DOC AIRBUS | AMM A320FLANDING GEAR - BITE - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
1. General
The L/G control system has two Landing Gear Control and Interface Units (LGCIU) (5GA1/5GA2). Each LGCIU has hardware and software to:
The LGCIU supplies data to the Centralized Fault Display System (CFDS) (Ref. AMM D/O 31-30-00-00). The CFDS, which is a maintenance aid system, has these components:
The ARINC 429 input and output busses connect the LGCIU to the CFDIU. The CFDIU is the interface between the LGCIU and the MCDUs. Each MCDU, when set to the interactive mode, lets the maintenance technicians:
** ON A/C NOT FOR ALL The L/G control system has two Landing Gear Control and Interface Units (LGCIU) (5GA1/5GA2). Each LGCIU has hardware and software to:
- continuously monitor the LGCIU/system for failures
- keep the failure data and also send this data to the other systems in the aircraft
- do a BITE test
- simulate the different positions of all (of) the L/G
- do the system tests during ground maintenance.
The LGCIU supplies data to the Centralized Fault Display System (CFDS) (Ref. AMM D/O 31-30-00-00). The CFDS, which is a maintenance aid system, has these components:
- the Centralized Fault Display and Interface Unit (CFDIU) (ITW)
- two Multifunction Control and Display Units (MCDU) (3CA1/3CA2).
The ARINC 429 input and output busses connect the LGCIU to the CFDIU. The CFDIU is the interface between the LGCIU and the MCDUs. Each MCDU, when set to the interactive mode, lets the maintenance technicians:
- read the fault data kept in the Non Volatile Random Access Memory (NOVOL RAM) of the LGCIU
- start the BITE test
- set the L/G simulation mode.
2. Component Location
** ON A/C NOT FOR ALL | FIN | FUNCTIONAL DESIGNATION | PANEL | ZONE | ACCESS DOOR | ATA REF |
|---|---|---|---|---|---|
| ** ON A/C ALL | |||||
| 5GA1 | LGCIU-1 | 93VU | 121 | 32-31-71 | |
| 5GA2 | LGCIU-2 | 94VU | 122 | 32-31-71 | |
3. System Description
A. Failure Monitoring
The failure monitoring software operates continuously after the completion of the power-up and the initialization. It does not have an effect on the operation of the LGCIU.
The software monitors the:
The failure monitoring software operates continuously after the completion of the power-up and the initialization. It does not have an effect on the operation of the LGCIU.
The software monitors the:
- L/G proximity-sensor inputs
- L/G control-lever inputs
- electrical power supplies
- L/G control-logic (discretes)
- ARINC 429 tranceiver inputs and outputs
- NOVOL RAM.
(1) Hardware Monitor
The software monitors the hardware every 100 milliseconds, for specified failure conditions TSM 32310003. To do this, the software compares the hardware signal values and examines the hardware indicators.
When the software finds a failure, it:
The software monitors the hardware every 100 milliseconds, for specified failure conditions TSM 32310003. To do this, the software compares the hardware signal values and examines the hardware indicators.
When the software finds a failure, it:
- Isolates the source of the failure
- Does a failure-filtering process, to make sure that it is not something that has become defective momentarily
- Keeps the failure data in the NOVOL RAM of the LGCIU
- Sends a failure signal to the CFDIU.
(2) Software Monitor
The LGCIU hardware uses a watchdog-timer to monitor the operation of the software in the unit. The watchdog-timer is a switching circuit which connects the software to the microprocessor. The software uses an 'audit trail check' to examine its internal circuits every 100 milliseconds. This makes sure that each software step goes in and goes out in the correct sequence. When the software finds that it is serviceable, it sets the watch-dog timer again. This must be done in less than 100 milliseconds from the time that it last occurred.
When the software finds a program error during the 'audit trail check', it does not set the watchdog-timer again. If the watchdog-timer is not set in less than 120 milliseconds, the hardware gets data that a software failure has occured (and sets the microprocessor). This set of the microprocessor lets the software (if it is serviceable) set the watchdog-timer. The failure of the software to set the watchdog-timer (the hardware sets the microprocessor a maximum of 4 times) causes:
When the microprocessor stops, the software changes the condition of the LGCIU to 'FAILED'. This causes the other LGCIU to control the L/G system (Ref. AMM D/O 32-31-00-00).
The LGCIU hardware uses a watchdog-timer to monitor the operation of the software in the unit. The watchdog-timer is a switching circuit which connects the software to the microprocessor. The software uses an 'audit trail check' to examine its internal circuits every 100 milliseconds. This makes sure that each software step goes in and goes out in the correct sequence. When the software finds that it is serviceable, it sets the watch-dog timer again. This must be done in less than 100 milliseconds from the time that it last occurred.
