AD 2018-10-05

We are superseding Airworthiness Directive (AD) 2016-23-01, which applied to all Airbus Model A310 series airplanes. AD 2016-23-01 required repetitive detailed inspections for cracking around the fastener holes in certain areas of the wing top skin panels, supplemental repetitive ultrasonic inspections for cracking around the fastener holes in certain other areas of the wing top skin panels, and repair if necessary. This AD adds an inspection and modification of the fastener holes of the wing top skin panels at a certain area. This AD also includes terminating action for certain inspections. This AD was prompted by an evaluation by the design approval holder (DAH) which indicates that the wing top skin panel fastener holes at a certain area are also subject to widespread fatigue damage (WFD). We are issuing this AD to address the unsafe condition on these products.

Final rule.

Adoption of the Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0 1. The authority citation for part 39 continues to read as follows:

Authority: 49 U.S.C. 106(g), 40113, 44701.

Sec. 39.13 [Amended]

0 2. The FAA amends Sec. 39.13 by removing Airworthiness Directive (AD) 2016-23-01, Amendment 39-18708 (81 FR 78899, November 10, 2016), and adding the following new AD:

2018-10-05 Airbus: Amendment 39-19280; FAA-2018-0071; Product Identifier 2017-NM-063-AD.

(a) Effective Date

This AD is effective June 19, 2018.

(b) Affected ADs

This AD replaces AD 2016-23-01, Amendment 39-18708 (81 FR 78899, November 10, 2016) (``AD 2016-23-01'').

(c) Applicability

This AD applies to all Airbus Model A310-203, -204, -221, -222, -304, -322, -324, and -325 airplanes, certificated in any category, all manufacturer serial numbers.(d) Subject

Air Transport Association (ATA) of America Code 57, Wings.

(e) Reason

This AD was prompted by an evaluation by the design approval holder (DAH) indicating that the wing top skin panel fastener holes at ribs 2 and 3 are subject to widespread fatigue damage (WFD). We are issuing this AD to detect and correct fatigue cracking around the fastener holes, which could result in reduced structural integrity of the airplane.

(f) Compliance

Comply with this AD within the compliance times specified, unless already done.

(g) Retained Repetitive Inspections, With Revised Service Information

This paragraph restates the requirements of paragraph (g) of AD 2016-23-01, with revised service information. Except as required by paragraph (i) of this AD: Within

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the initial compliance time and thereafter at the repetitive intervals specified in paragraphs (h)(1) through (h)(3) of this AD, as applicable, accomplish the actions specified in paragraphs (g)(1) and (g)(2) of this AD concurrently and in sequence, in accordance with the Accomplishment Instructions of Airbus Service Bulletin A310-57-2096, Revision 03, dated June 30, 2015, or Revision 04, dated December 5, 2016; except as provided by paragraph (j) of this AD. As of the effective date of this AD, use only Airbus Service Bulletin A310-57-2096, Revision 04, dated December 5, 2016, to accomplish the required actions.
(1) Accomplish a detailed inspection for cracking around the fastener holes in the wing top skin panels 1 and 2, along ribs 2 and 3, between the front and rear spars on the left- and right-hand sides of the fuselage.
(2) Accomplish an ultrasonic inspection for cracking around the fastener holes in the wing top skin panels 1 and 2, along ribs 2 and 3, between stringer (STG) 2 and STG10 on the left- and right-hand sides of the fuselage.

