Discussion \n\n\tThe 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 747-200C and -200F series airplanes. That NPRM was published in the Federal Register on August 16, 2007 (72 FR 45954). That NPRM proposed to require, among other actions, installing mounting brackets, support angles, and moisture curtains in the main equipment center. \n\nComments \n\n\tWe provided the public the opportunity to participate in the development of this AD. We have considered the comment received. \n\nRequest To Refer to Earlier Revision of a Referenced Service Bulletin \n\n\tBoeing requests that paragraph (g) of the NPRM be revised to include Boeing Alert Service Bulletin 747-38A2073, Revision 1, dated June 21, 1990; and Revision 2, dated April 26, 2001; as additional sources of service information for accomplishing the prior or concurrent requirements. Boeing states that this will align the NPRM with Boeing Alert Service Bulletin 747-38A2073, Revision 3, dated May 22, 2003 (referred to in the NPRM as an appropriate source of service information for accomplishing the prior or concurrent requirements). \n\tWe partially agree. We agree with Boeing that accomplishing the actions specified in Revisions 1 and 2 of Boeing Alert Service Bulletin 747-38A2073 is acceptable for compliance with the corresponding actions required by paragraph (g) of this AD. However, we do not agree that a change to the final rule is necessary. As mentioned in the Relevant Service Information section of the NPRM, AD 2001-24-30, amendment 39- 12547 (66 FR 64104, December 12, 2001), requires installing drip shields in accordance with Boeing Alert Service Bulletin 747-38A-2073, Revision 2; or in accordance with Revision 1 or Original Release, dated November 30, 1989, if done before the effective date of that AD. In addition, paragraph (h) of this AD states, ''Installation of drip shields before the effective date of this AD in accordance with paragraph (a) and Note 2 of AD 2001-24-30, amendment 39-12547, is acceptable for compliance with the corresponding actions in paragraph (g) of this AD.'' We have made no change to the final rule in this regard. \n\nConclusion \n\n\tWe have carefully reviewed the available data, including the comment received, and determined that air safety and the public interest require adopting the AD as proposed. \n\nInterim Action \n\n\tThis is considered to be interim action. The manufacturer has advised that it currently is developing another modification that will address the unsafe condition identified in this AD. Once this modification is developed, approved, and available, the FAA might consider additional rulemaking. \n\nCosts of Compliance \n\n\tThere are about 79 airplanes of the affected design in the worldwide fleet. The following table provides the estimated costs for U.S. operators to comply with this AD. \n\n\tEstimated Costs \n\n\nAction \nWork hoursAverage labor rate per hour \nParts \nCost per airplane \nNumber of U.S.-registered airplanes \nFleet cost \nInstallation \n3 \n$80 \n$8,960 \n$9,200 \n25 \n$230,000 \nPrior or concurrent requirements of AD 2001-24-30 \n32 \n80 \n4,497 \n7,057 \n25 \n176,425 \n\n\nAuthority for This Rulemaking \n\n\tTitle 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. \n\tWe 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. \n\nRegulatory Findings \n\n\tWe 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. \n\tFor the reasons discussed above, I certify that this AD: \n\t(1) Is not a ''significant regulatory action'' under Executive Order 12866; \n\t(2) Is not a ''significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and \n\t(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. \n\tWe prepared a regulatory evaluation of the estimated costs to comply with this AD andplaced it in the AD docket. See the ADDRESSES section for a location to examine the regulatory evaluation. \n\nList of Subjects in 14 CFR Part 39 \n\n\tAir transportation, Aircraft, Aviation safety, Incorporation by reference, Safety. \n\nAdoption of the Amendment \n\nAccordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows: \n\nPART 39--AIRWORTHINESS DIRECTIVES \n\n1. The authority citation for part 39 continues to read as follows: \n\n\tAuthority: 49 U.S.C. 106(g), 40113, 44701. \n\nSec. 39.13 (Amended) \n\n2. The Federal Aviation Administration (FAA) amends Sec. 39.13 by adding the following new airworthiness directive (AD):