Airworthiness Directives; Airbus Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

We propose to supersede Airworthiness Directive (AD) 2016-01-11, which applies to certain Airbus Model A320-211, -212, and -231 airplanes. AD 2016-01-11 requires repetitive inspections for cracking of the radius of the front spar vertical stringers and the horizontal floor beam on frame 36, repetitive inspections for cracking of the fastener holes of the front spar vertical stringers on frame 36, and repair if necessary. Since we issued AD 2016-01-11, we received a report that, during a center fuselage certification full scale fatigue test, cracks were found on the front vertical stringer at a certain frame. This proposed AD would add new thresholds and intervals for the repetitive inspections; would require, for certain airplanes, a modification of the center wing box area; and would expand the applicability. We are proposing this AD to address the unsafe condition on these products.

DATES:

We must receive comments on this proposed AD by January 29, 2018.

ADDRESSES:

You may send comments, using the procedures found in 14 CFR 11.43 and 11.45, by any of the following methods:

• Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.
• Fax: 202-493-2251.
• Mail: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590.
• Hand Delivery: Deliver to Mail address above between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

For service information identified in this NPRM, contact Airbus, Airworthiness Office-EIAS, 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. You may view this referenced service information at the FAA, Transport Standards Branch, 1601 Lind Avenue SW, Renton, WA. For information on the availability of this material at the FAA, call 425-227-1221.

Examining the AD Docket

You may examine the AD docket on the internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2017-1102; or in person at the Docket Management Facility between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this proposed AD, the regulatory evaluation, any comments received, and other information. The street address for the Docket Operations office (telephone 800-647-5527) is in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT:

Sanjay Ralhan, Aerospace Engineer, International Section, Transport Standards Branch, FAA, 1601 Lind Avenue SW, Renton, WA 98057-3356; telephone 425-227-1405; fax 425-227-1149.

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to send any written relevant data, views, or arguments about this proposal. Send your comments to an address listed under the ADDRESSES section. Include “Docket No. FAA-2017-1102; Product Identifier 2017-NM-078-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this proposed AD. We will consider all comments received by the closing date and may amend this proposed AD based on those comments.

We will post all comments we receive, without change, to http://www.regulations.gov,, including any personal information you provide. We will also post a report summarizing each substantive verbal contact we receive about this proposed AD.

Discussion

Fatigue damage can occur locally, in small areas or structural design details, or globally, in widespread areas. Multiple-site damage is widespread damage that occurs in a large structural element such as a single rivet line of a lap splice joining two large skin panels. Widespread damage can also occur in multiple elements such as adjacent frames or stringers. Multiple-site damage and multiple-element damage cracks are typically too small initially to be reliably detected with normal inspection methods. Without intervention, these cracks will grow, and eventually compromise the structural integrity of the airplane. This condition is known as widespread fatigue damage (WFD). It is associated with general degradation of large areas of structure with similar structural details and stress levels. As an airplane ages, WFD will likely occur, and will certainly occur if the airplane is operated long enough without any intervention.

The FAA's WFD final rule (75 FR 69746, November 15, 2010) became effective on January 14, 2011. The WFD rule requires certain actions to prevent structural failure due to WFD throughout the operational life of certain existing transport category airplanes and all of these airplanes that will be certificated in the future. For existing and future airplanes subject to the WFD rule, the rule requires that DAHs establish a limit of validity (LOV) of the engineering data that support the structural maintenance program. Operators affected by the WFD rule may not fly an airplane beyond its LOV, unless an extended LOV is approved.

The WFD rule (75 FR 69746, November 15, 2010) does not require identifying and developing maintenance actions if the DAHs can show that such actions are not necessary to prevent WFD before the airplane reaches the LOV. Many LOVs, however, do depend on accomplishment of future maintenance actions. As stated in the WFD rule, any maintenance actions necessary to reach the LOV will be mandated by airworthiness directives through separate rulemaking actions.

