CUSTOMER SERVICES DIRECTORATE

1 ROND POINT MAURICE BELLONTE

31707 BLAGNAC CEDEX FRANCE

TELEPHONE + 33 (0)5 61 93 33 33

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AOT ref: A53N007-14 Page 1 of 9 Date: 22/07/2014

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SUBJECT: ATA 53 – One-time inspection requirements for external repairs on 1.2 mm fuselage skin

AIRCRAFT TYPE: A319, A320, A321 

OUR REF.: A53N007-14 dated 22/07/2014.

1. AIRCRAFT AFFECTED

A319-100, A320-200, A321-100, A321-200

2. REFERENCED DOCUMENTATION

2.1 APPENDIX

APPENDIX 1: Tables of SRM affected repairs 

APPENDIX 2: A319 zoning figures of 1.2mm skin thickness panels

APPENDIX 3: A320 zoning figures of 1.2mm skin thickness panels

APPENDIX 4: A321 zoning figures of 1.2mm skin thickness panels

2.2 REFERENCES

Ref.1: A319/A320/A321 SRM

• 53-00-11 PB201

• 53-11-11 PB201

• 53-21-11 PB201

• 53-41-11 PB201

Ref.2: A319/A320/A321 NTM

• 51-10-15-270-801-A-01

Ref.3: A319/A320/A321 NTM

• 51-90-00-002-A

Ref.4: A319/A320/A321 NTM

• 51-10-08-250-803-A-01

Ref.5: A319/A320/A321 NTM

• 51-10-16-250-801-A-01

Ref.6: A319/A320/A321 AMM

• 53-35-13
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3. REASON

3.1 FACTS

During A320 family Extended Service Goal full scale fatigue tests, findings were seen at external skin 

repairs completed per SRM. It was determined that the inspection thresholds defined in accordance to 

the current SRM are insufficient to detect such findings.

The findings were limited to 1.2mm fuselage skin (refer to appendix 2, 3 and 4) and cover for all cut-out 

external repairs.

The internal repairs are not affected.

The cracks are not detectable with General Visual Inspection (GVI) from outside.

3.2 CONSEQUENCES

Non-detection of cracks may affect the structural integrity of the repaired fuselage skin.

3.3 AIM

The aim of this AOT is to call for:

• One time inspection in order to detect any cracks on 1.2 mm fuselage skin on Sections 11, 12, 

13, 14, 16 and 17 further to external doubler repairs embodied as:

o SRM (all revisions)

o All RDAS issued before 01 January 2005

o Permanent RDAS with inspections (Repair Category “B”) issued

 After 01 January 2005 

 Before 01 July 2014

o Concessions

o Modifications based on the same principle (e.g. antenna doubler)

o Repair approved outside Airbus DOA

• An update of SRM threshold inspection requirements 

The inspection thresholds (TH) for possible crack initiation have been calculated by fatigue analysis.

Note: Inspection intervals defined at the time of repair embodiment in the SRM, RDAS or concession 

remain valid for next repetitive inspections following this one time AOT inspection.

Note: Doubler repairs impacted by this AOT are related to the skin thickness value in fastener areas:
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Fuselage sections to be inspected are (refer to appendix 2, 3 and 4):

A319

• Sections 11 and 12 (Frame 1 thru 24)

• Sections 13 and 14 (Frame 24 thru 35)

• Sections 16 and 17 (Frame 47/51 thru 64)

A320

• Sections 11 and 12 (Frame 1 thru 24)

• Sections 13 and 14 (Frame 24 thru 35)

• Sections 16 and 17 (Frame 47 thru 64)

A321

• Sections 11 and 12 (Frame 1 thru 24)

• Sections 13 and 14 (Frame 24 thru 35.8)

• Sections 16 and 17 (Frame 47.5 thru 64)
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4. SHORT TERM ACTION

Operators must inspect any external doubler repairs in sections listed on paragraph 3.3 that have been 

applied through RDAS, concessions and /or as per SRM repairs defined in Appendix 1.

