• 1956 - Two planes collided over the Grand Canyon
• 1974 - Alternative airborne version using transponders
• Beacon-Based Collision Avoidance System (BCAS)
• 1981 - The FAA chose to pursue the onboard design
• BCAS was renamed TCAS
• 1986 - While TCAS still in development, collision occurred
• 1993 - Congress mandate all carrier acft operating w/in US
• 1997 - Final major change to the TCAS logic, version 7
Increasing aircraft collision.
Supplement radar information
system early 70s.
It bases its operation on the
signals emitted by the
Assists the pilot in preventing midair
The system interrogates the transponders
of other aircraft using his responses to
determine the flight paths of each.
With this information it discriminates
between traffic that may be at risk and
• A TA indicates that an aircraft
• is a potential threat
• RA may be necessary w/in, approx, the next 25 sec
• most commonly displayed as a yellow circle
• An RA indicates that an aircraft
• Is a threat
• displayed as a red square
• accompanied by a recommended vertical maneuver.