Discussion \n\n\n\tWe issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to include an AD that would apply to the specified products. That NPRM published in the Federal Register on February 8, 2012 (77 FR 6518). That NPRM proposed to require replacing the low-pressure oxygen hoses with non-conductive low-pressure oxygen hoses in the flight compartment. \n\nRelevant Service Information \n\n\n\tSince we issued the NPRM (77 FR 6518, February 8, 2012), Boeing has issued Alert Service Bulletin 777-35A0027, Revision 1, dated April 19, 2012. This service information was issued to remove airplanes from the effectivity that have had certain changes incorporated in production, update warranty information, and material price information. No additional work is necessary for airplanes changed in accordance with Boeing Alert Service Bulletin 777-35A0027, dated December 15, 2011. We have changed the final rule to reference Boeing Alert Service Bulletin777-35A0027, Revision 1, dated April 19, 2012. Additionally, we have updated the Costs of Compliance section of the final rule regarding the parts cost and warranty information. \n\nComments \n\n\n\tWe gave the public the opportunity to participate in developing this AD. The following presents the comments received on the proposal (77 FR 6518, February 8, 2012) and the FAA's response to each comment. \n\nSupport for the NPRM (77 FR 6518, February 8, 2012) \n\n\n\tThe Air Line Pilots Association (ALPA) stated it supports the NPRM (77 FR 6518, February 8, 2012). \n\nRequest To Shorten Compliance Time \n\n\n\tThe ALPA requested we shorten the compliance time for the replacement of the oxygen hoses from 18 months to 12 months. The commenter based this request on the impact that an oxygen fed fire on the flight deck would have on flight safety. \n\tWe disagree. In developing the proposed compliance time, we considered the safety implications, parts availability, and normal maintenance schedulesfor the timely accomplishment of replacement of the oxygen hoses. Further, the proposed compliance time is in keeping with the manufacturers' recommended compliance time. In consideration of all these factors, 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 not changed the AD in this regard. \n\nRequest To Increase Compliance Time \n\n\n\tUnited Airlines requested we increase the compliance time for the replacement of the oxygen hoses from 18 months to 24 months. The commenter stated that based on parts availability and its normal maintenance schedule, it believes that 24 months would be an appropriate interval for the timely accomplishment of the actions while maintaining an adequate level of safety. \n\tWe disagree with increasing the compliance time. As stated previously, in developing the proposed compliance time, we considered the safety implications, parts availability, and normal maintenance schedules for a timely accomplishment of replacement of the oxygen hoses. Further, the proposed compliance time is in keeping with the manufacturers' recommended compliance time. However, under the provisions of paragraph (i) of the final rule, we may approve requests for adjustments to the compliance time if data are submitted to substantiate that such an adjustment would provide an acceptable level of safety. We have not changed the AD in this regard. \n\nRequest To Add Applicability Language \n\n\n\tBoeing requested that we add language to paragraph (h) of the NPRM (77 FR 6518, February 8, 2012), stating that this paragraph applies only to any airplane ''affected by this AD.'' \n\tWe do not agree with the commenter's request. The applicability statement in all AD actions lists all airplanes affected by that AD. All of the requirements stated in an AD are applicable only to the airplanes listed in the applicability. We find no justification for making the requested change. We have not changed the AD in this regard. \n\nRequest for Clarification of Parts Installation Requirement \n\n\n\tAmerican Airlines (American) requested clarification of the requirement in paragraph (h) of the NPRM (77 FR 6518, February 8, 2012) that prohibits installing certain oxygen hoses after the effective date of the AD. American stated that the compliance time of paragraph (h) of the NPRM is prior to the compliance date of the low-pressure oxygen hose removal, and if a maintenance procedure is accomplished which would require the removal of the low-pressure oxygen hose, the same low-pressure oxygen hose cannot be re-installed. \n\tWe agree to clarify the requirement. Once we have determined that an unsafe condition exists, we generally specify not to allow that condition to be introduced into the fleet. Although the word ''install'' is generally considered to be broader than the word ''replace,'' for this AD operators can interpret it as meaning ''replace'' while remaining within the intent of the ''Parts Installation'' paragraph (paragraph (h) of this AD). By simply reinstalling a part removed during maintenance, the operator is not ''installing'' a different part. Therefore, removing a part to gain access and then reinstalling that same part for other maintenance activities not associated with the AD is acceptable. We have not changed the AD in this regard. \n\nConclusion \n\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. \n\tWe 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\n\tWe estimate that this AD affects 169 airplanes of U.S. registry. \n\tWe estimate the following costs to comply with this AD: \n\n\n\tEstimated Costs ---------------------------------------------------------------------------------------------------------------- \n\tCost per Cost on U.S. \n\tAction Labor cost Parts cost product operators ---------------------------------------------------------------------------------------------------------------- Replacement......................... 18 work-hours x $85 per $1,066 $2,596 $438,724 \n\thour = $1,530. ---------------------------------------------------------------------------------------------------------------- \n\n\n\n((Page 41047)) \n\n\n\tAccording to the manufacturer, some of the costs of this AD may be covered under warranty, thereby reducing the cost impact on affected individuals. We do not control warranty coverage for affected individuals. As a result, we have included all costs in our cost estimate. \n\nAuthority for This Rulemaking \n\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\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\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), \n\t(3) Will not affect intrastate aviation in Alaska, and \n\t(4) 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\nList of Subjects in 14 CFR Part 39 \n\n\n\tAir transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.