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Proposed Rule

Airworthiness Directives; General Electric Company (GE) GE90-110B1 and GE90-115B Turbofan Engines

Document Details

Information about this document as published in the Federal Register.

Published Document

This document has been published in the Federal Register. Use the PDF linked in the document sidebar for the official electronic format.

Start Preamble

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

We propose to adopt a new airworthiness directive (AD) for the products listed above, with certain part number (P/N) high-pressure compressor (HPC) stages 2-5 spools installed. This proposed AD would require eddy current inspection (ECI) or spot fluorescent penetrant inspection (FPI) of the stages 1-2 rotating seal teeth of the HPC stages 2-5 spool for cracks and would prohibit installation of HPC stator stage 1 interstage seals that are not pregrooved to prevent heavy rubs. This proposed AD was prompted by an aborted takeoff and two shop findings of cracks in the stages 1-2 rotating seal teeth. We are proposing this AD to detect cracks in the HPC stages 1-2 rotating seal teeth due to heavy rubs, which could result in failure of the stages 1-2 rotating seal of the HPC Start Printed Page 30574stages 2-5 spool, uncontained engine failure, and damage to the airplane.

DATES:

We must receive any comments on this proposed AD by July 11, 2011.

ADDRESSES:

You may send comments 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 proposed AD, contact General Electric, GE-Aviation, Room 285, 1 Newman Way, Cincinnati, Ohio 45215; e-mail: geae.aoc@ge.com; phone: 513-552-3272; fax: 513-552-3329. You may review copies of the referenced service information at the FAA, Engine & Propeller Directorate, 12 New England Executive Park, 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;​ 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 proposed AD, 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.

Start Further Info

FOR FURTHER INFORMATION CONTACT:

Jason Yang, Aerospace Engineer, Engine Certification Office, FAA, Engine & Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; phone: 781-238-7747; fax: 781-238-7199; e-mail: jason.yang@faa.gov.

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SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to send us 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-2011-0278; Directorate Identifier 2010-NE-10-AD” in the subject line of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this proposed AD. We will consider all comments received by the closing date and may amend the proposed AD 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 proposed AD.

Discussion

We received a report of an engine failure caused by the liberation of a portion of the HPC stages 1-2 rotating seal teeth, and subsequent reports of HPC stages 1-2 rotating seal teeth cracks, due to heavy rubs, found in engines in the shop. The heavy rubs are due to insufficient clearance between the rotating seal teeth and the abradable coating on the static seal. This proposed AD would require ECI or spot FPI of the stages 1-2 rotating seal teeth of the HPC stages 2-5 spool for cracks, and would prohibit installation of HPC stator stage 1 interstage seals that are not pregrooved in order to prevent heavy rubs. This condition, if not corrected, could result in failure of the stages 1-2 rotating seal of the HPC stages 2-5 spool, uncontained engine failure, and damage to the airplane.

Relevant Service Information

We reviewed GE Service Bulletin (SB) GE90-100 S/B 72-0320, Revision 02, dated October 1, 2010. That service information describes procedures for inspecting the stages 1-2 seal teeth for cracks.

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 on other products of the same type design.

Proposed AD Requirements

This proposed AD would require accomplishing the actions specified in the service information described previously.

Costs of Compliance

We estimate that this proposed AD would affect 19 GE90-110B1 and GE90-115B engines installed on airplanes of U.S. registry. We also estimate that it would take about 2 work-hours per engine to perform the proposed actions, and that the average labor rate is $85 per work-hour. Required parts would cost about $9,857 per engine. Based on these figures, we estimate the total cost of the proposed AD to U.S. operators to be $190,513.

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 that the 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; 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

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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

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

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Start Printed Page 30575 Authority: 49 U.S.C. 106(g), 40113, 44701.

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[Amended]

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

General Electric Company: Docket No. FAA-2011-0278; Directorate Identifier 2010-NE-10-AD.

Comments Due Date

(a) We must receive comments by July 11, 2011.

Affected ADs

(b) None.

Applicability

(c) This AD applies to General Electric Company (GE) GE90-110B1 and GE90-115B turbofan engines with high-pressure compressor (HPC) stages 2-5 spools, part numbers (P/Ns) 351-103-106-0, 351-103-107-0, 351-103-108-0, 351-103-109-0, 351-103-141-0, 351-103-142-0, 351-103-143-0 and 351-103-144-0, installed.

Unsafe Condition

(d) This AD was prompted by an aborted takeoff and two shop findings of cracks in the stages 1-2 rotating seal teeth. We are issuing this AD to detect cracks in the HPC stages 1-2 rotating seal teeth due to heavy rubs, which could result in failure of the stages 1-2 rotating seal of the HPC stages 2-5 spool, uncontained engine failure, and damage to the airplane.

Compliance

(e) Comply with this AD when the HPC forward case half is removed from the engine after the effective date of this AD, unless the actions have already been done.

Inspection

(f) Perform an eddy current inspection or a fluorescent penetrant inspection of the stage 1-2 seal teeth using paragraphs 3.B. or 3.C. of GE Service Bulletin (SB) GE90-100 S/B 72-0320, Revision 02, dated October 1, 2010.

Disposition of Spools with Cracked Seal Teeth

(g) If you find cracks, remove the HPC stages 2-5 spool from service.

Previous Credit

(h) An inspection performed before the effective date of this AD using SB GE90-100 S/B 72-0320 Revision 01, dated May 11, 2010, or earlier revision, satisfies the inspection requirement of this AD.

Installation Prohibition

(i) After the effective date of this AD, do not install any HPC forward case unless it has an HPC stator stage 1 interstage seals, P/N 351-109-503-0.

Alternative Methods of Compliance (AMOCs)

(j) The Manager, Engine Certification Office, has the authority to approve AMOCs for this AD if requested using the procedures found in 14 CFR 39.19.

Related Information

(k) Contact Jason Yang, Aerospace Engineer, Engine Certification Office, FAA, Engine & Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; phone: 781-238-7747; fax: 781-238-7199; e-mail: jason.yang@faa.gov, for more information about this AD.

(l) GE Service Bulletin GE90-100 S/B 72-0320, Revision 02, dated October 1, 2010, pertain to the subject of this AD. Contact General Electric, GE-Aviation, Room 285, 1 Newman Way, Cincinnati, Ohio 45215; e-mail: geae.aoc@ge.com; phone: 513-552-3272; fax: 513-552-3329, for a copy of this service information.

Start Signature

Issued in Burlington, Massachusetts, on May 20, 2011.

Peter A. White,

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

End Signature End Part End Supplemental Information

[FR Doc. 2011-13013 Filed 5-25-11; 8:45 am]

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