(h) Retained Compliance Times for Airplanes Not Previously Inspected, With No Changes

This paragraph restates the requirements of paragraph (h) of AD 2016-23-01, with no changes.
(1) For Model A310-203, -204, -221, and -222 airplanes: Do the actions required by paragraphs (g)(1) and (g)(2) of this AD at the later of the times specified in paragraphs (h)(1)(i) and (h)(1)(ii) of this AD. Repeat the inspections specified in paragraphs (g)(1) and (g)(2) of this AD thereafter at intervals not to exceed 2,000 flight cycles or 4,100 flight hours, whichever occurs first.
(i) Prior to the accumulation of 18,700 flight cycles or 37,400 flight hours since first flight of the airplane, whichever occurs first.
(ii) Within 30 days after December 15, 2016 (the effective date of AD 2016-23-01).
(2) For Model A310-304, -322, -324, and -325 airplanes having an average flight time (AFT) of less than 4 hours: Do the actions required by paragraphs (g)(1) and (g)(2) of this AD at the later of the times specified in paragraphs (h)(2)(i) and (h)(2)(ii) of this AD. Repeat the inspections specified in paragraphs (g)(1) and (g)(2) of this AD thereafter at intervals not to exceed 2,000 flight cycles or 5,600 flight hours, whichever occurs first.
(i) Prior to the accumulation of 17,300 flight cycles or 48,400 flight hours since first flight of the airplane, whichever occurs first.
(ii) Within 30 days after December 15, 2016 (the effective date of AD 2016-23-01).
(3) For Model A310-304, -322, -324, and -325 airplanes having an AFT of equal to or more than 4 hours: Do the actions required by paragraphs (g)(1) and (g)(2) of this AD at the later of the times specified in paragraphs (h)(3)(i) and (h)(3)(ii) of this AD. Repeat the inspections specified in paragraphs (g)(1) and (g)(2) of this AD thereafter at intervals not to exceed 1,500 flight cycles or 7,500 flight hours, whichever occurs first.
(i) Prior to the accumulation of 12,800 flight cycles or 64,300 flight hours since first flight of the airplane, whichever occurs first.
(ii) Within 30 days after December15, 2016 (the effective date of AD 2016-23-01).

(i) Retained Compliance Times for Airplanes Previously Inspected, With Revised Service Information

This paragraph restates the requirements of paragraph (i) of AD 2016-23-01, with revised service information. For airplanes previously inspected before December 15, 2016 (the effective date of AD 2016-23-01), using Airbus Service Bulletin A310-57-2096, dated May 6, 2008; Airbus Service Bulletin A310-57-2096, Revision 01, dated August 5, 2010; or Airbus Service Bulletin A310-57-2096, Revision 02, dated March 5, 2014: At the applicable compliance times specified in paragraphs (i)(1), (i)(2), and (i)(3) of this AD, accomplish the actions specified in paragraphs (g)(1) and (g)(2) of this AD concurrently and in sequence, in accordance with the Accomplishment Instructions of Airbus Service Bulletin A310-57-2096, Revision 03, dated June 30, 2015, or Revision 04, dated December 5, 2016. As of the effective date of this AD, use only Airbus Service Bulletin A310-57-2096, Revision 04, dated December 5, 2016, to accomplish the required actions. Repeat the inspections specified in paragraphs (g)(1) and (g)(2) of this AD thereafter at the repetitive intervals specified in paragraphs (h)(1), (h)(2), and (h)(3) of this AD, as applicable.
(1) For Model A310-203, -204, -221, and -222 airplanes: Do the actions required by paragraphs (g)(1) and (g)(2) of this AD within 3,500 flight hours or 1,700 flight cycles, whichever occurs first since the most recent inspection.
(2) For Model A310-304, -322, -324, and -325 airplanes having an AFT of less than 4 hours: Do the actions required by paragraphs (g)(1) and (g)(2) of this AD within 4,600 flight hours or 1,600 flight cycles, whichever occurs first since the most recent inspection.
(3) For Model A310-304, -322, -324, and -325 airplanes having an AFT of equal to or more than 4 hours: Do the actions required by paragraphs (g)(1) and (g)(2) of this AD within 6,100 flight hours or 1,200 flight cycles, whichever occurs first since the most recent inspection.

