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ALERT OPERATORS TRANSMISSION- AOT 

SUBJECT: ATA 57- INSPECT LH AND RH BOTTOM SKIN FASTENERS AT MAIN LANDING GEAR 

RIB 5 FOOTPRINT LOCATION FOR MIGRATED OR MISSING FASTENER 

AIRCRAFT TYPE: A318,A319,A320 

OUR REF.: A57N006-14 Rev 00 dated 04/December/2014 04-DEC-2014. 

1. AIRCRAFT AFFECTED 

Applicable to MSN 5817, 5826, 5837, 5848, 5855, 5864, 5875, 5886, 5896, 5910 and all A318, A319 

and A320 Aircraft delivered from MSN 5918 onwards. 

2. REFERENCED DOCUMENTATION 

2.1 APPENDIX 

AOT A57N006-14 Appendix A: decision tree for weekly inspection. 

AOT A57N006-14 Appendix B: decision tree for the 4 months inspection. 

AOT A57N006-14 Appendix C: reporting sheet. 

2.2 REFERENCES 

All limitations provided with concession suffix R related to this topic issued on delivered aircraft since 

November 2014 are superseded by this AOT. 

Ref. A: SRM 51-42-11 Paragraph 9 

Ref. B: AMM 57-51-37-000-008 Removal of the Access Door 

Ref. C: AMM 57-51-37-400-008 Installation of the Access Door 

Ref. D: AMM 51-78-00-615-005 Removal of Corrosion Preventive Compound 

Ref. E: AMM 51-78-00-916-001 Application of Temporary Protection System (TPS) 

3. REASON 

Inspection of Taperlok fasteners on A320 Family aircraft, located in the joint between the Main 

Landing Gear Support Rib lower flanges & lower wing skins on LH & RH wings, is required to ensure 

continued airworthiness. The inspection program is aimed at detecting Taperloks that have failed . 

3.1 FACTS 

During production of A318, A319, A320 wings a number of taperlok fasteners have been found failed 

after installation. Initial investigations highlight an issue with taperlok fasteners. The fasteners in 

question are located at the bottom skin of the MLG reinforcing plate, wing skin and Gear Support Rib 

5 lower flange (refer to fig . 1 and 2). 

The taperlok fasteners are installed on A318, A319 & A320 aircraft wings. A321 aircraft are NOT 

affected as wing assembly is done using parallel fasteners. 

AOT ref: A57N006-14 Rev 00 Page 1 of 15 Date: 04-Dec-2014 

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Figure 1- Location of affected fasteners 

FORWARD 

+ L + + OUTBOARD 

All fasteners heads identified as .A. to be inspected on a weekly basis 

Gear Support Rib D572-5Z580 

Figure 2a- Location of affected fasteners heads, view looking up 

AOT ref: A57N006-14 Rev 00 Page 2 of 15 Date: 04-Dec-2014 

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All fasteners tails/nuts 

identified on the inboard to 

be inspected on a weekly 

basis 

Gear support Rib D572-52SI!O 

FORWARD 

L 

All fasteners tails/nuts 

identified on the outboard to 

be inspected on a 4-monthly 

basis 

OUTBOARD 

Figure 2b- Location of affected fasteners tails/nuts. MLG support rib bottom flange upper 

surface 

3.2 CONSEQUENCES 

Failure of these fasteners may results in a reduction in the design margin of the structure. 

3.3AIM 

The aim of this AOT is to ensure that taperlok fasteners, affected by the failure mode, are identified 

and replaced in order to restore the design margin. 

Aircraft in the effectivity as per section1 are required to perform a weekly Detail Visual Inspection 

(DVI) of the external surface of the LH and RH lower wing surface for migrating or missing fasteners 

and of the inboard side of the MLG support rib lower flange for broken fastener tails/nuts (refer to fig . 

2a and 2b). 

