Discussion \n\n\tWe issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to include an airworthiness directive (AD) that would apply to certain Boeing Model 757-200, -200CB, and -300 series airplanes. That NPRM was published in the Federal Register on August 31, 2007 (72 FR 50290). That NPRM proposed to require a detailed inspection for damage of the wire bundle of the right recirculation fan, and repair if necessary. That NPRM also proposed to require re-routing the wire bundle of the right recirculation fan. \n\nActions Since the NPRM Was Issued \n\n\tThe NPRM referred to Boeing Service Bulletin 757-21-0109, dated December 15, 2006, as the appropriate source of service information for the proposed actions. Boeing has since revised that service bulletin. Boeing Service Bulletin 757-21-0109, Revision 1, dated October 30, 2008, clarifies certain procedures but otherwise adds no new actions. We have revised paragraphs (c) and (f) in this final rule to refer to Revision 1 of the service bulletin. We have added a new paragraph (g) to this final rule to provide credit for actions done before the effective date of the AD in accordance with the original service bulletin. We have renumbered subsequent paragraphs accordingly. \n\nComments \n\n\tWe gave the public the opportunity to participate in developing this AD. We considered the comments received from the two commenters. \n\nSupport for the NPRM \n\n\tBoeing concurs with the contents of the NPRM. \n\nRequest To Clarify Procedures \n\n\tContinental Airlines asks for clarification or instructions regarding the filler material between the e-clip, part number 411A4902- 7, and the wire and the clip in the depiction in Boeing Service Bulletin 757-21-0109, dated December 15, 2006. \n\tWe agree that further clarification is needed on this point. Boeing Service Bulletin 757-21-0109, Revision 1, dated October 30, 2008, provides a filler rod part number and corrects the reference in note (b) for Figure 3 and Figure 4 of that service bulletin. As stated previously, we have changed the final rule to refer to Revision 1 of the service bulletin as the appropriate source of service information for this final rule. \n\nRequest To Include Instructions for Modified Airplanes \n\n\tContinental Airlines requests that we revise the NPRM to provide instructions for airplanes that are not in the pre-modification state depicted by Boeing Service Bulletin 757-21-0109, dated December 15, 2006. \n\tWe find that clarification is necessary. Boeing Service Bulletin 757-21-0109, Revision 1, dated October 30, 2008, is now referenced in the final rule. It addresses six new wire configurations which take into account the known preexisting configurations. We have not changed the final rule regarding this issue. \n\nRequest To Revise NPRM To Require Different Method of Compliance \n\n\tContinental Airlines suggests using a heat shrinkable sleeve in place of the ''heat shrinkable'' sleeve TFE-2X, which the commenter states is in fact not heat shrinkable. The commenter states that in its experience tying the lacing tape around the sleeve is extremely difficult, and it does not believe that the sleeve will stay on much more than a year at best. \n\tWe infer that the commenter is requesting a different method of compliance. We disagree. Boeing Service Bulletin 757-21-0109, Revision 1, dated October 30, 2008, specifies to use a sleeve with part number 65C38488-2. We have not changed the final rule regarding this issue. However, under the provisions of paragraph (h) of this AD, we may approve a request for different compliance methods if the request includes data that prove that the new method provides an acceptable level of safety. \n\nExplanation of Change to Final Rule \n\n\tWe have clarified paragraph (h) of this AD to more accurately identify the information for requesting approval of an alternative method of compliance (AMOC). \n\nConclusion \n\n\tWe reviewed the relevant data, considered the comments received, and determined that air safety and the public interest require adopting the AD with the changes described previously. We also determined that these changes will not increase the economic burden on any operator or increase the scope of the AD. \n\nCosts of Compliance \n\n\tThere are about 920 airplanes of the affected design in the worldwide fleet. This AD affects about 560 airplanes of U.S. registry. The actions take about 2 work hours per airplane, at an average labor rate of $80 per work hour. Required parts cost about $81 per airplane. Based on these figures, the estimated cost of the AD for U.S. operators is $134,960, or $241 per airplane. \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\tWeare 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\tThis 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\n\tFor the reasons discussed above, I certify that this AD: \n\t(1) Is not a ''significant regulatory action'' underExecutive 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\tYou can find our regulatory evaluation and the estimated costs of compliance in the AD Docket. \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 FAA amends Sec. 39.13 by adding the following new AD: