TCAS791
Operating Instructions
Pilot’s Guide
2-5
Table 2-1. Controls and Indicators (Continued)
No
Description
12
No-Bearing Traffic Advisory
If bearing is not available for an intruder aircraft that meets the TA
criteria described in chapter 3, the TA takes the form of this amber
line of text beginning with the letters TA and including the intruder
aircraft’s range, a data tag, and a vertical trend arrow.
13
Own Aircraft
This symbol represents your aircraft.
14
Data Tag
These two digits indicate, in hundreds of feet, the relative altitude
of the intruder aircraft. A positive data tag is displayed above the
traffic symbol to emphasize that the intruder aircraft is above your
aircraft. Similarly, a negative data tag is displayed below the traffic
symbol. If the intruder is at the same altitude as your aircraft, 00
will be displayed above the traffic symbol if the intruder closed
from above, or below the symbol if the intruder closed from below.
The data tag for a vertically out of range TA remains at the
maximum or minimum altitude number for the current altitude
display mode until the intruder aircraft comes within the altitude
limits of the selected altitude display mode. The TCAS791 only
displays data tags for altitude reporting aircraft.
15
Out of Range Traffic Advisory
When an intruder aircraft that meets the TA criteria described in
chapter 3 is beyond the displayed range, the corresponding TA
symbol is this solid amber semicircle located at a position along the
outer range ring that indicates the relative bearing of the intruder
aircraft. Range is the only factor that determines whether a TA is
represented by a circle or a semicircle. For example, if a TA is
within the display range but outside of the selected altitude display
mode, it’s still represented by a circle instead of a semicircle.
–
Audio Alert Adjustment Screw
This 1-turn potentiometer inside the data card access door on front
of the TRC adjusts the volume of aural messages. If the volume
level preset at the factory is not appropriate for your installation,
use a small screwdriver to turn the screw clockwise to increase the
volume or counterclockwise to decrease the volume. Use extreme
caution if you adjust this screw. Applying too much pressure will
break the plastic adjustment screw housing off of the circuit board.