings and recommendations of the FAA's Baseline Study Group were provided to the Gore Commission. The Working Group did not address, and from all indications, never discussed the vulnerability of permitting 4 inch or less edged weapons through airline screening points and onto aircraft.
9/11 Commission Failure to Address Root Causes for Screening Failures