ALL OPERATORS TELEX

- ALL OPERATORS TELEX TO: A320 FAMILY OPERATORS SUBJECT: ATA32 MAIN LANDING GEAR (MLG) DOOR ACTUATOR INTERNAL BREAKAGE OUR REF: AOT A320-32A1390 DATED 10 February 2011 1. AIRCRAFT AFFECTED: All A318/A319/A320/A321 aircraft (A/C). 2. REFERENCED DOCUMENTATION:

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- Ref. 1: CMM 32-31-35, Figure 2, item80 Damping Housing 2: CMM 32-31-35, Figure 2, item 130 Spiroloc Ring 3: CMM 32-31-35, Figure 2, item 140**Dampin~ Rin~**  4: CMM 32-31-35, Figure 2, item 150 Retain1ng R1ng 5: MOD 38274 

### I Airbus SB 32-1338 dated of Jul 22/08 6: GE Aviation VSB 200

-32-528 7: EUAD 2006-0112R1 8: Airbus SB 32-1309R2 dated of sep 24/09 9: TSM 32-31-00-810

-857 "MLG Door (LH) does not open fully" 10: TSM 32-31-00-810-858 "MLG Door (RH) does not open fully" 11: TSM 32-31-00-810-860 "MLG door (LH) does not close fully" 12: TSM 32-31-00

-810

-861 "MLG door (RH) does not close fully" 13: FOT 999.0008/11 dated of03 February, 2011 14: OEB 209/1 3. REASONS: The purpose ofthis AOT is to advise A320 Family operators of recent cases ofMLG Door Actuator PN 114122012 (post-Ref. 5) internal damage and to recommend operators to perform a weekly check of specific centralized Fault Display System (CFDS) messages (refer to Para 4.2.1) and the repetitive door opening inspection (refer to Para 4.2.2). 3.1 FACTS: Further to introduction of door actuators PN 114122012(Post

-Ref. 5 standard) in Jul 2008, seven operators have recently experienced Post-Ref. 5MLG Door Actuator failures. The door actuator failures have been identified during maintenance ground door opening (by gravity) or following CFDS messages found on Post Flight Report (PFR). Maintenance reported the involved MLG Doors were difficult to manually open and confirmed the MLG Door Actuator being at the origin ofthe slow door operation. For most occurrences, CFDS messages were present on previous leg reports. 3.2 CONSEQUENCES: Ultimately, the internal parts failure may result in the Actuator Rod to extend slowly delaying the MLG Door operation or stopping just before the Page 1

### end of stroke preventing the door to reach the fully open position. This excessive actuator stiffness could potentially impair the free-fall extensionwhen Doors and MLG are extended by gravity. 3.3 AIM: The aim ofthis AOT is to recommend operators to perform on all door actuators pre and post MOD 38274/SB A320-32-1338 (Ref. 5) the following inspections: -weekly check of specific CFDS Messages (listed in Para 4.2.1), -Repetitive inspection of the MLG door actuator for restricted extension using the Ground Door Opening Handle. This AOT supersedes the Airbus ISB A320-32-1309 (Ref. 8). 3.4 INVESTIGATION: Initial investigation offailed actuators PN 114122012 (Post Ref. 5) internal part damage. Damping ring (Ref. 3), retaining ring (Ref. 4) spiroloc ring (Ref. 2) were found in multiple pieces. The damping housing (Ref. 1) showed extensive damage on its internal diameter (ID). showed and
The disassembly has highlighted that the same internal parts are failing on the Pre-Ref. 5 and Post-Ref. 5 actuators. Identification ofthe root cause is under investigation. In parallel, a sampling of in service Post-Ref. 5 standard actuators PN 114122012 has been launched by Airbus to aid the failure root cause analysis. 4. SHORT-TERM ACTIONS: 4.1 PLANNING AND MANPOWER: 4.1.1ACCOMPLISHMENT TIMESCALE: -The accomplishment ofthe weekly CFDS messages check mentioned in Para 4.2.1must be performed no later than two (2) weeks from receipt ofthisAOT. For all aircraft, repeat the CFDS messages check every week. -The accomplishment ofthe MLG door actuator inspection mentioned in Para 4.2.2 must be performed no later than 800 FC from receipt of this AOT. For all aircraft, repeat the MLG door actuators inspection at intervals not exceeding 425FC. 4.2 DESCRIPTION: 4.2.1 CFDS MESSAGES CHECK: Aslow door operation (during opening or closure) could lead to the following CFDS messages being triggered by both LGCIU (by pair) for the same MLG door. Airbus recommends A320 Family operators to perform a weekly check of the following CFDS messages: For slow door opening ofthe RH MLG door: Page 2- "323173 RL/G DOOR OPEN PROX SNSR 32GA TGT POS" (from LGCIU1) AND