In the context of WFD, this action is necessary to enable DAHs to propose LOVs that allow operators the longest operational lives for their airplanes, and still ensure that WFD will not occur. This approach allows for an implementation strategy that provides flexibility to DAHs in determining the timing of service information development (with FAA approval), while providing operators with certainty regarding the LOV applicable to their airplanes.

We issued AD 2016-01-11, Amendment 39-18370 (81 FR 3316, January 21, 2016) (“AD 2016-01-11”), for certain Airbus Model A320-211, -212, and -231 airplanes. AD 2016-01-11 was prompted by reports that indicate new repetitive inspections having new thresholds and intervals were needed and that additional work was needed to accomplish the inspections on airplanes on which a previous modification has been accomplished. AD 2016-01-11 requires repetitive high frequency eddy current (HFEC) inspections for cracking of the radius of the front spar vertical stringers and the horizontal floor beam on frame 36, repetitive rototest inspections for cracking of the fastener holes of the front spar vertical stringers on frame 36, and repair if necessary. We issued AD 2016-01-11 to detect and correct fatigue cracking of the front spar vertical stringers on the wings, which could result in the reduced structural integrity of the airplane.

Since we issued AD 2016-01-11, the European Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Union, has issued EASA Airworthiness Directive 2017-0099, dated June 8, 2017 (referred to after this as the Mandatory Continuing Airworthiness Information, or “the MCAI”), to correct an unsafe condition for certain Airbus Model A318 series airplanes; Model A319 series airplanes; Model A320-211, -212, -214, -231, -232, and -233 airplanes; and Model A321 series airplanes. The MCAI states:

During centre fuselage certification full scale fatigue test, cracks were found on the front vertical stringer at frame (FR) 36. Analysis of these findings indicated that a number of in-service aeroplanes could be similarly affected.

This condition, if not detected and corrected, could lead to crack propagation and consequent deterioration of the structural integrity of the aeroplane.

To address this potential unsafe condition, Airbus issued Airbus Service Bulletin (SB) A320-57-1016 to provide inspection instructions, and, consequently, [Directorate General for Civil Aviation] DGAC France issued AD 97-311-105 [which corresponds to FAA AD 98-18-26, Amendment 39-10742 (63 FR 47423, September 8, 1998)] to require those repetitive [high frequency eddy current (HFEC)] inspections [for cracking]. At the same time, modification in accordance with Airbus SB A320-57-1017 was introduced as (optional) terminating action for the repetitive inspections * * *.

After that [DGAC] AD was issued, and following new analysis, modification per Airbus SB A320-57-1017 was no longer considered to be terminating action for the repetitive inspections as required by DGAC France AD 97-311-105. Aeroplanes with [manufacturer serial number] MSN 0080 up to MSN 0155 inclusive were delivered with the addition of a 5 [millimeter] mm thick light alloy shim under the heads of 2 fasteners at the top end of the front spar vertical stringers (Airbus mod 21290P1546, which is the production line equivalent to in-service modification through Airbus SB A320-57-1017). Aeroplanes with MSN 0156 or higher are delivered with vertical stiffeners of the forward wing spar upper end with stiffener cap thickness increased from 4 to 6 mm (Airbus mod 21290P1547).

Prompted by these findings, Airbus issued SB A320-57-1178 Revision 01 to introduce new repetitive inspections and, consequently, EASA issued AD 2014-0069 [which corresponds to FAA AD 2016-01-11], superseding DGAC France AD 97-311-105 to require the new repetitive inspections, and, depending on findings, accomplishment of applicable corrective action(s).

Since AD 2014-0069 was issued, further investigations in the frame of the Widespread Fatigue Damage (WFD) campaign identified that some repetitive inspection thresholds and intervals have to be revised or introduced, and a new terminating action modification has been designed.