When the software finds a program error during the 'audit trail check', it does not set the watchdog-timer again. If the watchdog-timer is not set in less than 120 milliseconds, the hardware gets data that a software failure has occured (and sets the microprocessor). This set of the microprocessor lets the software (if it is serviceable) set the watchdog-timer. The failure of the software to set the watchdog-timer (the hardware sets the microprocessor a maximum of 4 times) causes:
- the hardware to stop the microprocessor
- the software to send a failure signal to the CFDIU and keep the failure data in the NOVOL RAM.
When the microprocessor stops, the software changes the condition of the LGCIU to 'FAILED'. This causes the other LGCIU to control the L/G system (Ref. AMM D/O 32-31-00-00).
B. Failure Monitoring
The Built in Test Equipment (BITE) controls the detection, filtering, generation, suppression, storage and reporting of LGCIU internal and external faults.
Faults can be found by a Built In Test (BIT) that:
The Built in Test Equipment (BITE) controls the detection, filtering, generation, suppression, storage and reporting of LGCIU internal and external faults.
Faults can be found by a Built In Test (BIT) that:
- operates continuously (CBIT)
- is performed after all resets (RBIT)
- is performed after a power reset only (PBIT)
- is performed during an initiated test (IBIT).
Faults can be found by passive checks or by active checks. The LGCIU has a built in test capability that detects and isolates the following fault conditions: - configuration pin programming failures
- proximity sensor and wiring failures
- proximity sensor and target unreasonable failures
- discrete input failures
- selector valve solenoid failures
- selector lever failures.
The LGCIU also has built in test functions to detect and isolate internal fault conditions that effect the LGCIU interfaces that follow: - selector valve solenoid control outputs
- discrete status and indication outputs
- AIRNC 429 outputs.
A built in test failure that has an effect on the LGCIU control of the landing gear and doors is a control fault. Confirmation of a control fault causes the LGCIU to set its select-out signal to inactive and disable its solenoid valve driver circuits. This prevents the defective LGCIU from controlling the landing gear and doors.
If the other LGCIU is servicable, its select-in signal will set to inactive and it will start to control the landing gear and doors.
(1) CBIT
When the LGCIU is energized, it continuously monitors itself and its interfaces. The LGCIU CBIT monitors do not change the operating properties of the subsystem Input/Output (I/O) signals.
When the LGCIU is energized, it continuously monitors itself and its interfaces. The LGCIU CBIT monitors do not change the operating properties of the subsystem Input/Output (I/O) signals.
(2) PBIT
The safety part of the PBIT monitors areas of the hardware and software which can have dormant failures. These areas are not monitored by the operational flight program. To detect failures, the PBIT will include a complete test of the hardware of the unit. The LGCIU does PBIT after a power-on reset. The LGCIU keeps the result of the PBIT in the BITE memory using the values HEALTHY or FAILED.
To set the PBIT result to HEALTHY, the test must be completed with no failures. The PBIT result is set to FAILED after a power reset. It will change to HEALTHY only after completion of a PBIT with no failures.
The tests that follow are done as part of PBIT:
The safety part of the PBIT monitors areas of the hardware and software which can have dormant failures. These areas are not monitored by the operational flight program. To detect failures, the PBIT will include a complete test of the hardware of the unit. The LGCIU does PBIT after a power-on reset. The LGCIU keeps the result of the PBIT in the BITE memory using the values HEALTHY or FAILED.
To set the PBIT result to HEALTHY, the test must be completed with no failures. The PBIT result is set to FAILED after a power reset. It will change to HEALTHY only after completion of a PBIT with no failures.
The tests that follow are done as part of PBIT:
- Watchdog Test
- Proximity Sensor Interface Watchdog Test
- Solenoid Enable Test
- LGCIU Internal Potentiometer Calibration Tests.
(a) Watchdog Test
The software will deliberately not start the external watchdog and makes sure that the watchdog starts a processor reset and increments the error count.
The software will deliberately not start the external watchdog and makes sure that the watchdog starts a processor reset and increments the error count.
(b) Proximity Sensor Interface Watchdog Test
The Proximity Sensor Interface (PSI) Watchdog monitors the refresh control signal caused by the hardware and used by the PSI.
This test makes sure that the PSI watchdog:
The Proximity Sensor Interface (PSI) Watchdog monitors the refresh control signal caused by the hardware and used by the PSI.
This test makes sure that the PSI watchdog:
- can sense a failure of the PSI refresh control signal
- creates a related error signal
- user functions react to the error signal.
(c) Solenoid Enable Test
The software creates solenoid drive enable signals. These are used by the high and low side drivers to disable the driver output as necessary.
The hardware will create selector valve solenoid command enable signals. These will be used by the high side and low side control logic to disable the commands to the high and low side drivers.
This test makes sure that each of the enable signals can be set to the disable state. The user function can then recognize the disable state.
The software creates solenoid drive enable signals. These are used by the high and low side drivers to disable the driver output as necessary.
