(g)
Memory card module The memory card interface is used to load data into the CPU or record data from the CPU. The memory card module supports either FLASH cards or RAM cards via the front panel Personal Computing Memory Card Interface Adapter (PCMIA) slot. The FLASH card or RAM card is inserted through the front panel. In one mode, data stored on the flash card memory manual is used to update program or data memory in the ILS. In another mode, the flash card functions as a data recorder.
(h)
Test modes In addition to the approach operating mode, the ILS has two test modes:
-
the functional test,
-
the self-test.
1 Functional test
_ The ILS can enter the functional test mode only when the FUNCTIONAL TEST INHIBIT signal is inactive, the air/ground discrete is on ground, AND a functional test is initiated via one of the following:
-
the front panel pushbutton switch,
-
the CFDIU. Once initiated, the unit immediately starts the functional test. The results of the test are provided on the ILS outputs. Functional testing continues without interruption as long as the ILS remains in functional test mode and above enabling conditions are true. The detection of a malfunction is considered as an ILS failure and annunciated at the end of the test sequence. During functional test, the ARINC 429 output words cycle through the FUNCTIONAL TEST sequence as shown below:
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--------------------------------------------------------------------------| INTERVAL | SSM | DDMs (Ref. NOTE 2) | --------------------------------------------------------------------------| First 3 s. | FAIL | 0 (both LOC and G/S) | |-------------------|--------|-------------------------------------------| | Next 2 s. | NCD | 0 (both LOC and G/S) | |-------------------|--------|-------------------------------------------| | Next 3 s. |Ref. | - 0.0775 (LOC) | | |NOTE 1 | - 0.0875 (G/S) | |-------------------|--------|-------------------------------------------| | Next 2 s. |Ref. | + 0.0048 DDM/60 ms (LOC) | | |NOTE 1 | + 0.0029 DDM/60 ms (G/S) | |-------------------|--------|-------------------------------------------| | Next 6 s. |Ref. | + 0.0775 (LOC) | | |NOTE 1 | + 0.0875 (G/S) | |------------------------------------------------------------------------| | NOTE 1 : The SSM is set to TEST if no faults are detected | | | | NOTE 2 : The deviations shown are loaded directly into the output | | words. These are not the results of the receiver injected | | test signals. | --------------------------------------------------------------------------
The following tests are performed when the functional test is requested:
a Both IF filters (LOC and G/S) are tested for bandpass
_ frequency response.
b A modulated RF test signal is generated to produce a
_ Localizer test deviation of 0.1 DDM. This test deviation is checked for accuracy of 1 DDM plus or minus 0.006 DDM. Failure of this test results in a LOC receiver failure annunciation.
c A modulated RF test signal is generated to produce a Glide
_ Slope test deviation of 0.2 DDM. This test deviation is checked for accuracy of 2 DDM plus or minus 0.012 DDM. Failure of this test results in a G/S receiver failure annunciation.
d The AGC voltages of the LOC and G/S receivers are checked
_ for acceptable range.
e Both synthesizers (LOC and G/S) are tested for lock/unlock
_ conditions.
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f Both anti-aliasing filters (LOC and G/S) are tested for
_ frequency response.
2 Self-test
_ The ILS receiver has the capability to perform a signal injection test on both the localizer and glide slope every 30 seconds. The test is executed if any of the following conditions are met:
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the ILS tuning frequency indicates Cruise mode but not while performing functional test,
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the ILS is in Normal mode but not while performing functional test and both the localizer deviation indicates "invalid" as determined by the localizer signal analysis,
-
the self-test is inhibited when the TUNE/FUNC TEST INHIBIT
discrete is asserted. The following actions are taken in self-test:
-
the deviations of both receivers are frozen to their last value for the duration of the test,
-
a modulated RF test signal is generated to produce a Localizer test deviation of 0.1 DDM. This test deviation is checked for accuracy of .1 DDM plus or minus 0.006 DDM. Failure of this test results in a LOC receiver failure annunciation,
-
a modulated RF test signal is generated to produce a Glide Slope test deviation of 0.2 DDM. This test deviation is checked for accuracy of .2 DDM plus or minus 0.012 DDM. Failure of this test results in a G/S receiver failure annunciation,
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