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AXP340 Transponder Installation Manual
10 March 2014
01201-00
Issue AF
Page 26
AVIDYNE CORPORATION
8. Normal Operation
8.1 Overview
On the front panel is a green backlit LCD display flanked buttons for IDENT, VFR squawk code, Mode
selection (MODE) and user function selection (FUNC) on the left side and a rotary selector knob plus a
CLR / backspace button on the right side of the front panel. A row of numeric buttons lie below the display.
8.2 Front Panel
8.3 Display
The display shows the operating mode of the transponder, the reported pressure altitude, and the current
squawk code and Flight ID. The reply indicator is active when the transponder replies to interrogations.
The pressure altitude is displayed as Flight level (100’s of feet), feet or meters, depending on the installation
configuration of pressure altitude units. When non-standard atmospheric conditions apply, this may not
match the altimeter indicated altitude, but will be correctly displayed by the ATC radar.
8.4 POWER ON/OFF
Press the MODE button to turn on the transponder.
Hold the MODE button for at least 3 seconds to turn off the transponder. A count down is displayed on the
left side of the screen. When the counter reaches zero and the screen turns off, release the MODE button.
8.5 MODE CONTROL
The MODE button also controls the operation mode of the transponder.
The possible states are as follows:
ALT
The transponder will respond to all interrogations.
ON
The transponder will respond to all interrogations, but altitude
reporting is suppressed.
GND
The transponder will respond to Mode S ground
interrogations from surface movement radar. This mode is
only available in installations that send a ground/air discrete
signal to transponder.
SBY
The transponder is on, but will not reply to any interrogations.
When airborne, the transponder should always be set to ALT unless otherwise directed by Air Traffic
Control.