In addition, Aircraft in the effectivity are required to perform a repeat DVI every 4 Months of the MLG 

Support Rib lower flange upper surface on outboard side of the MLG support rib lower flange for failed 

nuts I tails (refer to fig. 2b). 

AOT ref: A57N006-14 Rev 00 Page 3 of 15 Date: 04-Dec-2014 

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4. SHORT TERM ACTION 

For the weekly inspection: 

Refer to appendix AOT A57N006-14 Appendix A. 

In the event of no more than 1 finding (fastener migration or missing, tail/nuts missing) per side, the 

affected fastener needs to be removed (if in place) within 1 week and re-install within 4 months. 

NOTE: 

- In case of more than one finding per side, the operator has to replace affected fasteners before next 

flight leaving no more than 1 failed fastener until the 4 months inspection. 

- Remove/apply Temporary Protection System (TPS) in open hole as per Ref. D and E. 

-Apply 1 layer of speed tape over the affected location and 1 more layer overlapping it at go•. 

For the 4 months inspection: 

Refer to appendix AOT A57N006-14 Appendix B. 

In the event of finding (fastener migration or missing, tail/nuts missing) during DVI , fastener(s) needs 

to be replaced before further flight as per Ref. A. 

For both inspections, after fastener replacement, the inspections described in this AOT still have to be 

performed at the same intervals until further notice. 

4.1 PLANNING AND MANPOWER 

4.1.1 ACCOMPLISHMENT TIMESCALE 

For the weekly inspection: 

Do a DVI of the external surface of the LH an RH lower wing surface for migrating or missing 

fasteners and a DVI of the inboard MLG support rib lower flange for broken nut/tail. 

THRESHOLD: No later than 1 week from issuance of the AOT. 

GRACE PERIOD: N/A 

INTERVAL: No later than 1 week. 

AOT ref: A57N006-14 Rev 00 Page 4 of 15 Date: 04-Dec-2014 

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Fig. 3b example of finding (nut/tail missing on inboard area) 

Fig. 4 view of lower surface of MLG rib 5 area 

AOT ref: A57N006-14 Rev 00 Page 5 of 15 Date: 04-Dec-2014 

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Area to be 

inspected 

Fig. 5 view of inboard (looking outboard) of MLG rib 5. 

For the 4 months inspection: 

Do a DVI of the outboard MLG Support Rib lower flange fasteners and nuts 

THRESHOLD: No later than 4 Months after issuance of the AOT. 

GRACE PERIOD: N/A 

INTERVAL: No later than 4 months. 

Fig. 6 view of outboard (lool<ing inboard) of MLG rib 5. 

AOT ref: A57N006-14 Rev 00 Page 6 of 15 

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Area to be 

inspected 

Date: 04-Dec-2014 
~AIRBUS 

ALERT OPERATORS TRANSMISSION- AOT 

4.1 .2 MANPOWER 

The estimated amount of man hours to perform the weekly inspection is 1 hour per aircraft, both sides 

included. 

The estimated amount of man hours to perform the 4 months inspection is 2 hours per aircraft, both 

sides included. 

4.2 DESCRIPTION 

4.2.1 ACCESS 

For the weekly inspection: 

Support Equipment for access: 

• Access platform 2M (6 FT) adjustable, 

• Safety harness. 

Put an ACCESS PLATFORM 2M (6FT) in position. The use of magnifying tools may be required. 

For the 4 months inspection: 

Support Equipment for access: 

• Access platform 2M (6 FT) adjustable, 

• Safety harness. 

Work Zone and Access Panel: 

·Access Panel 574AB & 674AB (Door entrance of false rear spar area), 

·Warning & safety precautions: 

WARNING:MAKE SURE THAT THE GROUND SAFETY-LOCKS ARE IN POSITION ON THE 

LANDING GEAR. 

WARNING: PUT THE SAFETY DEVICES AND THE WARNING NOTICES IN POSITION BEFORE 

YOU START A TASK 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 CAUSE INJURY TO PERSONS 

AND/OR CAN CAUSE DAMAGE TO THE EQUIPMENT. 

