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Proposed Rule

Airworthiness Directives; General Electric Company (GE) CF6-80C2 Series and CF6-80E1 Series 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.

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AGENCY:

Federal Aviation Administration (FAA), Department of Transportation (DOT).

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to adopt a new airworthiness directive (AD) for GE CF6-80C2 series and CF6-80E1 series turbofan engines. This proposed AD would require installing doubler pads (deflectors) on stage 5 of certain LPT cases, or replacing those LPT cases with LPT cases that have the deflectors already installed. This proposed AD results from four events of hardware Start Printed Page 53492fragments, which liberated into the flowpaths and wore through LPT cases on CF6-80C2 and -80E1 series engines. We are proposing this AD to prevent an uncontained release of engine debris and loss of the structural integrity of the mount system that supports the engine. Loss of the mount system structural integrity could result in the engine separating from the airplane.

DATES:

We must receive any comments on this proposed AD by November 19, 2007.

ADDRESSES:

Use one of the following addresses to comment on this proposed AD.

  • DOT Docket Web site: Go to http://dms.dot.gov and follow the instructions for sending your comments electronically.
  • Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your comments electronically.
  • Mail: Docket Management Facility; U.S. Department of Transportation, 1200 New Jersey Avenue, SE., West Building, Ground Floor, Room W12-140, Washington, DC 20590.
  • Fax: (202) 493-2251.
  • Hand Delivery: 1200 New Jersey Avenue, SE., West Building, Ground Floor, Room W12-140, Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

You can get the service information identified in this proposed AD from Customer Support Center, GE Aircraft Engines, M/D Center Rm. 285, One Neumann Way, Cincinnati, OH 45216, U.S.A.; e-mail: geae.csc@ae.ge.com; International phone No.: (513) 552-3272; U.S.A. phone No.: 877-432-3272.

You may examine the comments on this proposed AD in the AD docket on the Internet at http://dms.dot.gov.

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FOR FURTHER INFORMATION CONTACT:

Robert Green, Aerospace Engineer, Engine Certification Office, FAA, Engine & Directorate, 12 New England Executive Park, Burlington, MA 01803; e-mail: robert.green@faa.gov; telephone (781) 238-7754; fax (781) 238-7199.

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SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to send us any written relevant data, views, or arguments regarding this proposal. Send your comments to an address listed under ADDRESSES. Include “Docket No. FAA-2007-28367; Directorate Identifier 2007-NE-19-AD” in the subject line of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the proposed AD. We will consider all comments received by the closing date and may amend the proposed AD in light of those comments.

We will post all comments we receive, without change, to http://dms.dot.gov, including any personal information you provide. We will also post a report summarizing each substantive verbal contact with FAA personnel concerning this proposed AD. Using the search function of the DOT Web site, anyone can find and read the comments in any of our dockets, including the name of the individual who sent the comment (or signed the comment on behalf of an association, business, labor union, etc.). You may review the DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78) or you may visit http://dms.dot.gov.

Examining the AD Docket

You may examine the docket that contains the proposal, any comments received and, any final disposition in person at the Docket Management Facility between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Office (telephone (800) 647-5527) is located at the street address stated in ADDRESSES. Comments will be available in the AD docket shortly after the Docket Management Facility receives them.

Discussion

We have received reports of four events, three on CF6-80C2 engines, and one on a CF6-80E1 engine, where the LPT case experienced up to 360 degrees circumferentially of wear and breach of the casing from separate failures of the high pressure turbine (HPT) stage 2 nozzle and the fan mid shaft. Such internal engine failures can result in rotor blade and nozzle vane fragments entering the LPT.

The geometry of the blade plane of the stage 5 LPT rotor allows the liberated fragments to accumulate between the LPT blade tips and the LPT case. Engine operation, even at reduced power or windmilling, causes accumulated debris to wear through the LPT case wall. Such a breach from internal engine failure can result in an uncontained release of engine debris and loss of the structural integrity of the mount system that supports the engine. This condition, if not corrected, could result in the engine separating from the airplane.

Relevant Service Information

We have reviewed and approved the technical contents of Service Bulletin (SB) CF6-80E1 S/B 72-0303, Revision 1, dated February 1, 2006; SB CF6-80C2 S/B 72-1171, Revision 1, dated February 1, 2006; and GE Repair Document RD 935-314-S3, dated August 10, 2006, that describes procedures for installing case skin doubler pads (deflectors) on stage 5 of the LPT case.

FAA's Determination and Requirements of the Proposed AD

We have evaluated all pertinent information and identified an unsafe condition that is likely to exist or develop on other products of this same type design. We are proposing this AD, which would require installing case skin doubler pads (deflectors) on stage 5 of the affected LPT case or replacing the case with a case that has deflectors installed, at the next disassembly of the LPT module after the effective date of the proposed AD. The proposed AD would require you to use the service information described previously to perform these actions.