For the reasons described above, this [EASA] AD retains the requirements of EASA AD 2014-0069, which is superseded, revises and introduces thresholds and intervals for the repetitive inspections, and expands the Applicability.

Required actions also include reporting. Although this proposed AD does not explicitly restate the requirements of AD 2016-01-11, this proposed AD would retain certain requirements of AD 2016-01-11. Those requirements are referenced in the service information identified below in “Related Service Information under 1 CFR part 51,” which is referenced in paragraph (i)(1) of this proposed AD. 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-2017-1102.

Related Service Information Under 1 CFR Part 51

Airbus has issued the following service information:

• Service Bulletin A320-57-1178, Revision 03, dated November 29, 2016; excluding Appendixes 01 and 04, and including Appendix 03, all dated November 29, 2016. Appendix 02 does not exist. The service information describes procedures for a rototest inspection for cracking of the radius of the front spar vertical stringers on frame 36, a HFEC for cracking of the horizontal floor beam, and an HFEC inspection for cracking of the fastener holes of the front spar vertical stringers.
• Service Bulletin A320-57-1200, dated November 20, 2015. The service information describes procedures for modifying the center wing box area, which includes related investigative and corrective actions. Related investigative actions include an HFEC inspection on the radius of the rib flanges, a rototest inspection of the fastener holes, detailed and high frequency eddy current inspections for cracking on the cut edges, detailed and rototest inspections on all open fastener holes and an inspection to determine if secondary structure brackets are installed. Corrective action includes reworking the secondary structure bracket and repair.

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.

FAA's Determination and Requirements of This Proposed AD

This product has been approved by the aviation authority of another country, and is approved for operation in the United States. Pursuant to our bilateral agreement with the State of Design Authority, we have been notified of the unsafe condition described in the MCAI and service information referenced above. We are proposing this AD because we evaluated all pertinent information and determined an unsafe condition exists and is likely to exist or develop on other products of the same type design.

Explanation of Compliance Time

The compliance time for the replacement specified in this proposed AD for addressing WFD was established to ensure that discrepant structure is replaced before WFD develops in airplanes. Standard inspection techniques cannot be relied on to detect WFD before it becomes a hazard to flight. We will not grant any extensions of the compliance time to complete any AD-mandated service bulletin related to WFD without extensive new data that would substantiate and clearly warrant such an extension.

Costs of Compliance

We estimate that this proposed AD affects 815 airplanes of U.S. registry.

The actions required by AD 2016-01-11, take about 24 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 2016-01-11 is $2,040 per product.

We also estimate that it would take about 25 work-hours per product to comply with the basic requirements of this proposed AD and 1 work-hour for reporting. The average labor rate is $85 per work-hour. Required parts would cost about $180 per product. Based on these figures, we estimate the cost of this proposed AD on U.S. operators to be $1,947,850, or $2,390 per product.

We have received no definitive data that would enable us to provide cost estimates for the repair of cracking specified in this proposed AD.

Paperwork Reduction Act

A federal agency may not conduct or sponsor, and a person is not required to respond to, nor shall a person be subject to penalty for failure to comply with a collection of information subject to the requirements of the Paperwork Reduction Act unless that collection of information displays a current valid OMB control number. The control number for the collection of information required by this NPRM is 2120-0056. The paperwork cost associated with this NPRM has been detailed in the Costs of Compliance section of this document and includes time for reviewing instructions, as well as completing and reviewing the collection of information. Therefore, all reporting associated with this NPRM is mandatory. Comments concerning the accuracy of this burden and suggestions for reducing the burden should be directed to the FAA at 800 Independence Ave. SW, Washington, DC 20591, ATTN: Information Collection Clearance Officer, AES-200.

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: General requirements.” 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 proposed AD would not have federalism implications under Executive Order 13132. This proposed AD would 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 this proposed regulation:

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

The Proposed Amendment

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

PART 39—AIRWORTHINESS DIRECTIVES

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

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

2. The FAA amends § 39.13 by removing Airworthiness Directive (AD) 2016-01-11, Amendment 39-18370 ( 81 FR 3316, January 21, 2016), and adding the following new AD:

Airbus: Docket No. FAA-2017-1102; Product Identifier 2017-NM-078-AD.

