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 all Boeing Model 777-200, -200LR, -300, and -300ER series airplanes. That NPRM was published in the Federal Register on July 10, 2007 (72 FR 37475). That NPRM proposed to require a one-time inspection to determine the material of the forward and aft gray water drain masts. For airplanes having composite gray water drain masts, that NPRM also proposed to require installation of a bonding jumper between a ground and the clamp on the tube of the forward and aft gray water composite drain masts. \n\nComments \n\n\tWe gave the public the opportunity to participate in developing this AD. We have considered the single comment received. \n\nRequest To Remove Airplanes From the Applicability Statement of the Proposed AD \n\n\tBoeing requests that we revise the applicability statement of the NPRM to remove certain airplanes. Boeing states that Model 777 airplanes beginning with line number 525 have a ground bracket and copper bonding jumper installed in production for the aft composite gray water drain mast, and an aluminum drain mast installed in the forward drain mast position. Additionally, Boeing points out that all Model 777-200LR series airplanes produced prior to line number 525 have a bonding jumper installed on the aft composite gray water drain mast and an aluminum forward gray water drain mast. Therefore, Boeing asserts that these airplanes should not be subject to this AD. \n\n\tWe partially agree. For the reasons Boeing stated, we have determined that these airplanes should not be subject to this AD. However, we do not agree to revise the applicability statement of this AD as suggested by Boeing. Instead, we have revised the applicability statement of this final rule to state, "This AD applies to Boeing Model 777-200, -300, and -300ER series airplanes, certificated in any category, as identified in Boeing Special Attention Service Bulletin 777-30-0014, dated July 24, 2006." We have confirmed that the effectivities of these service bulletins match the applicability suggested by Boeing. \n\nExplanation of Changes Made to This AD \n\n\tWe have confirmed with the airplane manufacturer that the composite and aluminum drain mast can be interchangeable. Therefore, we have added a new paragraph (i), "Parts Installation," to this final rule to prohibit installation of a composite gray water drain mast, unless a bonding jumper is also installed, as specified in paragraph (g) of this AD. We have also re-identified subsequent paragraphs accordingly. \n\nConclusion \n\n\tWe reviewed the relevant data, considered the comment 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\nCostsof Compliance \n\n\tThere are about 164 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\n\nWork hours\nAverage labor rate per hour\n\nParts\n\nCost per airplane\nNumber of U.S.-registered airplanes\n\nFleet cost\nInspection to determine gray water drain mast material\n1\n$80\nNone\n$80\n20\n$1,600\nInstallation of bonding jumper\n4 \n$80\nBetween $132 and $274, depending on kit and number of kits needed (1 or 2)\nBetween $452 and $594\nUp to 20\nBetween $9,040 and $11,880\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\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\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\n\t(1) Is not a "significant regulatory action" under Executive Order 12866, \n\n\t(2) Is not a "significant rule" under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979), and \n\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\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: