AD 2016-05-05

We are adopting a new airworthiness directive (AD) for all Airbus Model A300 series airplanes; Model A300 B4-600, B4-600R, and F4- 600R series airplanes, and A300 C4-605R Variant F airplanes (collectively called Model A300-600 series airplanes); and Model A310 series airplanes. This AD was prompted by reports of cracked aluminum support struts of the trimmable horizontal stabilizer (THS) caused by stress corrosion. This AD requires inspections to identify the part number of each support strut, repetitive inspections for cracking of the THS support strut ends, installation of reinforcing clamps on strut ends, and replacement of support struts, if necessary. We are issuing this AD to detect and correct cracked THS support struts, which could lead to the rupture of all four support struts making the remaining structure unable to carry limit loads, which could result in loss of the THS and reduced control of the airplane.

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 adding the following new airworthiness directive (AD):

2016-05-05 Airbus: Amendment 39-18423. Docket No. FAA-2015-0243; Directorate Identifier 2014-NM-114-AD.

(a) Effective Date

This AD becomes effective April 13, 2016.

(b) Affected ADs

None.

(c) Applicability

This AD applies to the Airbus airplanes specified in paragraphs (c)(1) through (c)(6) of this AD, certificated in any category, all manufacturer serial numbers.
(1) Airbus Model A300 B2-1A, B2-1C, B2K-3C, B2-203, B4-2C, B4- 103, and B4-203 airplanes.
(2) Airbus Model A300 B4-601, B4-603, B4-620, and B4-622 airplanes.(3) Airbus Model A300 B4-605R and B4-622R airplanes.
(4) Airbus Model A300 F4-605R and F4-622R airplanes.
(5) Airbus Model A300 C4-605R Variant F airplanes.
(6) Airbus Model A310-203, -204, -221, -222, -304, -322, -324, and -325 airplanes.

(d) Subject

Air Transport Association (ATA) of America Code 53, Fuselage.

(e) Reason

This AD was prompted by reports of cracked aluminum support struts of the trimmable horizontal stabilizer (THS) caused by stress corrosion. We are issuing this AD to detect and correct cracked THS support struts, which could lead to the rupture of all four support struts making the remaining structure unable to carry limit loads, which could result in loss of the THS and reduced control of the airplane.

(f) Compliance

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

(g) Inspection for Part Number

For airplanes in pre-modification 06101 configuration: Within 12 months after the effective date of this AD, do an inspection to identify the part number of each support strut installed on the THS at frame (FR) 91, in accordance with the Accomplishment Instructions of the applicable service bulletin identified in paragraphs (g)(1) through (g)(3) of this AD. A review of airplane maintenance records is acceptable in lieu of this inspection, provided those records can be relied upon for that purpose and the part number can be positively identified from that review. If no aluminum strut(s) having part number (P/N) R21449, R21449D, R21449G, or R21449H is found during any inspection required by this paragraph, no further action is required by this AD for that horizontal stabilizer, except for paragraph (l) of this AD.
(1) For Airbus Model A300 series airplanes: Airbus Service Bulletin A300-53-0395, dated February 14, 2014.
(2) For Airbus Model A300 B4-600, B4-600R, and F4-600R series airplanes, and A300 C4-605R Variant F airplanes (collectively called Model A300-600 series airplanes): Airbus Service Bulletin A300-53- 6174, dated February 14, 2014.
(3) For Airbus Model A310 series airplanes: Airbus Service Bulletin A310-53-2137, dated February 14, 2014.

