NAVIGATION AND
COMMUNICATION
AIRPLANE
OPERATIONS
MANUAL
2-18-24
Page
4
Code
02
OCTOBER 02, 2001
CMU NORMAL OPERATION
Pilot interface is accomplished through the FMS Control and
Display Unit (CDU). Data is entered in any field highlighted by a
cursor. Generally, when accessing a FMS page, the cursor will park
off the page. Selecting the ENTER key will place the cursor over
the first enterable field on the page. Data is then entered into the
field with the alphanumeric keys.
In some situations, flight progress and related data from the FMS
will prefill into the field but it is possible to change that data by
overriding that value with a manual data entry.
When SEND is pressed, the message goes into a queue for
transmission. If the aircraft is flying over a region or is grounded at
an airport not covered by a DSP (Data Link Service Provider)
reception or transmission of messages to or from a ground station
will not be successful.
Communications are eased by the use of the Main Menu page and
several submenus to quickly access each function or service
available.
CMU ABNORMAL OPERATION
The CMU has a Built-In Test (BIT) function that contains a
continuous monitor and self-test monitor. The continuous monitor
function monitors critical system parameters and record faults
found during normal operation.
The self-test monitor function is activated upon command from the
system controller, external discrete input, front test panel switch,
maintenance computer or a power-up event. The self-test monitor
will exercise various system functions, record faults found, and
annunciate the results of the test.
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