2018-16497. Airworthiness Directives; Airbus Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

We propose to supersede Airworthiness Directive (AD) 2017-22-07, which applies to certain Airbus Model A319 series airplanes; Model A320-211, -212, -214, -231, -232, and -233 airplanes; and Model A321-111, -112, -131, -211, -212, -213, -231, and -232 airplanes. AD 2017-22-07 requires repetitive inspections of the frame forks, and corrective actions if necessary. AD 2017-22-07 also includes optional modifications that constitute terminating action. Since we issued AD 2017-22-07, an evaluation was done by the design approval holder (DAH) indicating that the frame forks and outer skin on the forward and aft cargo compartment doors are subject to widespread fatigue damage (WFD), and a determination was made that a modification of the frame forks must be accomplished. This proposed AD would require modifying certain forward and aft cargo compartment doors, and related investigative and corrective actions. We are proposing this AD to address the unsafe condition on these products.

DATES:

We must receive comments on this proposed AD by September 17, 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: [phone].
• 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, 2 Rond Point Emile Dewoitine, 31700 Blagnac Cedex, France; telephone: [phone]; fax: [phone]; email: [e-mail]; internet: http://www.airbus.com. You may view this referenced 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.

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-2018-0641; 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 NPRM, the regulatory evaluation, any comments received, and other information. The street address for the Docket Operations office (telephone [phone]) 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, 2200 South 216th St., Des Moines, WA 98198; telephone and fax [phone].

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-2018-0641; Product Identifier 2018-NM-032-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 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 2017-22-07, Amendment 39-19087 (82 FR 56158, November 28, 2017) (“AD 2017-22-07”), for certain Airbus Model A319 series airplanes; Model A320-211, -212, -214, -231, -232, and -233 airplanes; and Model A321-111, -112, -131, -211, -212, -213, -231, and -232 airplanes. AD 2017-22-07 requires repetitive inspections of the frame forks, and corrective actions if necessary. AD 2017-22-07 also includes optional modifications that constitute terminating action. AD 2017-22-07 resulted from a report of cracks on frame forks and outer skin on the forward and aft cargo compartment doors. We issued AD 2017-22-07 to address cracks on the frame forks and outer skin on the forward and aft cargo compartment doors, which could lead to reduced structural integrity and failure of the cargo compartment door, possible decompression of the airplane, and injury to occupants.

Actions Since AD 2017-22-07 Was Issued

Since we issued AD 2017-22-07, an evaluation was done by the DAH indicating that the frame forks and outer skin on the forward and aft cargo compartment doors are subject to WFD, and a determination was made that a modification of the frame forks must be accomplished.

The European Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Union, has issued EASA Airworthiness Directive 2018-0024, dated January 29, 2018 (referred to after this as the Mandatory Continuing Airworthiness Information, or “the MCAI”), to correct an unsafe condition for certain Airbus Model A319 series 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. The MCAI states:

During full scale fatigue test, cracks were found on frame forks and outer skin on forward and aft cargo doors. To improve the fatigue behaviour of the frame forks, Airbus introduced modification (mod) 22948 in production, and issued inspection Service Bulletin (SB) A320-52-1032 and mod SB A320-52-1042, both recommended. Since those actions were taken, further improved cargo compartment doors were introduced in production through Airbus mod 26213, on aeroplanes having [manufacturer serial number] MSN 0759 and up.

In the frame of the Widespread Fatigue Damage (WFD) study, it was determined that repetitive inspection are necessary for aft and forward cargo compartment doors on aeroplanes that are in pre-mod 26213 configuration. Failure to detect cracks would reduce the cargo door structural integrity.

This condition, if not detected and corrected, could lead to cargo door failure, possibly resulting in decompression of the aeroplane and injury to occupants.

