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-2025-3433; Project Identifier MCAI-2025-01302-Q” 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.

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 George Weir, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590. Any commentary that the FAA receives which is not specifically designated as CBI will be placed in the public docket for this rulemaking.

The FAA issued AD 2025-11-10, Amendment 39-23056 (90 FR 23269, June 2, 2025) (AD 2025-11-10), to correct an unsafe condition on hot air balloons with Cameron fuel cylinders fitted with PRV adaptor part number (P/N) CB8426. AD 2025-11-10 was prompted by an MCAI originated by the Civil Aviation Authority (CAA), which is the airworthiness authority for the United Kingdom (UK). The UK CAA issued Emergency AD G-2025-0001R1-E, dated April 11, 2025, (CAA UK Emergency AD G-2025-0001R1-E) to correct an unsafe condition identified as cracks on the upper hex portion of PRV adaptors. AD 2025-11-10 required repetitively visually checking the fuel cylinder PRV adaptor for cracks, reporting any findings of a crack, and removing any fuel cylinder with a cracked PRV adaptor from service. A cracked PRV adaptor could lead to uncontrolled leakage of liquefied petroleum gas (LPG), which could result in an in-flight fire and consequent emergency landing. The FAA issued AD 2025-11-10 to address the unsafe condition on these products.

Since the FAA issued AD 2025-11-10, the UK CAA superseded CAA UK Emergency AD G-2025-0001R1-E and issued CAA UK Emergency AD G-2025-0004-E, dated August 1, 2025 (CAA UK Emergency AD G-2025-0004-E) (also referred to as the MCAI). The MCAI states that after an examination of 10 additional failed components and subsequent metallurgical analysis, a new replacement PRV adaptor was introduced into service to better address the unsafe condition. The MCAI requires repetitively visually checking the fuel cylinder PRV adaptor for cracks, removal from service of any fuel cylinder with a cracked PRV adaptor, and replacement of the PRV adaptor as terminating action for the repetitive checks. This condition, if not addressed, could lead to uncontrolled leakage of LPG, which could result in an in-flight fire and consequent emergency landing.

You may examine the MCAI in the AD docket at regulations.gov under Docket No. FAA-2025-3433.

These products have been approved by the civil aviation authority of another country and are approved for operation in the United States. Pursuant to the FAA's bilateral agreement with this State of Design Authority, that authority has notified the FAA of the unsafe condition described in the MCAI referenced above. The FAA is issuing this AD after determining that the unsafe condition described previously is likely to exist or develop on other products of the same type design.

This AD retains the repetitive check and removal requirements of AD 2025-11-10 and also requires replacement of the PRV adaptor as terminating action for the repetitive checks. The owner/operator (pilot) holding at least a private pilot certificate may perform the visual check and must enter compliance with the applicable paragraph(s) of the AD into the balloon maintenance records in accordance with 14 CFR 43.9(a) and 91.417(a)(2)(v). The pilot may perform this action because it only involves visually checking each PRV adaptor for cracks. This action could be performed equally well by a pilot or a mechanic. This is an exception to the FAA's standard maintenance regulations.

The MCAI applies to hot air balloons and certain airships. This AD only applies to hot air balloons because the airships identified in the MCAI do not have an FAA type certificate.

Although the MCAI specifies that if any fuel cylinder is found with a cracked PRV adaptor, it must be emptied of fuel prior to being removed from service, this AD does not require that action. While that action is encouraged for the general safety related to the leakage of LPG, it is not required to address the unsafe condition identified in this AD.

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 an LPG leak on the fuel cylinder could result in an in-flight fire or explosion, damaging the hot air balloon and leading to a forced emergency landing, which could injure balloon occupants and persons on the ground. 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.

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 FAA has determined that it has good cause to adopt this rule without prior notice and comment, RFA analysis is not required.

The FAA estimates that this AD affects 2,000 fuel cylinders installed on hot air balloons worldwide. The FAA estimates 100 hot air balloons of U.S. Registry may have an affected fuel cylinder installed.

The FAA estimates the following costs to comply with this AD:

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.

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.

Accordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows:

1. Section 157.23 of the Federal Energy Regulatory Commission's (Commission) regulations provides that, with respect to orders issued pursuant to sections 3 and 7(c) of the NGA  1 authorizing the construction of new natural gas transportation, export, or import facilities, no authorization to proceed with construction activities will be issued during the periods specified therein. In this final rule, the Commission amends its regulations to remove § 157.23 and modify § 153.4 to remove the reference to § 157.23. This action will advance the Commission's principal statutory mission under the Natural Gas Act “to encourage the orderly development of plentiful supplies of . . . natural gas at reasonable prices.”  2

2. On June 9, 2020, the Commission in Order No. 871  3 issued a final rule amending its regulations to add 18 CFR 157.23, precluding the issuance of authorizations to proceed with construction of projects authorized under sections 3 and 7(c) of the Natural Gas Act (NGA) during the period for filing requests for rehearing of initial orders, or while rehearing is pending. 4 Order No. 871 also revised § 153.4 of the Commission's regulations, which sets forth general requirements for NGA section 3 applications, to incorporate a cross-reference to § 157.23. The Commission issued Order No. 871 to address concerns raised in the then-pending appeal Allegheny Defense Project v. FERC   5 before the U.S. Court of Appeals for the District of Columbia Circuit (D.C. Circuit).

3. Following the issuance of Allegheny, in response to requests for clarification and rehearing of Order No. 871, the Commission in Order No. 871-A provided interested parties an opportunity to file initial and reply briefs on the arguments raised on rehearing and specific questions posed by the Commission. 6

4. After review of the briefs filed, the Commission in Order No. 871-B revised § 157.23 to provide that the rule prohibiting the issuance of construction authorizations pending rehearing would apply only when a request for rehearing raised issues reflecting opposition to project construction, operation, or need. 7 Order No. 871-B also revised § 157.23 to provide that the rule's restriction on issuing construction authorizations would expire, if no qualifying request or rehearing was filed or, if such a request was filed, when (1) the request was no longer pending ( i.e., it had been withdrawn or the Commission had acted on it), (2) the record of the proceeding was filed with the court of appeals, or (3) 90 days had passed from the date that the request might be deemed denied by operation of law under NGA section 19(a). 8 Finally, Order No. 871-B adopted a policy of presumptively staying, on a case-by-case basis where a pipeline developer has not already acquired all necessary property interests and where a landowner who would be subject to eminent domain proceedings protested, 9 an NGA section 7(c) certificate order during the 30-day period for seeking rehearing, and pending Commission resolution of any timely requests for rehearing filed by a landowner, until the earlier of the date on which the Commission (1) issues a substantive order on rehearing or otherwise indicates that the Commission will not take further action, or (2) 90 days following the date that a request for rehearing may be deemed to have been denied under NGA section 19(a). 10

5. In Order No. 871-C, the Commission addressed requests for rehearing and clarification of Order No. 871-B. 11 The Commission modified the discussion but did not change the outcome of Order No. 871-B. 12

6. On January 20, 2025, the President issued Executive Order 14154, seeking to eliminate delays in and streamline the permitting process for energy infrastructure projects, and noting that it is “in the national interest to unleash America's affordable and reliable energy and natural resources.”  13 On the same date, the President issued Executive Order 14156, which declares a national energy emergency and prioritizes the expansion of energy infrastructure as a matter of critical national and economic security. 14

7. On April 14, 2025, INGAA filed a petition for rulemaking requesting that the Commission adopt a rule rescinding Order No. 871, removing § 157.23 from the regulations, and amending § 153.4, which relates to applications to authorize liquefied natural gas facilities under NGA section 3, to remove the reference to § 157.23. 15 In its petition, INGAA argues that the stakeholder protections afforded by the D.C. Circuit's decision in Allegheny rendered the regulations promulgated under Order No. 871 unnecessary. 16 Specifically, INGAA maintains that Allegheny' s holding  17 protects stakeholders from the possibility that project construction may proceed before the completion of the Commission's review because that decision allows parties to “seek and receive a judicial stay of a certificate [or authorization] order as soon as 30 days after a request for rehearing” has been filed. 18 INGAA contends that the current Order No. 871 framework assumes that the Commission erred in authorizing a project. 19

8. Additionally, INGAA notes that when creating project schedules, project developers must work with contractors and vendors to set the timeframes to accommodate anticipated construction, material procurement, and environmental compliance requirements, as well as seasonal constraints. 20 It argues that Order No. 871's preemptive prohibition of the issuance of construction authorizations forces developers to account in their schedules for the maximum amount of time (150 days) that could be imposed as a result of a potential rehearing request, even where no eligible rehearing request is filed. 21 INGAA avers that Order No. 871 subjects project developers to unnecessary costs and construction delays regardless of whether developers account in advance for the potential delays which would be encountered should an eligible rehearing request be filed or fail to consider such potential delays and are forced to make last-minute schedule changes. 22