The hardware will create selector valve solenoid command enable signals. These will be used by the high side and low side control logic to disable the commands to the high and low side drivers.
This test makes sure that each of the enable signals can be set to the disable state. The user function can then recognize the disable state.
(d) LGCIU Internal Potentiometer Calibration Tests
During the potentiometer calibration test, the software reads the resistance values kept in the Non-Volatile memory (NVM) of each of the digital pots. It compares the read values with the values recorded in the LGCIU NVM.
During the potentiometer calibration test, the software reads the resistance values kept in the Non-Volatile memory (NVM) of each of the digital pots. It compares the read values with the values recorded in the LGCIU NVM.
(3) RBIT
Reset Bit (RBIT) is done after all resets, including power-on resets.
RBIT supplies fault cover for fault conditions that:
Reset Bit (RBIT) is done after all resets, including power-on resets.
RBIT supplies fault cover for fault conditions that:
- are not continuously monitored
- the testing is not limited by PBIT.
After reset, the LGCIU will find the cause of the reset from one of: - power-on reset
- reset caused by the external software watchdog timer
- reset caused by the internal software time (if applicable)
- reset due to other cause.
This lets the applicable test be done during recovery and helps with trouble shooting.
The tests that follow are done as part of RBIT: - Hardware/Software Compatibility
- RAM Test
- ROM Test
- NVM Test.
(a) Hardware/Software Compatibility
During RBIT, the software does a check of the hardware standard against the flight software standard.
During RBIT, the software does a check of the hardware standard against the flight software standard.
(b) RAM Test
The software writes to all addressable areas of internal RAM and reads back the data written for accuracy.
The software writes to all addressable areas of internal RAM and reads back the data written for accuracy.
(c) ROM Test
The software calculates a Cyclic Redundancy Check (CRC) of the boot and TPU software and compares the calculated CRC with the CRC in the related ROM.
The software calculates a Cyclic Redundancy Check (CRC) of the boot and TPU software and compares the calculated CRC with the CRC in the related ROM.
(d) NVM Test
The software tests the data contained in the initialisation area of NVM to find if the data is applicable.
The software tests the data contained in the initialisation area of NVM to find if the data is applicable.
(4) IBIT
Initiated BIT (IBIT) is done from the CFDS when interactive mode is active. The operator starts the IBIT through the MCDU. During IBIT, the software will force proximity sensor inputs to specified values to test the discrete outputs. A subset of PBIT and RBIT tests will be done at this time.
The IBIT includes all checks that are done during CBIT. The reset times applied during CBIT can be different from the reset times applied during IBIT.
The test that follows is done during IBIT:
Initiated BIT (IBIT) is done from the CFDS when interactive mode is active. The operator starts the IBIT through the MCDU. During IBIT, the software will force proximity sensor inputs to specified values to test the discrete outputs. A subset of PBIT and RBIT tests will be done at this time.
The IBIT includes all checks that are done during CBIT. The reset times applied during CBIT can be different from the reset times applied during IBIT.
The test that follows is done during IBIT:
(a) Interface Signals Test
The interface signals test toggles the discrete output drivers to check for failures. These failures are not always found when the aircraft is on the ground.
The simulation mode function is used to force the proximity sensor inputs. All proximity sensor channels that can be simulated, are simulated to the target near and target far position. The CBIT alogrithms do a check of the discrete output status data received from the hardware. It compares the data to the values expected by the software to find faults. If the values are not the same, a fault is found.
The interface signals test toggles the discrete output drivers to check for failures. These failures are not always found when the aircraft is on the ground.
The simulation mode function is used to force the proximity sensor inputs. All proximity sensor channels that can be simulated, are simulated to the target near and target far position. The CBIT alogrithms do a check of the discrete output status data received from the hardware. It compares the data to the values expected by the software to find faults. If the values are not the same, a fault is found.
C. BITE Test
The BITE test is software controlled and to start it you must make a test selection on the MCDU. The test is a process that operates most of the LGCIU hardware circuits. To prevent movement of the L/G and the L/G doors, it does not operate the solenoid driver of the:
Approximately 7 seconds is necessary to complete the test.
The failure conditions that do not show during the normal operation of the LGCIU can be found during the BITE test. This is because this function operates the hardware circuits. The Failure Condition Tables give these failure conditions.
During a BITE test:
At the end of the BITE test the BITE:
A hardware interlock prevents the operation of the BITE test during flight. This interlock is operated by:
The hardware interlock is overridden when the aircraft electrical circuits are energized from the external power (Ref. AMM D/O 24-41-00-00).
The BITE test is software controlled and to start it you must make a test selection on the MCDU. The test is a process that operates most of the LGCIU hardware circuits. To prevent movement of the L/G and the L/G doors, it does not operate the solenoid driver of the:
- selector valves
- baulk solenoid of the L/G control lever.
Approximately 7 seconds is necessary to complete the test.
