ITP Traffic List
Last aircraft First aircraft
32 NM AHEAD OF 45 NM BEHIND
Figure 3-27: Sorting of the ITP Traffic List
The TCAS computer also indicates when the ITP maneuver is in progress (refer to Figure 3-28), or when a standard procedure instead of ITP is sufficient to perform a climb or a descent (refer to Figure 3-29).
3.6.4.2.4. Combination of TCAS and ADS-B Information
TCAS information is based on TCAS measurements (refer to 3.1.2 – TCAS Principle). ADS-B information is based on GPS sensor of surrounding aircraft. Therefore, ADS-B information is supposed to be more accurate than TCAS information.
The TCAS computer uses the best positioning source for display. Most of the time, the TCAS computer will use ATSAW information. However, the TCAS computer do NOT display the ATSAW symbol of a surrounding aircraft on ND (or the traffic information in the MCDU Traffic List) for the following reasons:
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When ADS-B information is outdated by 3 s, or
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When the position of the surrounding aircraft received by ADS-B differs from its TCAS position by:
.
0.5 NM in range, or
.
200 ft in altitude, or
.
± 30° in bearing.
- When the surrounding aircraft transmits:
.
For surrounding aircraft equipped with a DO-260 transponder: a NUC value from 0 to 4 inclusive
.
For surrounding aircraft equipped with a DO-260A transponder:
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A NIC value between 0 and 5 inclusive, or
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A SIL value between 0 and 1 inclusive, or
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A NAC value between 0 and 5 inclusive.
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When the surrounding aircraft does not transmit its track or position, or
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When the GPS position of the own aircraft is lost for more than 5 min, or downgraded (HIL higher than 0.5 NM).
The TCAS computer displays the TCAS Only symbol when:
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The TCAS computer does not display the ATSAW symbol for the reasons above
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The TCAS information is available.
3.6.4.2.5. Information sources for ADS-B traffic
The following table provides the sources of information displayed for ADS-B traffic.
Information Primary source Secondary source Remarks
Aircraft identification ADS-B N/A
Position ADS-B N/A The ADS-B traffic position is taken from GPS sensors of ADS-B traffic. The ADS-B traffic position is checked against its TCAS range (refer to C.2.5 – ITP Distance) for the verification of ADS-B data integrity.
Wake vortex category ADS-B N/A
IAS ADS-B N/A
GS ADS-B N/A
Vertical speed ADS-B TCAS The TCAS function determines the vertical speed thanks to successive TCAS interrogations.
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