Airworthiness Directives; General Electric Company CF6-45 and CF6-50 Series Turbofan Engines

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

We propose to supersede an existing airworthiness directive (AD) that applies to General Electric Company (GE) CF6-45 and CF6-50 series turbofan engines. The existing AD requires replacing certain forward and aft centerbodies of the long fixed core exhaust nozzle (LFCEN) assembly. Since we issued that AD, we became aware that other forward and aft centerbodies are also affected. This proposed AD would add certain new centerbodies requiring replacement. This proposed AD is prompted by the discovery of more part numbers (P/Ns) of centerbodies requiring replacement. We are proposing this AD to prevent the forward and aft centerbody of the LFCEN assembly from separating from the engine, damage to the engine, and damage to the airplane.

DATES:

We must receive comments on this proposed AD by February 18, 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 AD, contact General Electric Company, GE-Aviation, Room 285, 1 Neumann Way, Cincinnati, OH 45215, telephone 513-552-3272; fax 513-552-3329; e-mail: geae.aoc@ge.com. 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.

FOR FURTHER INFORMATION CONTACT:

Tomasz Rakowski, Aerospace Engineer, Engine Certification Office, FAA, Engine & Propeller Directorate; phone: 781-238-7735; fax: 781-238-7199; e-mail: tomasz.rakowski@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to send any written relevant data, views, or arguments about this proposed AD. Send your comments to an address listed under the ADDRESSES section. Include “Docket No. FAA-2006-24145; Directorate Identifier 2006-NE-06-AD” at the beginning 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 this 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

On February 12, 2009, we issued AD 2009-04-17, Amendment 39-15823 (74 FR 8735, February 26, 2009), for GE CF6-45 and CF6-50 series turbofan engines. That AD requires replacing LFCEN assembly forward centerbodies P/N 1313M55G01 or G02, P/N 9076M28G09 or G10, and aft centerbodies P/N 1313M56G01 or 9076M46G05 with modified centerbodies. That AD resulted from reports of separation of centerbodies from the engine due to high imbalance engine conditions caused by events including bird strikes. Separation of the centerbodies from the engine would cause engine damage and airplane damage. We issued that AD to prevent the forward and aft centerbody of the LFCEN assembly from separating from the engine, damage to the engine, and damage to the airplane.

Actions Since Existing AD Was Issued

Since we issued AD 2009-04-17, we identified seven additional centerbody P/Ns that should have been included in the AD. These centerbodies are of the same design and construction as those identified in the original AD and therefore, are subject to the same unsafe condition. We added forward centerbodies P/N 9076M28G05, G06, G08, P/N 9076M82G01, G03, and aft centerbodies P/N 9076M46G02, G04 to the applicability of this proposed AD to remove them from service.

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.

Proposed AD Requirements

This proposed AD would add forward centerbody P/Ns 9076M28G05, G06, and G08, P/Ns 9076M82G01, G03, and aft centerbody P/Ns 9076M46G02, G04, to those P/Ns in AD 2009-04-17 to be removed from service.

Costs of Compliance

We estimate that this proposed AD would affect 383 GE CF6-45 and CF6-50 series turbofan engines installed on airplanes of U.S. registry. We also estimate that it would take about 44 work hours per engine to perform the actions required by this AD, and that the average labor rate is $85 per work-hour. Required parts would cost about $11,000 per engine. Based on these figures, we estimate the total cost of this AD to U.S. operators to be $5,645,420.

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),

(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.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Safety

The Proposed Amendment

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

PART 39—AIRWORTHINESS DIRECTIVES

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

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