- "323173 RL/G DOOR OPEN PROX SNSR 34GA TGT POS" (from LGCIU2) For slow door opening of the LH MLG door:

- "323173 LL/G DOOR OPEN PROX SNSR 33GA TGT POS" (from LGCIU1) AND

- "323173 LL/G DOOR OPEN PROX SNSR 35GA TGT POS" (from LGCIU2) For slow door closure of the RH MLG door:

- "323173 RL/G DOOR CLOSED PROX SNSR 26GA TGT POS" (from LGCIU1) AND

- "323173 RL/G DOOR CLOSED PROX SNSR 28GA TGT POS" (from LGCIU2) For slow door closure of the LH MLG door:

- "323173 LL/G DOOR CLOSED PROX SNSR 27GA TGT POS" (from LGCIU1) AND

- "323173 LL/G DOOR CLOSED PROX SNSR 29GA TGT POS" (from LGCIU2) If a pair of above CFDS messages (fromLGCIU1 

### &LGCIU2)are found on the PFR for the same flight, the door actuator inspection mentioned in Para 4.2.2 of this AOT must be performed prior to the next flight to ensure smooth operation of the door actuator. If the movement of the door actuator is found to be restricted (stiff action or reduced stroke) during the inspection mentioned in Para 4
.2.2, the affected MLG door actuator must be replaced prior to the next flight. For further trouble shooting recommendations, refer to the associated TSM tasks Ref. 9, 10, 11 and 12. NOTE: The above mentioned TSM tasks will be revised to recommend door actuator inspection as per Para 4.2.2 of this AOT. The revision ofTSM Tasks Ref. 9, 10, 11 and 12 is targeted for end of March 2011. 4
.2
.2 DOOR ACTUATOR IN SPECTION: Accomplish the following repetitive inspection every 425 FC: MANPOWER: For actuator inspection: Total manhours:1.5 Elapsed time (hours):1.0 GENERAL: WARNING: MAKE SURE THAT THE SAFETY DEVICES AND THE WARNING NOTICES ARE IN POSITION BEFORE YOU START ATASK ON OR NEAR:

- THE FLIGHT CONTROLS

- THE FLIGHT CONTROL SURFACES

- THE LANDING GEAR AND THE RELATED DOORS

- COMPONENTS THAT MOVE
. MOVEMENT OF COMPONENTS CAN KILL OR INJURE PERSONS. Page 3

### WARNING: MAKE SURE THAT THE GROUND SAFETY-LOCKS ARE CORRECTLY INSTALLED ON THE LANDING GEAR. T

HIS PREVENTS UNWANTED MOVEMENT OF THE LANDING GEAR. WARNING: MAKE SURE THAT YOU OBEY ALL THE WARNINGS AND THE CAUTIONS INCLUDED IN THE REFERENCED PROCEDURES. NOTE:The procedure that follows is applicable tothe LH and RH MLG doors. INSPECTION: (a)Manually open the L HMLG door by using the door opening controlhandle as perAMM 32-12-00 page block 201, and make sure that: -The door.opens**~y** 