(h) Repetitive High Frequency Eddy Current (HFEC) Inspections

For airplanes in post-modification 06101 configuration; and for airplanes in pre-modification 06101 configuration on which any aluminum support strut(s) having P/N R21449, P/N R21449D, P/N R21449G, or P/N R21449H is found: Within the applicable compliance times specified in paragraph (h)(1), (h)(2), or (h)(3) of this AD, do an HFEC inspection for cracking of the aluminum THS support strut ends at FR 91, in accordance with the Accomplishment Instructions of the applicable service bulletin identified in paragraphs (g)(1) through (g)(3) of this AD. Reinforcing clamps already installed on strut ends must be removed before accomplishing the HFEC inspection and re-installed after the inspection, in accordance with the AccomplishmentInstructions of the applicable service bulletin specified in paragraphs (g)(1) through (g)(3) of this AD. Repeat the inspection thereafter at intervals not to exceed 24 months.
(1) For airplanes having manufacturer serial number (MSN) 0499 through MSN 0747 inclusive (post-mod 06101): Within 12 months after the effective date of this AD.
(2) For airplanes having MSN 0748 through MSN 0878 inclusive (post-mod 06101): Within 18 months after the effective date of this AD.
(3) For airplanes having MSN 0001 through MSN 0498 inclusive (pre-mod 06101) having one or more aluminum struts: Within 24 months after the effective date of this AD.

(i) Installation of Reinforcing Clamps

Concurrently with the initial HFEC inspection required by paragraph (h) of this AD, identify struts having P/N R21449, P/N R21449D, P/N R21449G, or P/N R21449H with no reinforcing clamps previously installed, and before next flight, install reinforcing clamps on each strut end, in accordance with theAccomplishment Instructions of the applicable service bulletin specified in paragraphs (i)(1) through (i)(3) of this AD.
(1) For Airbus Model A300 series airplanes: Airbus Service Bulletin A300-53-0394, dated February 14, 2014.
(2) For Airbus Model A300 B4-600, B4600R, and F4-600R series airplanes, and A300 C4-605R Variant F airplanes (collectively called Model A300-600 series airplanes): Airbus Service Bulletin A300-53- 6172, dated February 14, 2014.

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(3) For Airbus Model A310 series airplanes: Airbus Service Bulletin A310-53-2136, dated February 14, 2014.

(j) Corrective Actions

If, during any inspection required by paragraph (h) of this AD, any cracking is found, before further flight, replace the affected THS support strut(s) with serviceable struts and install clamps on each strut end, in accordance with the Accomplishment Instructions of the applicable service bulletin identified in paragraphs (g)(1) through (g)(3) of this AD.

(k) Clarification

Installation of reinforcing clamps as required by paragraph (i) of this AD, and the replacement of support struts and/or the installation of clamps as required by paragraph (j) of this AD, do not constitute terminating action for the repetitive inspections required by paragraph (h) of this AD.

(l) Reporting

At the applicable time specified in paragraphs (l)(1) and (l)(2) of this AD: After accomplishment of any inspection required by paragraph (g) of this AD, report all inspection results to Airbus, including no findings, in accordance with the Accomplishment Instructions of the applicable service bulletins specified in paragraphs (g)(1) through (g)(3) of this AD.
(1) If the inspection was done on or after the effective date of this AD: Submit the report within 30 days after the inspection.
(2) If the inspection was done before the effective date of this AD: Submit the report within 30 days after the effective date of this AD.

(m) Other FAA AD Provisions

The following provisions also apply to this AD:
(1) Alternative Methods of Compliance (AMOCs): The Manager, International Branch, ANM-116, Transport Airplane Directorate, 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 Branch, send it to ATTN: Dan Rodina, Aerospace Engineer, International Branch, ANM-116, Transport Airplane Directorate, FAA, 1601 Lind Avenue SW., Renton, WA 98057- 3356; telephone 425-227-2125; fax 425-227-1149. 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. The AMOC approval letter must specifically reference this AD.
(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 Branch, ANM-116, Transport Airplane Directorate, 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) 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 5 minutes 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.

(n) Related Information

Refer to Mandatory Continuing Airworthiness Information (MCAI) EASA Airworthiness Directive 2014-0164, dated July 11, 2014, for related information. This MCAI may be found in the AD docket on the Internet at http://www.regulations.gov/#!documentDetail;D=FAA-2015- 0243-0002.