(a) Comments Due Date

We must receive comments by January 29, 2018.

(b) Affected ADs

This AD replaces AD 2016-01-11, Amendment 39-18370 (81 FR 3316, January 21, 2016) (“AD 2016-01-11”).

(c) Applicability

This AD applies to Airbus Model A318-111, -112, -121, and -122 airplanes; Model A319-111, -112, -113, -114, -115, -131, -132, and -133 airplanes; Model A320-211, -212, -214, -216, -231, -232, and -233 airplanes; and Model A321-111, -112, -131, -211, -212, -213, -231, and -232 airplanes; certificated in any category; all manufacturer serial numbers, except airplanes specified in paragraphs (c)(1) and (c)(2) of this AD.

(1) Model A319 and A320 series airplanes on which Airbus Modification (Mod) 160000 (structural reinforcement for sharklet installation) has been embodied in production.

(2) Model A321 series airplanes on which Airbus Modification (Mod) 160021 (structural reinforcement for sharklet installation) has been embodied in production.

(d) Subject

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

(e) Reason

This AD was prompted by a report that, during a center fuselage certification full scale fatigue test, cracks were found on the front vertical stringer at frame (FR) 36. We are issuing this AD to detect and correct fatigue cracking of the front spar vertical stringers on the wings, which could result in the reduced structural integrity of the airplane.

(f) Compliance

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

(g) Definition of Airplane Configurations

For the purposes of this AD, airplane configurations are defined in table 1 to paragraphs (g), (h), (i)(1), and (j) of this AD and table 2 to paragraphs (g) and (i)(1) of this AD.

(h) Actions Required for Previously Inspected Airplanes

For Configuration 1, 2, or 3 airplanes, as identified in table 1 to paragraphs (g), (h), (i)(1), and (j) of this AD, on which the inspections specified in Airbus Service Bulletin A320-57-1178, dated October 29, 2013, have been accomplished before the effective date of this AD; but the additional work specified in Airbus Service Bulletin A320-57-1178, Revision 01, dated May 28, 2014, including Appendix 01, dated May 28, 2014, has not been accomplished before the effective date of this AD: Before accomplishing the initial inspection required by paragraph (i)(1) of this AD, contact the Manager, International Section, Transport Standards Branch, FAA; or the European Aviation Safety Agency (EASA); or Airbus's EASA Design Organization Approval (DOA) for further instructions and accomplish those instructions accordingly.

(i) Repetitive Inspections

(1) Within the compliance time defined in table 3 to paragraph (i)(1) of this AD, as applicable to airplane configuration as identified in table 1 to paragraphs (g), (h), (i)(1), and (j) of this AD and table 2 to paragraphs (g) and (i)(1) of this AD, accomplish a special detailed inspection (SDI) for cracking of the radius of the front spar vertical stringers and the horizontal floor beam and the fastener holes on frame 36, in accordance with the Accomplishment Instructions of Airbus Service Bulletin A320-57-1178, Revision 03, dated November 29, 2016.

(2) If no cracking is found during any inspection required by paragraph (i)(1) of this AD, repeat the inspection required by paragraph (i)(1) of this AD thereafter at intervals not to exceed the inspection interval values defined in table 4 to paragraphs (i)(2) and (l) of this AD, except as provided by paragraph (l) of this AD.

(j) Modification

For A320 series airplanes, Configuration 1, 2, or 3 as identified in table 1 to paragraphs (g), (h), (i)(1), and (j) of this AD: Within the compliance time defined in table 5 to paragraph (j) of this AD, as applicable, modify the center wing box area, including doing all applicable related investigative and corrective actions, in accordance with the Accomplishment Instructions of Airbus Service Bulletin A320-57-1200, dated November 20, 2015, except as required by paragraph (k) of this AD. Do all applicable related investigative and corrective actions before further flight.

