BendixKing KTA 910 System KTA 970 - Manual (Page 16)

Rev 2
KTA 870/KMH 880 Pilot’s Guide TAS Theory of Operation and Symbology
006-18265-0000
8
TAS SURVEILLANCE VOLUMES
Surveillance volume is that volume of airspace within which other aircraft
with Mode S or ATCRBS transponders are tracked by own aircraft’s
TAS. The display volume is controlled by the operator and is not neces-
sarily the same as the tracking volume.
(1) Range Tracking Volumes
The size of the range tracking volume is dependent on whether tracking
is occurring on a directional or OMNI antenna and attenuation levels
applied to the transmitted pulses from the TAS processor’s transmitter.
The typical range tracking volume is pictured as a circle.
The maximum range for TAS is 18 nm. However, there are instances
when you may see intruders out to 36 nm. TAS reduces range tracking
volumes in high density areas to reduce the number of receptions to be
processed by TAS and for interference limiting. TAS can track as many
as 45 aircraft and displays up to 30 of them.
(2) Altitude Tracking Volumes
TAS tracks other transponder equipped aircraft that are within a relative
altitude of +/-10,000 feet.
TAS AURAL INHIBITS
TAS will inhibit the aural annunciation using the following order of prece-
dence: (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 and no radio altimeter
installed, the aural annunciation is not inhibited by the TAS processor,
unless weight-on-wheels indicates on the ground. The aural annuncia-
tion is enabled above 600 feet AGL in aircraft equipped with a radio
altimeter.
TAS TRAFFIC DISPLAY SYMBOLS
TAS will display three different traffic symbols on the traffic display. The
type of symbol selected by TAS is based on the Intruder’s location and
closing rate. Relative bearing and distance to the Intruder are shown by
the position of the Intruder symbol in relation to the own-aircraft symbol.
The symbols change shape and color as separation decreases between
your aircraft and Intruders to represent increasing levels of urgency.
The traffic symbols may also have an associated altitude tag that shows
relative altitude in hundreds of feet. A + sign and number above the
symbol means the Intruder is above your altitude. A - sign and number
beneath indicates the Intruder is below your altitude. A trend arrow
appears when the Intruder’s vertical rate is 500 feet per minute or
greater.