According to Colleen O'Hara of Rannoch:
http://www.rannoch.com/TCASFCW.html
Overcoming Growing Pains
The idea for TCAS dates to 1956, when two planes collided over the Grand Canyon, and airlines realized they needed a collision avoidance system. TCAS is an outgrowth of a system developed in the 1970s that was called the Beacon Collision Avoidance System and used transponders located on airplanes. The system was replaced by the family of TCAS systems in 1981.
The success of TCAS is attributed to an unusual level of cooperation between the FAA and the airlines. FAA funded most of the development and design of the system. Mitre developed the system logic, and the FAA Tech Center and a team of contractors handled software verification and validation and performed operational tests. MIT Lincoln Laboratory developed air-to-air surveillance.
TCAS, like most complex systems, had its growing pains. "When TCAS was deployed, there were a lot of nuisance alerts, and pilots and controllers were losing confidence in the system," said Andy Zeitlin, principal engineer for avionics at Mitre CAASD. "We changed the system to fix that, and the results were dramatic." Version 7 of TCAS, which reduces the number of false alarms, was approved in December and will begin appearing as early as the end of this year.
"TCAS is a good example of [what good can be done] when we work together in the interest of safety," said Albert Prest, vice president of operations at the Air Transport Association.
"TCAS is an industry program that would not have occurred without FAA leadership," said Capt. Robert Buley, a pilot and manager of flight technology development at Northwest Airlines.
"If it were not for a congressional mandate, we would still be designing this. Had we not had the mandate, there would have been more collisions we would have had to live with," Buley said.
Buley has been involved with TCAS in one form or another since the 1970s. He is chairman of the RTCA standards committee that led the TCAS standards-and-design effort. All the time devoted to TCAS has been time well-spent, he said. "I will be walking down an airport concourse and a pilot will stop me and shake my hand and say, 'Thanks for TCAS,' " he said. "I even get calls from overseas."
There's no question TCAS has saved lives. Since its introduction, the number of reported near collisions has dropped, said Larry Nivert, the FAA's TCAS program manager. "There is a correlation between the date TCAS was introduced and now and the drop in near midair collisions. It's certainly an indication that TCAS has had a positive effect."
”Thanks for TCAS!”