### gravity alone to at least the point atwhich the actuator 1s vert1cal -The movement ofthe door is smooth and continuous (there are no sudden changes ofvelocity) -The door should open from fully closed position tothe point at which the door actuator is vertical either at, or before, 30 seconds. Timing is to start at the point of initial LG door movement away from the "closed" position. (b)If the door has not fully opened make sure that: -The door can be easily pushed to the fully open position with just one hand -The resistance tomotion is smooth (hydraulic resistance only) (c)With the door fully open, measure the dimension 'DIM' shown in the attached appendix Adiagram. -Dimension DIM must be >385mm (d) Move the door by hand away from the fully open position for approx 30 degrees and back to the fully open position, to make sure that: -The resistance tomotion is smooth (hydraulic resistance only) (e) The LH MLG door actuatormust be replaced ifany ofthe checks in steps (a) to (d) fail (f) Repeat the work steps (a) to (e) for the RH MLG door REPAIR: (a) Replacement ofthe MLG door actuator. -Remove the MLG door actuator as perAMM 32-31-35, Page block 401. -Install the MLG door actuator as per AMM 32-31-35, Page block 401. NOTE: The door actuators PN 114122012 (Post-Ref. 5 standard) is not considered as a terminating action ofthe repetitive inspections as required by this AOT. It is anticipated that this AOT being mandatory by EASA new AD with supersedure of EASA AD 2006-0112R1 (Ref. 7). Page 44.3 SPARES: In case of door actuator replacement, please be advised that actuator PN 114122011 can be installed in place of actuator PN 114122012 without any conditions or restrictions. The current documentation reflects an interchangeability code (ICY) 01 between PN 114122011 and PN 114122012. The documentation will be revised to reflect an ICY 02 between PN 114122011 and PN 114122012. This IPC revision is targeted for May 2011
. 5. FURTHER ACTIONS: Airbus recommends A320 Family operators to put on hold the accomplishment of door actuator modification from PN 114122011 to PN 114122012 as per SB A320-32-1338 (Ref
. 5) and GE AVIATION VSB 200-32-528 (Ref
. 6). Anew Inspection service Bulletin (ISB) applicable to Pre and Post MOD 38274/SB A320-32-1338 (Ref
. 5) actuators will be issued by end ofApril 2011. This ISB will cover repetitive inspection of Para 4.2.2 and will supersede previous ISB A320-32-1309 Rev 02 (Ref. 8). 6. FURTHER INFORMATION: AFlight Operations Telex (FOT) number 999.0008/11 (Ref
. 13) has been issued to introduce the OEB 209/1 (Ref. 14) for modification of the flight crew procedure in case of "L/G GEAR NOT DOWNLOCKED" warning. This will introduce a delay of two (2) minutes prior to selecting gravity extension. If the gear extension sequence is interrupted due to a stiff door actuator, hydraulic pressure will continue to act to extend the actuator during this two minute period
. 7. AOT APPROVAL: THE TECHNICAL CONTENT OF THIS AOT HAS BEEN APPROVED UNDER EASA DESIGN ORGANIZATION APPROVAL EASA
.21J
.031
. 8. REPORTING/ACKNOWLEDGEMENT: OPERATORS ARE REQUESTED TO ACKNOWLEDGE RECEIPT OF THIS AOT WITHIN 48 HOURS AFTER RECEIPT TO: Mrs. L
. BONNET SEEL E

-mail laetitia.bonnet@airbus
.com Fax : +33 (0)5 67 19 12 OS THIS ACKNOWLEDGMENT CAN BE MADE THROUGH THE AIRBUS FIELD SERVICE OFFICE WHERE AVAILABLE. QUESTIONS ABOUT THIS AOT AND INSPECTION RESULTS WITH FINDINGS ARE TO BE SENT TO AIRBUS CUSTOMER SERVICES ENGINEERING AS SOON AS POSSIBLE, AFTER THE AOT APPLICATION, TO THE ATTENTION OF: Mr. Jean-Marc Lacanette, SEEL1, Phone: +33(0) 5 67
.19.16
.21 Fax: +33(0) 5 67.19.12.05 Page 5

### E-mail: jean-marc.lacanette@airbus
.com Best regards
. A. VIEILLARD VICE PRESIDENT A320 FAMILY PROGRAMME CUSTOMER SERVICES DIRECTORATE

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