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Proposed Rule

Airworthiness Directives; General Electric Company Turboshaft Engines

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AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

We propose to adopt a new airworthiness directive (AD) for certain General Electric Company (GE) CT7-8A and CT7-9B model turboshaft engines. This proposed AD was prompted by reports from the manufacturer that the high-pressure compressor (HPC) impeller installed on these engines may have suffered from material degradation during the manufacturing process. This proposed AD would require removal of the affected HPC impellers. We are proposing this AD to address the unsafe condition on these products.

DATES:

We must receive comments on this proposed AD by July 31, 2017.

ADDRESSES:

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: Deliver to Mail address above between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

For service information identified in this NPRM, 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 & Propeller Directorate, 1200 District Avenue, Burlington, MA. For information on the availability of this material at the FAA, call 781-238-7125.

Examining the AD Docket

You may examine the AD docket on the Internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2017-0452; or in person at the Docket Management Facility between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this NPRM, the regulatory evaluation, any comments received, and other information. The street address for the Docket Office (phone: 800-647-5527) is in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

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FOR FURTHER INFORMATION CONTACT:

Martin Adler, Aerospace Engineer, Engine Certification Office, FAA, Engine & Propeller Directorate, 1200 District Avenue, Burlington, MA 01803; phone: 781-238-7157; fax: 781-238-7199; email: martin.adler@faa.gov.

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SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to send any written relevant data, views, or arguments about this proposal. Send your comments to an address listed under the ADDRESSES section. Include “Docket No. FAA-2017-0452; Directorate Identifier 2017-NE-14-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this NPRM. We will consider all comments received by the closing date and may amend this NPRM 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 NPRM.

Discussion

We learned from the manufacturer that the affected HPC impellers installed on CT7-8A and CT7-9B turboshaft engines may have suffered from material degradation during the manufacturing process. This condition, if not corrected, could result in failure of the HPC impeller, uncontained HPC impeller release, damage to the engine, and damage to the airplane/helicopter.

Related Service Information

We reviewed GE Service Bulletin (SB) CT7-TP S/B 72-0524, dated June 16, 2016. The SB describes procedures for replacing the affected HPC impellers.

FAA's Determination

We are proposing 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.Start Printed Page 27635

Proposed AD Requirements

This proposed AD would require removal of the affected HPC impellers.

Costs of Compliance

We estimate that this proposed AD affects 1 engine installed on a helicopter of U.S. registry.

We estimate the following costs to comply with this proposed AD:

Estimated Costs

ActionLabor costParts costCost per productCost on U.S. operators
Replace HPC impeller0 work-hours × $85 per hour = $0$70,000$70,000$70,000

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, 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.

Regulatory Findings

We determined that this proposed AD would not have federalism implications under Executive Order 13132. This proposed AD would 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 proposed regulation:

(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.

Start List of Subjects

List of Subjects in 14 CFR Part 39

  • Air transportation
  • Aircraft
  • Aviation safety
  • Incorporation by reference
  • Safety
End List of Subjects

The Proposed Amendment

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

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PART 39—AIRWORTHINESS DIRECTIVES

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

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Authority: 49 U.S.C. 106(g), 40113, 44701.

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[Amended]
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2. The FAA amends § 39.13 by adding the following new airworthiness directive (AD):

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General Electric Company: Docket No. FAA-2017-0452; Directorate Identifier 2017-NE-14-AD.

(a) Comments Due Date

We must receive comments by July 31, 2017.

(b) Affected ADs

None.

(c) Applicability

This AD applies to General Electric Company (GE) CT7-8A and CT7-9B model turboshaft engines with a high-pressure compressor (HPC) impeller, part number 5123T51P02, and serial number, GLHTPH9G, GLHTPP7P, or GLHTPJHN, installed.

(d) Subject

Joint Aircraft System Component (JASC) Code 7230, Turbine Engine Compressor Section.

(e) Unsafe Condition

This AD was prompted by reports from the manufacturer that the HPC impeller installed on these engines may have suffered from material degradation during the manufacturing process. We are issuing this AD to prevent failure of the HPC impeller. This unsafe condition, if not corrected, could result in failure of the HPC impeller, uncontained HPC impeller release, damage to the engine, and damage to the airplane/helicopter.

(f) Compliance

Comply with this AD within the compliance times specified, unless already done.

(1) For CT7-9B engines, remove the affected HPC impeller from service at the next engine shop visit after the effective date of this AD, or prior to accumulating 12,000 cycles since new, whichever is earlier.

(2) For CT7-8A engines, remove the affected HPC impeller from service at the next engine shop visit after the effective date of this AD, or prior to accumulating 1,500 engine hours after the effective date of this AD, whichever is earlier.

(g) Definition

For the purpose of this AD, an “engine shop visit” is the induction of an engine into the shop for maintenance involving the separation of pairs of major mating engine flanges.

(h) Alternative Methods of Compliance (AMOCs)

The Manager, Engine Certification Office, FAA, may approve AMOCs for this AD. Use the procedures found in 14 CFR 39.19 to make your request. You may email your request to: ANE-AD-AMOC@faa.gov.

(i) Related Information

(1) For more information about this AD, contact Martin Adler, Aerospace Engineer, Engine Certification Office, FAA, Engine & Propeller Directorate, 1200 District Avenue, Burlington, MA 01803; phone: 781-238-7157; fax: 781-238-7199; email: martin.adler@faa.gov.

(2) GE Service Bulletin CT7-TP S/B 72-0524, dated June 16, 2016, can be obtained from GE using the contact information in paragraph (i)(3) of this proposed AD.

(3) For service information identified in this proposed AD, 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.

(4) 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.

Start Signature

Issued in Burlington, Massachusetts, on June 8, 2017.

Robert J. Ganley,

Acting Manager, Engine & Propeller Directorate, Aircraft Certification Service.

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[FR Doc. 2017-12242 Filed 6-15-17; 8:45 am]

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