(k) Corrective Action

If any crack is found during any inspection required by this AD: Before further flight, repair using a method approved by the Manager, International Section, Transport Standards Branch, FAA; or the EASA; or Airbus's EASA DOA. If approved by the DOA, the approval must include the DOA-authorized signature. Where Airbus Service Bulletin A320-57-1178, Revision 03, dated November 29, 2016; and Airbus Service Bulletin A320-57-1200, dated November 20, 2015; specify to contact Airbus for appropriate action, and specifies that action as “RC” (Required for Compliance), accomplish corrective actions in accordance with this paragraph.

(l) Previous Repairs

For airplanes that have been repaired in the inspection area specified in paragraph (i)(1) of this AD before the effective date of this AD, using a method approved by the Manager, International Section, Transport Standards Branch, FAA; or the EASA; or Airbus's EASA DOA: Accomplish repetitive SDIs within the compliance time defined in those repair instructions for repetitive SDIs. If no compliance time is identified in the repair instructions for repetitive SDIs, accomplish the repetitive SDIs required by paragraph (i)(2) of this AD at the compliance times defined in table 4 to paragraphs (i)(2) and (l) of this AD.

(m) No Terminating Action

Modification or repair of an airplane, as specified in paragraph (j) or (k) of this AD, does not constitute terminating action for the repetitive inspections required by this AD, unless it is specified otherwise in a repair method approved by the Manager, International Section, Transport Standards Branch, FAA; or the EASA; or Airbus's EASA DOA.

(n) Reporting Requirement

Submit a report of the findings (both positive and negative) of the inspections required by paragraphs (i) and (j) of this AD to “Airbus Service Bulletin Reporting Online Application” on Airbus World ( https://w3.airbus.com/ ), at the applicable time specified in paragraph (n)(1) or (n)(2) of this AD.

(1) If the inspection was done on or after the effective date of this AD: Report within 30 days after that inspection.

(2) If the inspection was done before the effective date of this AD: Report within 30 days after the effective date of this AD.

(o) 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 manager of the International Section, send it to the attention of the person identified in paragraph (p)(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 the EASA; or Airbus's EASA DOA. If approved by the DOA, the approval must include the DOA-authorized signature.

(3) Required for Compliance (RC): Except as specified in paragraph (k) of this AD, 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.

(4) Reporting Requirements: A federal agency may not conduct or sponsor, and a person is not required to respond to, nor shall a person be subject to a penalty for failure to comply with a collection of information subject to the requirements of the Paperwork Reduction Act unless that collection of information displays a current valid OMB Control Number. The OMB Control Number for this information collection is 2120-0056. Public reporting for this collection of information is estimated to be approximately [XX] per response, including the time for reviewing instructions, completing and reviewing the collection of information. All responses to this collection of information are mandatory. Comments concerning the accuracy of this burden and suggestions for reducing the burden should be directed to the FAA at 800 Independence Ave. SW, Washington, DC 20591, Attn: Information Collection Clearance Officer, AES-200.

(p) Related Information

(1) Refer to Mandatory Continuing Airworthiness Information (MCAI) EASA Airworthiness Directive 2017-0099, dated June 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-2017-1102.

(2) For more information about this AD, contact Sanjay Ralhan, Aerospace Engineer, International Section, Transport Standards Branch, FAA, 1601 Lind Avenue SW, Renton, WA 98057-3356; telephone 425-227-1405; fax 425-227-1149.

(3) For service information identified in this AD, contact Airbus, Airworthiness Office-EIAS, 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. You may view this service information at the FAA, Transport Standards Branch, 1601 Lind Avenue SW, Renton, WA. For information on the availability of this material at the FAA, call 425-227-1221.