TECHNISONIC INDUSTRIES LIMITED
TDFM-9300 Installation Instructions
TiL 13RE471 Rev. D Issue 5
24
2.24
POST INSTALLATION EMI TEST
PURPOSE
The purpose of this test is to identify any interference that the TDFM-9300 transceiver
may cause with existing aircraft systems.
TEST CONDITIONS
The TDFM-9300 transceiver should be installed and function tested. The antenna VSWR
should be checked. A forward/reverse power check with an in-line wattmeter should show
no more than 10% reflected power. For the following tests, ensure that the output power
is set to high.
METHODOLOGY
Most of the EMI tests can be accomplished on the ground. In some cases, flight testing is
required or is easier. If the aircraft is approved for IFR operations, then it is mandatory
that interference between the TDFM-9300 transceiver and the approach aids be checked
in flight.
The GPS should be operational and navigating with at least the minimum compliment of
satellites. The VHF comm should be set to the frequencies indicated with the squelch
open. VOR/DME receivers should be set to the frequencies indicated and selected for
display. If possible, set up a DME ramp test set on the frequencies indicated and adjust
the output until the flags are out of view. The transponder and encoder should be
monitored with ramp test equipment. Set the output of the transponder test set to 3db
above the output necessary to achieve 90% reply. If possible, set the ADF to a nearby
navigation station.
Modulate the TDFM-9300 transmitter on the indicated frequencies for at least 20 seconds.
Observe the GPS for any degradation in satellite status or availability or flags. Listen for
any noise or detected audio signals on the VHF comm(s). Listen for any noise or detected
audio signals on the VOR/LOC receiver audio; look for any moment of flags or needles on
the VOR/LOC/GS navigation display(s). Observe the transponder for any loss of reply or
spurious reply.
List the power plant, fuel, and other electric instruments in the chart provided and note
any anomalies that occur while transmitting. Assess the results.
If the aircraft is equipped with an autopilot or a stability augmentation system, then test fly
the aircraft and verify that operation of the TDFM-9300 transceiver does not have adverse
effects on these systems. After checking for gross effects at a safe altitude, fly an
approach with each of the different navigation systems coupled to the autopilot (ILS,
GPS, etc.) and look for any anomalies.
RESULTS
If the installed system passes all of the applicable EMI tests, then no further action is
required. If interference is observed, then the interference must be assessed against the
appropriate standards of airworthiness for the system in question. For example, it is
permissible for a VFR certified GPS to lose navigation capability while the TDFM-9300
unit is transmitting, providing that it recovers properly and promptly, but it is not
permissible for an IFR Approach certified GPS to be affected in the same way. A
complete discussion of all the standards of airworthiness to be applied in assessing EMI
effects is beyond the scope of this document.
Summary of Contents for TDFM-9300
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