To address this unsafe condition, Airbus issued SB A320-52-1171 to provide instructions for repetitive special detailed inspections (SDI). This SB was later revised to correct the list of affected cargo doors. Airbus also issued SB A320-52-1170, introducing a door modification which would allow terminating the repetitive SDI[s].

Consequently, EASA issued AD 2016-0187 [which corresponds to FAA AD 2017-22-07] to require repetitive SDI[s] of the affected cargo doors and, depending on findings, the accomplishment of applicable repairs. That [EASA] AD also included reference to SB A320-52-1170 as optional terminating action.

Since that [EASA] AD was issued, further investigations linked to the WFD analysis highlighted that, to meet the WFD requirements, it is necessary to require embodiment of the terminating action modification.

For the reason described above, this [EASA] AD retains the requirements of EASA AD 2016-0187, which is superseded, and requires modification of all affected cargo doors, which constitutes terminating action for the repetitive SDI[s] required by this [EASA] AD.

The related investigative action is a high frequency eddy current (HFEC) rotating probe inspection for cracks. Corrective actions include, among other things, oversizing and cold-expanding any affected holes and repair. 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-2018-0641.

Related Service Information Under 1 CFR Part 51

Airbus has issued the following service information.

• Service Bulletin A320-52-1171, Revision 02, dated April 10, 2017, which describes procedures for repetitive special detailed inspections of all frame forks in the beam 4 area of any affected door, and corrective actions.
• Service Bulletin A320-52-1042, Revision 2, dated January 14, 1997, which describes procedures for modification of all affected forward and aft cargo compartment doors.
• Service Bulletin A320-52-1170, including Appendices 01 and 02, dated September 5, 2016, which describes procedures for modifying all affected forward and aft cargo compartment doors, including oversize and cold working of riveting for all frame forks.

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 these same type designs.

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.

Paragraphs (j)(2) and (j)(3) of AD 2017-22-07 allowed an optional terminating modification that could be done at any time. This proposed AD would still permit that optional terminating modification, but with new limitations on the compliance time, i.e., the optional modification must be done on or after the accumulation of 21,700 flight cycles since first installation of the door on an airplane in order to terminate the repetitive inspections. The repetitive inspections are not terminated if the modification is done before the accumulation of 21,700 flight cycles since first installation of the door on an airplane. These limitations match those in EASA AD 2018-0024, dated January 29, 2018.

Costs of Compliance

We estimate that this proposed AD affects 88 airplanes of U.S. registry.

We estimate the following costs to comply with this proposed AD:

Action	Labor cost	Parts cost	Cost per product	Cost on U.S. operators
Modification	24 work-hours × $85 per hour = $2,040	Up to $240	Up to $2,280	Up to $200,640.
Inspection	25 work-hours × $85 per hour = $2,125	$0	$2,125	$187,000.

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 proposed 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.

§ 39.13

[Amended]

2. The FAA amends § 39.13 by removing Airworthiness Directive (AD) 2017-22-07, Amendment 39-19087 ( 82 FR 56158, November 28, 2017), and adding the following new AD:

Airbus: Docket No. FAA-2018-0641; Product Identifier 2018-NM-032-AD.

(a) Comments Due Date

We must receive comments by September 17, 2018.

(b) Affected ADs

This AD replaces AD 2017-22-07, Amendment 39-19087 (82 FR 56158, November 28, 2017) (“AD 2017-22-07”).

(c) Applicability

This AD applies to Airbus 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, manufacturer serial numbers through 0758 inclusive.

(d) Subject

Air Transport Association (ATA) of America Code 52, Doors.

(e) Reason

This AD was prompted by an evaluation by the design approval holder (DAH) indicating that the frame forks and outer skin on the forward and aft cargo compartment doors are subject to widespread fatigue damage (WFD), and a determination that a modification of the frame forks must be accomplished. We are issuing this AD to address cracks on the frame forks and outer skin on the forward and aft cargo compartment doors, which could lead to reduced structural integrity and failure of the cargo compartment door, possible decompression of the airplane, and injury to occupants.

