TRAFFIC ALERT AND COLLISION AVOIDANCE SYSTEM (TCAS) (Cont)
- Pressing the TEST button will start a self-test program that will verify proper operation of the TA and RA displays
and of the aural advisories. The TEST mode does not affect normal TCAS operation. Should an actual TA or RA
occur during TEST sequence, the test is automatically terminated and the advisory is announced and displayed
THREAT LEVELS AND DATA TAGS
The system provides four types of advisories:
- Traffic Advisories (solid amber circle) - Traffic advisories (TA) symbols appear on the MFD, when target(s) is pro-
jected to converge with the TCAS equipped airplane in approximately 35 seconds, with the closest point of the
approach being inside a minimum vertical separation envelope. Traffic advisories are generated for aircraft with
operative Mode S, Mode C, or Mode A transponders. The relative bearing and range of the intruder are displayed
- Resolution Advisory (solid red square) - Resolution advisories (RA) symbols appear on the MFD, when target(s) is
predicted to penetrate the protected vertical envelope in approximately 25 seconds. An RA display on the PFD ver-
tical speed indicator (VSI) indicates the vertical rate that must be achieved to maintain safe separation. During an
RA, red and green bands overlay the VSI scale. Red band indicates what vertical speed range should be avoided
and the green band indicates the vertical speed needed to achieve safe separation. The red band indicates pitch
rates that should be avoided and fly the vertical speeds within the green band. RA display can only be issued if an
intruder airplane is equipped with a Mode S transponder
- Proximity Traffic (solid cyan color diamond) - Proximity traffic (PROX) symbols appear on the MFD when non-
threat airplane(s), which have a flight path that approaches the collision area. The PT symbol is displayed if the tar-
get does not qualify for a TA but is currently within
±
6 nm and
±
1200 feet of the TCAS airplane
- Other Traffic (open cyan color diamond) - The other traffic (OT) is in the surveillance area, but is not a collision
threat
When altitude data is available, an ALT TAG shows the altitude of each intruder aircraft on the TCAS traffic display. When
the altitude of the intruder aircraft is more than that of the interrogation aircraft, ALT TAG shows above the traffic symbol.
When the altitude of the intruder aircraft is less than that of the interrogation aircraft, ALT TAG shows below the traffic
symbol. If the intruder aircraft altitude changes at a rate of
±
500 ft./min. or more, an arrow after the traffic symbol shows
the altitude change direction.
The TCAS system provides no indication of traffic conflicts if the intruder airplane is without an operative transponder.
The TUNE and TCAS CONTROL pages on the CDU are another way to control TCAS mode selection.
RESOLUTION ADVISORY
Resolution advisories (RA) advise the pilot that corrective action is required to avoid an intruder. RAs show on the vertical
speed scale to indicate forbidden/acceptable vertical speeds. TCAS overlays are available on both the PFD and MFD. A
TCAS only map is available on the MFD. Identical TCAS control selections show on both onside and cross-side MFDs so
that either pilot can make TCAS control selections. Also aural alerts will sound over the cockpit audio system.
TRAFFIC ADVISORY
A traffic advisory (TA) is issued when an intruding aircraft penetrating the 35 second TCAS surveillance area and is con-
sidered by the TCAS computer to be a possible threat. The traffic advisory provides the flight crew with an opportunity to
use the TCAS page on the MFD to assist in visually locating the intruding aircraft.
The following advisories are shown on the PFD and MFD and heard on the speakers:
- Aural advisory TRAFFIC TRAFFIC is sounded
- Amber CAS TRAFFIC is displayed below the VSI scale on the PFD
- Amber TAs are shown on the TCAS page of the MFD as a solid amber circle
Challenger Global 300 - Navigation
Page 10