Section 923
GARMIN GTX 328 Transponder
923 - 4
Page Date: 5. December 2008
Pilot´s Operating Handbook
EXTRA 300L
923.1.1
MODE SELECTION KEYS
OFF
Powers off the GTX 328. Pressing STBY, ON or ALT Key powers on the transponder displaying the
last active identification code.
STBY
Selects the standby mode. When in standby mode, the transponder will not reply to any inter-
rogations.
ON
Selects Mode A. In this mode the transponder replies to interrogations, as indicated by the Reply
Symbol. Replies do not include altitude information.
ALT
Selects Mode A and Mode C. In ALT mode, the transponder replies to identification and altitude
interrogations as indicated by the Reply Symbol. Replies to altitude interrogations include the
standard pressure altitude received from an external altitude source, which is not adjusted for
barometric pressure. Any time the function ON or ALT is selected the transponder becomes an
active part of the Air Traffic Control Radar Beacon System (ATCRBS). The transponder also
responds to interrogations from TCAS equipped aircraft.
923.1.2
CODE SELECTION
Code selection is done with eight keys (
0 – 7
) providing 4,096 active identification codes. Pushing
one of these keys begins the code selection sequence. Digits that are not yet entered appear as
dashes. The new code is activated when the fourth digit is entered. Pressing the
CLR
Key moves
the cursor back to the previous digit. Pressing the
CLR
Key when the cursor is on the first digit of
the code, or pressing the
CRSR
Key during code entry, removes the cursor and cancels data entry,
restoring the previous code. Press the
CLR
Key up to five seconds after code entry is complete
to return the cursor to the fourth digit. The numbers
8
and
9
are not used for code entry, only for
entering a Count Down time, and contrast and display brightness.
IMPORTANT CODES:
1200 The VFR code for any altitude in the US (Refer to ICAO standards elsewhere)
7000 The VFR code commonly used in Europe (Refer to ICAO standards)
7500 Hijack code (Aircraft is subject to unlawful interference)
7600 Loss of communications
7700 Emergency
7777 Military interceptor operations (Never squawk this code)
0000 Military use (Not enterable)
Page Date: 5. December 2008
Summary of Contents for 300L
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