Discussion
We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to certain Airbus SAS Model A350-941 airplanes. The NPRM published in the Federal Register on August 16, 2018 (83 FR 40708). The NPRM was prompted by a review of the Airbus A350 structure design principles database for type definition that revealed that the balancer fitting part, installed on the tail cone, on a certain FR has several corrosion-resistant stainless steel nuts that do not meet the requirements for protection against corrosion. The NPRM proposed to require application of a new additional overcoat sealant and elastic varnish on the affected nuts and fasteners.
We are issuing this AD to address several corrosion-resistant stainless steel nuts installed on elementary aluminum parts, which do not meet the requirements for protection against corrosion, and if not corrected, could reduce the 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 2018-0123, dated June 4, 2018 (referred to after this as the Mandatory Continuing Airworthiness Information, or ``the MCAI''), to correct an unsafe condition for certain Airbus SAS Model A350-941 airplanes. The MCAI states:
[[Page 56703]]
Following a complete review of the Airbus A350 structure design principles database for type definition, it was revealed that the balancer fitting part, installed on the tail cone, lower section of Frame (FR) 103, has several corrosion resistant stainless steel nuts installed on elementary aluminium parts, which does not meet the requirements for protection against corrosion.
This condition, if not corrected, could reduce the structural integrity of the aeroplane.
To address this unsafe condition, Airbus developed production mod 110319 to improve protection against corrosion, and issued the SB [Airbus Service Bulletin A350-53-P024] to provide modification instructions for in-service pre-mod aeroplanes. At the same time the production mod 110348 is equivalent to in-service solution.
For the reasons described above, this [EASA] AD requires a modification, adding new additional overcoat sealant and elastic varnish on the affected nuts and fastener heads.
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- 0758.
Comments
We gave the public the opportunity to participate in developing this final rule. The following presents the comments received on the NPRM and the FAA's response to each comment.
Support for the NPRM
The Air Line Pilots Association, International (ALPA) indicated their support for the NPRM.
Request To Clarify the Proposed AD's Applicability
The commenter Mary Dunn inquired about the proposed AD's effect on similar airplanesand if the actions proposed in the NPRM are proactive or retroactive.
We acknowledge the comment and note that this AD will only affect certain Airbus SAS Model A350-941 airplanes, not airplanes similar to Airbus SAS Model A350-941 airplanes. The unsafe condition has only been identified to affect Airbus SAS Model A350-941 airplanes, not other models, so no action is needed on other airplane models. This AD does have both proactive and retroactive components, in that this AD applies to existing Airbus SAS Model A350-941 airplanes, as specified in paragraph (c) of this AD, while the actions required by paragraph (g) of this AD will be embodied on future Airbus SAS Model A350-941 airplanes in production. No change to this AD has been made 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 final rule 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 addressing 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 Service Bulletin A350-53-P024, dated April 3, 2018. This service information describes procedures for application of a new additional overcoat sealant and elastic varnish on the affected nuts and fasteners. 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 7 airplanes of U.S. registry. We estimate the following costs to comply with this AD:
Estimated Costs ----------------------------------------------------------------------------------------------------------------
Costper Cost on U.S.
Labor cost Parts cost product operators ---------------------------------------------------------------------------------------------------------------- 2 work-hours x $85 per hour = $170........................... $500 $670 $4,690 ----------------------------------------------------------------------------------------------------------------
According to the manufacturer, some or all of the costs of this AD may be covered under warranty, thereby reducing the cost impact on affected individuals. We do not control warranty coverage for affected individuals. As a result, we have included all known costs in our cost estimate.
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, describesin 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 and associated appliances to the Director of the System Oversight Division.
Regulatory Findings
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
[[Page 56704]]
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.