Inventor Of TCAS Was 89

If you've ever been alerted by the urgent warnings from your cockpit-mounted collision avoidance system, calling your attention to nearby traffic you hadn't seen... you have George B. Litchford Sr. to thank. The prolific inventor, who worked on aircraft navigation and surveillance systems for some 60 years, passed away February 28 at the age of 89.

Litchford was hired by Sperry Gyroscope Research Labs in 1941, and set about trying to find a way to alert pilots to nearby hazards. It was Litchford who determined signals from an aircraft's transponder could be used not only by controllers on the ground, but also by other aircraft... and the idea of the Traffic alert and Collision Avoidance System, or TCAS, was born.

The need for such devices on commercial aircraft was clear to officials, in the aftermath of a 1956 midair collision over the Grand Canyon... but it took another 30 years -- until a midair collision involving an Aeromexico DC-9 and a private plane over Los Angeles, that killed 82 people -- before Congress mandated TCAS be installed on all commercial aircraft rated to carry more than 10 passengers.

"He was an industry leader in developing one of the most significant aviation safety systems ever designed," industry safety consultant John Cox told The New York Times.

In addition to his work on TCAS, Litchford also earned a patent for use of aircraft transponder signals by private, ground-based tracking stations, to track the movement of aircraft. He licensed the technology to a company called MegaData, which later became Passur. The company now operates that system at 90 locations worldwide, and airlines use that data to track operations.

Litchford, a fellow of the American Institute of Aeronautics and Astronautics, also worked on developing a safer landing system for use on US Navy aircraft carriers, and on equipment to help civilian planes land in low visibility conditions.

FMI: http://adsb.tc.faa.gov/TCAS.htm