(3)  
The CMC uses inputs from various sensors to define a flight leg for the fault history. If both CMCs fail, a discrete from the AIR/GND relay determines a flight leg.

 (4)  
The BITE circuits test the operation of the ADF receiver. They also check the input data from the FMC and CDUs. BITE status can be checked by initiating a self-test on the front panel of the ADF receiver. The BITE test can also be done by the CMC through the CDUs. The results of a test are shown on the CDU and on the front of the ADF receiver.

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 (5)  Faults are sent from the BITE circuits to the processor circuits. The CMC can initiate a ground test through the processor circuits. The results are sent to the EIUs.
 C. ADF Self-Test
 (1)  
System self-test is always initiated at power turn on. It also can be initiated at any other time by pressing the TEST button on the ADF receiver front panel.

 (2)  
If the test passes, "TEST COMPLETE, NO FAILURES" will be displayed on the front panel LCD display. If the test fails, "TEST COMPLETE, FAILURES" will be displayed. If the "TEST COMPLETE, FAILURES" screen is displayed, pressing the "WHY?" pushbutton on the right puts the system into the display failure mode where individual system failures are displayed one per page.

 D. ADF System - CMC Menu Selection on CDU (AMM 45-10-00/201)
 (1)  
Any one of the three CDUs can request fault information and initiate tests of the ADF receivers through the CMC. The left CMC normally provides outputs to the ADF receivers. When the left CMC fails, the right CMC automatically provides outputs to the ADF receiver.

 (2)  
Pressing the MENU key on the CDU causes the CDU menu to be displayed. From the CDU menu, the CMC menu can be selected by pressing the appropriate Line Select Key (LSK).

 (3)  
The CMC menu has two pages which are selected by the NEXT and PREV keys. Selections that apply to ADF are:

 (a)  
EXISTING FAULTS

 (b)  
GROUND TEST

 (c)  
FAULT HISTORY

 (4)  
ADF System - Existing Faults

 (a)  The EXISTING FAULTS menu displays the systems which have active faults. Pressing LSK 3L will cause the EXISTING FAULTS MESSAGE page to be displayed. This page displays the existing faults for the navigation system.

 (5)  
ADF System - Ground Test

 (a)  The ground test systems page identifies the ATA chapters which have ground test capability through the central maintenance system.
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 (b)  
The GROUND TEST menu allows the operator to perform ground tests of specific Line Replaceable Units (LRUs). Pressing line select key (LSK) 3L performs a ground test of the left ADF receiver. This test is identical to the self test that can be performed from the ADF receiver except that it is initiated from any CDU and the results are displayed on the CDU.

 (c)  
The word PASS indicates passage of the ground test. Failure of the ground test is indicated by the word FAIL. Pressing the adjacent LSK causes the GROUND TESTS RESULTS page to be displayed. This page gives more specific information about the test failure.

 (6)  ADF System - Fault History
 (a)  
The FAULT HIST menu page displayed on CDU lists the systems that have fault messages in the fault history memory.

 (b)  
The FAULT HIST SUMMARY page provides a summary of the messages held for the selected system.

 (c)  
The FAULT HISTORY MSG page provides specific information about a particular fault.

 E.  Control
 (1)  To place the ADF system in operation, the following steps are required:
 (a)  
　
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