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Proposed Rule

Airworthiness Directives; General Electric Company CF6-50C Series Turbofan Engines

Document Details

Information about this document as published in the Federal Register.

Published Document

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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 certain General Electric Company (GE) CF6-50C series turbofan engines. This proposed AD would require reworking the forward fan stator case and installing a fan module secondary containment shield. This proposed AD results from reports of uncontained fan blade failures causing damage and separation of airplane hydraulic lines. We are proposing this AD to prevent uncontained fan blade failures, which can result in separation of airplane hydraulic lines, damage to critical airplane systems, and possible loss of airplane control.

DATES:

We must receive any comments on this proposed AD by June 16, 2006.

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, 400 Seventh Street, SW., Nassif Building, Room PL-401, Washington, DC 20590-0001.
  • Fax: (202) 493-2251.
  • Hand Delivery: Room PL-401 on the plaza level of the Nassif Building, 400 Seventh Street, SW., 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 General Electric Company via GE-Aviation, Attn: Distributions, 111 Merchant St., Room 230, Cincinnati, Ohio 45246, telephone (513) 552-3272; fax (513) 552-3329.

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:

Karen Curtis, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; telephone (781) 238-7192; 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-2006-24171; Directorate Identifier 2006-NE-08-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 DOT Docket Office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Office (telephone (800) 647-5227) is located on the plaza level of the Department of Transportation Nassif Building at the street address stated in ADDRESSES. Comments will be available in the AD docket shortly after the Docket Management Facility receives them.

Discussion

In the service history of the CF6-50C series turbofan engine, there have been more than 40 fan blade failure events. In two of these events, fragments were uncontained, impacting airplane hydraulic lines. In another of these events, the fan case bulged, separating a hydraulic line. Failure of fan blades can result from material defects, foreign object ingestion, or bird ingestion. Fan blade uncontainment can result depending on the size and kinetic energy of the released fan blade fragments, the impact location, and the design capability and integrity of the containment structure. Continued safe flight and landing might be compromised if uncontained fan blade fragments impact critical airplane system components, such as hydraulic lines. This condition, if not corrected, could result in uncontained fan blade failures, which can result in separation of airplane hydraulic lines, damage to critical airplane systems, and possible loss of airplane control.

Relevant Service Information

We have reviewed and approved the technical contents of GE Service Bulletin (SB) No. CF6-50 S/B 72-0985, Revision 1, dated September 15, 1998 (Airbus) and GE SB No. CF6-50 S/B 72-0986, Revision 1, dated September 15, 1998 (McDonnell Douglas). These SBs describe procedures for reworking the forward fan stator case and installing a fan module secondary containment shield.

Differences Between the Proposed AD and the Manufacturer's Service Information

The SBs recommend compliance at the operator's convenience. We Start Printed Page 19662determined that a stricter compliance schedule is necessary. The European Aviation Safety Agency issued AD 2004-0007, on December 15, 2004, which required compliance by December 14, 2005. However, due to insufficient parts availability, we propose to require compliance no later than June 30, 2007.

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 engines of this same type design. We are proposing this AD, which would require reworking certain CF6-50C forward fan stator cases and installing secondary containment shields at the next engine shop visit after the effective date of the proposed AD, but no later than June 30, 2007.

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 226 CF6-50C series turbofan engines installed on airplanes of U.S. registry. We also estimate that it would take about 2.5 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 $9,451 per engine. Based on these figures, we estimate the total cost of the proposed AD to U.S. operators to be $2,181,126.

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 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); 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. See the ADDRESSES section for a location to examine the regulatory evaluation.

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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-2006-24171; Directorate Identifier 2006-NE-08-AD.

Comments Due Date

(a) The Federal Aviation Administration (FAA) must receive comments on this airworthiness directive (AD) action by June 16, 2006.

Affected ADs

(b) None.

Applicability

(c) This AD applies to General Electric Company (GE) CF6-50C, CF6-50C1, CF6-50C2, CF6-50C2B, CF6-50C2F, and CF6-50C2R turbofan engines, with a forward fan stator case, part number 9064M53G04, GO5, G06, G07, G08, G09, G10, G12, or G13, installed. These engines are installed on, but not limited to, Airbus A300, McDonnell Douglas DC-10 series, and DC-10-30F (KC-10A, KDC-10) airplanes.

Unsafe Condition

(d) This AD results from reports of uncontained fan blade failures causing damage and separation of airplane hydraulic lines. We are issuing this AD to prevent uncontained fan blade failures, which can result in separation of airplane hydraulic lines, damage to critical airplane systems, and possible loss of airplane control.

Compliance

(e) You are responsible for having the actions required by this AD performed within the compliance times specified unless the actions have already been done.

(f) At the next engine shop visit after the effective date of this AD, but no later than June 30, 2007, rework the forward fan stator case and install the fan module secondary containment shield.

(1) For engines on Airbus 300 series airplanes, use paragraph 3, Accomplishment Instructions, of GE SB No. CF6-50 S/B 72-0985, dated December 2, 1991 or Revision 1, dated September 15, 1998, to do the rework and installation.

(2) For engines on McDonnell Douglas airplanes, use paragraph 3, Accomplishment Instructions, of GE Service Bulletin (SB) No. CF6-50 S/B 72-0986, dated December 2, 1991 or Revision 1, dated September 15, 1998, to do the rework and installation.

(g) The rework and installation specified in paragraphs (f)(1) through (f)(2) of this AD can also be done on-wing.

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) European Aviation Safety Agency airworthiness directive 2004-0007, dated December 15, 2004, also addresses the subject of this AD.

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Issued in Burlington, Massachusetts, on April 11, 2006.

Francis A. Favara,

Manager, Engine and Propeller Directorate, Aircraft Certification Service.

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[FR Doc. E6-5645 Filed 4-14-06; 8:45 am]

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