P/N 11934-S28
5 of 8
Cirrus Design
Section 9
SR20
Supplements
While providing the usual identification code and pressure altitude
information as Mode A and C transponders, the Mode S transponder
also uses a unique aircraft address to enhance the tracking
capabilities of ATC and other Mode S transponder-equipped aircraft.
The interrogations that ground-based surveillance radar transmit
include the identification information of the target airplane ensuring
that when other aircraft receive the interrogation, they will not respond.
Digitized altitude information is provided by the altitude digitizer
(encoder) plumbed into the airplane static system. The transponder
and integrated controls are mounted in the center console. The
transponder control provides active code display, code selection,
IDENT button, and test functions. The display is daylight readable and
is automatically dimmed through a photocell. The controller buttons
are dimmed through the INST lights control on the instrument panel
bolster. The transponder antenna is mounted on the underside of the
fuselage just aft of the firewall. 28 VDC for transponder operation is
controlled through the Avionics Master Switch on the bolster switch
panel. 28 VDC for receiver, transmitter, and altitude encoder operation
is supplied through the 2-amp ENCODER/XPONDER circuit breaker
on the Avionics Non-Essential.
Reply Light
The reply light is the small reverse video “R” immediately below the
mode annunciation in the display window. The reply light will blink
each time the transponder replies to ground interrogations. The light
will remain on during the 18-second IDENT time interval.
Mode Selector Keys
The mode selector keys are located in a circular arrangement
immediately to the left of the display window. The selected mode is
annunciated at the left side of the display immediately adjacent to the
selector keys. The four positions are:
OFF
- Turns off all power to the GTX 330 transponder. The
transponder should be off until the engine is started. Normally, the
transponder can be left in the STBY position and allow the Avionics
Power Switch to control system power.
STBY
- Powers the transponder in standby mode. The last active
identification code will be selected. In STBY, the transponder will not
Original: 07-03-04
Summary of Contents for SR20
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Page 22: ...2 2 P N 11934 003 Section 2 Cirrus Design Limitations SR20 Placards 2 21 Revision A6 ...
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