1. Parking brake selector valve

2. Parking brake selector valve
C xxx
C xxx
A319, A320, A321 aircraft
C xxx
A330, A340 aircraft
OEM: MESSIER BUGATTI

3. Parking brake selector valve
The parking brake selector valve is located in the aircraft belly. The hydraulic unit is controlled by an integrated electrical actuator assembly.
The parking brake selector valve connects the different components and pressurizes the parking brake system at a decreased pressure.
Engine
Material

4. Workscope
AJWT have developed a comprehensive work scope on brake selector valves to ensure reliability in service.
Initial test
Repair
Built-in reliability
Reason for removal is analyzed to confirm unit condition. Tests are performed In accordance to CMM specifications with particular emphasis on common fault areas.
According to test results and reason for removal repair is executed including aesthetics.
A standard set of components are replaced irrespective of fault diagnosis during initial test. Engineering supplemental instructions applied to further enhance reliability. Zero returns for motor faults since implementation of this repair. As per CMM there is no overhaul required.
Salvaged

5. Hydraulic test complex
Four state-of-the-art hydraulic test complexes, supported by two independent power stations
Capable of system operating pressures of up to 6000 psi as demand requires
Capable of testing current and next generation aircraft servo flight controls, hydraulic valves, actuators and accumulators just to name a few…

6. Common fault
Motor part number: and does not turn, or turns intermittently
Intermittent faults or failure’s of the 2 motors due to carbon build up from normal operation
Leading to improper function of the motor and brush assembly and can lead to failure of the parking brake
Motor 1-2 and micro switches show carbon build up
Cleaned, Repaired and Verified Motor 1-2 and micro switches
Actuator assembly cover shows contamination/dirt and carbon build up from motors

7. Engineering instructions
The CMM instructions only state to simply clean the motor and surrounding area to remedy this fault. If fault persists replace faulty motor(s). AJWT has gone a step further and has implemented an engineering instruction created early 2016.
A cleaning procedure for motor part number: and
Both motors and electrical attached parts are completely disassembled, inspected and thoroughly cleaned
A thorough verification test of each motor is completed before installation on higher assemby
End result:
Ensures a more reliable unit with a longer life on wing before future failure. A cost savings without the need to replace the motors.

8. Repaired / verified / installed / tested
Motors repaired in accordance with engineering supplemental instructions and micro switches both verified and installed. A complete test is done once installed on higher assembly in accordance with CMM instructions.

9. Finished product
Unserviceable unit
Serviceable unit

10. Accepted under warranty
Reliability of repair
In 2016
78 units were received
Accepted under warranty

11. Ajwt tracking Editable
AJWT ERP will immediately alert technicians to P/N’s & S/N’s previously seen by the shop.
Any return units, whether within or outwit warranty are flagged for further review
Reason for previous removal taken into consideration in repair
Additional “stress” testing undertaken under Engineering guidance where applicable

12. AJWT customer reporting
AJWT undertakes a Quarterly review of all warranties (all part numbers) to identify any trends and to ensure appropriate corrective action is initiated. In this instance AJWT will monitor removal rates and trends.
Causes of failure reviewed and tracked
Customer specific work scopes implemented to address any identified issues
Regular customer review covering MTBUR (Mean Time Between Unscheduled Removal), reason for removal and reliability improvement programs are available.
Full reliability reporting subject to sharing of customer information e.g. flight hours, times, cycles etc.

13. Thank you sales@ajw-technique.com +1 514 339 5099