The failure conditions that do not show during the normal operation of the LGCIU can be found during the BITE test. This is because this function operates the hardware circuits. The Failure Condition Tables give these failure conditions.
During a BITE test:
- the software failure-monitor function continues to operate
- the hardware failure-monitor function does not operate
- the LGCIU transmits incorrect L/G position information (ARINC 429 and discrete signals)
- the Sign/Status Matrix field of each ARINC 429 word is set to Functional Test
- the NOVOL RAM keeps all the failure data.
At the end of the BITE test the BITE:
- sends a CFDS message, or the signal TEST OK, to the CFDIU
- sets the Sign/Status Matrix field of each ARINC 429 word to Failed or Normal
- sends the failure data to the NOVOL RAM.
A hardware interlock prevents the operation of the BITE test during flight. This interlock is operated by:
- a signal from the Brake and Steering Control Unit (BSCU) (when the aircraft wheel speed is 70 kts or more)
- a 'not compressed' signal from the L/G.
The hardware interlock is overridden when the aircraft electrical circuits are energized from the external power (Ref. AMM D/O 24-41-00-00).
D. BITE Test (Fault Handling)
When a fault is identified by the BITE test, the fault handling is as follows:
When a fault is identified by the BITE test, the fault handling is as follows:
(1) Fault Code
Each fault code that is found and isolated by the LGCIU is given a unique code. The code information and troubleshooting data is given in TSM 32310003.
Each fault code that is found and isolated by the LGCIU is given a unique code. The code information and troubleshooting data is given in TSM 32310003.
(2) Shop Replaceable Unit (SRU) Code
The SRU code identifies the shop replaceable unit where the fault has occurred:
The SRU code identifies the shop replaceable unit where the fault has occurred:
| ------------------------------------------------ |
| ! SRU Code | Hex Value | SRU ! |
| !----------------------------------------------! |
| ! X | 3 | External to the LGCIU ! |
| !----------------------------------------------! |
| ! Y | 2 | Driver Card ! |
| !----------------------------------------------! |
| ! Z | 1 | Control Card ! |
| ------------------------------------------------ |
(3) Confirmation/Recovery
All faults are monitored during a number of monitoring cycles. This will ignore faults that are not necessary. A fault can be recovered in a set time, until it is confirmed as a fault.
The fault is recorded if it is not recovered before the set time in the BITE memory. ARINC data is sent as necessary.
A subset of faults is corrected when they are confirmed. When a fault is confirmed, it stays recorded in the BITE memory. The related maintenance data will continue to be transmitted to the CFDS.
After a fault is recovered, if the same fault is confirmed again during the same flight, the occurrence count for that fault will be increased.
All faults are monitored during a number of monitoring cycles. This will ignore faults that are not necessary. A fault can be recovered in a set time, until it is confirmed as a fault.
The fault is recorded if it is not recovered before the set time in the BITE memory. ARINC data is sent as necessary.
A subset of faults is corrected when they are confirmed. When a fault is confirmed, it stays recorded in the BITE memory. The related maintenance data will continue to be transmitted to the CFDS.
After a fault is recovered, if the same fault is confirmed again during the same flight, the occurrence count for that fault will be increased.
E. Failure Data
The failure monitoring software makes sure that the failure found is correct. This is done when it has completed its isolation and failure-filtering process. The failure data is then kept in a specified area of the NOVOL RAM in the LGCIU.
If a failure occurs when the aircraft is in flight, the failure data goes into the flight memory. The flight memory has the capacity to keep the data of 30 failures. Each failure data entry can be kept in the memory for a maximum of 64 flights. The data kept in the memory for 64 flights automatically erases at the start of the subsequent flight. If the memory becomes full in less than 64 flights, each new entry causes the initial entry to erase.
The data for a specified failure only goes into the memory once during each flight. If there is an intermittent failure during a flight, the software:
If a failure occurs when the aircraft is on the ground, (this includes those failures found during a BITE test), this data goes into the ground memory. The ground memory has the capacity to keep the data of 3 failures. When it is full, each new entry causes the initial entry to erase. All the failure data in the ground memory automatically erases at the start of the subsequent flight.
The NOVOL RAM keeps:
Each failure signal identifies a specified LRU and gives the FIN and ATA references of that LRU. The Failure Indication Tables give a list of the failure messages for each of the LGCIUs.
The other data kept with each failure message is as follows:
The data for a specified failure goes into the NOVOL RAM. At the same time, the failure message also goes to the CFDIU (CFDS Normal Mode). To see all the failure data kept in the NOVOL RAM, (the failure messages and the other related data), it is necessary to make the applicable selections on an MCDU (CFDS Menu Mode).
The failure monitoring software makes sure that the failure found is correct. This is done when it has completed its isolation and failure-filtering process. The failure data is then kept in a specified area of the NOVOL RAM in the LGCIU.
