Altitude Check; Lighting Bus; Temperature; Gps Interface - Honeywell BendixKing KT 74 Installation Manual

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.
Message Issue Description
Antenna The transponder has detected that there is
fault a fault in the antenna cabling or antenna
connection.
Output The transponder has detected that it
power low transmitted at a lower power level than
expected. This may be caused by:
 Poor antenna connection in the
transponder tray
 Poor antenna cable connections
 A transponder hardware fault.
No ADS-B Valid ADS-B position data has not been
position received for either:
 180 seconds from system start-up
 2 seconds once a GPS position data
has been received by the transponder.
© Honeywell International Inc. Do not copy without express permission of Honeywell.
INSTALLATION MANUAL
89000007

Table 4-1. Warning Messages

Initial Action
Check transmitter cabling and
connection to antenna.
Check cabling. connection at the
transponder tray and transmitter
Check cabling to GPS and GPS
antenna position and connection.
Page 4-7
15 Nov 2013