(j) Retained Compliance Times if No Ultrasonic Equipment Is Available, With Revised Service Information

This paragraph restates the requirements of paragraph (j) of AD 2016-23-01, with revised service information. If no ultrasonic equipment is available for the initial or second inspection required by paragraph (g) or (h) of this AD, accomplish the detailed inspection specified in paragraph (g)(1) of this AD within the applicable compliance times specified in paragraphs (j)(1) and (j)(2) of this AD. After accomplishing the detailed inspection, do the inspections specified in paragraphs (g)(1) and (g)(2) of this AD at the applicable compliance times specified by paragraphs (i)(1), (i)(2), and (i)(3) of this AD. Subsequently, repeat the inspections specified in paragraphs (g)(1) and (g)(2) of this AD thereafter at the applicable repetitive intervals specified in paragraphs (h)(1), (h)(2), and (h)(3) of this AD.
(1) For airplanes not previously inspected before December 15, 2016 (the effective date of AD 2016-23-01), using the service information identified in paragraph (j)(2)(i), (j)(2)(ii), (j)(2)(iii), or (j)(2)(iv) of this AD: Do the actions required by paragraph (g)(1) of this AD within the initial compliance time specified by paragraphs (h)(1), (h)(2), and (h)(3) of this AD, as applicable.
(2) For airplanes previously inspected before December 15, 2016 (the effective date of AD 2016-23-01), using the service information identified in paragraph (j)(2)(i), (j)(2)(ii), (j)(2)(iii), or (j)(2)(iv) of this AD: Do the actions required by paragraph (g)(1) of this AD within the applicable compliance times specified in paragraphs (i)(1), (i)(2), and (i)(3) of this AD.
(i) Airbus Service Bulletin A310-57-2096, dated May 6, 2008.
(ii) Airbus Service Bulletin A310-57-2096, Revision 01, dated August 5, 2010.
(iii) Airbus Service Bulletin A310-57-2096, Revision 02, dated March 5, 2014.
(iv) Airbus Service Bulletin A310-57-2096, Revision 03, dated June 30, 2015.

(k) Retained Repair of Cracking, With No Changes

This paragraph restates the requirements of paragraph (k) of AD 2016-23-01, with no changes. If any cracking is found during any inspection required by paragraph (g), (h), (i), or (j) of this AD, before further flight, repair the cracking using a method approved by the Manager, International Section, Transport Standards Branch, FAA; or the European Aviation Safety Agency (EASA); or Airbus's EASA Design Organization Approval (DOA). If approved by the DOA, the approval must include the DOA-authorized signature. Accomplishing the repair specified in this paragraph terminates the repetitive inspections required by paragraph (g), (h), (i), or (j) of this AD, as applicable, for the repaired area only.

(l) Retained Definition of AFT, With No Changes

This paragraph restates the requirements of paragraph (l) of AD 2016-23-01, with nochanges. For the purposes of this AD, the AFT should be established as specified in paragraphs (l)(1), (l)(2), and (l)(3) of this AD for the determination of the compliance times.
(1) The inspection threshold is defined as the total flight hours accumulated (counted from take-off to touch-down), divided by the total number of flight cycles accumulated at the effective date of this AD.
(2) The initial inspection interval is defined as the total flight hours accumulated divided by the total number of flight cycles accumulated at the time of the initial inspection threshold.
(3) The second inspection interval is defined as the total flight hours accumulated divided by the total number of flight cycles accumulated between the initial and second inspection threshold. For all inspection intervals onwards, the average flight time is the flight hours divided by the flight cycles accumulated between the last two inspections.

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(m) New Requirements of This AD: Rib2 Inspection and Modification

At the compliance time specified in paragraph (n) of this AD, as applicable, accomplish the actions specified in paragraphs (m)(1) and (m)(2) of this AD concurrently and in sequence, in accordance with the Accomplishment Instructions of Airbus Service Bulletin A310-57-2106, dated November 14, 2016.
(1) Accomplish a special detailed inspection to determine the diameter of the fastener holes in the wing top skin panels 1 and 2, at rib 2 of both wings.
(2) Modify the fastener holes.

