FAA History Lesson -- June 23 (08)

From the FAA Historical Chronology, 1926-1996...

”Jun 23, 1981: Administrator Helms announced FAA's decision to adopt the Threat Alert and Collision Avoidance System, soon renamed the Traffic Alert and Collision Avoidance System (TCAS). The TCAS system was an evolutionary improvement of the Beacon Collision Avoidance System (BCAS) that the agency had been developing (see Mar 1976). Like BCAS, TCAS would work in conjunction with the Air Traffic Control Radar Beacon System (ATCRBS) transponder already in wide use. It would also be compatible with the next-generation transponder, originally designated the Discrete Address Beacon System (DABS) and later known as Mode S (see Dec 27, 1978, and Oct 5, 1984).

Two types of the new collision avoidance system were planned. TCAS I, intended for general aviation use, would in its basic form simply alert the pilot to the proximity of another aircraft carrying TCAS I or a conventional ATCRBS transponder. More expensive TCAS I versions would have some ability to provide certain data on the altitude and/or "o'clock" position of threat aircraft. TCAS II would provide more sophisticated advisories, including data on range and bearing of transponder-equipped aircraft. When the transponder aboard the threat aircraft had altitude-reporting capability, TCAS II's advisories would also include altitude data. In the case of two aircraft equipped with TCAS II, coordinated advisories would be provided. TCAS II would suggest vertical escape manuevers. If feasible, the system might be enhanced to include both vertical and horizontal escape manuevers, a version later designated TCAS III. TCAS was expected to overcome a fundamental limitation of BCAS by its ability to operate effectively even in the highest air traffic densities. This modified the need for a new ground-based collision avoidance system, and led to discontinuance of the Automatic Traffic Advisory and Resolution System (ATARS) project, originally known as Intermittent Positive Control (see Mar 4, 1976).

On Nov 13, 1981, FAA announced a contract with Bendix Corporation to provide two TCAS II engineering models to be tested and then enhanced to advise pilots of horizontal escape manuevers. (See Mar 18, 1987.) “

June of 1981. A full five months before I hired on with FAA. I’m now retired -- 27 years later. We still don’t have TCAS III.

If feasible, the system might be enhanced to include both vertical and horizontal escape manuevers, a version later designated TCAS III.

Yep. NextGen is right around the corner. Just you wait (27 years) and see.

”Jan 10, 1989: FAA published a rule requiring the Traffic Alert and Collision Avoidance System (TCAS II) on all airliners with more than 30 passenger seats operating in U.S. airspace (see Mar 18, 1987). The airlines were to phase in TCAS II by Dec 30, 1991. On Apr 9, 1990, however, FAA extended the TCAS II compliance schedule completion date to Dec 30, 1993 (an extension that also applied to wind shear warning equipment: see Sep 22, 1988). The Jan 10, 1989, rule also required turbine-powered commuter aircraft with 10 to 30 passenger seats to install the simpler TCAS I by Feb 9, 1995, a deadline later extended to Dec 31, 1995. “

Once the FAA decides what NextGen is, it won’t take but, oh...say a dozen years, for them to require it be installed on all commercial aircraft.

Don Brown
June 23, 2008