If a failure occurs when the aircraft is in flight, the failure data goes into the flight memory. The flight memory has the capacity to keep the data of 30 failures. Each failure data entry can be kept in the memory for a maximum of 64 flights. The data kept in the memory for 64 flights automatically erases at the start of the subsequent flight. If the memory becomes full in less than 64 flights, each new entry causes the initial entry to erase.
The data for a specified failure only goes into the memory once during each flight. If there is an intermittent failure during a flight, the software:
- puts the data into the memory the first time that the failure occurs
- counts the number of times the failure occurs again (the software can make a maximum of 4 counts)
- puts the count value into the memory with the applicable failure data.
If a failure occurs when the aircraft is on the ground, (this includes those failures found during a BITE test), this data goes into the ground memory. The ground memory has the capacity to keep the data of 3 failures. When it is full, each new entry causes the initial entry to erase. All the failure data in the ground memory automatically erases at the start of the subsequent flight.
The NOVOL RAM keeps:
- a failure message
- more data related to the message.
Each failure signal identifies a specified LRU and gives the FIN and ATA references of that LRU. The Failure Indication Tables give a list of the failure messages for each of the LGCIUs.
The other data kept with each failure message is as follows:
- the aircraft identification code
- the date on which the failure occurred
- the time when the failure first occurred
- the flight in which the failure occurred. (This shows as a negative number. EG, -01 is the last flight and -02 is the flight before that).
- a code that identifies the failure condition (Ref. Failure Condition Tables)
- the number of times in a flight that the same failure occurred
- the flight phase when the failure first occurred
- a SRU identification letter. (The letter A tells you that the failure is external to the LGCIU. The letters B thru J tells you that the failure is of a component in the LGCIU).
The data for a specified failure goes into the NOVOL RAM. At the same time, the failure message also goes to the CFDIU (CFDS Normal Mode). To see all the failure data kept in the NOVOL RAM, (the failure messages and the other related data), it is necessary to make the applicable selections on an MCDU (CFDS Menu Mode).
F. Failure Data
When the fault confirmation procedure has been completed, the failure data is kept in the BITE memory.
The BITE memory has 5 flight zones as follows:
When the fault confirmation procedure has been completed, the failure data is kept in the BITE memory.
The BITE memory has 5 flight zones as follows:
- In Flight Failures (Zone 1)
- Trouble Shooting Data (Zone 2)
- Ground Report Failures (Zone 3)
- Shop Data (Zone 4)
- In Flight Class 3 Failures (Zone 5).
(1) In Flight Failures (Zone 1)
The In Flight Failure data is made up of the Fault Code and the SRU Code.
The LGCIU keeps zone 1 fault data. The data is kept for the current flight and the 63 flights before. The LGCIU has the capacity to keep the data of 30 faults. The total number of faults in current flight and the 63 flights before cannot be more than 30. Only data for the 30 most recent faults will be kept.
The In Flight Failure data is made up of the Fault Code and the SRU Code.
The LGCIU keeps zone 1 fault data. The data is kept for the current flight and the 63 flights before. The LGCIU has the capacity to keep the data of 30 faults. The total number of faults in current flight and the 63 flights before cannot be more than 30. Only data for the 30 most recent faults will be kept.
(2) Trouble Shooting Data (Zone 2)
Zone 2 has extra failure data to help with trouble shooting onboard the aircraft. The zone 2 fault data gives the system condition when the fault occurs for the first time.
The data includes the items that follow:
Zone 2 has extra failure data to help with trouble shooting onboard the aircraft. The zone 2 fault data gives the system condition when the fault occurs for the first time.
The data includes the items that follow:
- fault code
- fault occurence count
- temperature monitoring data
- reset counter
- reason for last reset
- flight phase
- flight leg
- offside LGCIU activity
- proximity sensor near/far state
- proximty sensor OK/fail state
- discrete input states
- landing gear selector lever position
- selector valve commands
- discrete output transistor states
- power supply states.
(3) Ground Report Failures (Zone 3)
Trouble shooting data for class 1, class 2 and class 3 faults that occur on the ground are stored in zone 3. Only faults found during operation in NORMAL maintenance modes are recorded. Faults found during operation in INTERACTIVE mode will not be recorded in zone 3. These faults are available through the Ground Scanning function. Only the faults that have not been recorded in zone 1 or zone 5 for the current flight, will be kept in zone 3.
Trouble shooting data for class 1, class 2 and class 3 faults that occur on the ground are stored in zone 3. Only faults found during operation in NORMAL maintenance modes are recorded. Faults found during operation in INTERACTIVE mode will not be recorded in zone 3. These faults are available through the Ground Scanning function. Only the faults that have not been recorded in zone 1 or zone 5 for the current flight, will be kept in zone 3.
(4) Shop Data (Zone 4)
A processor reset is caused by a subset of faults. The confirmation of these faults is a function of the watchdog reset count.