(n) New Compliance Times for Rib 2 Inspection and Modification

(1) For Model A310-203, -204, -221, and -222 airplanes: Do the actions required by paragraphs (m)(1) and (m)(2) of this AD at the later of the times specified in paragraphs (n)(1)(i) and (n)(1)(ii) of this AD.
(i) Prior to the accumulation of 40,000 flight cycles or 93,300 flight hours since first flight of the airplane, whichever occurs first.
(ii) Within 30 days after the effective dateof this AD.
(2) For Model A310-304, -322, -324, and -325 airplanes having an AFT of less than 4 hours: Do the actions required by paragraphs (m)(1) and (m)(2) of this AD at the later of the times specified in paragraphs (n)(2)(i) and (n)(2)(ii) of this AD.
(i) Prior to the accumulation of 40,000 flight cycles or 116,000 flight hours since first flight of the airplane, whichever occurs first.
(ii) Within 30 days after the effective date of this AD.
(3) For Model A310-304, -322, -324, and -325 airplanes having an AFT of 4 hours or more: Do the actions required by paragraphs (m)(1) and (m)(2) of this AD at the later of the times specified in paragraphs (n)(3)(i) and (n)(3)(ii) of this AD.
(i) Prior to the accumulation of 30,000 flight cycles or 150,000 flight hours since first flight of the airplane, whichever occurs first.
(ii) Within 30 days after the effective date of this AD.

(o) New Requirements of This AD: Rib 3 Inspection and Modification

At the compliance time specified in paragraph (p) of this AD, as applicable, accomplish the actions specified in paragraphs (o)(1) and (o)(2) of this AD concurrently and in sequence, in accordance with the Accomplishment Instructions of Airbus Service Bulletin A310-57-2107, dated November 14, 2016.
(1) Accomplish a special detailed inspection to determine the diameter of the fastener holes in the wing top skin panels 1 and 2, at rib 3 of both wings.
(2) Modify the fastener holes.

(p) New Compliance Times for Rib 3 Inspection and Modification

(1) For Model A310-203, -204, -221, and -222 airplanes: Do the actions required by paragraphs (o)(1) and (o)(2) of this AD at the later of the times specified in paragraphs (p)(1)(i) and (p)(1)(ii) of this AD.
(i) Prior to the accumulation of 46,400 flight cycles or 92,900 flight hours since first flight of the airplane, whichever occurs first.
(ii) Within 30 days after the effective date of this AD.
(2) For Model A310-304, -322, -324,and -325 airplanes having an AFT of less than 4 hours: Do the actions required by paragraphs (o)(1) and (o)(2) of this AD at the later of the times specified in paragraphs (p)(2)(i) and (p)(2)(ii) of this AD.
(i) Prior to the accumulation of 45,400 flight cycles or 127,300 flight hours since first flight of the airplane, whichever occurs first.
(ii) Within 30 days after the effective date of this AD.
(3) For Model A310-304, -322, -324, and -325 airplanes having an AFT of 4 hours or more: Do the actions required by paragraphs (o)(1) and (o)(2) of this AD at the later of the times specified in paragraphs (p)(3)(i) and (p)(3)(ii) of this AD.
(i) Prior to the accumulation of 33,800 flight cycles or 169,000 flight hours since first flight of the airplane, whichever occurs first.
(ii) Within 30 days after the effective date of this AD.

(q) New Corrective Actions

If any cracking is found during any inspection required by paragraph (m), (n), (o), or (p) of this AD, before further flight, repair the cracking using a method approved by the Manager, International Section, Transport Standards Branch, FAA; or EASA; or Airbus's EASA DOA. If approved by the DOA, the approval must include the DOA-authorized signature. Accomplishing the repair specified in this paragraph terminates the repetitive inspections required by paragraph (g), (h), (i), or (j) of this AD, as applicable, for the repaired area only.

