Comments Invited The FAA invites you to send any written data, views, or arguments about this final rule. Send your comments using a method listed under the ADDRESSES section. Include Docket No. FAA-2026-1332 and Project Identifier AD-2026-00084-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. Except 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 regulations.gov , including any personal information you provide. The agency will also post a report summarizing each substantive verbal contact received about this final rule. Confidential Business Information CBI 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 Derrick Herrera, Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 817-222-5140; email: derrick.r.herrera@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. Background The FAA has received two reports of in-flight events of excessive cabin and flight deck temperatures that could not be controlled by the flightcrew using existing procedures. An investigation found these events resulted from the BAT BUS SECT 2 circuit breaker (CB3062) on the SPCU tripping. The SPCU gives automatic and manual control of the battery and standby buses. The BAT BUS SECT 2 provides power to air conditioning and cabin pressure functions, including the left and right pack flow control valve solenoids (On/Off), left and right pack overheat protection circuits, zone supply duct overheat protection circuits, and cabin pressure manual mode control. The BAT BUS SECT 2 circuit breaker trip causes an unintended erroneous electrical ground signal to the smart ram air door actuators (SRADAs), which in turn causes both ram air deflector doors to extend (close), thus reducing cooling airflow to the air conditioning heat exchangers. The reduced airflow causes insufficient cooling of the hot bleed air, which causes both packs to supply excessively hot air to the cabin and flight deck. This air conditioning system malfunction could cause an uncontrollable, excessively high temperature in the cabin and flight deck. This condition, if not addressed, could lead to injury or incapacitation of flightcrew and passengers, which could result in the inability to maintain safe flight and landing. The FAA is issuing this AD to address the unsafe condition on these products. Explanation of Existing AFM Procedures and Procedures Required by This AD This AD provides flightcrew procedures for a controlled descent, an attempt to reset the tripped BAT BUS SECT 2 circuit breaker and, if that attempt is unsuccessful, selecting engine bleed switches OFF. This AD includes three AFM procedures, one of which is revised (Cabin Temperature Hot procedure) as shown in Appendix 1 of this AD, another of which is new (Cabin Temperature Hot BAT BUS Sect 2 Circuit Breaker Trips procedure) as shown in Appendix 2 of this AD, and the other procedure currently exists in the quick reference handbook (QRH) but not in the existing AFM (PACK procedure) as shown in Appendix 3. FAA's Determination The 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. AD Requirements This AD requires revising the Operating Procedures section of the existing AFM to provide the flightcrew with non-normal checklists if the BAT BUS SECT 2 circuit breaker in the SPCU trips. Interim Action The FAA considers this AD to be an interim action. An assessment of the SPCU found that two environmental control system (ECS) circuit breakers (C262 and C263) downstream of the SPCU may also trip. The FAA is considering further rulemaking to provide flightcrew procedures for addressing tripped ECS circuit breakers. Additionally, the manufacturer is currently developing a modification to address the unsafe condition identified in this AD. Once this modification is developed, FAA-approved, and available, the FAA might consider additional rulemaking. Justification for Immediate Adoption and Determination of the Effective Date Section 553(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. An 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 a tripped BAT BUS SECT 2 circuit breaker, and resulting effects on the cabin environment that cannot be controlled via normal procedures, could lead to injury or incapacitation of flightcrew and passengers, which could result in the inability to maintain safe flight and landing. Additionally, the compliance time in this AD is shorter than the time necessary for the public to comment and for publication of the final rule. Accordingly, notice and opportunity for prior public comment are impracticable and contrary to the public interest pursuant to 5 U.S.C. 553(b). In 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. Regulatory Flexibility Act The 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. Costs of Compliance The FAA estimates that this AD affects 771 airplanes of U.S. registry. The FAA estimates the following costs to comply with this AD: Estimated Costs Action Labor cost Parts cost Cost per product Cost on U.S. operators AFM Revision 1 work-hour × $85 per hour = $85 $0 $85 $65,535 Authority for This Rulemaking Title 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. The 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. Regulatory Findings 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. For the reasons discussed above, I certify that this AD: (1) Is not a "significant regulatory action" under Executive Order 12866, and (2) Will not affect intrastate aviation in Alaska. List of Subjects in 14 CFR Part 39 Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety. The Amendment Accordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows: PART 39-AIRWORTHINESS DIRECTIVES 1. The authority citation for part 39 continues to read as follows: Authority: 49 U.S.C. 106(g), 40113, 44701. § 39.13 [Amended] 2. The FAA amends § 39.13 by adding the following new airworthiness directive: 2026-04-05 The Boeing Company: Amendment 39-23265; Docket No. FAA-2026-1332; Project Identifier AD-2026-00084-T. (a) Effective Date This airworthiness directive (AD) is effective February 24, 2026. (b) Affected ADs None. (c) Applicability This AD applies to all The Boeing Company Model 737-8, 737-9, and 737-8200 airplanes, certificated in any category. (d) Subject Air Transport Association (ATA) of America Code 24, Electrical Power. (e) Unsafe Condition This AD was prompted by reports of in-flight events of excessive cabin and flight deck temperatures that could not be controlled by the flightcrew using existing procedures. The FAA is issuing this AD to address a tripped BAT BUS SECT 2 circuit breaker that could lead to an air conditioning system malfunction causing an uncontrollable, excessively high temperature in the cabin and flight deck. The unsafe condition, if not addressed, could lead to injury or incapacitation of flightcrew and passengers, which could result in the inability to maintain safe flight and landing. (f) Compliance Comply with this AD within the compliance times specified, unless already done. (g) Revision of Existing Airplane Flight Manual (AFM) Within 30 days after the effective date of this AD, revise the Operating Procedures section of the existing AFM to include the information specified in appendices 1 through 3 of this AD. This may be done by inserting a copy of appendices 1 through 3 of this AD into the AFM. (h) Alternative Methods of Compliance (AMOCs) (1) The Manager, AIR-520, Continued Operational Safety Branch, FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. In accordance with 14 CFR 39.19, send your request to your principal inspector or responsible Flight Standards Office, as appropriate. If sending information directly to the manager of the certification office, send it to the attention of the person identified in paragraph (i) of this AD. Information may be emailed to: AMOC@faa.gov . Before using any approved AMOC, notify your appropriate principal inspector, or lacking a principal inspector, the manager of the responsible Flight Standards Office. (2) An AMOC that provides an acceptable level of safety may be used for any repair, modification, or alteration required by this AD if it is approved by The Boeing Company Organization Designation Authorization (ODA) that has been authorized by the Manager, AIR-520, Continued Operational Safety Branch, FAA, to make those findings. To be approved, the repair method, modification deviation, or alteration deviation must meet the certification basis of the airplane, and the approval must specifically refer to this AD. (i) Additional Information For more information about this AD, contact Derrick Herrera, Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 817-222-5140; email: derrick.r.herrera@faa.gov (j) Material Incorporated by Reference None. BILLING CODE 4910-13-P Appendix 1 of AD 2026-04-05-Cabin Temperature Hot Procedure ER24FE26.000 ER24FE26.001 ER24FE26.002 ER24FE26.003 Appendix 2 to AD 2026-04-05-Cabin Temperature Hot BAT BUS SECT 2 Circuit Breaker Trips Procedure ER24FE26.004 ER24FE26.005 ER24FE26.006 Appendix 3 of AD 2026-04-05-PACK Procedure ER24FE26.007 ER24FE26.008 ER24FE26.009 Issued on February 17, 2026. Lona C. Saccomando, Acting Deputy Director, Integrated Certificate Management Division, Aircraft Certification Service.