AD 2018-03-13

This AD is effective February 28, 2018.

The Director of the Federal Register approved the incorporation by reference of a certain publication listed in this AD as of February 28, 2018.

We must receive comments on this AD by March 30, 2018.

You may send comments, using the procedures found in 14 CFR 11.43 and 11.45, by any of the following methods:

• Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.

• Fax: 202-493-2251.

• Mail: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590.

• Hand Delivery: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

For service information identified in this final rule, contact General Electric Company, GE-Aviation, Room 285, 1 Neumann Way, Cincinnati, OH 45215; phone: 513-552-3272; fax: 513-552-3329; email: geae.aoc@ge.com. You may view this service information at the FAA, Engine and Propeller Standards Branch, 1200 District Avenue, Burlington, MA 01803. For information on the availability of this material at the FAA, call 781-238-7759. It is also available on the internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2017-0943.

Michael Richardson-Bach, Aerospace Engineer, ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803; phone: 781-238-7747; fax: 781-238-7199; email: michael.richardson-bach@faa.gov.

We received a report that a condition was found after an incident where the main propeller shaft on a GE CT7-9B failed in flight, resulting in the loss of the propeller. The condition is cracking initiating from undiscovered corrosion in the dowel pin hole on the flange of the main propeller shaft. This proposed AD would require visually inspecting the main propeller shaft for wear and corrosion and FPI for cracks. This condition, if not addressed, could result in failure of the main propeller shaft, resulting in in-flight loss of the propeller, loss of engine thrust control, and damage to the airplane. We are issuing this AD to address the unsafe condition on these products.

A similar propeller separation incident occurred in 1992 because of a material defect. The affected parts were purged from the field at that time.

We reviewed SPM 70-32-03, SPOT-FLUORESCENT PENETRANT INSPECTION, TASK 70-32-03-230-002, from the GE Commercial Engine Standard Practices Manual GEK 9250, Rev. 106, dated April 01, 2007. This procedure provides instruction for spot FPI.

We also reviewed MM 72-10-00, PROPELLER GEARBOX INSPECTION and MM 72-10-00, PROPELLER GEARBOX—CLEANING, from the GE CT7B Maintenance Manual SEI-576, Rev. 60, dated October 1, 2017. These procedures provides instructions for inspection and cleaning, respectively, of the main propeller shaft.

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 reviewed GE Service Bulletin (SB) CT7-TP S/B 72-0531, dated June 22, 2017. The SB references standard procedures for initial and repetitive visual and FPI of the main propeller shaft for SF340 aircraft.

We also reviewed GE SB CT7-TP S/B 72-0533, dated October 3, 2017. The SB references standard procedures for initial and repetitive visual and FPI of the main propeller shaft for CN235 aircraft.

We are issuing this AD because we evaluated all the relevant information and determined the unsafe condition described previously is likely to exist or develop in other products of the same type design.

This AD requires visually inspecting the main propeller shaft for wear and corrosion and FPI for cracks.

The inspection plan in this AD adds visual inspection and FPI to the repetitive inspections. This AD adds upper limits to the “inspect within” times to avoid conflicting times to inspect.

An unsafe condition exists that requires the immediate adoption of this AD without providing an opportunity for public comments prior to adoption. The FAA has found that the risk to the flying public justifies waiving notice and comment prior to adoption of this rule because the compliance time for the action is less than the time required for public comment. Therefore, we find that notice and opportunity for prior public comment are impracticable. In addition, for the reason stated above, we find that good cause exists for making this amendment effective in less than 30 days.

This AD is a final rule that involves requirements affecting flight safety and was not preceded by notice and an opportunity for public comment. However, we invite you to send any written data, views, or arguments about this final rule. Send your comments to an address listed under the ADDRESSES section. Include the docket number Docket No. FAA-2017-0943 and Product Identifier 2017-NE-34-AD at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this final rule. We will consider all comments received by the closing date and may amend this final rule because of those comments.

We will post all comments we receive, without change, to http://www.regulations.gov, including any personal information you provide. We will also post a report summarizing each substantive verbal contact we receive about this final rule.

We estimate that this AD affects 176 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 that this AD:

(1) Is not a “significant regulatory action” under Executive Order 12866,

(2) Is not a “significant rule” under 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):