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1 Dec 2003
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MAINTENANCE MANUAL
CAS-100 COLLISION AVOIDANCE SYSTEM
Use or disclosure of information on this page is subject to the restrictions in the proprietary notice of this document.
Table 19. CTA-81B Control Unit Controls and Indicators
(cont)
Control/Indicator
(See Figure 11)
Function
NOTES:
1. The TCAS operating modes are requested from the transponder/TCAS control unit (For example,
TA/RA
mode is requested by turning function selector switch to TA/RA). The TCAS processor can or can not go
into the requested mode dependent on prevailing conditions. For example: If TA/RA mode is requested
from the control unit and own aircraft is below 500 feet AGL, the TCAS automatically defaults to TA ONLY
mode (TCAS sensitivity level No. 2) regardless of the TA/RA mode request from the panel.
2. In-flight or on-the-ground status of own aircraft is calculated with the weight-on-gear (air/ground) strut
switch input to the transponder and TCAS processor.
3. The TCAS can be strapped to show all the traffic, all the time or only when a TA or RA is present.
4. If own aircraft is below 500 feet AGL, the TCAS automatically ignores the TA/RA position of the switch and
defaults to TA ONLY mode. The TCAS functions as shown for the ATC 1 TA position (in-flight) of the
Function Selector Switch in this table.
5. Holding the FL switch pushed for longer than 15 seconds will not show flight level altitudes for longer than
15 seconds.
6. The range at which RAs or TAs are generated by the TCAS is unaffected by the TCAS RANGE switch.
7. The presence of the intruder aircraft that are categorized as RA or TA and are more than the set display
range, is shown by 1/2 target symbols at the edge of the screen. The position of the 1/2 symbol shows the
approximate bearing of the intruder. The 1/2 symbol color and shape shows if the off-scale intruder is an
RA or TA (1/2 red square for off-scale RA; 1/2 yellow circle for off-scale TA). When this occurs, the aircraft
symbol can be shown by increasing the set range on the TCAS RANGE switch.
8. RA, TA, and proximity category aircraft displays are unaffected by the ABOVE/NORM/BELOW switch.
(RA and TA aircraft 8700 feet of own aircraft are shown regardless of the ABOVE/NORM/BELOW
switch position. Proximity category aircraft are always 1200 feet altitude of own aircraft).
9. The TCAS RANGE switch is not supplied on all versions of the CTA-81B. When a PPI, TA/VSI, or
dedicated traffic display having optional range selectors is used, range selection is made at the traffic
display. Other versions have range selection to 40 nautical miles.