Shop data gives a procedure to clear the fault. If the fault is found again after multiple resets, the fault will be confirmed.
When the fault has been confirmed, the LGCIU will store the related data in zone 4 of the BITE memory. The data in zone 4 of the BITE memory is only available for display while the LGCIU is in shop mode
A processor reset is caused by a subset of faults. The confirmation of these faults is a function of the watchdog reset count.
Shop data gives a procedure to clear the fault. If the fault is found again after multiple resets, the fault will be confirmed.
When the fault has been confirmed, the LGCIU will store the related data in zone 4 of the BITE memory. The data in zone 4 of the BITE memory is only available for display while the LGCIU is in shop mode
(5) In Flight Class 3 Failures (Zone 5)
For class 3 faults, the BITE memory zone 5 stores data as follows:
For class 3 faults, the BITE memory zone 5 stores data as follows:
- fault code
- SRU code
- fault occurence count
- date and time that the fault was found first
- flight phase during which the fault was first found.
Class 3 faults are removed from the memory at the subsequent engine start.
G. Landing Gear Simulation Function
The L/G simulation function is an aid to the maintenance technicians during the trouble shooting and the maintenance tasks. With this function it is not necessary to:
During the simulation of a L/G configuration the:
The L/G simulation function is an aid to the maintenance technicians during the trouble shooting and the maintenance tasks. With this function it is not necessary to:
- lift the aircraft on jacks (to operate the proximity sensors on the shock absorbers)
- operate the L/G.
During the simulation of a L/G configuration the:
- LGCIU supplies output data that agrees with the simulated, and not the correct, configuration
- ARINC 429 and discrete signals go to the applicable interface systems (Ref. AMM D/O 32-62-00-00).
H. CFDS
The CFDS has two modes of operation, Normal and Menu.
Normal Mode
The continuous failure monitoring operates only in normal mode. It continuously sends the status and the failure messages (Ref. LGCIU BITE Messages) to the CFDS. The CFDIU keeps the failure messages in its memory until the start of the subsequent flight. These messages can be seen when you set the MCDU to CFDS-LAST LEG REPORT (Ref. AMM D/O 31-32-00-00).
The CFDS has two modes of operation, Normal and Menu.
Normal Mode
The continuous failure monitoring operates only in normal mode. It continuously sends the status and the failure messages (Ref. LGCIU BITE Messages) to the CFDS. The CFDIU keeps the failure messages in its memory until the start of the subsequent flight. These messages can be seen when you set the MCDU to CFDS-LAST LEG REPORT (Ref. AMM D/O 31-32-00-00).
I. For LGCIU part number 664700500A4x only:
Menu Mode
This mode is only available while the aircraft is on the ground. With a MCDU set to LGICU-1 or LGCIU-2, the applicable LGCIU sends a menu of the failure data and test items to the MCDU. Each LGCIU menu contains these items:
Menu Mode
MCDU - LGCIU Menu and Replies to Key SelectionThis mode is only available while the aircraft is on the ground. With a MCDU set to LGICU-1 or LGCIU-2, the applicable LGCIU sends a menu of the failure data and test items to the MCDU. Each LGCIU menu contains these items:
- LAST LEG REPORT
- PREVIOUS LEG REPORT
- LRU IDENTIFICATION
- TROUBLE SHOOTING DATA
- GROUND SCANNING
- TEST
- LANDING GEAR SIMULATION.
NOTE: Continuous failure monitoring does not operate in menu mode. BITE failure monitoring operates only momentarily at the start of the Test selection.
J. For LGCIU part number 80-178-02-880xx only:
Menu Mode
This mode is only available while the aircraft is on the ground. With a MCDU set to LGICU-1 or LGCIU-2, the applicable LGCIU sends a menu of the failure data and test items to the MCDU. Each LGCIU menu contains these items:
Menu Mode
This mode is only available while the aircraft is on the ground. With a MCDU set to LGICU-1 or LGCIU-2, the applicable LGCIU sends a menu of the failure data and test items to the MCDU. Each LGCIU menu contains these items:
- LAST LEG REPORT
- PREVIOUS LEG REPORT
- LRU IDENTIFICATION
- TROUBLE SHOOTING DATA
- GROUND SCANNING
- TEST
- LANDING GEAR SIMULATION
- CLASS 3 FAULTS
- GROUND REPORT.
NOTE: Continuous failure monitoring does not operate in menu mode. BITE failure monitoring operates only momentarily at the start of the Test selection.
K. For LGCIU part numbers 664700500A4x and 80-178-02-880xx:
(1) LAST LEG REPORT
This display shows the failure messages kept in the NOVOL RAM during the last flight. It can show a maximum of two failure messages at one time. The display will show more failure messages when you use the NEXT PAGE key. This will have no effect if the display shows all of the failure messages.
This display shows the failure messages kept in the NOVOL RAM during the last flight. It can show a maximum of two failure messages at one time. The display will show more failure messages when you use the NEXT PAGE key. This will have no effect if the display shows all of the failure messages.
