Background \n\n\n\tThe FAA has received a report of a water supply line that detached above an EE cooling filter, leading to water intrusion into the forward EE bay, on a Model 777F series airplane with 34,000 total flight hours and 6,000 total flight cycles. \n\tDuring potable water servicing on ground, the operator received multiple messages appearing on the engine indication and crew alert system (EICAS) indicating multiple affected EE line replaceable units (LRUs). Further investigation revealed that the location of a joint on a swaged end fitting ferrule of a corrosion resistant stainless steel (CRES) water supply line had become partially or fully detached from the tube, causing water to spill onto an EE cooling filter (directly below the fitting) in the left-hand sidewall at station (STA) 571. The amount and duration of the water spillage are unknown. The cooling filter became saturated with the water, which was then blown via the EE cooling system into multiple EE LRUs located in the EE bay. \n\tWater that has been ingested or has entered into the EE cooling system via the cooling filter can be circulated to multiple EE racks and can accumulate on the LRUs, particularly where forced air cooling occurs. Water ingress to these LRUs can affect multiple EE bay racks and LRUs, resulting in loss of functionality or inaccurate output of critical electrical systems and possible loss of control of the airplane. The FAA is issuing this AD to address the unsafe condition on these products. \n\tModel 777F series airplanes line numbers (L/Ns) 960 and subsequent have a joint at this location from the factory-installed CRES tube assembly. Boeing released Service Bulletin 777-38-0042 as an economic service bulletin providing operators with airplanes prior to L/N 960 instructions to retrofit to this configuration at their discretion. Therefore, this AD will require deactivation of the potable water system for all 777F with this joint installed either in production or through performance of Boeing SB 777-38-0042. \n\nFAA's Determination \n\n\n\tThe FAA is issuing this AD because the agency has determined the unsafe condition described previously is likely to exist or develop in other products of the same type design. \n\nRelated Service Information Under 1 CFR Part 51 \n\n\n\tThe FAA reviewed Boeing MOM-MOM-21-0089-01B, dated February 26, 2021. This service information specifies procedures for deactivating the potable water system. This service information is reasonably available because the interested parties have access to it through their normal course of business or by the means identified in the ADDRESSES section. \n\nAD Requirements \n\n\n\tThis AD requires accomplishing the actions specified in the service information already described, except as discussed under ''Differences Between this AD and the Service Information.'' This AD also prohibits the future accomplishment of the actions specified in Boeing Service Bulletin 777-38-0042. \n\nDifference Between This AD and the Service Information \n\n\n\tBoeing MOM-MOM-21-0089-01B, dated February 26, 2021, specifies one Safety Action and six Recommended Actions. Although the FAA recommends accomplishment of all of these actions, this AD requires only deactivation of the potable water system, as specified in the Safety Action of the service information. \n\nInterim Action \n\n\n\tThe FAA considers this AD to be an interim action. The manufacturer is currently developing a 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\nJustification for Immediate Adoption and Determination of the Effective Date \n\n\n\tSection 553(b)(3)(B) of the Administrative Procedure Act (APA) (5 U.S.C. 551 et seq.) authorizes agencies to dispense with notice and comment procedures for rules when the agency, for ''good cause,'' finds that those procedures are ''impracticable, unnecessary, or contrary to the public interest.'' Under this section, an agency, upon finding good cause, may issue a final rule without providing notice and seeking comment prior to issuance. Further, section 553(d) of the APA authorizes agencies to make rules effective in less than thirty days, upon a finding of good cause. \n\tAn unsafe condition exists that requires the immediate adoption of this AD without providing an opportunity for public comments prior to adoption. The FAA has found that the risk to the flying public justifies forgoing notice and comment prior to adoption of this rule because water that has entered the EE cooling system via the cooling filter can affect multiple EE bay racks and LRUs, resulting in loss of functionality or inaccurate output of critical electrical systems and possible loss of control of the airplane. Accordingly, notice and opportunity for prior public comment are impracticable and contrary to the public interest pursuant to 5U.S.C. 553(b)(3)(B). \n\tIn addition, the FAA finds that good cause exists pursuant to 5 U.S.C. 553(d) for making this amendment effective in less than 30 days, for the same reasons the FAA found good cause to forgo notice and comment. \n\nComments Invited \n\n\n\tThe FAA invites you to send any written data, views, or arguments about this final rule. Send your comments to an address listed under ADDRESSES. Include Docket No. FAA-2021-0133 and Project Identifier AD- 2021- 00234-T at the beginning of your comments. The most helpful comments reference a specific portion of the final rule, explain the reason for any recommended change, and include supporting data. The FAA will consider all comments received by the closing date and may amend this final rule because of those comments. \n\tExcept for Confidential Business Information (CBI) as described in the following paragraph, and other information as described in 14 CFR 11.35, the FAA will post all comments received, without change, to https://www.regulations.gov, including any personal information you provide. The agency will also post a report \n\n((Page 12811)) \n\nsummarizing each substantive verbal contact received about this final rule. \n\nConfidential Business Information \n\n\n\tCBI is commercial or financial information that is both customarily and actually treated as private by its owner. Under the Freedom of Information Act (FOIA) (5 U.S.C. 552), CBI is exempt from public disclosure. If your comments responsive to this AD contain commercial or financial information that is customarily treated as private, that you actually treat as private, and that is relevant or responsive to this AD, it is important that you clearly designate the submitted comments as CBI. Please mark each page of your submission containing CBI as ''PROPIN.'' The FAA will treat such marked submissions as confidential under the FOIA, and they will not be placed in the public docket of this AD. Submissions containing CBI should be sent to Courtney Kronenberger, Aerospace Engineer, Cabin Safety and Environmental Systems Section, FAA, Seattle ACO Branch, 2200 South 216th St., Des Moines, WA 98198; phone and fax: 206-231-3986; email: Courtney.A.Kronenberger@faa.gov. Any commentary that the FAA receives that is not specifically designated as CBI will be placed in the public docket for this rulemaking. \n\nRegulatory Flexibility Act \n\n\n\tThe requirements of the Regulatory Flexibility Act (RFA) do not apply when an agency finds good cause pursuant to 5 U.S.C. 553 to adopt a rule without prior notice and comment. Because the FAA has determined that it has good cause to adopt this rule without notice and comment, RFA analysis is not required. \n\nCosts of Compliance \n\n\n\tThe FAA estimates that this AD affects 58 airplanes of U.S. registry. The FAA estimates 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 ---------------------------------------------------------------------------------------------------------------- Deactivation of potable water system.. 2 work-hours x $85 per $0 $170 $9,860 \n\thour = $170. ---------------------------------------------------------------------------------------------------------------- \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\tThe FAA is 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, and \n\t(2) Will not affect intrastate aviation in Alaska. \n\nList of Subjects in 14 CFR Part 39 \n\n\n\tAir transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.