DOC AIRBUS | AMM A320FMAINTENANCE AND SAFETY TESTS/BITE - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
1. General
A. Maintenance
The Electrical Flight Control System (EFCS) is a maintenance system installed around the two Flight Control Data Concentrators (FCDCs).
The functions of the FCDCs are to:
The Electrical Flight Control System (EFCS) is a maintenance system installed around the two Flight Control Data Concentrators (FCDCs).
The functions of the FCDCs are to:
EFCS Maintenance System- Collect the failures detected by the Elevator Aileron Computers (ELACS) and the Spoiler Elevator Computers (SECs)
- Compare the received data
- Give the maintenance messages to the Centralized Fault Display Interface Unit (CFDIU).
B. Periodic Tests
The CFDIU is used for the two periodic tests through the Multipurpose Control & Display Unit (MCDU):
The CFDIU is used for the two periodic tests through the Multipurpose Control & Display Unit (MCDU):
- Aileron servocontrol damping-test
- Elevator servocontrol damping-test.
C. Automatic Tests
These tests are used to detect the failures which cannot be seen on the standby channels and the failures which cannot be detected by continuous monitoring.
These tests are used to detect the failures which cannot be seen on the standby channels and the failures which cannot be detected by continuous monitoring.
2. Interface
For the Centralized Fault Display System (CFDS), the FCDCs are the type-1 systems. The FCDCs are interfaced with the CFDIU through the ARINC 429 buses.
The data related to the FCDCs are:
** ON A/C NOT FOR ALL For the Centralized Fault Display System (CFDS), the FCDCs are the type-1 systems. The FCDCs are interfaced with the CFDIU through the ARINC 429 buses.
The data related to the FCDCs are:
- Maintenance messages
- Tests
- Control surface positions that are transmitted through the ARINC 429 buses.
3. Operation
A. Maintenance - General
The Line Replaceable Unit (LRU) failures detected in the flight by the ELACs and the SECs are memorized by the FCDCs. The data will be stored in the non-volatile memories and are permanently transmitted to the CFDIU under label 356.
On the ground, in the MCDU, the display related to the maintenance messages in clear language is effected according to:
The Line Replaceable Unit (LRU) failures detected in the flight by the ELACs and the SECs are memorized by the FCDCs. The data will be stored in the non-volatile memories and are permanently transmitted to the CFDIU under label 356.
On the ground, in the MCDU, the display related to the maintenance messages in clear language is effected according to:
- Display specific to the CFDS for line maintenance (rapid troubleshooting).
- Display specific to the flight controls for deeper maintenance.
(1) LAST LEG REPORT
This function displays all the system failures which appeared during the last flight.
The messages include:
This function displays all the system failures which appeared during the last flight.
The messages include:
- The failed LRU with the ATA reference number
- The time of occurrence
- The date.
(2) PREVIOUS LEGS REPORT
This function displays messages related to the failures which appeared during the last 64 flights.
The messages include:
This function displays messages related to the failures which appeared during the last 64 flights.
The messages include:
- The failed LRU with the ATA reference number
- The time and date of occurrence
- The flight number.
(3) SYSTEM REPORT/TEST
This function gives access to the different systems (specially to the flight controls).
This function gives access to the different systems (specially to the flight controls).
C. Maintenance - Flight Control Menu
This menu is specially for the main-base maintenance of the flight controls.
The sub-menu displayed are:
These two sub-menus have the same functions, which are:
This menu is specially for the main-base maintenance of the flight controls.
The sub-menu displayed are:
- EFCS 1
- EFCS 2
- SFCC 1
- SFCC 2.
These two sub-menus have the same functions, which are:
- LAST LEG REPORT
- PREVIOUS LEGS REPORT
- LRU IDENTIFICATION
- GROUND SCAN
- CLASS 3 FAULTS
- TEST
- MEMORY.
(1) LAST LEG REPORT (7)
It displays the failures of the last flight that affect the flight controls.
The messages include:
It displays the failures of the last flight that affect the flight controls.
The messages include:
- The date
- The aircraft identification
- The flight number
- The time
- The failed LRU with its ATA reference.
(2) PREVIOUS LEGS REPORT (7)
It displays the failures of the last 64 flights that affect the flight controls.
The display is identical with the CFDS menu (Ref. Para. (1) (b)).
It displays the failures of the last 64 flights that affect the flight controls.
The display is identical with the CFDS menu (Ref. Para. (1) (b)).
(3) LRU IDENTIFICATION
This page displays the part numbers of the flight control computers.
This page displays the part numbers of the flight control computers.
(4) GROUND SCAN
This function is used on the ground to display the failures which are present at the time of the request.
Thus, this function can confirm a troubleshooting.
This function is used on the ground to display the failures which are present at the time of the request.
Thus, this function can confirm a troubleshooting.
(5) MEMORY
The function MEMORY is used to read the internal memories. It provides the BITE data or information for the shop use and the equipment sellers.
The function MEMORY is used to read the internal memories. It provides the BITE data or information for the shop use and the equipment sellers.
(6) TROUBLE SHOOTING DATA
The TROUBLE SHOOTING DATA allows to display the fault information and the data related to the system status before and after the failure occurrence.
This information is stored with each failure message.
The TROUBLE SHOOTING DATA can be called from the "LAST LEG REPORT", "PREVIOUS LEG REPORT" and the "GROUND REPORT".
The TROUBLE SHOOTING DATA complete the maintenance message in order to find the failures which are not easy to find. But, it does not give more information than the failure message.
The TROUBLE SHOOTING DATA allows to display the fault information and the data related to the system status before and after the failure occurrence.
This information is stored with each failure message.
The TROUBLE SHOOTING DATA can be called from the "LAST LEG REPORT", "PREVIOUS LEG REPORT" and the "GROUND REPORT".
The TROUBLE SHOOTING DATA complete the maintenance message in order to find the failures which are not easy to find. But, it does not give more information than the failure message.
4. Test
This function is displayed on the MCDU by the FCDCs. It performs the functions that follow:
This function is displayed on the MCDU by the FCDCs. It performs the functions that follow:
- Start the tests related to the flight controls
- Display the test results on the MCDU.
- Elevator servocontrol damping-test
- Aileron servocontrol damping-test.
A. Elevator Servocontrol Damping-Test
This test is started from the MCDU. It provides the indications and guidance to conduct the test.
The test is operated by the FCDC and it is performed by SEC1 and SEC2.
The SECs control the deflections of the surfaces by pressurizing the each servocontrol at the same time and alternatively.
This test is started from the MCDU. It provides the indications and guidance to conduct the test.
The test is operated by the FCDC and it is performed by SEC1 and SEC2.
The SECs control the deflections of the surfaces by pressurizing the each servocontrol at the same time and alternatively.
- If the test is possible
For each movement, the FCDC memorizes a deflection speed and a pressure drop to deduct the damping coefficient.
The indication "L ELEV TEST OK" or "ELEV TEST OK" is displayed on the MCDU.
The value of the damping coefficient can be obtained and displayed through the TEST REPORT. - If the test is not possible
The indication "ELEV TEST NOT POSSIBLE" is displayed on the MCDU.
If the computer identifies defect, the engagement condition code are displayed on the MCDU.
B. Aileron Servocontrol Damping-Test
The test is conducted in the same procedure as the elevator servocontrol test.
The test is operated by the FCDC and performed by the two ELACs.
The test is conducted in the same procedure as the elevator servocontrol test.
The test is operated by the FCDC and performed by the two ELACs.
- If the test is possible
Same measurements as the elevator damping test is performed.
The indication "R AIL TEST OK" or "L AIL TEST OK" is displayed on the MCDU.
The value of the damping coefficient can be obtained and displayed through the TEST REPORT. - If the test is not possible
The indication "AIL TEST NOT POSSIBLE" is displayed on the MCDU.
If the computer identifies defect, the engagement condition code are displayed on the MCDU.
C. Conditions Required to Initialize the Tests
(1) Conditions required by the FCDC to start the test
(a) For all the tests
- Aircraft on ground without movement:
. Minimum one ELAC and two SECs send ground condition
. LGCIU "NOSE GEAR STATUS" wired signal at compressed state
. "ENGINE PRESSURE STATUS" is at low state
. Minimum of two SECs give "WHEEL SPEED less than 6 KTS" information
. No SEC sends "WHEEL SPEED more than 66 KTS" information. - Three hydraulic system pressure on:
. Minimum of three computers (ELAC or SEC) send "B, G, Y HIGH PRESSURE" information.
(b) For aileron damping test
- SEC1 & SEC2 P/BSW "OFF"
- Both ELACs OK.
(c) For elevator damping test
- ELAC1 & ELAC2 P/BSW "OFF"
- SEC1 & SEC2 OK.
(2) Conditions required by ELAC to start the test
- Both ELACs available
- Three hydraulic pressure available
- Ground condition
- Both side sticks are at neutral position
- Wheel speed less than 6 Kts
- The three Air Data/Inertial Reference System (ADIRS) are off
- The two FCDCs are available.
(3) Conditions required by the SEC to start the test
- Ground condition
- Air Data Reference (ADR) OFF
- Wheel speed less than 6 kts
- Both FCDCs available.
NOTE: When the test is not possible, A hexa code is displayed on the MCDU in order to help the operator.
When the FCDC is in MENUE mode. the FCDC FAULT warning is displayed on the upper ECAM. D. Automatic Tests
These tests are built in order to detect the failures which are not detected by the permanent monitoring of the fault.
Usually these tests are permitted when the aircraft is on the ground without movement.
These tests are built in order to detect the failures which are not detected by the permanent monitoring of the fault.
Usually these tests are permitted when the aircraft is on the ground without movement.
(1) THS test
This test is performed by the ELACs and SECs in the conditions that follow:
This test is performed by the ELACs and SECs in the conditions that follow:
- The aircraft is on the ground without movement.
- Three hydraulic systems pressurized
- Pitch attitude lower than 5°
The aim of this test is to check the capability of each computer which controls the THS electrical motor power supply switching or the THS enable signal.
If the test is incorrect, a warning "ELAC PITCH FAULT" (when an ELAC is affected) or a CLASS2 message (when a SEC is affected) and a specific maintenance message are displayed.
The ground adjustment of the THS is done by the ELAC1 in order to check the availability of the ELAC1 THS control loop.
(2) Aileron changeover test
This test is made only by the ELACs.
It is done one time per flight in order to check that each ELAC is able to drive the aileron servocontrol mode (active or damped).
The test is enabled when :
This test is made only by the ELACs.
It is done one time per flight in order to check that each ELAC is able to drive the aileron servocontrol mode (active or damped).
The test is enabled when :
- The aircraft is on the ground without movement.
- Three hydraulic pressures are available
- The elevators are at neutral position and it is stopped in short time as one of these conditions disappears.
In case of incorrect test, a warning "AIL SERVO FAULT" and a maintenance message are displayed.
(3) Elevator test
(a) Mechanical disconnection monitoring
It is make sure by ELAC1 in order to check the related elevator servocontrols which are not disconnected from the elevator.
If there is a disconnection, the failure is detected during the check list. A warning "ELEV SERVO FAULT" and a maintenance message are displayed.
It is make sure by ELAC1 in order to check the related elevator servocontrols which are not disconnected from the elevator.
If there is a disconnection, the failure is detected during the check list. A warning "ELEV SERVO FAULT" and a maintenance message are displayed.
(b) Elevator changeover test
The conditions for this test is same as that of the aileron test.
Each ELAC checks its capability to drive the mode of the elevator servocontrol. Failure will cause the loss of pitch control in the affected ELAC and the loss of elevator control in the related SEC (if the SEC is affected by the failure). This failure will give the warning "ELAC PITCH FAULT" or "ELEV SERVO FAULT" and a maintenance message.
The conditions for this test is same as that of the aileron test.
Each ELAC checks its capability to drive the mode of the elevator servocontrol. Failure will cause the loss of pitch control in the affected ELAC and the loss of elevator control in the related SEC (if the SEC is affected by the failure). This failure will give the warning "ELAC PITCH FAULT" or "ELEV SERVO FAULT" and a maintenance message.
(4) Spoiler servovalve relay test
The monitoring of the relay is made by the reading of the normally-closed contact status:
The monitoring of the relay is made by the reading of the normally-closed contact status:
- When hydraulic pressure is high, the relays are closed
- When hydraulic pressure is low, the relays are open.
If failure is detected, the affected SEC disconnects. This failure will give the warning "SEC FAULT".