AD 2017-05-09

This AD becomes effective April 13, 2017.

The Director of the Federal Register approved the incorporation by reference of a certain publication listed in this AD as of April 13, 2017.

For service information identified in this final rule, contact CFM International Inc., Aviation Operations Center, 1 Neumann Way, M/D Room 285, Cincinnati, OH 45125; phone: 877-432-3272; fax: 877-432-3329; email: aviation.fleetsupport@ge.com. You may view this service information at the FAA, Engine & Propeller Directorate, 1200 District Avenue, Burlington, MA. For information on the availability of this material at the FAA, call 781-238-7125. It is also available on the Internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2016-9128.

Kasra Sharifi, Aerospace Engineer, Engine Certification Office, FAA, Engine & Propeller Directorate, 1200 District Avenue, Burlington, MA 01803; phone: 781-238-7773; fax: 781-238-7199; email: kasra.sharifi@faa.gov.

We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to the specified products. The NPRM was published in the Federal Register on November 1, 2016 (81 FR 75761). The NPRM proposed to correct an unsafe condition for the specified products.

We have received 9 reports of failure of the RDS on CFM CFM56-5B engines. CFM has identified an affected population of RDSs suspected of generating unbalance levels that would lead to failure of the RDS bearing. This AD requires removal of the RDS assembly and the RDS outer housing for the affected population. This condition, if not corrected, could result in failure of the RDS, which could lead to failure of one or more engines, loss of thrust control, and damage to the airplane.

We gave the public the opportunity to participate in developing this AD. We considered the comments received.

Delta Air Lines (Delta) requested that we withdraw the NPRM or reduce the applicability to RDS assemblies not returned to CFM. Delta stated that the suspect population will likely be in voluntary compliance by the effective date of this AD. Delta also stated that CFM requested that the affected parts be returned to CFM, which will ensure no returned parts are installed in the future.

We disagree. The FAA has found that an unsafe condition exists, which requires removal of parts. The SB alone does not constitute a regulatory requirement, so this AD is required to mandate removal of parts from service. Compliance with the actions specified in this AD are mandatory, including the portions of the SB that are incorporated by reference (IBR) in this AD. We did not change this AD.

Delta requested that this AD include a statement in the compliance section stating that compliance can be shown by a records review. Delta reasons that this will allow a credit for previous action.

The phrase “unless already done...” in paragraph (f) of this AD already provides credit for operators that have complied with this AD before the effective date of this AD. We did not change this AD.

CFM requested that we expand the applicability of this AD to include all CFM56-5 models not listed in paragraph (c) of this AD. CFM reasons that the affected RDS part numbers (P/Ns) are eligible for installation on other CFM56-5 model series not listed in paragraph (c) of this AD.

We disagree. We are issuing this AD to prevent failure of the RDS, which could lead to dual in-flight shutdown (IFSD), in the affected engines, loss of control, and damage to the airplane. RDS P/Ns are a known population and applicability represents those engines in which they were installed. We did not change this AD.

We reviewed the available data, including the comments received, and determined that air safety and the public interest require adopting this AD as proposed.

CFM International S.A. has issued Service Bulletin (SB) CFM56-5B S/B 72-0934, dated August 1, 2016. The SB describes procedures for removal of the affected RDS assembly and the RDS outer housing. 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 eight engines installed on airplanes of U.S. registry.

We estimate the following costs to comply with this AD:

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.

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 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 to the extent that it justifies making a regulatory distinction, 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 adding the following new airworthiness directive (AD):