External doubler repairs installed on the aircraft can be identified through available operator 

documentation or through inspection of the aircraft.

4.1 PLANNING AND MANPOWER

4.1.1 ACCOMPLISHMENT TIMESCALE

Inspection must be accomplished as per timescale detailed in paragraphs 4.1.1.b and 4.1.1.c.

The AOT one time inspection per Ref. 2, can be repetitively postponed if inspections with nil findings are 

accomplished with a threshold and interval as follows:

Doubler Width DVI per Ref 3 HFEC per Ref 4 

≤160 mm 100 FC 200 FC

160 mm< Width ≤185 mm 50 FC 130 FC

Note: DVI per Ref 3 and HFEC per Ref 4 aim at detecting a crack that grows out of the doubler into the 

free skin area.

a. Definitions:

• SMALL skin repairs: Maximum cut-out to 2 fasteners pitch.

• LIMITED skin repairs: Maximum cut-out limited to a length of half a frame bay and a width of 

one stringer bay.

• UNLIMITED skin repairs: Cut-out beyond SMALL and LIMITED skin repairs requirements.

b. SMALL and LIMITED skin repairs:

Note: Doubler thickness measurement is under operators responsibility.

Note: In case, repair records are not available then AOT inspections requirements must be 

considered from aircraft first flight.

• For all aircrafts and fuselage sections except A319 and A321 S16/17 above window line

Compliance time

For Doubler with thickness > 1.4mm, at the latest of the 3 conditions:

• 33400FC from repair embodiment 

or

• 1500 FC from AOT issuance without exceeding 36400 FC from repair embodiment

or

• 350 FC from AOT issuance

For Doubler with thickness = 1.4mm, at the latest of the 3 conditions:

• 45000FC from repair embodiment 

or

• 1500 FC from AOT issuance without exceeding 49100 FC from repair embodiment

or

• 350 FC from AOT issuance

Table 3 – SMALL and LIMITED skin repairs (except A319/A321 S16/17 above window line)
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• For A319 and A321 Section 16/17 above window line:

Compliance time

For Doubler with thickness > 1.4mm, at the latest of the 3 conditions:

• 29500FC from repair embodiment 

or

• 1500 FC from AOT issuance without exceeding 32000 FC from repair embodiment

or

• 350 FC from AOT issuance

For Doubler with thickness = 1.4mm, at the latest of the 3 conditions:

• 39800FC from repair embodiment 

or

• 1500 FC from AOT issuance without exceeding 43200 FC from repair embodiment

or

• 350 FC from AOT issuance

Table 4 – SMALL and LIMITED skin repairs on A319/A321 S16/17 above window line
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c. UNLIMITED skin repairs:

Note: Doubler thickness measurement is under operators responsibility.

Note: In case repair records are not available then AOT inspections requirements must be 

considered from aircraft first flight.

• For all A/C and fuselage sections except A319 and A321 S16/17 above window line:

Compliance time

For Doubler with thickness > 1.4mm, at the latest of the 2 conditions:

• 28700FC from repair embodiment 

or

• 350 FC from AOT issuance

For Doubler with thickness = 1.4mm, at the latest of the 2 conditions:

• 38700FC from repair embodiment 

or

• 350 FC from AOT issuance

Table 5 – UNLIMITED skin repairs (except A319/A321 S16/17 above window line)

• For A319 Section 16/17 above window line:

Compliance time

For Doubler with thickness > 1.4mm, at the latest of the 2 conditions:

• 26100FC from repair embodiment 

or

• 350 FC from AOT issuance

For Doubler with thickness = 1.4mm, at the latest of the 2 conditions:

• 35200FC from repair embodiment 

or

• 350 FC from AOT issuance

Table 6 – UNLIMITED skin repairs on A319 S16/17 above window line

• For A321 Section 16/17 above window line:

Compliance time

For Doubler with thickness > 1.4mm, at the latest of the 2 conditions:

• 25200FC from repair embodiment 

or

• 350 FC from AOT issuance

For Doubler with thickness = 1.4mm, at the latest of the 2 conditions:

• 34000FC from repair embodiment 

or

• 350 FC from AOT issuance

Table 7 – UNLIMITED skin repairs on A321 S16/17 above window line
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4.1.2 MANPOWER

The manpower to perform this AOT could vary depending the aircraft situation, from repairs records 

review only through to repair replacement if needed.

4.2 DESCRIPTION

4.2.1 ACCESS

WARNING: Be careful when you use consumable materials. Obey the material manufacturer's

instructions and your local regulations.

Access to skin fuselage underneath belly fairing panel 191AT as per AMM Ref 6. Procedure 53-35-13 

May 2014 revision or subsequent ones.

4.2.2 INSPECTION REQUIREMENTS

Inspection is aiming to detect crack on skin underneath the doubler repair on fasteners area (no fastener 

removal is necessary).

Inspection of the repairs embodied through RDAS, concessions and /or the SRM repairs has to be 

performed in accordance with May 2014 revision or subsequent ones of the:

• External inspection per NTM (Ref.2) procedure 51-10-15-270-801-A-01 “Inspection for Shallow 

Cracks in Multi-Layered Joint Structures”

or

• Internal inspection per NTM (Ref.5) procedure 51-10-16-250-801-A-01 “Inspection for SubSurface Cracks in Al-Alloy Structure”.

Repetitively inspections aiming at postponing one time inspections have to be performed in accordance 

with May 2014 revision of the NTM Ref.3 or Ref. 4 or subsequent ones.

Note: Removal of the repair sealant could be necessary when performing referenced NTM procedures.
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4.2.3 FINDINGS

a. SMALL and LIMITED skin repairs:

• In case of no findings on skin then inspection intervals and methods remain applicable if any.

Note: Operators have the possibility to re-life the embodied repairs:

o Remove doubler repair per SRM standard practices in order to determine the exact 

damage size and report details to Airbus.

o Perform new repair according to SRM or RDAS, by increasing the cut-out to next 

possible size or contact Airbus for specific RDAS.

• In case of findings on skin then operators should before next flight:

o Remove doubler repair per SRM standard practices in order to determine the exact 

damage size and report details to Airbus.

o Perform new repair according to SRM or RDAS, by increasing the cut-out to next 

possible size (without waiting Airbus feedback) or contact Airbus for specific RDAS.

or

o Contact Airbus for specific RDAS.

b. UNLIMITED skin repairs:

-For repair that has accumulated less than 20 000FC, in case of no findings on skin then

inspection intervals and methods remain applicable if any.

-In all other cases, contact Airbus repairs daily support for further instructions.

SEOE1/SEOE2/SEOE3

Customer Services

Fax: +33 (0)5 61 93 28 73

Mailto:

region1.StructureRepairSupport@airbus.com

region2.StructureRepairSupport@airbus.com

region3.StructureRepairSupport@airbus.com
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5. FURTHER INFORMATION

5.1 FOLLOW-UP PLAN

Inspection Service Bulletin (ISB) is planned to be issued to cancel and supersede this AOT.

5.2 IMPACTED DOCUMENTATION

SRM (Ref.1) threshold will be updated accordingly with next revisions.

Until availability of SRM (Ref.1) update thresholds provided as per #4.1.1 of this AOT should be 

considered in case of new embodiment of SRM repairs per #3.

6. AOT APPROVAL

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

7. REPORTING

Questions about this AOT and inspection results with or without findings are to be sent to Airbus

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

Julien MAZIEUX

Structure repair engineer

SRM development – SEOEM

CUSTOMER SERVICES

Phone: +33 (0)5 67 19 10 25

Mailto: srm.StructureRepairSupport@airbus.com

Best Regards,

Jean-Luc MOUYSSET

VICE PRESIDENT ENGINEERING SUPPORT

CUSTOMER SERVICES

Gilles DE-CEVINS

VICE PRESIDENT A320 PROGRAMME

CUSTOMER SERVICES