(d)
The optical disk drive module records flight data under the microprocessor and DMU logic control. The QAR records the data on a 3.5 inch (128 MB) optical disk.
(e)
At the start of a QAR recording, the DMU controls the turn-on of the QAR. This allows for inertia of the mechanical medium to reach recording speed.
(f)
The QAR can record under manual control and/or automatic control. Manual control (continuous recording) is initiated by the cockpit crew via the CDU. Automatic control (incremental recording) is under the control of ACMS DMU Logic.
(g)
Manual control QAR recording is controlled by the CDU menu which allows start or stop of QAR recording and defines the length of the manual recording in terms of hours and minutes.
(h)
If a manual QAR recording is still in progress after the last engine has been shut down, then the DMU will automatically terminate the manually initiated QAR recording.
B. Built-in-Test function
(1)
The DMU contains software to perform built-in-test (BIT) to determine the functionality of the DMU hardware and to detect a DMU hardware failure.
(2)
During the DMU initialization, the software is responsible for initializing various hardware interfaces, initializing memory contents and software functions, and performing power-up BIT.
(3)
During the normal operation of DMU, the software continuously performs the continuous BIT to check the DMU hardware functions.
(4)
If the DMU malfunctions, a DMU FAIL indicator will come on, a READ switch may be used to test the fault indicator. A BITE test of the DMU can also be accomplished by accessing to the CMC ground test menu using any CDU.
(5)
From the ground test menu, selecting the LSK next to the DMU enables the DMU to perform its test. If the DMU passes the test, the word PASS is shown. If it fails, the word FAIL is shown.
(6)
Pressing the LSK next to FAIL causes the GROUND TESTS RESULT page to be displayed. This shows the DMU failures that occurred in the tests.
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C. ACMS CDU MENU
(1) You can see the ACMS menu on the center CDU. To get access to the ACMS menu on the CDU, first push the MENU key, then push the line select key (LSK) adjacent to ACMS. These selections show on the ACMS menu:
NOTE: The title and the selections can be different if an
____ airline custom application software is installed.
(a)
VERSIONS AND P/N
(b)
DATA DISPLAY
(c)
STATUS
(d)
DEVICE INTERFACES
(e)
MISCELLANEOUS
(f)
IDU DIM/TEST
(2) This is what each selection on the ACMS menu does:
(a)
The VERSIONS AND P/N selection shows the DMU hardware and software part numbers.
(b)
The DATA DISPLAY selection shows the DATA DISPLAY menu, which has three selections: 1) The DITS DATA selection lets you see the ARINC 429 bus
inputs to the DMU.
2) The DISCRETE DATA selection lets you see the binary values (0 = ground; 1 = open) of the 28 discrete ports wired to the DMU.
3) The MNEMONIC DATA selection lets you see real-time airplane data such as the aircraft type and the input subframe counter.
(c) The STATUS selection shows the DMU STATUS display, which shows this: 1) Results of the DMU bootstrap EPROM checksum test. 2) Results of the application flash EPROM checksum test. 3) Results of the IOP self test. 4) The BUS ACTIVITY selection, which shows the status for each
of the DITS ports connected to the DMU.
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(d)
The DEVICE INTERFACES selection shows a list of the LRUs that are connected to the DMU. Selection of each LRU shows the status of the device or tests that you can do.
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