L. For LGCIU part number 664700500A4x only:
(1) PREVIOUS LEG REPORT
This display shows the failure messages (maximium of 30) kept in the NOVOL RAM during the last 63 flights. At the top of the display, the last message kept shows first.
Each page of the display shows a maximum of three failure messages. The NEXT PAGE key lets you see the subsequent failure messages. When the last message shows and you use the NEXT PAGE key, it causes the first failure message to show again.
If you move a LGCIU to a different aircraft, it keeps the failure data of the aircraft it was on before. The aircraft on which each failure occurred can be identified. The specified aircraft identification code shows when the applicable failure message shows.
If the LGCIU is put in a different position (for example side 2 not side 1), the FIN(S) of the stored failure(s) will change to agree with the side where the LGCIU is installed.
This display shows the failure messages (maximium of 30) kept in the NOVOL RAM during the last 63 flights. At the top of the display, the last message kept shows first.
Each page of the display shows a maximum of three failure messages. The NEXT PAGE key lets you see the subsequent failure messages. When the last message shows and you use the NEXT PAGE key, it causes the first failure message to show again.
If you move a LGCIU to a different aircraft, it keeps the failure data of the aircraft it was on before. The aircraft on which each failure occurred can be identified. The specified aircraft identification code shows when the applicable failure message shows.
If the LGCIU is put in a different position (for example side 2 not side 1), the FIN(S) of the stored failure(s) will change to agree with the side where the LGCIU is installed.
M. For LGCIU part number 80-178-02-880xx only:
(1) PREVIOUS LEG REPORT
This display shows the failure message (maximum of 30) kept in the NOVOL RAM during the last 63 flights. At the top of the display, the last message kept shows first.
Each page of the display shows two failure messages.
The NEXT PAGE key lets you see the subsequent failure messages. When the last message shows and you use the NEXT PAGE key, it causes the first failure message to show again.
If you move a LGCIU to a different aircraft, it keeps the failure data of the aircraft it was on before. The aircraft on which each failure occured can be identified. The specified aircraft identification code will show when the applicable failure message shows.
If the LGCIU is put in a different position (for example side 2 not side 1), the FIN(S) of the stored failure(s) will change to agree with the side where the LGCIU is installed.
This display shows the failure message (maximum of 30) kept in the NOVOL RAM during the last 63 flights. At the top of the display, the last message kept shows first.
Each page of the display shows two failure messages.
The NEXT PAGE key lets you see the subsequent failure messages. When the last message shows and you use the NEXT PAGE key, it causes the first failure message to show again.
If you move a LGCIU to a different aircraft, it keeps the failure data of the aircraft it was on before. The aircraft on which each failure occured can be identified. The specified aircraft identification code will show when the applicable failure message shows.
If the LGCIU is put in a different position (for example side 2 not side 1), the FIN(S) of the stored failure(s) will change to agree with the side where the LGCIU is installed.
N. For LGCIU part numbers 664700500A4x and 80-178-02-880xx:
(1) LRU IDENTIFICATION
This display shows the part numbers of the LGCIU hardware and software.
This display shows the part numbers of the LGCIU hardware and software.
O. For LGCIU part number 664700500A4x only:
(1) TROUBLE SHOOTING DATA
This display shows the failure data kept in the NOVOL RAM. It has two types of page, one for flight failures and one for ground failures. For those failures that occur in flight, the page heading includes the aircraft identification code. For those failures that occur on the ground, the message GROUND replaces the aircraft identification code.
The page for flight failures can show a maximum of three lines of data. The page for ground failures can show a maximum of seven lines of data. The sequence in which the data shows, and the procedure for the NEXT PAGE key, is the same as that for the PREVIOUS LEG REPORT.
If a failure has occured since the last flight, there will be some failure data in the ground memory of the NOVOL RAM. The selection of the TROUBLE SHOOTING DATA key causes the display to show this data first (GROUND page).
If an aircraft flies with a failure that first occurred on the ground, the display page shows a ground flight phase number (EG, 01 on the applicable line of data).
The trouble shooting data shows on different pages when the:
This display shows the failure data kept in the NOVOL RAM. It has two types of page, one for flight failures and one for ground failures. For those failures that occur in flight, the page heading includes the aircraft identification code. For those failures that occur on the ground, the message GROUND replaces the aircraft identification code.
The page for flight failures can show a maximum of three lines of data. The page for ground failures can show a maximum of seven lines of data. The sequence in which the data shows, and the procedure for the NEXT PAGE key, is the same as that for the PREVIOUS LEG REPORT.
If a failure has occured since the last flight, there will be some failure data in the ground memory of the NOVOL RAM. The selection of the TROUBLE SHOOTING DATA key causes the display to show this data first (GROUND page).
