Traffic Depiction
It is important to note that not all traffic may be displayed
and that TIS-A is only an aide to visual acquisition.
TIS-A is there to assist you to visually acquire other
aircraft around you and does not provide any information
other than making you aware of other aircraft around you
that the Mode-S terminal radar can “see.” This may not
include all traffic around you. Only transponder-equipped
aircraft that are visible to the terminal radar sensor will be
broadcast to your aircraft. Up to eight (8) targets may be
displayed at any given time. This is a limitation of the
ground sensor since the ground sensor provides the data
via the radar pulse.
Your position (ownship symbol) is located at the tip of the
triangle icon at the bottom center of the screen. The traffic
function is always shown in heading mode, meaning that
track-based flight plan information is not overlaid. Traffic
can also be shown on the Custom Map and in a small
thumbnail view presented in the upper left corner of the
screen.
Traffic targets are displayed relative to the ownship
symbol and include a relative altitude in 100’s of feet
above (+) or below (-) your aircraft’s altitude. Targets
also include a climb (
£
) or descent arrow (
¤
) next to the
relative altitude when the climb or descent rates are
greater than 500 feet per minute.
Targets are displayed at full brightness for the first six (0
to 6) seconds. If the TIS-A data is not refreshed, the
targets will be displayed at a reduced brightness for the
next six (6 to 12) seconds during an interval known as
“coasting,” and removed from the display after 12 seconds.
“Coasting” usually results from the TIS-A sensor missing
a radar sweep. This typically happens because the aircraft
antenna line of sight to the radar has been obstructed,
most likely by either terrain or because the aircraft is
banking.
60
Detailed Operation
