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Operating Instructions
TCAS791
2-2 Pilot’s Guide
Table 2-1. Controls and Indicators (Continued)
No Description
2
Vertical Trend Arrow
A vertical trend arrow indicates that the intruding aircraft is
descending (down arrow) or ascending (up arrow) at a rate greater
than 500 fpm. No arrow is shown for non-altitude reporting aircraft.
3
Traffic Advisory (TA)
A TA consists of a visual symbol on-screen and an aural
“traffic,
traffic”
message over a cockpit speaker or headset. When an
intruder aircraft that meets the TA criteria described in chapter 3 is
within the displayed range (inside or outside of the selected altitude
display mode), the corresponding visual symbol is this solid amber
circle located at a position on the screen that indicates the relative
bearing and range of the intruder aircraft.
In general, a TA will occur when an intruder aircraft is detected
within 15–30 seconds of a possible collision, or within 0.2–0.55
nmi and ±600 ft to ±800 ft of your aircraft.
4
Proximity Advisory (PA)
PAs indicate the relative location of any traffic not generating a
traffic advisory but which is within 4 nautical miles (nmi) and
±1,200 ft of your aircraft. Non-altitude reporting aircraft are
considered to be at the same altitude as your aircraft.
5
No-Bearing No-Altitude Traffic Advisory
If bearing and altitude are 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 consisting of the letters TA and the
intruder aircraft’s range.
6
Range Rings
The range rings indicate distance from your aircraft. Figure 2-2 lists
the distances of the range rings on the CD605. On the CD605, the
range rings are centered on the own aircraft symbol in the middle of
the screen.
On some alternate displays, the aircraft symbol is located at the
lower center of the screen which causes clipping of the TCAS
display range area. (See figure 2-3.) On these displays, the 12:00
position on or near the outer range ring represents the selected
range, but as you move around to the 6:00 position on the outer
range ring, the range displayed decreases to 60 percent or lower of
the selected range depending on the display.