AD 2005-08-10

This AD becomes effective May 24, 2005.

The incorporation by reference of certain publications listed in the AD is approved by the Director of the Federal Register as of May 24, 2005.

For service information identified in this AD, contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207.

Docket: The AD docket contains the proposed AD, comments, and any final disposition. You can examine the AD docket on the Internet at http://dms.dot.gov, or in person at the Docket Management Facility office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Management Facility office (telephone (800) 647-5227) is located on the plaza level of the Nassif Building at the U.S. Department of Transportation, 400 Seventh Street SW., room PL-401, Washington, DC. This docket number is FAA-2004-19810; the directorate identifier for this docket is 2004-NM-119-AD.

Doug Pegors, Aerospace Engineer, Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 917-6504; fax (425) 917-6590.

The FAA proposed to amend 14 CFR Part 39 with an AD for certain Boeing Model 737-600, -700, and -800 series airplanes. That action, published in the Federal Register on December 14, 2004 (69 FR 74465), proposed to require doing a general visual inspection for sealant at the interface of the upper spar fittings, strut side skins, and the fittings of the thrust reverser strut fairing on the engine struts; and applying an injection seal or silicone sponge rubber with fillet seal if necessary.

We provided the public the opportunity to participate in the development of this AD. We have considered the comments that have been submitted on the proposed AD. Three commenters support the proposed AD.

A commenter supports the proposed AD, but requests that the compliance time of 18 months or 3,500 flight cycles be shortened. The commenter suggests that, due to the low cost of modifying an airplane, short repair time, and the potential severity of a failure, the compliance time is too long.

We do not agree with the commenter's suggestion. In developing an appropriate compliance time, we considered the safety implications and normal maintenance schedules for timely accomplishment of the required inspection and repair. Further, we arrived at the compliance time with operator and manufacturer concurrence. In consideration of all of these factors, we determined that the compliance time, represents an appropriate interval in which the engine nacelle struts can be inspected, and repaired if required, in a timely manner within the fleet, while still maintaining an adequate level of safety. Operators are always permitted to accomplish the requirements of an AD at a time earlier than the specified compliance time. If additional data are presented that would justify a shorter compliance time, we may consider further rulemaking on this issue.

We have carefully reviewed the available data, including the comments that have been submitted, and determined that air safety and the public interest require adopting the AD as proposed.

There are about 257 airplanes worldwide of the affected design. This AD will affect about 99 airplanes of U.S. registry. The inspection will take about 2 work hours per airplane, at an average labor rate of $65 per work hour. Based on these figures, the estimated cost of the AD for U.S. operators is $12,870, or $130 per airplane.

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 regulatory evaluation of the estimated costs to comply with this AD. See the ADDRESSES section for a location to examine the regulatory evaluation.

Accordingly, under the authority delegated to me by the Administrator, the FAA 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 (AD):