(r) New Terminating Actions

(1) Accomplishment of the modification specified in paragraph (m) of this AD constitutes terminating action for the repetitive special detailed inspections required by paragraph (g)(2) of this AD for the modified fastener holes at top skin rib 2 for that airplane. After modification, the un-modified fastener holes at top skin rib 2 between the front and rear spars remain subject to the repetitive inspections required by paragraph (g)(1) of this AD.
(2) Accomplishment of the modification specified in paragraph (o) of this AD constitutes terminating action for the repetitive special detailed inspections required by paragraph (g)(2) of this AD for the modified fastener holes at top skin rib 3 for that airplane. After modification, the un-modified fastener holes at top skin rib 3 between the front and rear spars remain subject to the repetitive inspection required by paragraph (g)(1) of this AD.

(s) Other FAA AD Provisions

(1) Alternative Methods of Compliance (AMOCs): The Manager, International Section, Transport Standards Branch, FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. In accordance with 14 CFR 39.19, send your request to your principal inspector or local Flight Standards District Office, as appropriate. If sending information directly to the International Section, send it to the attention of the person identified in paragraph (t)(2) of this AD. Information may be emailed to: 9-ANM-116-AMOC-REQUESTS@faa.gov. Before using any approved AMOC, notify your appropriate principal inspector, or lacking a principal inspector, the manager of the local flight standards district office/certificate holding district office.
(2) Contacting the Manufacturer: As of the effective date of this AD, for any requirement in this AD to obtain corrective actions from a manufacturer, the action must be accomplished using a method approved by the Manager, International Section, Transport Standards Branch, FAA; or EASA; or Airbus's EASA DOA. If approved by the DOA, the approval must include the DOA-authorized signature.
(3) Required for Compliance (RC): If any service information contains procedures or tests that are identified as RC, those procedures and tests must be done to comply with this AD; any procedures or tests that are not identified as RC are recommended. Those procedures and tests that are not identified as RC may be deviated from using accepted methods in accordance with the operator's maintenance or inspection program without obtaining approval of an AMOC, provided the procedures and tests identified as RC can be done and the airplane can be put back in an airworthy condition. Any substitutions or changes to procedures or tests identified as RC require approval of an AMOC.

(t) Related Information

(1) Refer to Mandatory Continuing Airworthiness Information (MCAI) EASA AD 2017-0081, dated May 8, 2017, for related information. This MCAI may be found in the AD docket on the internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2018-0071.
(2) For more information about this AD, contact Dan Rodina, Aerospace Engineer, International Section, Transport Standards Branch, FAA, 2200 South 216th St., Des Moines, WA 98198; telephone and fax: 206-231-3225.

(u) Material Incorporated by Reference

(1) The Director of the Federal Register approved the incorporation by reference (IBR) of the service information listed in this paragraph under 5 U.S.C.552(a) and 1 CFR part 51.
(2) You must use this service information as applicable to do the actions required by this AD, unless this AD specifies otherwise.
(3) The following service information was approved for IBR on June 19, 2018.
(i) Airbus Service Bulletin A310-57-2096, Revision 04, dated December 5, 2016.
(ii) Airbus Service Bulletin A310-57-2106, dated November 14, 2016.
(iii) Airbus Service Bulletin A310-57-2107, dated November 14, 2016.
(4) The following service information was approved for IBR on December 15, 2016 (81 FR 78899, November 10, 2016).
(i) Airbus Service Bulletin A310-57-2096, Revision 03, dated June 30, 2015.

