SkyTrac Systems Ltd.
Document Rev. 02.010 ISAT-100-OPD-SOI Page 21 of 26
Restricted Proprietary and Confidential Information
The L-Band antenna (TNC connector) VSWR should be checked. A forward/reverse
power check with an in-line wattmeter should show no more than 10% reflected
power.
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 ISAT-100 and the approach aids be
checked in-flight.
The existing on-board GPS should be operational and navigating with at least the
minimum compliment of satellites. The VHF Comm should be set to commonly used
frequencies with the squelch open. VOR/DME receivers should be 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.
Operate the ISAT-100 unit for at least 10 minutes in default mode (i.e. factory set to
transmit to the satellite system every one minute). This will provide 10 transmissions
during the test procedure. DO NOT CHANGE THE DEFAULT TRANSMISSION
INTERVAL UNITL AFTER ALL POST INSTALLATION TESTS ARE COMPLETED.
Observe the GPS for any degradation in satellite status, 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 movement 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 on the EMI/RFI Test Report
(DOC0302) and note any anomalies that occur while transmitting. Assess the results.
If the aircraft is equipped with an autopilot or stability augmentation system, then test
fly the aircraft and verify that operation of the ISAT-100 unit 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.
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 ISAT-
100 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.
The document reference is online, please check the correspondence between the online documentation and the printed version.
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