AD 2018-03-22

This AD is effective March 21, 2018.

For service information identified in this final rule, contact GE Aviation Czech s.r.o., Beranových 65, 199 02 Praha 9—Letňany, Czech Republic; phone: +420 222 538 111; fax: +420 222 538 222. You may view this service information at the FAA, Engine & Propeller Standards Branch, 1200 District Avenue, Burlington, MA. For information on the availability of this material at the FAA, call 781-238-7759.

Robert Green, Aerospace Engineer, ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803; phone: 781-238-7754; fax: 781-238-7199; email: robert.green@faa.gov.

We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to GE Aviation Czech s.r.o. M601D-11, M601E-11, M601E-11A, M601E-11AS, M601E-11S, and M601F turboprop engines. The NPRM published in the Federal Register on September 22, 2017 (82 FR 44355). The NPRM was prompted by a design review by the manufacturer that determined PT rotors with certain disks have less overspeed margin than originally stated during product certification. The NPRM proposed to require removal of the affected PT disks. We are issuing this AD to correct the unsafe condition on these products.

The MCAI states:

It was identified during a recent design review that power turbine (PT) rotors with certain disks, part number (P/N) M601-3220.6 and P/N M601-3220.7, have a reduction in the declared theoretical PT rotor overspeed limit.

This condition, if not corrected, may lead to high energy debris release in case of PT rotor overspeed occurrence, possibly resulting in damage to, and/or reduced control of, the aeroplane.

You may obtain further information by examining the MCAI in the AD docket on the internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2017-0658.

We gave the public the opportunity to participate in developing this final rule. We considered the comment received. Cody Hargis (not further identified) supported the NPRM.

We reviewed the relevant data, considered the comment received, and determined that air safety and the public interest require adopting this final rule as proposed.

We reviewed GE Aviation Czech s.r.o. Alert Service Bulletin (ASB) No. ASB-M601E-72-50-00-0069, ASB-M601D-72-50-00-0052, ASB-M601F-72-50-00-0035, ASB-M601T-72-50-00-0028, and ASB-M601Z-72-50-00-0038, (single document), dated February 21, 2017. The ASB describe procedures for replacing the PT disk.

We estimate that this AD affects 50 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.

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 engines, propellers, and associated appliances to the Manager, Engine and Propeller Standards Branch, Policy and Innovation Division.

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, 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):