AD 2017-19-23

This AD is effective November 1, 2017.

The Director of the Federal Register approved the incorporation by reference of a certain publication listed in this AD as of November 1, 2017.

For service information identified in this final rule, 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. It is also available on the Internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2017-0498.

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.

We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to supersede AD 2015-15-10, Amendment 39-18219 (80 FR 43928, July 24, 2015) (“AD 2015-15-10”). AD 2015-15-10 applied to all Airbus Model A318, A319, A320, and A321 series airplanes. The NPRM published in the Federal Register on June 2, 2017 (82 FR 25542). The NPRM was prompted by the establishment of an additional life limit for the THSA, based on flight cycles. The NPRM proposed to require repetitive detailed inspections of certain THSAs, and related investigative and corrective actions if necessary. We are issuing this AD to detect and correct wear of the THSA, which could reduce the remaining life of the THSA, possibly resulting in premature failure and consequent reduced controllability 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 Airworthiness Directive 2016-0184, dated September 13, 2016 (referred to after this as the Mandatory Continuing Airworthiness Information, or “the MCAI”), to correct an unsafe condition for all Airbus Model A318 and 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. The MCAI states:

In the frame of the A320 Extended Service Goal (ESG) project and the study on the Trimmable Horizontal Stabilizer Actuator (THSA), a sampling programme of in-service units was performed and several cases of wear at different THSA levels were reported.

This condition, if not detected and corrected, would reduce the remaining life of the THSA, possibly resulting in premature failure and consequent reduced control of the aeroplane.

Prompted by these findings, Airbus issued Service Bulletin (SB) A320-27-1227 to provide THSA inspection instructions. Consequently, EASA issued AD 2014-0011 (later revised) [which corresponds to AD 2015-15-10] to require repetitive inspections of the THSA [and related investigative and corrective actions] and to introduce a life limit for the THSA, based on flight hours (FH).

Since EASA AD 2014-0011R1 was issued, an additional life limitation has been established, based on flight cycles (FC). Furthermore, United Technologies Corporation Aerospace Systems (UTAS), the THSA manufacturer, issued an SB which, after accomplishment on THSA, increases the life limit of the THSA.

For the reasons described above, this [EASA] AD retains the requirements of EASA AD 2014-0011R1, which is superseded, and introduces an additional FC life limit for the affected THSA. This [EASA] AD also provides a revised life limit for the THSA after UTAS SB accomplishment on that THSA.

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-2017-0498.

We gave the public the opportunity to participate in developing this AD. We considered the comments received. Air Line Pilots Association, International (ALPA) and United Airlines expressed their support for the NPRM.

The NPRM specified that a THSA that had been repaired in-shop as specified in UTAS Component Maintenance Manual 27-44-51 would be an equivalent method of compliance for the initial inspection required by paragraph (h) of this AD. We have revised paragraph (m) of this AD to specify that a THSA that has been repaired in-shop using a method approved by the Manager, International Section, Transport Standards Branch, FAA; or the EASA; or Airbus's EASA Design Organization Approval (DOA), is acceptable for compliance with the initial inspection required by paragraph (h) of this AD. We have also added Note 1 to paragraph (m) of this AD to reference UTAS Component Maintenance Manual 27-44-51 as an additional source of guidance for the in-shop repair of the THSA.

We reviewed the relevant data, considered the comments received, and determined that air safety and the public interest require adopting this AD with the changes described previously and 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.

We also determined that these changes will not increase the economic burden on any operator or increase the scope of this AD.

Airbus has issued Service Bulletin A320-27-1227, Revision 03, dated April 29, 2016. This service information describes procedures for repetitive special detailed inspections for wear of the THSA, and related investigative and corrective actions.

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.

We estimate that this AD affects 1,182 airplanes of U.S. registry.

We estimate the following costs to comply with this AD:

We have received no definitive data that would enable us to provide cost estimates for the spectrometric analysis of the oil drained from the THSA gearbox. We estimate the following costs to do any necessary replacements or overhauls that would be required based on the results of the inspection. We have no way of determining the number of aircraft that might need these replacements or overhauls:

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.

We determined that this AD will not have federalism implications under Executive Order 13132. This AD will not have a substantial direct effect on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government.

For the reasons discussed above, I certify that this AD:

1. Is not a “significant regulatory action” under Executive Order 12866;

2. Is not a “significant rule” under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979);

3. Will not affect intrastate aviation in Alaska; and

4. Will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act.

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

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

2. The FAA amends § 39.13 by removing Airworthiness Directive (AD) 2015-15-10, Amendment 39-18219 (80 FR 43928, July 24, 2015), and adding the following new AD: