Revision 4 - December 17,1998 Ryan TCAD 9900 Series Page 4-6
E. Verify there are no other sources of interference (i.e. engines or accessories).
4.5.2 INTERFERENCE CHECK, OTHER EQUIPMENT
This check is to insure the TCAD does not interfere with other equipment in the aircraft.
To substantiate the immunity of the VHF navigation and communications equipment,
perform the following tests:
A. Apply power to the avionics bus and to both communications and navigation
radios.
B. Open the squelch on the primary communications radio and apply power to
the Model 9900 TCAD.
C. Select various frequencies for a general test of the communications radio
receiver. Then select 120.000 MHz, 122.000 MHz, 124.000 MHz, and
128.000 MHz and attempt to discern RF interference caused by the Model
9900. If such interference is experienced, confirm by removing power to the
systems by pulling the respective circuit breakers.
D. Repeat the exercise for the secondary communications radio receiver. Note
any unacceptable interference.
E. Tune each of the navigation receivers to the frequency of 109.2 and 115.2
MHz and listen for any discernible interference and observe interruption of
DME on those corresponding frequencies. Note any unacceptable
interference.
F. Selectively tune each of the communications radio receivers to each whole
Megahertz frequency beginning at 118 MHz and ending at 135 MHz and note
any discernible interference. Note any unacceptable interference.
G. Selectively tune each of the communications transceivers and navigation
receivers to each alternate kHz frequency beginning at 118.000 MHz and
ending at 135.975 MHz. Note any unacceptable interference.
H. Close the squelches on each of the communications transceivers and repeat
the above test to identify any spurious responses.
I. Selectively and alternatively transmit and modulate each of the
communications transmitters at 118.000 MHz, 126.975 MHz, and 135.975
MHz while observing the Model 9900 Display in normal operation. Note any
unacceptable interference.
J. Observe the Model 9900 while in flight and apply various changing loads to
the aircraft electrical system, i.e., applying power to landing lights, cycling
landing gear, etc. Note any unacceptable interference.
K. Observe any other anomaly in other radios such as the ADF, the Marker
Beacon, the Transponder, GPS navigation equipment, weather detection,
autopilot and the DME when applying power to the Model 9900.
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