User's Manual
SYSTEM DESCRIPTION AND INSTALLATION MANUAL
T
3
CAS/Part No.9005000
The TAWS/RWS becomes deactivated upon Aircraft Power Down.
Specific TAWS/RWS functions can become unavailable if an Internal or
External parameter needed for normal operation of the TAWS/RWS
functions is unavailable or invalid.
The TAWS predictive CPA modes may become deactivated upon the
selection of the “Terrain Inhibit” switch. The purpose of the “Terrain
Inhibit” switch is to allow the aircraft to operate without nuisance or
unwanted warnings at airports that are not in the system database.
Additionally, there may be some “VFR only” airports where unique terrain
features are in close proximity to the runway. The “Terrain Inhibit” switch
should NOT be engaged for normal operations.
C. Transponder Operation
An ATCRBS Transponder responds to ATCRBS interrogations with a Mode A (4096
code) reply or Mode C (altitude status) reply contingent upon the type of interrogation
received. Interrogations are received by the transponder on 1030 MHz and replies are
transmitted by the transponder on 1090 MHz. All ATCRBS transmissions are between
the ground station and aircraft. A Mode S Transponder receives and transmits on the
same frequencies as the ATCRBS Transponder and can receive and transmit ATCRBS
interrogations and replies. However, the Mode S Transponder was developed for Mode S
operation and can function alone as Mode S or in conjunction with TCAS. When
functioning alone as Mode S, all Mode S transmissions are between the ground station
and aircraft. When functioning in conjunction with TCAS, transmissions may also be from
aircraft to aircraft.
Mode S System operation begins when aircraft power is applied. Initial self-test is
performed automatically upon power-up and is completed in approximately 1 second.
Self-testing of the system occurs continuously while in the power-on mode. If a
transponder failure occurs, it is indicated on the control panel. Other failures are indicated
via front panel-mounted LEDs on the transponders; however, these failure indications are
not available to the pilot. All failures, whether hard or intermittent, are recorded in the
transponder maintenance memory for analysis by maintenance personnel.
After power-up, the pilot enters the assigned 4096 code via the control panel. This code
is the ATC identification code for that aircraft and is used during ATCRBS (Mode A)
interrogations and replies. Mode S interrogations and replies use a 24-bit address code
entered into transponder memory automatically upon power-up. Each aircraft has its own
unique address that is permanently programmed to the airframe. No manual entry of this
address is available.
The system can be placed in STANDBY mode. When the STANDBY mode is selected,
the transponder reply transmit capability (Mode S or ATCRBS) is disabled. The remaining
transponder functions are operational, including Built-In-Test (BIT). STANDBY mode is
typically engaged while on the ground to prevent unnecessary RF traffic. It is disengaged
just prior to takeoff and engaged again upon landing. In addition, an air/ground switch,
which functions as part of the Weight-On-Wheels (WOW) circuitry, can disable ATCRBS
Transponder reply capability while the aircraft is on the ground if this feature has been
enabled. To disable ATCRBS or ground replies with the air/ground switch, the
appropriate air/ground transponder discrete must be connected. Refer to the
REMOVAL/INSTALLATION section of this manual for details on this interface. Mode S
Pub. No. 8600200-001, Revision 004
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04 Nov 2014
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