Red Flag -Transponders Not Required to Track Errant Aircraft

Most people don’t realize that on September 11th, planes were known to be high jacked and flying around the Eastern US for over 70 minutes.  After September 11th, many wondered why our air force was unable to stop the high jacked aircraft, especially American Airlines Flight 77 which struck the Pentagon.  American Airlines Flight 11 was high jacked at 8:14. By 8:25 Boston air traffic controllers confirmed that the flight was indeed high jacked and the aircraft struck the North Tower of the World Trade Center at 8:46.   At 9:03, United Airlines Flight 175 struck the South Tower and at that time, the whole world knew that America was under attack.  It was not until 9:37 that American Airlines Flight 77 hit the Pentagon.

Therefore, it was a full hour and 10 minutes between the time the FAA knew that Flight 11 was high jacked and the time Flight 77 hit the Pentagon.  How could this happen?  The area around the Pentagon and Washington D.C. is some of the most heavily defended airspace in the World.  This fact led many to believe there had to be a stand down order issued which would have prevented Standard Operating Procedures from allowing these aircraft to be intercepted.  A stand-down is defined as “a relaxation from a state of readiness or alert”.  This certainly took place regarding air defenses on 9/11.

One explanation offered was that the terrorists turned off the electronic device known as a transponder, which helps identify aircraft on radar.  As stated by the 9/11 Commission, it is possible, though more difficult, to track an aircraft by its primary radar returns without the transponder.  However, unlike transponder data, primary radar returns do not show the aircraft’s identity and altitude.

The 9-11 commission failed to consider the fact that the US military has more than just ground radar at their disposal.  In 2006 a golf ball was hit off the International Space Station.  New Scientist magazine reported that the ball was too small to be tracked by ground radar, but noted that,

“US military radar can track space debris as small as 10 centimeters across, and can sometimes see things as small as 5 cm wide if it is in just the right orbit.”

There are 35 USAF bases within range of the 9/11 flights, which included the restricted airspace surrounding the Pentagon, Capitol Hill and the White House.  It is hard to believe that a military which possesses such a highly-sophisticated radar system would not have been able to track the high jacked aircraft without a transponder signal.

Commercial airliners do not need their transponders on in order to be tracked by the FAA and NORAD.  If America was being attacked by aircraft belongin