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(ii) Reserved.
(5) For service information identified in this AD, contact Airbus SAS, Airworthiness Office--EAW, 1 Rond Point Maurice Bellonte, 31707 Blagnac Cedex, France; telephone: +33 5 61 93 36 96; fax: +33 5 61 93 44 51; email: account.airworth-eas@airbus.com; internet: http://www.airbus.com.
(6) You may view this service information at the FAA, Transport Standards Branch, 2200 South 216th St., Des Moines, WA. For information on the availability of this material at the FAA, call 206-231-3195.
(7) You may view this service information that is incorporated by reference at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal-register/cfr/ibr-locations.html.

Discussion

We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to supersede AD 2016-23-01, Amendment 39-18708 (81 FR 78899, November 10, 2016) (``AD 2016-23-01''). AD 2016-23-01 applied to all Airbus Model A310 series airplanes. The NPRM published in the Federal Register on February 8, 2018 (83 FR 5579). The NPRM was prompted by an evaluation done by the DAH which indicates that the wing top skin panel fastener holes at a certain area are subject to WFD. The NPRM would continue to require repetitive detailed inspections for cracking around the fastener holes in certain areas of the wing top skin panels, supplemental repetitive ultrasonic inspections for cracking around the fastener holes in certain other areas of the wing top skin panels, and repair if necessary. The NPRM proposed to add an inspection and modification of the fastener holes of the wing top skin panels at a certain area. The NPRM also includes terminating actionfor certain inspections. We are issuing this AD to detect and correct fatigue cracking around the fastener holes, which could result in reduced structural integrity of the airplane.
The European Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Union, has issued EASA AD 2017-0081, dated May 8, 2017 (referred to after this as the Mandatory Continuing Airworthiness Information, or ``the MCAI''), to correct an unsafe condition for all Airbus Model A310 series airplanes. The MCAI states:

Following scheduled maintenance, cracks were found around the wing top skin panels fastener holes at Rib 2, between Stringer (STG) 2 and STG14.
This condition, if not detected and corrected, could reduce the structural integrity of the aeroplane.
To address this issue, Airbus developed an inspection programme, and published Service Bulletin (SB) A310-57-2096, providing instructions for repetitive detailed inspections (DET) to ensure that any visible cracks in the wing top skin panels 1 and 2 along Rib 2 are detected on time and repaired appropriately. Consequently, EASA issued AD 2008-0211 [which corresponds to FAA AD 2010-04-03, Amendment 39-16196 (75 FR 6852, February 12, 2010) (``AD 2010-04- 03)] to require implementation of that inspection programme.
After that [EASA] AD was issued, Airbus improved the inspection programme, revising SB A310-57-2096 accordingly, to include a special detailed inspection (SDI), using an ultrasonic method, to allow earlier crack detection, to subsequently reduce the scope of potential repair action, and to extend the intervals of the repetitive inspections.
Consequently, EASA issued AD 2014-0200 (later revised), retaining the requirements of EASA AD 2008-0211, which was superseded, and required supplementary repetitive SDI [for cracking] of the wing top skin panel 1 and 2 between STG2 and STG10 at Rib 2 [and repair if needed], as described in Airbus SB A310-57-2096 Revision 02.
Since EASA AD 2014-0200R1 was issued, a Widespread Fatigue Damage (WFD) analysis concluded that the inspection programme had to be extended to include the wing top skin panels at Rib 3 attachments, and Airbus issued SB A310-57-2096 Revision 03 accordingly, to provide the necessary instructions. Consequently, EASA issued [EASA] AD 2016-0005 [which corresponds to FAA AD 2016- 23-01], retaining the requirements of EASA AD 2014-0200R1, which was superseded, and extending the inspection area to include Rib 3.
In addition to changes to the inspected area, WFD analysis identified structural modification points for certain fastener holes, located at each attachment from STG2 to STG10, at Ribs 2 and 3 on both wings.
Airbus developed modification (mod) 13785 and mod 13786, consisting of an SDI, followed by an oversize of the defined holes on Ribs 2 and 3 on both wings. Airbus issued SB A310-57-2106 and SB A310-57-2107 to provide in-service modification instructions for top skin attachments toRib 2 and Rib 3 respectively. Accomplishment of these modifications at the specified time will reset the fatigue life of the attachment holes at the top skin attachment to Rib 2 and Rib 3 to the Limit of Validity (LOV). Airbus issued inspection SB A310-57-2096 Revision 04 to account for the inspection requirements post-modification.
For the reasons describe above, this [EASA] AD retains the requirements of EASA AD 2016-0005, which is superseded, requires modifications to the top skin attachment holes at Rib 2 and Rib 3, and defines the inspection requirements for Rib 2 and Rib 3 after modification.

