Plausibility Of 9/11 Aircraft Attacks Generated
By GPS-Guided Aircraft Autopilot Systems
Aidan Monaghan, Journal of 9/11 Studies (pdf with refs.)
Because information collected after the terrorist attacks of September 11, 2001 has raised questions about the alleged ability and motivation of the people accused of piloting four Boeing 757 and 767 planes into the WTC, the Pentagon, and a field in Pennsylvania, speculation has since lingered regarding the covert use of technology that day to navigate the four airliners precisely without onboard pilot control. US federal government and civil aviation industry publications describe the development and implementation, pre- Sep 11 2001, of state-of-the-art systems capable of facilitating precise automated navigation of the Boeing 757 and 767 aircraft used that day to a given destination.
The Global Positioning System (GPS) is a space-based radio-navigation system that generates accurate positioning, navigation and timing information for civil use at no cost. The information signal can be obtained through the use of GPS signal receiving equipment. Augmented GPS signal service, intended to replace dated and expensive ground-based aviation navigation signals, was developed during the mid-to-late 1990s by the FAA and Raytheon. Known as the Wide Area Augmentation System (WAAS), precisely surveyed ground-based Wide-area Reference Stations monitor and collect GPS satellite signal errors. Ground-based Wide-area Master Stations then transmit corrected GPS signal information to ground-based Ground Uplink Stations, that then transmit the corrected GPS signal information to Geostationary Satellites. These satellites then broadcast the corrected positional information back to Earth for use within a GPS-like signal. The FAA announced on Aug 24 2000 — just 13 months prior to the Sep 11 2001 attacks — that the WAAS signal was available pending final approval by the FAA. Horizontal and vertical positional data accurate to between 1m and 3m, and sufficient for Category I precision aircraft runway approaches, was now available throughout the contiguous US.
During numerous FAA and NASA sponsored runway approach and touchdown test flights between 1994 and 2002, involving augmented GPS positional signals and the auto-land systems of Boeing 757, 767 and other Boeing 700 series aircraft, horizontal and vertical positional accuracies of just several meters or less were routinely achieved. The four aircraft used to carry out the Sep 11 2001 terrorist attacks were also Boeing 757-200 and 767-200 model aircraft. During Oct 1994 at NASA’s Crows Landing Flight Facility in California, 110 autopilot approaches and touchdowns of a United Airlines Boeing 737 aircraft facilitated by augmented GPS positional signals were successfully conducted, with “accuracies on the order of a few cm” being consistently achieved. During Oct 1994, augmented GPS signal flight tests sponsored by the FAA in cooperation with Ohio University were conducted. 50 autopilot approaches and touchdowns were successfully performed by a donated United Parcel Service Boeing 757-200 series aircraft. The augmented GPS positional signal was integrated into the aircraft Flight Management System (FMS). During Jul and Aug 1995, Honeywell, Boeing and NASA sponsored tests using NASA’s Boeing 757-200 test aircraft and performed 75 autopilot approaches and touchdowns. The predicted augmented GPS system aircraft positional accuracy of 1m to 2m was successfully achieved. During Aug 1999, multiple augmented GPS signal autopilot approach and touchdown tests were performed using a donated United Parcel Service 767 aircraft.
These tests were sponsored by the FAA and were centered on the prototype GPS-based Local Area Augmentation System (LAAS), which is intended to compliment the FAA’s WAAS signal. The LAAS signal can provide aircraft positional accuracy of less than 1m vertically and laterally. On Aug 25 2001, a Fed-Ex 727-200 aircraft equipped with a Rockwell-Collins GNLU-930 Multi-Mode Receiver, conducted six full auto-lands during joint USAF/Raytheon sponsored test flights, using the Joint Precision Approach and Landings System (JPALS), the military augmented GPS counterpart of the civil LAAS system. On Jan 17 2002, a series of auto-coupled (hands-off) approaches, through touchdown and rollout, were conducted to further test the LAAS system with a Fed-Ex Boeing 737-900, equipped with a Rockwell-Collins GLU-920 Multi-Mode receiver. The augmented GPS capable GLU-920 Multi-Mode receiver pre-dates September 2001, and is designed for use within the Boeing 757-200 and 767-200 model aircraft, like those used during the Sep 11 2001 terrorist attacks.
The installation of GPS signal utilizing avionics systems for use in the Boeing 757 and 767 model aircraft like those involved in the Sep 11 2001 terrorist attacks was planned several years prior. On Sep 6 1996, Rockwell-Collins Commercial Avionics announced plans by Boeing and major commercial airlines to install Rockwell-Collins Multi-Mode Receiver (MMR) landing systems within their Boeing 757 and 767 aircraft. The MMR system can utilize the WAAS signal as well as the basic GPS signal, the VHF, UHF, VOR navigation signals and eventually the LAAS navigation signal. On Sep 7 1998, Honeywell International announced plans by American Airlines and United Airlines to install the GPS-capable Pegasus Flight Management System (FMS), with 150-waypoint route capacity, within their Boeing 757 and 767 aircraft. An aircraft FMS is comprised of three major systems including an aircraft’s Auto-Flight System. Aircraft Auto-Flight Systems were utilized during the aforementioned GPS signal test flight approaches and touchdowns. By 1999, Boeing 757 and 767 aircraft contained digital flight control systems that can “automatically fly the airplanes on preselected routes, headings, speed or altitude maneuvers.”
On Oct 9 2001, Cubic Defense Systems Inc. applied for a US patent that removes control of an aircraft from its pilot and utilizes an aircraft’s auto-pilot system to implement an uninterruptable preprogrammed auto-pilot flight plan in order to navigate an aircraft to a given destination during an emergency. This would be accomplished through the use of an electronic or mechanical relay or relays, that become activated by pilot operation of an aircraft hijack notification system. Surprisingly to some, none of the four aircraft destroyed on Sep 11 2001 are known to have entered unique transponder hijack notification codes, suggesting either modified function or insufficient activation time. One optional feature of the Cubic system is termination of an aircraft’s ability to communicate. In two cases, hijacker communications reportedly aimed at passengers on board AA11 and UA93 on Sep 11 2001 were heard instead by air traffic controllers, suggesting modified communication functions. The Cubic patent also references Honeywell’s 1995 augmented GPS flight navigation research and development, presumably as a signal navigation aid. The system also envisions the use of new aircraft flight instructions transmitted by a remote sender, that would override aircraft functions already underway and direct an aircraft auto-pilot system to navigate an aircraft to a predetermined landing destination.
A data link interface between an aircraft Flight Management System (FMS) and the Management Unit for the Aircraft Communication Addressing and Reporting System (ACARS), was developed during the early 1990s. This communication system allows for the update of an aircraft FMS in mid-flight. An aircraft auto-pilot system is part of the FMS. Because the Flight Data Recorders (FDRs) for AA11 and UA175 were not recovered, details regarding the operation of each aircraft are not known. The FDRs for AA77 and UA93 were recovered and indicate pilot control of each aircraft. However, the FDR readout file for AA77 was completed four hours and fifteen minutes before the said FDR was recovered, suggesting false or altered FDR information. And the FDRs for AA77 and UA93 are virtually the only ones during the previous 20 years of major NTSB US aviation mishap investigations, for which unique inventory control serial numbers were not published. Such serial numbers are required to facilitate FDR data readouts. In fact the NTSB possesses no records pertaining to the positive identification of the FDRs for AA77 and UA93.
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