C.t\UTION BE CAREFUL WHEN YOU DO 11.11\INTENAHC~ TASKS ON TIIF WING TR/I.ILIN(, 

EDGE. 

DO NOT CAUSE DAMAGE TO THE. ELE:CTRIGAL CABLE R<'\CEV\Ii\ Y"', 

- 00 NOT CAUSE 0/I.Mi\GE TC THE fLt:.CTRIGAL CABLE INST/Ill.ATION~· 

- !\:lAKE SURE THJ.\T THEEl Eel· fCt,· CABLES ARE INSl Al LED <.,.QRRE.C l L Y. 

INCORRECT INSTALLA.llON CAN CAUSE: DAMAGE. 

Put an ACCESS PLATFORM 2M (6FT) in position. The use of magnifying tools may be required. 

Perform access as per Ref. Band C. 

AOT ref: A57N006-14 Rev 00 Page 7 of 15 Date: 04-Dec-2014 

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4.2.2 INSPECTION REQUIREMENTS 

Do a DVI of the external surface of the LH an RH bottom skin lower wing surface for migrated or 

missing fasteners. 

Do a DVI of the INBOARD/OUTBOARD MLG Support Rib lower flange fasteners and nuts for missing 

nuts I tails . 

4.2.3 FINDINGS 

Failed fasteners (broken, migrated, missing) 

Failed tail/nut (broken, missing) 

In case of finding, refer to Appendix A and B. 

If a failed fastener is to be removed the following instructions are to be followed : 

• Mark the orientation of the fastener on the head (i.e. inboard/outboard). 

• Mark the location of the fastener on bolting diagram as per AOT A57N006-14 Appendix C. 

• Remove affected fastener as per Ref. A. 

• All effort should be made not to damage the fracture surface of the fastener during removal. 

• The fastener and associated nut/tail is to be returned to Airbus. 

• Report all findings to Airbus . 

If finding please report to Airbus as per AOT A57N006-14 Appendix C. 

4.3 SPARES AND TOOLING 

Fasteners part numbers affected: 

nominal 1st oversize 2nd oversize 

NSA 5486-9-27N NSA 5487-9-27N NSA 5488-9-27N 

NSA 5486-9-28N NSA 5487-9-28N NSA 5488-9-28N 

NSA 5486-9-29N NSA 5487-9-29N NSA 5488-9-29N 

NSA 5486-9-30N NSA 5487-9-30N NSA 5488-9-30N 

NSA 5486-9-31 N NSA 5487-9-31 N NSA 5488-9-31 N 

l·fw :.g; .. 'I& .. 

NSA 5486-1 0-22N NSA 5487-10-22N NSA 5488-10-22N 

NSA 5486-10-28N NSA 5487-10-28N NSA 5488-10-28N 

NSA 5486-10-29N NSA 5487-10-29N NSA 5488-10-29N 

NSA 5486-1 0-30N NSA 5487-10-30N NSA 5488-1 0-30N 

NSA 5486-10-31N NSA 5487-10-31N NSA 5488-10-31 N 

NSA 5486-1 0-32N NSA 5487-10-32N NSA 5488-10-32N 

NSA 5486-10-33N NSA 5487-10-33N NSA 5488-1 0-33N 

NSA 5486-10-35N NSA 5487-10-35N NSA 5488-10-35N 

Nuts part numbers affected: 

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NSA5472-9K7 

NSA5472-10K7 

Tooling list as per Ref. A to be made available. 

5. FURTHER INFORMATION 

5.1 FOLLOW-UP PLAN 

This repeat inspection is to be continued until Airbus has defined a terminating action to this AOT. 

Pending the level of finding this AOT may be revised to refine its instructions. 

TFU is under preparation for follow-up. 

