BendixKing CAS 66A - Manual (Page 12)

TCAS I SURVEILLANCE VOLUMES
Surveillance volume is that volume of airspace within which other air-
craft with Mode S or ATCRBS transponders are tracked by own air-
craft’s TCAS.
(1) Range Tracking Volumes
The shape and size of the range tracking volume is dependent on
whether Mode S or ATCRBS transponders are being interrogated,
whether tracking is occurring on a directional or OMNI antenna, and
attenuation levels applied to the transmitted pulses from the TCAS
processor’s transmitter. The typical range tracking volume is pictured
as an ellipse. The distance behind own-aircraft is about one half of
the forward distance. The tracking range to either side of own-aircraft
is about two thirds of the maximum forward distance.
The maximum forward range for TCAS is 40 nm. TCAS reduces
range tracking volumes in high density areas to reduce the number of
receptions to be processed by TCAS and for interference limiting.
TCAS can track as many as 45 aircraft and displays up to 30 of them.
(2) Altitude Tracking Volumes
TCAS I tracks other transponder equipped aircraft that are within a rel-
ative altitude of +/-9,000 feet.
TCAS I AURAL INHIBITS
TCAS I will inhibit the aural annunciation using the following order of
precedence: (1) below 400 feet AGL (if equipped with radio altimeter)
OR (2) when the landing gear is Extended (no radio altimeter
installed). For installations aboard aircraft with fixed landing gear, the
aural annunciation is never inhibited by the TCAS I processor. The
aural annunciation is enabled above 600 feet AGL in aircraft equipped
with a radio altimeter.
Theory of Operation and Symbology
8 Effective Date 5/93 006-08746-0000 Rev 0
TCAS I Pilots Guide 2/8/06 3:52 PM Page 8