(f) Compliance

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

(g) Retained Definition of Affected Door, With No Changes

This paragraph restates the definition in paragraph (g) of AD 2017-22-07, with no changes. For the purpose of this AD, an “affected door” is a forward or aft cargo compartment door, having any part number listed in table 1 to paragraph (g) of this AD, except a cargo compartment door on which Airbus Service Bulletin A320-52-1042 or Airbus Service Bulletin A320-52-1170 is embodied.

(h) Retained Repetitive Special Detailed Inspection of Frame Forks, With No Changes

This paragraph restates the requirements of paragraph (h) of AD 2017-22-07, with no changes. At the latest of the compliance times listed in paragraphs (h)(1) through (h)(4) of this AD: Do a special detailed inspection of all frame forks in the beam 4 area of any affected door as defined in paragraph (g) of this AD, in accordance with the Accomplishment Instructions of Airbus Service Bulletin A320-52-1171, Revision 02, dated April 10, 2017, except as specified in paragraphs (l) and (m) of this AD. Repeat the inspection thereafter at intervals not to exceed 3,000 flight cycles. A review of the airplane delivery or maintenance records is acceptable to identify any affected door installed on the airplane, provided that the cargo compartment door part number can be conclusively determined from that review.

(1) Before exceeding 37,500 flight cycles since first installation of the door on an airplane.

(2) Within 900 flight cycles after January 2, 2018 (the effective date of AD 2017-22-07), without exceeding 41,950 flight cycles since first installation of the door on an airplane.

(3) Within 50 flight cycles after January 2, 2018 (the effective date of AD 2017-22-07), for a door having reached or exceeded 41,900 flight cycles since first installation on an airplane.

(4) Within 3,000 flight cycles since the last inspection of the door as specified in Airbus Service Bulletin A320-52-1032.

(i) Retained Corrective Actions, With No Changes

This paragraph restates the requirements of paragraph (i) of AD 2017-22-07, with no changes. If any crack is found during any inspection required by paragraph (h) of this AD, before further flight, do all applicable corrective actions in accordance with the Accomplishment Instructions of Airbus Service Bulletin A320-52-1171, Revision 02, dated April 10, 2017, except as specified in paragraphs (l) and (m) of this AD. Accomplishment of applicable corrective actions does not constitute terminating action for the repetitive inspections.

(j) Terminating Modification

Before the accumulation of 56,300 total flight cycles, but not before the accumulation of 21,700 total flight cycles since first installation of the affected door on an airplane: Modify all affected doors of an airplane, including accomplishment of all applicable related investigative and corrective actions, in accordance with the Accomplishment Instructions of Airbus Service Bulletin A320-52-1170, including Appendices 01 and 02, dated September 5, 2016. Accomplishing this modification constitutes terminating action for the repetitive inspections specified in paragraph (h) of this AD for that airplane, provided that, after modification, no affected door is re-installed on that airplane.

(k) Retained Optional Terminating Action, With Changes Related to Compliance

This paragraph restates the requirements of paragraph (j) of AD 2017-22-07, with changes related to compliance.

(1) Modification of all affected doors of an airplane before the effective date of this AD, in accordance with the Accomplishment Instructions of Airbus Service Bulletin A320-52-1042, Revision 2, dated January 14, 1997, constitutes terminating action for the repetitive inspections specified in paragraph (h) of this AD and a method of compliance for the modification required by paragraph (j) of this AD, for that airplane, provided that, after modification, no affected door is re-installed on that airplane. On or after the effective date of this AD, the modification required by paragraph (j) of this AD must be done.