Modification of the fastener holes at top skin ribs 2 and 3 constitutes terminating action for certain repetitive special detailed inspections. You may examine the MCAI in the AD docket on the internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2018-0071.

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Comments

We gave the public the opportunity to participate in developing this AD. We considered the comment received. FedEx supported the NPRM.

Conclusion

We reviewed the available data, including the comment received, and determined that air safety and the public interest require adopting this AD as proposed, except for minor editorial changes. We have determined that these minor changes:
Are consistent with the intent that was proposed in the NPRM for correcting the unsafe condition; and
Do not add any additional burden upon the public than was already proposed in the NPRM.

Related Service Information Under 1 CFR Part 51

Airbus has issued the following service information.
Airbus Service Bulletin A310-57-2096, Revision 04, dated December 5, 2016. This service information describes procedures for detailed and ultrasonic inspections for cracking around the fastener holes of wing top skin panels 1 and 2, at ribs 2 and 3, on the left- and right-hand sides of the fuselage.
Airbus Service Bulletin A310-57-2106, dated November 14, 2016. This service information describes procedures for a special detailed inspection and modification of the fastener holes of wing top skin panels 1 and 2, at rib 2.
Airbus Service Bulletin A310-57-2107, dated November 14, 2016. This service information describes procedures for a special detailed inspection and modification of the fastener holes of wing top skin panels 1 and 2, at rib 3.
This service information is reasonably available because the interested parties have access to it through their normal course of business or by the means identified in the ADDRESSES section.

Costs of Compliance

We estimate that this AD affects 8 airplanes of U.S. registry.
The actions required by AD 2016-23-01, and retained in this AD, take about 8 work-hours per product, at an average labor rate of $85 per work-hour. Based on these figures, the estimated cost of the actions that are required by AD 2016-23-01 on U.S. operators to be $5,440, or $680 per product.
We also estimate that it takes about 95 work-hours per product to comply with the basic requirements of this AD. Required parts will cost about $10,200 per product. The average labor rate is $85 per work-hour. Based on these figures, we estimate the cost of this AD on U.S. operators to be $146,200, or $18,275 per product.
In addition, we estimate that any necessary modification will take about 40 work-hours and require parts costing $10,000, for a cost of $13,400 per product. We have no way of determining the number of aircraft that might need these actions.

Authority for This Rulemaking

Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, section 106, describes the authority of the FAA Administrator. Subtitle VII: Aviation Programs, describes in more detail the scope of the Agency's authority.
We are issuing this rulemaking under the authority described in Subtitle VII, Part A, Subpart III, Section 44701: ``Generalrequirements.'' Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.
This AD is issued in accordance with authority delegated by the Executive Director, Aircraft Certification Service, as authorized by FAA Order 8000.51C. In accordance with that order, issuance of ADs is normally a function of the Compliance and Airworthiness Division, but during this transition period, the Executive Director has delegated the authority to issue ADs applicable to transport category airplanes to the Director of the System Oversight Division.

Regulatory Findings

We determined that this AD will not have federalism implications under Executive Order 13132. This AD will not have a substantial direct effect on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government.
For the reasons discussed above, I certify that this AD:
1. Is not a ``significant regulatory action'' under Executive Order 12866;
2. Is not a ``significant rule'' under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979);
3. Will not affect intrastate aviation in Alaska; and
4. Will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.