AD 2007-05-14

This AD becomes effective April 9, 2007.

You can get the service information identified in this AD from General Electric Company via Lockheed Martin Technology Services, 10525 Chester Road, Suite C, Cincinnati, Ohio 45215, telephone (513) 672-8400, fax (513) 672-8422.

You may examine the AD docket on the Internet at http://dms.dot.gov or in Room PL-401 on the plaza level of the Nassif Building, 400 Seventh Street, SW., Washington, DC.

James Lawrence, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; telephone (781) 238-7176; fax (781) 238-7199.

The FAA proposed to amend 14 CFR part 39 with a proposed AD. The proposed AD applies to GE CF6-80C2 series turbofan engines. We published the proposed AD in the Federal Register on December 13, 2006 (71 FR 74873). That action proposed to require replacing certain installed part number (P/N) and serial number (SN) cast titanium weld-repaired forward engine mount platforms and cast titanium forward mount yokes, with a forged titanium or a non-welded cast titanium part.

You may examine the docket that contains the AD, 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) 647-5227) 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 DMS receives them.

We provided the public the opportunity to participate in the development of this AD. We have considered the comments received.

Commenters from Lufthansa Technik, KLM Royal Dutch Airlines, Airbus and Alitalia state that this AD is also applicable to the engines installed in the A310 and MD-11 airplanes. We agree. We inadvertently omitted the Airbus A310 and MD-11 airplanes from the Applicability section of the proposed rule. These airplanes are included in the Applicability section of the AD.

Commenters from Lufthansa Technik, KLM Royal Dutch Airlines, Airbus and Alitalia also state that because the AD mandates requirements contained in GE Service Bulletins, CF6-80C2 S/B 72-1206 and CF6-80C2 S/B 72-1207, the FAA should reference the service bulletins in the final rule. We agree. The service bulletins' accomplishment instructions contain information such as applicable Aircraft Maintenance Manual sections that would clarify requirements of the AD. A reference to the service bulletins is included in the Related Information Section of the AD.

Representatives from Lufthansa Technik and KLM Royal Dutch Airlines note that paragraph (h) of the applicability section identifies a weld repair in a redundant area of the yoke, but Table 3 identifies the weld repair in a non-redundant area of the yoke. The FAA needs to correct this inconsistency in the final rule. We agree and have changed the heading of Table 3 to read, “Weld-Repaired Forward Engine Mount Yokes Requiring Replacement That Have a Weld Repair in a Redundant Area of the Yoke.”

We have carefully reviewed the available data, including the comments received, and determined that air safety and the public interest require adopting the AD with the changes described previously. We have determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD.

There are 25 engines in service that contain the substandard forward engine mount platforms and 59 engines in service that contain the substandard forward engine mount yokes. We estimate that this proposed AD would affect 84 CF6-80C2 engines installed on airplanes of U.S. registry. We estimate that it would take 34 work-hours per engine to replace the weld-repaired cast titanium forward engine mount platforms and the weld-repaired cast titanium forward engine mount yokes. The average labor rate is $80 per work-hour. Required forward engine mount parts would cost about $12,168 per engine. Required forward engine mount yoke parts would cost about $39,560 per engine. Based on these figures, we estimate the total cost of the proposed AD to U.S. operators to be $2,866,720.

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.

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

(1) Is not a “significant regulatory action” under Executive Order 12866;

(2) Is not a “significant rule” under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and

(3) 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.

We prepared a summary of the costs to comply with this AD and placed it in the AD Docket. You may get a copy of this summary at the address listed under ADDRESSES.

Accordingly, under the authority delegated to me by the Administrator, the Federal Aviation Administration amends 14 CFR part 39 as follows:

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

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