INSTALLATION MANUAL
89000007
Page 4-7
15 Nov 2013
© Honeywell International Inc. Do not copy without express permission of Honeywell.
4.4.2 Altitude
Check
The altitude check displays the current state of the altitude inputs. Individual
Gillham code lines are shown to assist in fault tracing.
4.4.3 Lighting
Bus
The lighting bus check displays the voltage on the lighting bus to assist in
verifying the correct operation of the lighting bus.
4.4.4 Temperature
The internal temperature of the transponder can be displayed. The display is
in degrees Celsius.
4.4.5 GPS
Interface
The GPS interface check provides a simple confidence check that the
transponder is receiving data on the RS232 input. Note that this check does
not attempt to decode the received data; it is intended only to provide a quick
wiring check in the hangar. To assure that the interface is fully operable the
aircraft should be tested with the transponder in normal operating mode, with
the GPS receiver operating correctly, and a ramp test of the transmitted
parameters completed.
4.5 Warnings and Faults
The messages shown in Table 4-1 and Table 4-2 may appear on the screen of the
KT 74 transponder. These tables provide further information on the possible cause
and actions to take in the event these occur.
Table 4-1. Warning Messages
Message
Issue Description
Initial Action
Antenna
fault
The transponder has detected that there is
a fault in the antenna cabling or antenna
connection.
Check transmitter cabling and
connection to antenna.
Output
power low
The transponder has detected that it
transmitted at a lower power level than
expected. This may be caused by:
Check cabling. connection at the
transponder tray and transmitter
Poor antenna connection in the
transponder tray
Poor antenna cable connections
A transponder hardware fault.
No ADS-B
position
Valid ADS-B position data has not been
received for either:
Check cabling to GPS and GPS
antenna position and connection.
180 seconds from system start-up
2 seconds once a GPS position data
has been received by the transponder.
