BendixKing CAS 67A TCAS II - Manual (Page 9)

TCAS II Pilot’s Guide
Effective Date 4/99 006-08499-0000 Rev 5 7
Operation
TCAS II OPERATION
The TCAS II system monitors the airspace surrounding your aircraft
by interrogating the transponder of intruding aircraft. The interrogation
reply enables TCAS II to compute the following information about the
intruder:
1. Range between your aircraft and the intruder.
2. Relative bearing to the intruder.
3. Altitude and vertical speed of the intruder, if reporting altitude.
4. Closing rate between the intruder and your aircraft.
Using this data TCAS II predicts the time to, and the separation at,
the intruder’s closest point of approach (CPA). Should TCAS II pre-
dict that certain safe boundaries may be violated, it will issue a Traffic
Advisory (TA) to alert the crew that closing traffic is in the vicinity.
If the intruder continues to close, TCAS II will issue a Resolution
Advisory (RA) to maintain safe vertical separation between your air-
craft and the intruder. TCAS II bases the alarms on a five second
crew reaction time to achieve adequate separation. Increase or rever-
sal of an RA requires a reaction in two and one half seconds.
Two TCAS II equipped aircraft will coordinate their resolution advi-
sories using a Mode S transponder data link. The coordination
ensures that complementary advisories are issued in each aircraft.
The crew should promptly but smoothly follow the advisory. Since the
maneuvers are coordinated, the crew should never maneuver in the
opposite direction of the advisory.
TCAS II can track as many as 45 aircraft, display up to 30 of them
and can coordinate a resolution advisory for up to three intruders at
once. The advisories are always based on the least amount of devia-
tion from the flight path while providing safe vertical separation.