9-38
GTN 625/635/650 Pilot’s Guide
190-01004-03 Rev. P
Traffic
Altitude
(Feet*)
TA Time to CPA
(Seconds)
RA Time to CPA
(Seconds)
0 - 1,000
20
RA not issued below
1,000 feet
1,000 - 2,350
25
15
2,350 - 5,000
30
20
5,000 - 10,000
40
25
10,000 - 20,000
45
30
20,000 and above
48
35
*
System uses pressure altitude except when Radar Altitude is available. Radar Altitude takes
precedence over pressure altitude reporting
.
Table 9-17 Altitude-based TCAS II TA/RA Alert Thresholds
The TCAS II system categorizes detected traffic into four groups of increasing
collision threat potential:
•
Other Traffic
(OT), displayed as a hollow white diamond, is not currently
a threat.
•
Proximate Traffic
(PT), displayed as a filled white diamond, is not
currently a threat, but is within 6 nm and ±1,200 feet of the own-aircraft
altitude.
•
Traffic Advisory
(TA), displayed as a filled yellow circle, indicates traffic is
within 20-48 seconds of a potential collision area. If a Traffic Map is shown,
and the TA traffic is beyond the selected map range, the system displays a
half-TA symbol at the edge of the map at the approximate relative bearing
of the TA traffic. If TA traffic subsequently meets the criteria for an RA, the
system will issue an RA.
•
Resolution Advisory
(RA), displayed as a filled red square, indicates
traffic is within 15-35 seconds of a potential collision area. If a Traffic
Map is shown, and the RA traffic is beyond the selected map range, the
system displays a half-RA symbol at the edge of the map positioned at the
approximate relative bearing to the RA traffic.
Summary of Contents for GTN 625
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