5.2 IMPACTED DOCUMENTATION 

N/A 

AOT ref: A57N006-14 Rev 00 Page 9 of 15 Date: 04-Dec-2014 

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6. AOT APPROVAL 

The technical content of this document is approved under the authority of DOA nr. EASA.21J.031. 

It is anticipated that this AOT will be mandated by the issuance of an EASA Airworthiness Directive. 

7. REPORTING 

Questions about this AOT should be sent to the SEES2 department via the on-line TechRequest tool. 

Inspection results with findings are to be sent (ref AOT A57N006-14 Appendix C) to Airbus Customer 

Services engineering as soon as possible, after the AOT application, to the attention of: 

Julie BLANCHOT 

Structure Engineer 

Structure Engineering - SEES2 

CUSTOMER SERVICES 

Phone: +33(0)5 61 93 60 20 

Fax: +33 (0)5 61 93 36 14 

Mailto: julie.blanchot@airbus.com 

Ludovic MENARD 

Outer Wing Product Leader 

Structure Engineering - SEES2 

CUSTOMER SERVICES 

Phone: +33(0)5 67 19 16 36 

Fax: +33 (0)5 61 93 36 14 

Mailto: Ludovic.menard@airbus.com 

Best Regards, 

Jean-Luc MOUYSSET 

VICE PRESIDENT ENGINEERING SUPPORT 

CUSTOMER SERVICES 

Gilles DE CEVINS 

VICE PRESIDENT A320 PROGRAMME 

CUSTOMER SERVICES 

AOT ref: A57N006-14 Rev 00 Page 10 of 15 Date: 04-Dec-2014 

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AOT A57N006-14 Appendix A: decision trees for weekly inspection. 

NOTE: 

In case of more than one finding per side, the operator has 

to replace affected fasteners before next flight leaving no 

more than 1 failed fastener until the 4 months inspection. 

AOT ref: A57N006-14 Rev 00 Page 11 of 15 

~AIRBUS SAS. 2014. /\Ll RIGHTS RESERVED. CONFIDENTIAL AND PROPRIETARY DOCUMENT 

Date :04/Dec/2014 
AIRBUS 

ALERT OPERATORS TRANSMISSION- AOT 

AOT A57N006-14 Appendix A: decision trees for weekly inspection. 

NOTE: 

In case of more than one finding per side, the operator has 

to replace affected fasteners before next flight leaving no 

more than 1 failed fastener until the 4 months inspection. 

AOT ref: A57N006-14 Rev 00 Page 12 of 15 

Cl AIRBUS S AS 2014 All RIGHTS RESERVED CONFIDENTIAL AND PROPRIETARY DOCUMENT 

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AOT A57N006-14 Appendix 8: decision trees for the 4-monthly inspection 

AOT ref: A57N006-14 Rev 00 Page 13 of 15 Date:04/Dec/2014 

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AOT A57N006-14 Appendix C: reporting sheet 

AOT 57N006-14 REPORTING SHEET 

AIC MSN 

OPERATOR 

FLIGHT CYCLES 

FLIGHT HOURS 

DATE OF INSPECTION I 

G~v Svpport Rib. OSU.Sl:SSO 

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AOT A57N006-14 Appendix C: reporting sheet 

Fastener 

Number 

RETURN TO: 

LH side RH side 

Julie BLANCHOT 

julie. blanchot@airbus .com 

TEL +33 (0)5 61 93 60 20 

FAX +33 (0)5 61 93 36 14 

AIRBUS 

Missing Migrated 

Fastener Fastener 

Ludovic MENARD 

ludovic.menard@airbus.com 

TEL +33 (0)5 67 19 16 36 

FAX +33 (0)5 61 93 36 14 

CUSTOMER SERVICES ENGINEERING-SEES2 

WING -PYLON- STABILIZER 

1 rond point Maurice Bellante 

31707 BLAGNAC CEDEX 

France 

Nut I Tail 

missing 

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