AD 2007-23-08

This AD becomes effective December 20, 2007.

The Director of the Federal Register approved the incorporation by reference of certain publications listed in the AD as of December 20, 2007.

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

Binh V. Tran, Aerospace Engineer, Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue SW., Renton, Washington 98057-3356; telephone (425) 917-6485; fax (425) 917-6590.

The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to include an AD that would apply to certain Boeing Model 747-400, 747-400D, 747-400F, 757-200, 767-200, 767-300, and 767-300F series airplanes. That NPRM was published in the Federal Register on July 3, 2007 (72 FR 36378). That NPRM proposed to require inspecting to determine the date code of the time delay relay for the cargo fire suppression system, and replacing the relay if necessary.

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

ABX Air states that it removed the affected relay from its Boeing Model 767-200 airplanes in accordance with Boeing Service Bulletin 767-26-0016, and therefore cannot perform the proposed requirements. ABX requests that we state in the AD that the proposed requirements apply only to airplanes with the time delay relay installed.

We agree that the AD does not apply to airplanes that do not have the time delay relay installed. However, we disagree with the request to change the AD to specify that it does not apply to airplanes with the relay removed. Paragraph (g) of the AD requires an inspection of specific relays and notes the part numbers. If that part number is not installed on the airplane, the airplane is not subject to the replacement requirements of paragraph (h) of the AD. We have not changed the AD in this regard.

Boeing requests that we revise the Summary section of the NPRM to clarify which bottles are discharged by the time delay relay. Specifically Boeing requests that we add the word “secondary” as shown in the following sentence: “The time delay relay controls when the secondary fire bottles discharge.”

We agree that the addition of the word “secondary” clarifies the sentence. We have changed the Summary section of the AD as requested. We have also added the sentence to paragraph (d) of the AD for clarity.

Boeing requests that we clarify the second paragraph of the Discussion section of the NPRM because that paragraph states that the listed airplanes have two halon bottles. Boeing states that some of the systems have more than two halon bottles.

We agree that Boeing's clarification improves the paragraph. However, since that section of the preamble does not reappear in the final rule, no change to the final rule is necessary.

As requested by Boeing, we have added an “in” before the words “Table 1” in paragraph (c) of this AD, and we have added the word “an” before the words “uncontrollable fire” in paragraph (d) of this AD.

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 about 1,871 airplanes of the affected design in the worldwide fleet. This AD affects about 702 airplanes of U.S. registry. The inspection takes about 1 work hour per airplane, at an average labor rate of $80 per work hour. Based on these figures, the estimated cost of the AD for U.S. operators is $56,160, or $80 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 and placed it in the AD docket. 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 Federal Aviation Administration (FAA) amends § 39.13 by adding the following new airworthiness directive (AD):