(2)
Proximate aircraft Targets are defined as proximate traffic if the difference between their altitude and that of the TCAS aircraft is less than 1200 ft and if their range is within 6 NM. Their presentation on the ND is conditioned by the presence of another TA or RA intruder (THREAT TRAFFIC function). Generally aircraft not in the immediate vicinity enter into this category. Depending on their trajectory, they may:
-conserve this status and move away without an advisory being declared. In this case the pilot is informed of their presence on the ND by a white filled diamond symbol and can monitor their progress, or
-have a trajectory liable to lead to a conflict situation and in this case they require a traffic advisory and their symbol changes.
(3)
Traffic advisory aircraft
(Ref. Fig. 022) When an intruder is relatively near but does not represent an immediate threat the TCAS issues a traffic advisory. Its presence is displayed on the ND by an amber filled circle. Its display is accompanied by an aural alert: "Traffic Traffic". The pilot is therefore aware of its presence and knows its range and relative bearing. Its display is linked to vertical separation and time TAU before CPA values. Depending on its trajectory, an intruder may conserve this status and move away, or it may become a collision threat. In this case avoidance maneuvers are suggested to the pilot via a resolution advisory.
(4)
Resolution advisory aircraft
(Ref. Fig. 022) In resolution displays, the intruder is represented on the ND by a red filled square and corrective orders are issued on the vertical speed scale of the PFD. Crossing into resolution advisory occurs for a TAU time threshold 10 to 15 seconds lower than a traffic advisory threshold. Vertical separation between the two aircraft is also taken into account for this category. There are two types of resolution advisory, in function of the vertical separation value:
-Preventive Advisories
-Corrective Advisories.
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(a)
Preventive Advisory In this case the vertical separation is less than a threshold S1 and greater than a threshold S2. The advisory instructs the pilot to avoid certain deviations from current vertical rate, this measure being sufficient to avoid a risk of collision. On the PFD speed scale, the forbidden values are indicated by red sectors.
(b)
Corrective advisory In this case, the vertical separation is lower than the threshold S2. On the vertical speed scale of the PFD, colored sectors depict avoidance maneuvers to be performed:
-red sector = forbidden vertical speeds
-green "fly to" sector = a vertical speed range to be respected.
(Ref. Fig. 022)
R **ON A/C 001-049, 051-061, 101-149, 201-207, 211-299, 301-399, 401-499,
(c) Aural alerts Trajectory correction or holding visual orders are accompanied by synthesized voice announcements whose level cannot be adjusted by the pilot. These announcements are generated by the TCAS computer and broadcast via the cockpit loud speakers. These messages and their meanings are described below:
-
"CLIMB, CLIMB, CLIMB". Climb at the rate shown by the green sector on the PFD (1500 ft/mn),
-
"CLIMB, CROSSING CLIMB, CLIMB, CROSSING CLIMB". As above except that it further indicates that own flight path will cross through that of the intruder,
-"REDUCE CLIMB, REDUCE CLIMB". Reduce vertical speed to that shown by the green sector on the PFD,
-"INCREASE CLIMB, INCREASE CLIMB" Follows a "climb" advisory. The vertical speed of the aircraft should be increased (2500 ft/mn),
-"CLIMB, CLIMB NOW, CLIMB, CLIMB NOW". Follows a "descend" advisory when a reversal in sense is required to achieve safe vertical separation from a maneuvering intruder,
-
"DESCEND, DESCEND, DESCEND" Descend at the rate indicated by the green sector on the PFD (-1500 ft/mn),
-
"DESCEND, CROSSING DESCEND, DESCEND, CROSSING DESCEND"
R 1EFF : 001-049, 051-099, 101-149, 151-199, 1 34-43-00Page 80 1201-207, 211-299, 301-399, 401-499, 1Aug 01/05 1 1 1CES 1 As above except that it further indicates that own flight path will cross through that of the intruder,
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