Aircraft CMCS Testing Procedures Quiz

17 Questions

What does the CMCS prevent during flight?

Running tests

What does the 'ground test enable switch' do?

Interrupts all test signals in NORMAL position

What action should be taken after pressing the line select key next to the 'FAIL' message during a test?

Press a different LS key to take corrective action

What is the purpose of the switch guard?

To avoid accidental operation during flight

What does a clear message in the system test result indicate?

The CSU failure is confirmed and must be replaced

What is the main purpose of the different test functions on a CMC?

To verify that a faulty component is indeed faulty

What does a 'Pass' test result indicate?

No fault was found during the test

When are Confidence tests typically used in the Boeing CMC system?

For preflight checks

When does a 'Test OK' result occur?

When no failure is detected

What action is recommended if in doubt about a test result?

Refer to the maintenance manual for test content

What must be fulfilled before the start of a complementary test according to the text?

Hydraulic system must be pressurized or HYD ON

What is the purpose of the Ground tests available for all major systems in the Boeing CMC system?

To perform safety checks before flight

What should be done after the test result is presented?

Bring the aircraft back to the status before starting the test

What is the purpose of BITE in the testing process described?

Generate inputs to actuators and valves

Which tests are only available in certain systems in the Airbus CMC system?

Complementary test and Output test

What is the purpose of Input Monitoring information provided by the Boeing CMC?

To provide data about system input in coded format

What triggers the 'test in progress' message to appear on the BITE Display during testing?

Sending a test request signal to the system computer

Study Notes

Test Results and Safety Features

Test results are available for printout and datalink
Tests are not allowed to run during flight to prevent influencing flight safety
The CMCS prevents tests during flight by special safety features
Some Boeing confidence tests can run during flight, but with safety features

System Test

The system test is primarily a computer test, comparable to the power-up test
It tests certain systems and electrical sensors
No special preconditions are needed, as input signals to the system and mechanical parts that can move are not tested
Test results show:
- Test OK if no failure is detected
- The name of the LRU that failed the test if a failure is detected

Understanding Test Results

A test result can only be trusted if all components responsible for a reported fault have been tested
If in doubt, refer to the troubleshooting or maintenance manual
A clear message in the test result confirms the failure of the suspected LRU

Additional Data Retrieval Functions

The Boeing CMC menu item "Other Functions" provides additional data retrieval functions
These include:
- SHOP FAULTS information for workshop people
- INPUT MONITORING information about system input data in coded format
- Configuration data about the computer program version

CMCS Tests

CMCS tests have two main purposes:
1. To confirm that an LRU is really faulty
2. To ensure that a repair or component removal solved the problem
Airbus CMC system: up to three different tests are available
- System test
- Complementary test (only available in certain systems)
- Output test (only available in certain systems)
Boeing CMC system: two different types of tests are available
- Ground tests (available for all major systems)
- Confidence tests (available for only a few systems)

Test Operation

Select the system to be tested and the test to be performed
Send a test request signal to the system computer
The BITE displays "Test in Progress" while controlling the test steps
The test result is displayed on the screen
Press the line select key to view detailed test results
If the test fails, press the LS key to get information on corrective action needed

Test your knowledge on aircraft Central Maintenance Computer System (CMCS) testing procedures. Learn about the safety features that prevent tests during flights and the specific tests that can be run during flight. Explore the importance of the ground test enable switch and the test sequence switch guard.

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