(2) Modification of all affected doors of an airplane including accomplishment of all applicable related investigative and corrective actions, if done before the effective date of this AD in accordance with the Accomplishment Instructions of Airbus Service Bulletin A320-52-1170, dated September 5, 2016, except as specified in paragraph (l) of this AD, constitutes terminating action for the repetitive inspections specified in paragraph (h) of this AD and a method of compliance for the modification required by paragraph (j) of this AD, for that airplane, provided that, after modification, no affected door is re-installed on that airplane. On or after the effective date of this AD, the modification required by paragraph (j) of this AD must be done.

(3) Modification of all affected doors on an airplane, in case of finding damaged frame forks, as specified in an Airbus Repair Design Approval Sheet (RDAS), if done before the effective date of this AD and done in accordance with 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); constitutes terminating action for the repetitive inspection specified in paragraph (h) of this AD and a method of compliance for the modification required by paragraph (j) of this AD, for that airplane, provided that, after modification, no affected door is re-installed on that airplane. On or after the effective date of this AD, the modification required by paragraph (j) of this AD must be done.

(l) Retained Exception to Service Information

This paragraph restates the requirements of paragraph (k) of AD 2017-22-07, with no changes. Where Airbus Service Bulletin A320-52-1170, including Appendices 01 and 02, dated September 5, 2016; or Airbus Service Bulletin A320-52-1171, Revision 02, dated April 10, 2017; specifies to contact Airbus for appropriate action, and specifies that action as “RC” (Required for Compliance): Before further flight, accomplish corrective actions in accordance with the procedures specified in paragraph (p)(2) of this AD.

(m) Retained No Reporting Requirement

This paragraph restates the requirements of paragraph (l) of AD 2017-22-07, with no changes. Although Airbus Service Bulletin A320-52-1171, Revision 02, dated April 10, 2017, specifies to submit certain information to the manufacturer, and specifies that action as “RC,” this AD does not include that requirement.

(n) Retained Credit for Previous Actions

This paragraph restates the requirements of paragraph (m) of AD 2017-22-07, with no changes.

(1) This paragraph provides credit for the actions required by paragraphs (h) and (i) of this AD, if those actions were performed before January 2, 2018 (the effective date of AD 2017-22-07), using Airbus Service Bulletin A320-52-1171, dated October 29, 2015, provided that it can be conclusively determined that any part number D52371000018 was also inspected as specified in paragraph (h) of this AD.

(2) This paragraph provides credit for the actions required by paragraphs (h) and (i) of this AD, if those actions were performed before January 2, 2018 (the effective date of AD 2017-22-07), using Airbus Service Bulletin A320-52-1171, Revision 01, dated September 5, 2016.

(o) Parts Installation Limitation

As of the effective date of this AD, no person may install, on any airplane, an affected door specified in paragraph (g) of this AD, unless less than 56,300 flight cycles have accumulated since first installation of the door on an airplane, and unless the door has been inspected in accordance with the requirements of paragraph (h) of this AD and all applicable corrective actions have been done in accordance with paragraph (i) of this AD.

(p) Other FAA AD Provisions

The following provisions also apply to this AD:

(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 (p)(2) of this AD. Information may be emailed to: [e-mail]. 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: 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 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.

(3) Required for Compliance (RC): Except as specified in paragraphs (l) and (m) 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.

(q) Related Information

(1) Refer to Mandatory Continuing Airworthiness Information (MCAI) EASA Airworthiness Directive 2018-0024, dated January 29, 2018, 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-2018-0641.

(2) For more information about this AD, contact Sanjay Ralhan, Aerospace Engineer, International Section, Transport Standards Branch, FAA, 2200 South 216th St., Des Moines, WA 98198; telephone and fax [phone].

(3) For service information identified in this AD, contact Airbus, Airworthiness Office—EIAS, 2 Rond Point Emile Dewoitine, 31700 Blagnac Cedex, France; telephone: [phone]; fax: [phone]; email: [e-mail]; internet: http://www.airbus.com. 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.

Issued in Des Moines, Washington, on July 24, 2018.

James Cashdollar,

Acting Director, System Oversight Division, Aircraft Certification Service.