AD 2025-21-01 ACTIVE

The FAA is superseding Airworthiness Directive (AD) 2025-11- 10, which applied to Cameron Balloons Ltd. (Cameron) fuel cylinders fitted with certain pressure relief valve (PRV) adaptors on hot air balloons. AD 2025-11-10 required repetitively visually checking the PRV adaptor for cracks and removing any fuel cylinder with a cracked PRV adaptor from service. Since the FAA issued AD 2025-11-10, a new replacement part was introduced into service. 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 FAA is issuing this AD to address the unsafe condition on these products.

Final rule; request for comments.

1. The authority citation for part 39 continues to read as follows: Authority: 49 U.S.C. 106(g), 40113, 44701. 2. The FAA amends § 39.13 by: a. Removing Airworthiness Directive 2025-11-10, Amendment 39-23056 (90 FR 23269, June 2, 2025); and b. Adding the following new airworthiness directive: 2025-21-01 Cameron Balloons Ltd.: Amendment 39-23173; Docket No. FAA-2025-3433; Project Identifier MCAI-2025-01302-Q. (a) Effective Date This airworthiness directive (AD) is effective October 27, 2025. (b) Affected ADs This AD replaces AD 2025-11-10, Amendment 39-23056 (90 FR 23269, June 2, 2025) (AD 2025-11-10). (c) Applicability (1) This AD applies to all hot air balloons, certificated in any category, with a fuel cylinder installed that is fitted with Cameron Balloons Ltd. pressure relief valve (PRV) adaptor part number (P/N) CB8426. Note 1 to paragraph (c)(1): Cameron Balloons Alert Service Bulletin No. 36, Revision 2, dated July 3, 2025, provides information related to this AD, including fuel cylinders that may be fitted with PRV adaptor P/N CB8426. (2) These fuel cylinders are installed on hot air balloon models including, but not limited to, those of the design approval holders identified in paragraphs (c)(2)(i) through (viii) of this AD. (i) Adams Aerostats LLC. (ii) Aerostar International Inc. (iii) Ballonbau Wörner GmbH. (iv) Cameron Balloons Ltd. (v) Eagle Balloons Corp. (vi) JR Aerosports, Ltd. (vii) Kubí?ek Factory s.r.o. (formerly Balóny Kubí?ek spol. s.r.o.). (viii) Lindstrand Balloons Ltd. (d) Subject Joint Aircraft System Component (JASC) Code 2800, Aircraft Fuel System. (e) Unsafe Condition This AD was prompted by cracks on the upper hex portion of PRV adaptors installed on certain Cameron Balloons Ltd. fuel cylinders. The FAA is issuing this AD to address failure of a PRV adaptor. This condition, if not addressed, could lead to uncontrolled leakage of liquefied petroleum gas, which could result in an in-flight fire and consequent emergency landing. (f) Compliance Comply with this AD within the compliance times specified, unless already done. (g) Required Actions (1) Before further flight after the effective date of this AD and thereafter before each flight, visually check the fuel cylinder PRV adaptor for any cracks. (2) The owner/operator (pilot) holding at least a private pilot certificate may perform the visual checks required by paragraph (g)(1) of this AD and must enter compliance with the applicable paragraph of this AD into the balloon maintenance records in accordance with 14 CFR 43.9(a) and 91.417(a)(2)(v). The record must be maintained as required by 14 CFR 91.417, 121.380, or 135.439. (3) Replace the fuel cylinder PRV adaptor with a fuel cylinder PRV adaptor having P/N CB7922 at whichever compliance time in paragraph (g)(3)(i) or (ii) occurs first. (i) Before further flight if any crack is found during any visual check required by paragraph (g)(1) of this AD. (ii) At or before the next scheduled periodic PRV inspection. (4) The replacement required by paragraph (g)(3) of this AD terminates the repetitive visual check requirement of paragraph (g)(1) of this AD. (h) Special Flight Permits Special flight permits are prohibited. (i) Alternative Methods of Compliance (AMOCs) The Manager, International Validation 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 local Flight Standards District Office, as appropriate. If sending information directly to the manager of the International Validation Branch, send it to the attention of the person identified in paragraph (j)(1) of this AD and email to AMOC@faa.gov . Before using any approved AMOC, notify your appropriate principal inspector, or lacking a principal inspector, the manager of the local flight standards district office/certificate holding district office. (j) Additional Information (1) For more information about this AD, contact George Weir, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (817) 222-4045; email: george.a.weir@faa.gov . (2) For material identified in this AD that is not incorporated by reference, contact Cameron Balloons Ltd., St John Street, Bedminster, Bristol, BS3 4NH, United Kingdom; phone: +44 0 117 9637216; email: technical@cameronballoons.co.uk ; website: cameronballoons.co.uk . (k) Material Incorporated by Reference None. Issued on October 7, 2025. Steven W. Thompson, Acting Deputy Director, Compliance & Airworthiness Division, Aircraft Certification Service. [FR Doc. 2025-19532 Filed 10-9-25; 8:45 am]BILLING CODE 4910-13-P