9. Further, INGAA claims that Order No. 871 increased the number of rehearing requests, that non-landowner parties have filed most of the rehearing requests since the promulgation of Order No. 871, and that the regulation has become a tool to delay authorized projects. 23 INGAA contends that the interests of project developers and landowners are unbalanced and that the burdens imposed on developers are not justified. 24 INGAA maintains that if the Commission rescinds Order No. 871 landowners will not be materially impacted because they would still have statutory and other regulatory protections, such as the ability to file with the Commission rehearing requests of certificate and authorization orders and motions to stay the certificate or authorization order, as well as to seek an emergency judicial stay of the certificate holder's exercise of eminent domain if needed. 25

10. Finally, INGAA states that rescinding Order No. 871 would be consistent with the Administration's priorities to develop reliable energy infrastructure. 26 INGAA argues that the Commission has previously proposed rules that are justified by federal policies established in prior Executive Orders. 27

11. On June 18, 2025, the Commission issued an order temporarily waiving § 157.23 for one year, until June 30, 2026 (Waiver Order). At the same time, the Commission issued a Notice of Proposed Rulemaking (NOPR), which proposed to permanently remove § 157.23 from its regulations and revise § 153.4 to eliminate the cross-reference to § 157.23. 28 The Commission proposed to remove § 157.23 to respond to the imperative to remove barriers to the construction of necessary energy infrastructure.

12. In the NOPR, the Commission noted its broad authority under NGA section 16  29 to rescind regulations as it finds appropriate to carry out the provisions of the NGA, and its statutory duties under NGA section 7(e) to issue certificates for proposed pipelines that are required by the present or future public convenience and necessity and under NGA section 3 to authorize import or export facilities unless such facilities are inconsistent with the public interest. 30

13. The Commission recognized that construction of natural gas infrastructure is a complex process and explained that, due to timing constraints and other outside factors effecting construction, a potential 150-day delay in the start of construction could cause further unforeseen delays that might jeopardize the availability of a project's capacity or reliability benefits within the timeframe when they are needed, which could frustrate the objectives of approved projects. 31 The Commission acknowledged that there is widespread recognition that adequate natural gas infrastructure is critical to meet the increasing natural gas and electric system demand, particularly during periods of high demand, and to ensure the reliability of both systems. 32 The Commission cited several reports analyzing projected growth in natural gas and electricity demand and the role of natural gas infrastructure in supporting reliability and demand, and executive actions that have also recognized resource adequacy and reliability concerns. 33

14. The Commission stated that the ruling in Allegheny provides safeguards to stakeholders' interests and ensures that parties may seek to halt the commencement of construction during the pendency of a rehearing request. 34 The Commission emphasized that it carefully considers and balances the alleged harms of a proposed project, including potential impacts to landowners and communities, against its benefits before issuing a certificate or authorization and that it will continue to consider whether additional protections are warranted in individual proceedings. 35

15. In addition to requesting public comments on the NOPR proposal to eliminate § 157.23 in its entirety, the Commission posed two specific questions. The Commission sought comment on whether it should instead revise § 157.23 to (1) limit its scope while maintaining some protections for certain types of stakeholders or (2) reduce the time period on the limitation for issuing authorizations to proceed with construction. 36

16. Several entities filed motions to intervene, without comment. 37 Comments on the NOPR were due July 24, 2025. In response to the NOPR, 23 comments were filed. The Commission received 11 comments from various individuals and organizations opposing the Commission's proposal to remove § 157.23;  38 and 12 comments from various entities supporting the removal of § 157.23. 39 We have considered these comments in developing this final rule.

17. Public Interest Organizations argue that the Waiver Order was, in essence, an improper rulemaking and that the NOPR offers a post-promulgation comment period and functions as an attempt to cure the Commission's failure to engage in notice and comment rulemaking prior to issuing that order. 40 They maintain that the Commission's contemporaneous issuance of the Waiver Order and the NOPR reflect the Commission's commitment to remove § 157.23 before soliciting public comment, and therefore, the Commission's rulemaking effort is fatally flawed. 41