System Description
TCAS791
1-2
Pilot’s Guide
Transmitter Receiver Computer (TRC)
The TRC is the primary unit of the TCAS791. It contains the circuitry
necessary to convert inputs into aural and visual advisories of intruding
aircraft. The TRC can track up to 35 intruder aircraft simultaneously. If the
TRC is tracking more than eight intruder aircraft, to reduce clutter, it will
only display the eight most threatening ones. If the TRC is tracking eight
or fewer intruder aircraft, it will display all the intruders. The TRC also
contains Built-In Test Equipment (BITE) which can detect faults or fail-
ures and verify that the TCAS791 is operating properly.
Control Display Unit (CDU)
The CD605 is a self-contained unit that provides display and control func-
tions. The display is a high resolution Cathode Ray Tube (CRT). The CRT
displays data in three colors: white, cyan (blue), and amber (yellow) on a
black background. (See figure 1-2.)
You may choose to display TCAS information on a compatible EFIS or
IVSI/TCAS display in lieu of, or in addition to the CD605. The alternate
displays provide display functions similar to the CD605, but require dis-
crete switches mounted in the cockpit.
Interaction of Major Components
Figure 1-3 shows how the major components of the TCAS791 connect to each
other and to other aircraft systems.
Notes on Figure 1-3:
1. You can use the TCAS791 without a radio altitude input,
but when you’re flying at low altitudes, you may see more
Figure 1-2. Typical Screen on the CD605 Control Display Unit (CDU)