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-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. 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 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. Background 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. Actions Since AD 2025-11-10 Was Issued 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. FAA's Determination 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. AD Requirements 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. Differences Between This AD and the MCAI 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. 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 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. 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 FAA has determined that it has good cause to adopt this rule without prior notice and comment, RFA analysis is not required. Costs of Compliance 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: Estimated Costs Action Labor cost Parts cost Cost per product Cost on U.S. operators Visually check fuel cylinder PRV adaptor 1 work-hour × $85 per hour = $85 (per visual check) $0 $85 (per visual check) $8,500 (per visual check). Replace fuel cylinder PRV adaptor 2 work-hours × $85 per hour = $170 29 199 19,900. 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: a. Removing Airworthiness Directive 2025-11-10, Amendment 39-23056 (90 FR 23269, June 2, 2025); and b. Adding the following new airworthiness directive: 2025-21-01 Cameron Balloons Ltd.: Amendment 39-23173; Docket No. FAA-2025-3433; Project Identifier MCAI-2025-01302-Q. (a) Effective Date This airworthiness directive (AD) is effective October 27, 2025. (b) Affected ADs This AD replaces AD 2025-11-10, Amendment 39-23056 (90 FR 23269, June 2, 2025) (AD 2025-11-10). (c) Applicability (1) This AD applies to all hot air balloons, certificated in any category, with a fuel cylinder installed that is fitted with Cameron Balloons Ltd. pressure relief valve (PRV) adaptor part number (P/N) CB8426. Note 1 to paragraph (c)(1): Cameron Balloons Alert Service Bulletin No. 36, Revision 2, dated July 3, 2025, provides information related to this AD, including fuel cylinders that may be fitted with PRV adaptor P/N CB8426. (2) These fuel cylinders are installed on hot air balloon models including, but not limited to, those of the design approval holders identified in paragraphs (c)(2)(i) through (viii) of this AD. (i) Adams Aerostats LLC. (ii) Aerostar International Inc. (iii) Ballonbau Wörner GmbH. (iv) Cameron Balloons Ltd. (v) Eagle Balloons Corp. (vi) JR Aerosports, Ltd. (vii) Kubí?ek Factory s.r.o. (formerly Balóny Kubí?ek spol. s.r.o.). (viii) Lindstrand Balloons Ltd. (d) Subject Joint Aircraft System Component (JASC) Code 2800, Aircraft Fuel System. (e) Unsafe Condition This AD was prompted by cracks on the upper hex portion of PRV adaptors installed on certain Cameron Balloons Ltd. fuel cylinders. The FAA is issuing this AD to address failure of a PRV adaptor. This condition, if not addressed, could lead to uncontrolled leakage of liquefied petroleum gas, which could result in an in-flight fire and consequent emergency landing. (f) Compliance Comply with this AD within the compliance times specified, unless already done. (g) Required Actions (1) Before further flight after the effective date of this AD and thereafter before each flight, visually check the fuel cylinder PRV adaptor for any cracks. (2) The owner/operator (pilot) holding at least a private pilot certificate may perform the visual checks required by paragraph (g)(1) of this AD and must enter compliance with the applicable paragraph of this AD into the balloon maintenance records in accordance with 14 CFR 43.9(a) and 91.417(a)(2)(v). The record must be maintained as required by 14 CFR 91.417, 121.380, or 135.439. (3) Replace the fuel cylinder PRV adaptor with a fuel cylinder PRV adaptor having P/N CB7922 at whichever compliance time in paragraph (g)(3)(i) or (ii) occurs first. (i) Before further flight if any crack is found during any visual check required by paragraph (g)(1) of this AD. (ii) At or before the next scheduled periodic PRV inspection. (4) The replacement required by paragraph (g)(3) of this AD terminates the repetitive visual check requirement of paragraph (g)(1) of this AD. (h) Special Flight Permits Special flight permits are prohibited. (i) Alternative Methods of Compliance (AMOCs) The Manager, International Validation 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 local Flight Standards District Office, as appropriate. If sending information directly to the manager of the International Validation Branch, send it to the attention of the person identified in paragraph (j)(1) of this AD and email to AMOC@faa.gov . Before using any approved AMOC, notify your appropriate principal inspector, or lacking a principal inspector, the manager of the local flight standards district office/certificate holding district office. (j) Additional Information (1) For more information about this AD, contact George Weir, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (817) 222-4045; email: george.a.weir@faa.gov . (2) For material identified in this AD that is not incorporated by reference, contact Cameron Balloons Ltd., St John Street, Bedminster, Bristol, BS3 4NH, United Kingdom; phone: +44 0 117 9637216; email: technical@cameronballoons.co.uk ; website: cameronballoons.co.uk . (k) Material Incorporated by Reference None. Issued on October 7, 2025. Steven W. Thompson, Acting Deputy Director, Compliance & Airworthiness Division, Aircraft Certification Service.

You may send comments, using the procedures found in 14 CFR 11.43 and 11.45, by any of the following methods: - Federal eRulemaking Portal: Go to regulations.gov. Follow the instructions for submitting comments. - Fax: (202) 493-2251. - Mail: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590. - Hand Delivery: Deliver to Mail address above between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. AD Docket: You may examine the AD docket at regulations.gov under Docket No. FAA-2025-3433; or in person at Docket Operations between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this final rule, the mandatory continuing airworthiness information (MCAI), any comments received, and other information. The street address for Docket Operations is listed above.

George Weir, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (817) 222-4045; email: george.a.weir@faa.gov .