If an aircraft flies with a failure that first occurred on the ground, the display page shows a ground flight phase number (EG, 01 on the applicable line of data).
The trouble shooting data shows on different pages when the:
- NOVOL RAM keeps the data on different dates
- data refers to a different aircraft.
P. For LGCIU part number 80-178-02-880xx only:
(1) TROUBLE SHOOTING DATA
This display shows the system data kept in zone 2 of the BITE memory during a class 1 or class 2 fault. If there are no failures, the text 'no fault detected' is shown.
One message is displayed on each page. If there is more than one message, the NEXT PAGE can be used to display more messages.
The troubleshooting data page displays:
This display shows the system data kept in zone 2 of the BITE memory during a class 1 or class 2 fault. If there are no failures, the text 'no fault detected' is shown.
One message is displayed on each page. If there is more than one message, the NEXT PAGE can be used to display more messages.
The troubleshooting data page displays:
- The fault that caused the data to be kept
- The date of the fault
- The time and ATA chapter of the fault
- The system data.
The data is shown as a block made of hexadecimal characters put into fifteen four-digit words. The fifteen words are shown over three lines.
For more information, TSM 32310003.
Q. For LGCIU part numbers 664700500A4x and 80-178-02-880xx:
(1) GROUND SCANNING
The ground scanning function gives a procedure to access data related with faults that are currently active. When a fault is confirmed during ground scanning, the data related with the fault is not kept in the LGCIU BITE memory. It will be available for display on the ground scanning page.
The ground scanning function gives a procedure to access data related with faults that are currently active. When a fault is confirmed during ground scanning, the data related with the fault is not kept in the LGCIU BITE memory. It will be available for display on the ground scanning page.
(2) TEST
When you make a TEST selection on the MCDU, the display will show:
When you make a TEST selection on the MCDU, the display will show:
- TEST WAIT (10 secs).
- TEST OK
- TEST, the CFDS failure indication(s) (Ref. Tables 1 and 2), and the message END OF TEST.
(3) LANDING GEAR SIMULATION
When the MCDU is set to LANDING GEAR SIMULATION, the L/G simulation display shows. This display gives seven L/G configurations:
When you make a selection from this display, the display changes to one which gives these four L/G positions:
An arrow-head shape (<) shows adjacent to the indications for the positions not held by the L/G.
The arrow-head shape shows that a simulation of these positions can be made. When you make a simulation selection of these positions, the arrow-head shape goes out of view.
For example - The NLG is locked down and compressed:
When the MCDU is set to LANDING GEAR SIMULATION, the L/G simulation display shows. This display gives seven L/G configurations:
| NOSE NOSE + LH |
| LEFT HAND NOSE + RH |
| RIGHT HAND |
| LH + RH |
| NOSE + LH + RH |
When you make a selection from this display, the display changes to one which gives these four L/G positions:
| COMPRESSED |
| EXTENDED |
| DOWN LOCKED |
| UP LOCKED |
An arrow-head shape (<) shows adjacent to the indications for the positions not held by the L/G.
The arrow-head shape shows that a simulation of these positions can be made. When you make a simulation selection of these positions, the arrow-head shape goes out of view.
For example - The NLG is locked down and compressed:
| COMPRESSED - L/G position |
| <EXTENDED - can be simulated |
| DOWN LOCKED - L/G position |
| <UP LOCKED - can be simulated. |
R. For LGCIU part number 80-178-02-880xx only:
(1) CLASS 3 REPORT
The Class 3 Report shows class 3 faults recorded in the BITE LGCIU memory zone 5 for the current flight. The class 3 faults are removed from the memory at the subsequent engine start.
The Class 3 Report shows class 3 faults recorded in the BITE LGCIU memory zone 5 for the current flight. The class 3 faults are removed from the memory at the subsequent engine start.
(2) GROUND REPORT
The display gives the failure messages stored in the BITE LGCIU memory zone 3 for those failures that:
The display gives the failure messages stored in the BITE LGCIU memory zone 3 for those failures that:
- occur or have occured when the aircraft is on the ground.
If there are no failures, the text 'no fault detected' will be displayed. The display will show two messages on each page. If there are more than two messages, the NEXT PAGE key can be used to display them. The ground report message is removed from the memory at the subsequent engine start.
Faults confirmed during ground scanning are not kept in the LGCIU BITE memory. They will not be shown as part of the ground report.
4. Power Supply
Not applicable
** ON A/C NOT FOR ALL Not applicable
5. Interface
Not applicable
** ON A/C NOT FOR ALL Not applicable
6. Component Description
Not applicable
** ON A/C NOT FOR ALL Not applicable
7. Operation/Control and Indicating
For Failure Indication Data-Tables and Failure Condition Tables, TSM 32310003.
** ON A/C NOT FOR ALL For Failure Indication Data-Tables and Failure Condition Tables, TSM 32310003.
8. BITE Test
Not applicable
Not applicable