TCAS II V7.1 Intro booklet

Operational Performance Standards
(MOPS). Engineering flight tests of this
equipment were conducted on the
manufacturers' aircraft as well as FAA
aircraft. Using data collected during these
flight tests, along with data collected during
factory and ground testing, both
manufacturers’ equipment were certified via
a limited Supplemental Type Certificate
(STC) for use in commercial revenue
service.
The Bendix-King units were operated by
United Airlines on a B737-200 and a DC8-
73 aircraft. Northwest Airlines operated the
Honeywell equipment on two MD-80
aircraft. Over 2000 hours of operating
experience were obtained with the United
aircraft and approximately 2500 hours of
operating experience were obtained with the
Northwest installations.
The experience provided by these
operational evaluations resulted in further
enhancements to the TCAS II logic,
improved test procedures, and finalized the
procedures for certification of production
equipment. The most important information
obtained from the operational evaluations
was the nearly unanimous conclusion that
TCAS II was safe, operationally effective,
and ready for more widespread
implementation.
Version 6.0 / 6.04a Implementation
In 1986 the collision between a DC-9 and a
private aircraft over Cerritos, California
resulted in a Congressional mandate (Public
Law 100-223) that required some categories
of U.S. and foreign aircraft to be equipped
with TCAS II for flight operations in U.S.
airspace. Based on Public Law 100-223,
FAA issued a rule in 1989 that required all
passenger carrying aircraft with more than
30 seats flying in U.S. airspace to be
equipped with TCAS II by the end of 1991.
This law was subsequently modified by
Public Law 101-236 to extend the deadline
for full equipage until the end of 1993.
Based on the successful results of the inservice
evaluations, RTCA published
Version 6.0 of the TCAS II MOPS (DO-
185) in September 1989 and Version 6.0
units were put into full-time revenue service
in the U.S. starting in June 1990.
As part of the mandated implementation, an
extensive operational evaluation of TCAS,
known as the TCAS Transition Program
(TTP), was initiated in late 1991. In
conjunction with the TTP in the U.S.,
EUROCONTROL conducted extensive
evaluations of TCAS operations in Europe
and the Japan Civil Aviation Bureau (JCAB)
conducted similar assessments of TCAS II
performance in Japanese and surrounding
airspace. Other countries also conducted
operational evaluations as the use of TCAS
began to increase.
The system improvements suggested as a
result of these TCAS II evaluations led to
the development and release of Version
6.04a of the TCAS II MOPS (DO-185)
published by RTCA in May 1993. The
principal aim of this modification was the
reduction of nuisance alerts which were
occurring at low altitudes and during leveloff
maneuvers and the correction of a
problem in the altitude crossing logic.
Version 7.0 Implementation
The results of the TTP evaluation of Version
6.04a indicated that the actual vertical
displacement resulting from an RA response
was often much greater than 300 feet, and
TCAS was having an adverse affect on the
controllers and the ATC system. This led to
the development of Version 7.0 and
numerous changes and enhancements to the
collision avoidance algorithms, aural
annunciations, RA displays, and pilot
training programs to: (1) reduce the number
of RAs issued, and (2) minimize altitude
displacement while responding to an RA.
Also included were: horizontal miss distance
filtering to reduce the number of
unnecessary RAs, more sophisticated multithreat
logic, changes to reduce nuisance
repetitive TAs on RVSM routes in slow
closure situations, changes to increase the
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