Costs of Compliance

We estimate that this proposed AD would affect 854 GE CF6 engines installed on airplanes of U.S. registry. We also estimate that it would take about 30 work-hours per engine to perform the proposed actions, and that the average labor rate is $80 per work-hour. Required parts would cost about $10,170 per engine. Based on these figures, we estimate the total cost of the proposed AD to U.S. operators to be $10,734,780.

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 have determined that this proposed AD would not have federalism implications under Executive Order Start Printed Page 5349313132. 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 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); and

3. Would not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act.

We prepared a regulatory evaluation of the estimated costs to comply with this proposed AD. You may get a copy of this summary at the address listed under ADDRESSES.

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List of Subjects in 14 CFR Part 39

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The Proposed Amendment

Under the authority delegated to me by the Administrator, the Federal Aviation Administration 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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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:

General Electric Company: Docket No. FAA-2007-28367; Directorate Identifier 2007-NE-19-AD.

Comments Due Date

(a) The Federal Aviation Administration (FAA) must receive comments on this airworthiness directive (AD) action by November 19, 2007.

Affected ADs

(b) None.

Applicability

(c) This AD applies to the CF6-80C2 and CF6-80E1 engines specified in the following Table 1 of this AD. These engines are installed on, but not limited to, Airbus A300, A310, and A330 series airplanes, Boeing 747 and 767 series airplanes, and McDonnell Douglas MD11 series airplanes.

Table 1.—Applicable Engines by Engine Model

Engine modelWith low pressure turbine (LPT) case part No. (P/N) installed
CF6-80C2A1, -80C2A2, -80C2A3, -80C2A5, -80C2A5F, -80C2A8, -80C2B1, -80C2B1F, -80C2B1F1, -80C2B1F2, -80C2B2, -80C2B2F, -80C2B3F, -80C2B4, -80C2B4F, -80C2B5F, -80C2B6, -80C2B6F, -80C2B6FA, -80C2B7F, -80C2B8F, -80C2D1F, and -80C2L1F1336M99G01, 1336M99G02, 1336M99G03, 1336M99G04, 1336M99G06, 1336M99G07, 1336M99G08, 1336M99G09, 1336M99G10, 1336M99G12, 1336M99G13, or 1336M99G15. 1647M68G05, 1647M68G08, 1647M68G09, 1647M68G15. 1713M73G01, 1713M73G02, or 1713M73G05. 9367M99G11or 9367M99G17.
CF6-80E1A1, -80E1A2, -80E1A3, -80E1A4, -80E1A4/B1647M68G02, 1647M68G04, 1647M68G07, 1647M68G12, or 1647M68G13.

Unsafe Condition

(d) This AD results from four events of hardware fragments, which liberated into the flowpaths and wore through LPT cases on CF6-80C2 and -80E1 series engines. We are issuing this AD to prevent an uncontained release of engine debris and loss of the structural integrity of the mount system that supports the engine. Loss of the mount system structural integrity could result in the engine separating from the airplane.

Compliance

(e) You are responsible for having the actions required by this AD performed the next time the LPT module is disassembled, but not to exceed 8 years after the effective date of this AD, unless the actions have already been done.

CF6-80C2 Engines

(f) For CF6-80C2 engines specified in Table 1 of this AD that have an LPT case with a P/N specified in Table 1 of this AD, do either of the following:

(1) Rework the LPT case to install deflectors. Use the Accomplishment Instructions of GE Service Bulletin (SB) CF6-80C2 S/B 72-1171, Revision 1, dated February 1, 2006, and Repair Document (RD) 935-314-S3, dated August 10, 2006, to rework the LPT case, or

(2) Install an LPT case that has case skin doubler pads.

CF6-80E1 Engines

(g) For CF6-80E1 engines specified in Table 1 of this AD, that have an LPT case with a P/N specified in Table 1 of this AD, do either of the following:

(1) Rework the LPT case to install deflectors. Use the Accomplishment Instructions of SB CF6-80E1 S/B 72-0303, Revision 1, dated February 1, 2006, and RD 935-314-S3, dated August 10, 2006, to rework the LPT case, or

(2) Install an LPT case that has case skin doubler pads.

Alternative Methods of Compliance

(h) The Manager, Engine Certification Office, has the authority to approve alternative methods of compliance for this AD if requested using the procedures found in 14 CFR 39.19.

Related Information

(i) None.

(j) Contact Robert Green, Aerospace Engineer, Engine Certification Office, FAA, Engine & Directorate, 12 New England Executive Park, Burlington, MA 01803; e-mail: robert.green@faa.gov; telephone (781) 238-7754; fax (781) 238-7199, for more information about this AD.

Start Signature

Issued in Burlington, Massachusetts, on September 11, 2007.

Francis A. Favara,

Manager, Engine and Propeller Directorate, Aircraft Certification Service.

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[FR Doc. E7-18418 Filed 9-18-07; 8:45 am]

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