(o) 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 applicableto do the actions required by this AD, unless this AD specifies otherwise.
(i) Airbus Service Bulletin A300-53-0394, dated February 14, 2014.
(ii) Airbus Service Bulletin A300-53-0395, dated February 14, 2014.
(iii) Airbus Service Bulletin A300-53-6172, dated February 14, 2014.
(iv) Airbus Service Bulletin A300-53-6174, dated February 14, 2014.
(v) Airbus Service Bulletin A310-53-2136, dated February 14, 2014.
(vi) Airbus Service Bulletin A310-53-2137, dated February 14, 2014.
(3) 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.
(4) You may view this service information at the FAA, Transport Airplane Directorate, 1601 Lind Avenue SW., Renton, WA. For information on the availability of this material at the FAA, call 425-227-1221.
(5) 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 by adding an AD that would apply to all Airbus Model A300 series

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airplanes; Model A300 B4-600, B4-600R, and F4-600R series airplanes, and A300 C4-605R Variant F airplanes (collectively called Model A300- 600 series airplanes); and Model A310 series airplanes. The NPRM published in the Federal Register on February 18, 2015 (80 FR 8571).
The European Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Union, has issued EASA Airworthiness Directive 2014-0164, dated July 11, 2014 (referred to after this as the Mandatory Continuing Airworthiness Information, or ``the MCAI''), to correct an unsafe condition for all Airbus Model A300 series airplanes; Model A300 B4-600, B4-600R, and F4-600R series airplanes, and A300 C4-605R Variant F airplanes (collectively called Model A300-600 series airplanes); andModel A310 series airplanes. The MCAI states:

During scheduled maintenance, several Trimmable Horizontal Stabilizer (THS) support struts were found cracked at the strut ends. The THS is supported and articulated at frame (FR) 91 in the tail cone. Lateral movement is prevented by four diagonal support struts.
Investigations revealed that the cracks were caused by stress corrosion and propagated from the inside to the outside of the strut.
This condition, if not detected and corrected, could lead to the rupture of all four THS support struts at FR91, which would make the remaining structure unable to carry limit loads, potentially resulting in loss of the Horizontal Tail Plane.
To address this unsafe condition, EASA issued AD 2014-0121 [http://ad.easa.europa.eu/ad/2014-0121] to require repetitive High Frequency Eddy Current (HFEC) inspections of the THS support strut ends, installation of reinforcing clamps on strut ends and, depending on findings, replacement of damagedsupport struts. Installation of reinforcing clamps on strut ends is considered a temporary solution pending introduction of a re-designed support strut.
Since that [EASA] AD was issued, it was discovered that the [EASA] AD appeared to also require HFEC inspections of steel struts, which are not prone to cracking. The unsafe condition exists only on support struts made of aluminum, which were introduced through Airbus modification (mod) 06101, but may also have been installed in service as replacement parts on aeroplanes in pre-mod 06101 configuration.
For the reason described above, this [EASA] AD retains the requirements of EASA AD 2014-0121, which is superseded, and clarifies the need for an initial identification of the support struts installed on aeroplanes in pre-mod 06101 configuration. The related Airbus Service Bulletins (SB) remain unchanged.

You may examine the MCAI in the AD docket on the Internet at http://www.regulations.gov/#!documentDetail;D=FAA-2015-0243-0002.

Comments

We gave the public the opportunity to participate in developing this AD. We have considered the comments received. The following presents the comments received on the NPRM (80 FR 8571, February 18, 2015) (``the NPRM'') and the FAA's response to each comment.

Request To Remove Repetitive Inspections From the NPRM

FedEx stated that Airbus Service Bulletin A300-53-6172, dated February 14, 2014 and Airbus Service Bulletin A310-53-2136, dated February 14, 2014, require an application of sealant and installation of a clamp over the affected area. FedEx stated periodic re-inspections for cracking of the THS support strut ends would induce further damage since it requires removal of the reinforcing clamps and sealant before accomplishing the HFEC inspection.
We infer from the commenter's statement that FedEx requests removal of the repetitive inspection requirement from the proposed AD. We disagree because if operators follow established procedures, removal of the sealant should not introduce damage to the support struts installed on the THS. We have not changed this final rule in this regard.

Request To Remove Installation Requirement From the NPRM

FedEx and United Parcel Service (UPS) stated they disagree with the requirement to install the clamping. Both commenters claimed that installing reinforcing clamps will not resolve any stress mitigation and crack progression. UPS stated that the NPRM proposed to require repair prior to further flight, if cracking is identified. FedEx and UPS stated that repetitive inspections provide a sufficient level of safety on the struts and that the installation of reinforcement clamps does not enhance the support strut installation, but adds an additional cost without a corresponding safety benefit. FedEx and UPS requested removal of the clamp installation requirement specified by paragraphs (i) and (j) of the proposed AD.
We disagree to remove the requirement to install clamping from paragraphs (i) and (j) of this AD. The clamping reduces the circumferential stresses in the rod-ends and supports the circular shape of the rod ends. As a result, stress corrosion of the rod is stopped, or partially reduced, due to the lower circumferential stresses. We have not changed this final rule in this regard.

Request To Remove Certain References From Paragraph (l) of the NPRM

UPS requested that we remove reference to paragraphs (i)(1) through (i)(3) of the proposed AD from paragraph (l) of the proposed AD. UPS stated the service bulletins identified in paragraphs (i)(1) through (i)(3) of the proposed AD do not include an inspection form or inspection requirements within the accomplishment instructions of the service information and therefore these documents should not be referenced in paragraph (l) of the proposed AD, which specifies reporting inspection results.
We agree with the request because paragraph (l) of this AD only requires the reporting of certain inspections results. Paragraph (i) of this AD requires an installation of reinforcing clamps. We have revised paragraph (l) of this AD to remove the reference to paragraphs (i)(1) through (i)(3) of this AD.
We have also revised paragraph (l) of this AD by removing a reference to paragraph (h) of this AD in order to match the reporting requirement specified in the MCAI. Paragraph (l) of the proposed AD refers to inspections required by both paragraphs (g) and (h) of the proposed AD. However, reporting is only required for inspections required by paragraph (g) of this AD.

Request To Revise Costs of Compliance

FedEx requested that we revise the Costs of Compliance paragraph of the proposed AD to accurately reflect the cost of replacing cracked struts. FedEx stated it agrees that struts that are determined to be cracked should be replaced but finds that this adds an additional financial burden to the airlines. FedEx stated there are no warranty provisions stated in the manufacturer's service information to mitigate the additional expense of replacing struts, nor is it accounted for in the NPRM.
We disagree because the conditional cost of replacing the struts was accounted for in the NPRM by using the standard part cost for non- avionics parts of $10,000 and an estimate that any necessary follow-on actions would take about 15 work-hours. Further, we do not control warranty coverage for affected individuals. We have not changed this final rule in this regard.

Request To Include Installation of Steel Struts as Terminating Action

FedEx requested that we revise the NPRM to state that the installation of steel struts constitutes a terminating

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action for the repetitive inspections specified by paragraph (h) of the proposed AD. FedEx noted that Airbus may be developing a solution that would terminate the repetitive inspections, but as of yet, Airbus has not published any service information that would eliminate the need for the repetitive inspections specified by paragraph (h) of the proposed AD.
We disagree to change this final rule because terminating action is not available at this time. When terminating action becomes available, the FAA may consider installation of the new design struts as an alternative method of compliance (AMOC) to this AD once the manufacturer's design solution is released. We have not changed this final rule in this regard.

Request To Extend the Repetitive Inspection Interval

UPS requested that we extend the repetitive inspection interval required by paragraph (h) of the proposed AD. UPS stated that a manufacturer's investigation identified the cracking to be the result of inter-granular stress corrosion and that for cracking to develop, three factors need to be present: a material flaw at the granular level, an environmental condition for corrosion to develop, and a tensile load to induce damage development/propagation at the material flaw. UPS added that the area is already protected with anti-corrosion materials. UPS stated that based on the low occurrence of cracking, the propagation properties of cracking due to stress corrosion, and the age of the fleet, fleet airworthiness can be maintained using all three operational parameters--flight hours, flight cycles, and calendar time. UPS requested that we revise the repetitive inspection interval from 24 months to 5,000 flight hours, 2,500 flight cycles, or 36 months, whichever occurs first.
We do not agree with the request to extend the repetitive inspection required by paragraph (h) of this AD because the UPS proposal is not supported by analysis or data. In developing an appropriate compliance time for the actions specified in paragraph (h) of this AD, we considered the safety implications and normal maintenance schedules for the timely accomplishment of the specified actions. We have determined that the proposed interval will ensure an acceptable level of safety and allow the actions to be done during scheduled maintenance intervals for most affected operators. However, affected operators may request an AMOC to request an extension of the repetitive inspection interval under the provisions of paragraph (m)(1) of this AD by submitting data and analysis substantiating that the change would provide an acceptable level of safety. We have not changed this final rule in this regard.

Request To Delay Rule Due to Pending Release of New Design of Support Strut and Service Information

FedEx and UPS requested that the release date of the NPRM be suspended pending Airbus's release of a newly designed support strut that, if installed, would be terminating action for the repetitive inspections proposed by the NPRM. FedEx stated the manufacturer is working on service information that contains a terminating action for the repetitive inspections proposed in the NPRM, but as of yet, has not been published. UPS stated that suspending the release of the NPRM would prevent extra work for the FAA and operators.
We disagree with delaying issuance of this final rule until new service information or a new design becomes available. We consider that to delay this AD action would be inappropriate, in light of the identified unsafe condition. When new service information or a new design becomes available, we may consider additional rulemaking. We may also consider new service information and/or installation of the new design struts as an AMOC to this AD. Operators may apply for an AMOC in accordance with the provisions of paragraph (m)(1) of this AD. We have not changed this final rule in this regard.

Conclusion

We reviewed the relevant data, considered the comments 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 A300-53-0394, dated February 14, 2014. This service information describes procedures for reinforcing the support struts of the THS at frame 91 in the fuselage tail section of Airbus Model A300 series airplanes.
Airbus Service Bulletin A300-53-0395, dated February 14, 2014. This service information describes procedures for inspecting for cracking of the support struts of the THS at frame 91 in the fuselage tail section of Airbus Model A300 series airplanes.
Airbus Service Bulletin A300-53-6172, dated February 14, 2014. This service information describes procedures for reinforcing the support struts of the THS at frame 91 in the fuselage tail section of Airbus Model A300-600 series airplanes.
Airbus Service Bulletin A300-53-6174, dated February 14, 2014. This service information describes procedures for inspecting for cracking of the support struts of the THS at frame 91 in the fuselage tail section of Airbus Model A300-600 series airplanes.
Airbus Service Bulletin A310-53-2136, dated February 14, 2014. This service information describes procedures for reinforcing the support struts of the THS at frame 91 in the fuselage tail section of Airbus Model A310 series airplanes.
Airbus Service Bulletin A310-53-2137, dated February 14, 2014. This service information describes procedures for inspecting for cracking of the support struts of the THS at frame 91 in the fuselage tail section of Airbus Model A310 series airplanes.
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 174 airplanes of U.S. registry.
We also estimate that it will take about 5work-hours per product to comply with the basic requirements of this AD, and 1 work-hour per product for reporting. The average labor rate is $85 per work-hour. Required parts will cost about $2,100 per product. Based on these figures, we estimate the cost of this AD on U.S. operators to be $454,140, or $2,610 per product.
In addition, we estimate that any necessary follow-on actions will take about 15 work-hours and require parts costing $10,000, for a cost of $11,275 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

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detail the scope of the Agency's authority.
We are issuing this rulemaking under the authority described in ``Subtitle VII, PartA, 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.

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'' underthe 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.

Examining the AD Docket

You may examine the AD docket on the Internet at http://www.regulations.gov/#!docketDetail;D=FAA-2015-0243; 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 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.

List of Subjects in 14 CFR Part 39

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