NOTE : Level 1 corresponds to Standby Mode in which no advisory is
____ generated.
NOTE : This table indicates the threshold based on own aircraft altitude.
____ Each aircraft altitude depends on an hysteresis:
-1000 plus or minus 100 ft,
-2350 plus or minus 200 ft,
-5000 plus or minus 500 ft,
-10,000 plus or minus 500 ft,
-20,000 plus or minus 500 ft,
-42,000 plus or minus 500 ft. For example, to switch from sensitivity level 3 to sensitivity level 2, the altitude must fall below 900 ft. However, to switch from sensitivity level 2 to sensitivity level 3, the altitude value must go above 1100 ft.
(Ref. Fig. 024B)
There are two other means of modifying the sensitivity level:
-selecting TA only mode on the ATC/TCAS control unit forces level
2. In this case, intruders of all types are displayed but will not be transformed into RA symbols and no vertical speed modification indications will be issued.
-the ATC/Mode S equipped ground stations may modify the sensitivity level of the aircraft TCAS via the uplink without, however, having the capability to force the Standby Mode. If several ground stations command sensitivity levels, the TCAS logic selects the lowest level. Definition of priority logic: First a sensitivity level based on altitude is selected. Level 2 is selected if the radio altimeter altitude is less than 1000
R 1EFF : 001-049, 101-105, 151-199, 201-210, 1 34-43-00Page 99 1 1 May 01/05 1 1 1CES 1
ft. Level 2 is also selected if own aircraft is configured such
that both CLIMB and DESCEND RAs are inhibited. Level 3 is
selected if the aircraft is above 1000 ft and below 2350 ft AGL.
If the aircraft is above 2350 ft AGL, barometric altitude is
used to select either level 4 (below 5000 ft), 5 (from 5000 to
10,000 ft), 6 (from 10,000 to 20,000 ft), and 7 (above 20,000
ft).
ATC/TCAS control unit input is read by the TCAS computer. If the
pilot has selected Automatic Mode (TA/RA), then the
altitude-based sensivity level will be used in comparisons to
determine the final level.
From all sensitivity level commands, if any, received from
ground stations, the lowest is selected.
If the TA ONLY mode is selected, either manually via the control
unit or by a ground station, the altitude-based sensitivity
level is used for TA thresholds and the RAs are inhibited.
Otherwise, the lowest of all inputs is chosen.
R
R **ON A/C 001-049, 101-149, 151-199, 201-299, 301-399, 401-499,
R G. Information Display
R The TCAS information is presented on the CAPT and F/O NDs of the EFIS
R system. Additional messages can also be presented on the display units of
R the ECAM system.
R (1) Traffic information on the ND
R Target aircraft are presented on the ND in ROSE or ARC mode but not
R in PLAN mode.
R These traffic indications show the situation in the surveillance
R zone.
R The aircraft present in this zone are represented by symbols whose
R shape and color correspond to the type of intruders defined in the
R TCAS.
R The symbols are positioned on the ND so as to depict their relative
R bearing and range. Data tags are associated with intruders.
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