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-2025-3996; Project Identifier MCAI-2025-01201-R" 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 Kurt Ladendorf, 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 2025-06-51, Amendment 39-23007 (90 FR 15310, April 10, 2025) (AD 2025-06-51), which was originally published as an Emergency AD dated March 21, 2025, for Bell Model 505 helicopters, serial numbers 65011 and subsequent with ballast kit part number (P/N) SLS-706-201-007 installed. AD 2025-06-51 was prompted by an MCAI originated by Transport Canada, which is the aviation authority for Canada. Transport Canada issued Emergency AD CF-2025-17, dated March 19, 2025, (Transport Canada Emergency AD CF-2025-17) to correct an unsafe condition identified as deformation and improper pin engagement in the knuckles of the door hinge on the aft movable ballast box assembly, which could allow the ballast weights to escape the ballast box and strike the tail rotor assembly. AD 2025-06-51 required removing all ballast weights from the aft movable ballast box assembly and prohibited the use of ballast weights within the aft movable ballast box assembly. The FAA issued AD 2025-06-51 to prevent damage and departure of tail rotor blades, loss of tail rotor thrust, and severe vibrations. The unsafe condition, if not addressed, could result in loss of control of the helicopter. Actions Since AD 2025-06-51 Was Issued Since the FAA issued AD 2025-06-51, Transport Canada superseded Transport Canada Emergency AD CF-2025-17 and issued Transport Canada AD CF-2025-35, dated July 4, 2025 (Transport Canada AD 2025-35) (also referred to as the MCAI). The MCAI states the manufacturer has developed a modification to the ballast box door assembly which provides a terminating action for the prohibition from using ballast weights within the aft movable ballast box assembly. Also, the MCAI corrects an error in the ballast kit part number in the applicability section. The correct part number for the movable ballast kit is P/N SLS-706-201-001, instead of the aft movable ballast box assembly P/N SLS-706-201-007. The preamble to AD 2025-06-51 explained that the FAA considered the requirements "interim action" and was considering further rulemaking. The FAA has now determined that further rulemaking is indeed necessary, and this AD follows from that determination. You may examine the MCAI in the AD docket at regulations.gov under Docket No. FAA-2025-3996. Material Incorporated by Reference Under 1 CFR Part 51 The FAA reviewed Transport Canada AD CF 2025-35, which specifies procedures for removing all ballast weights (P/N SLS-706-201-001) from the aft movable ballast box assembly (P/N SLS-706-201-007) and prohibits the use of ballast weights within the aft movable ballast box assembly. Transport Canada AD CF2025-35 also specifies installing a modification to the hinge of the aft movable ballast box door, by including a longer two-inch hinge assembly and adjusting the thickness of the rubber pad of the door assembly, which constitutes a terminating action for the prohibition of using ballast weights within the aft movable ballast box assembly. This material 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. FAA's Determination These products have been approved by the civil aviation authority (CAA) 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 requires accomplishing the actions specified Transport Canada CF-2025-35, described previously, as incorporated by reference, except for any differences identified as exceptions in the regulatory text of this AD. This includes requiring the actions of AD 2025-06-51 until the terminating action is done. The owner/operator (pilot) holding at least a private pilot certificate may revise the existing rotorcraft flight manual (RFM) by inserting the flight manual supplement, which contains procedures when the Movable Ballast Kit (SLS-706-201) is installed, and must enter compliance with the applicable paragraph(s) of the AD into the helicopter maintenance records in accordance with 14 CFR 43.9(a) and 91.417(a)(2)(v). The pilot may perform these actions because they only involve revising the existing RFM for the helicopter. These actions could be performed equally well by a pilot or a mechanic. This is an exception to the FAA's standard maintenance regulations. Explanation of Required Compliance Information In the FAA's ongoing efforts to improve the efficiency of the AD process, the FAA developed a process to use some CAA ADs as the primary source of information for compliance with requirements for corresponding FAA ADs. The FAA has been coordinating this process with manufacturers and CAAs. As a result, Transport Canada AD CF-2025-35 is incorporated by reference in this AD. This AD requires compliance with Transport Canada AD CF-2025-35 in its entirety through that incorporation, except for any differences identified as exceptions in the regulatory text of this AD. Material required by Transport Canada AD CF-2025-35 for compliance will be available at regulations.gov under Docket No. FAA-2025-3996 after this AD is published. 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 ballast weights escaping the ballast box have a high potential of striking the tail rotor assembly, which could result in damage and departure of tail rotor blades, loss of tail rotor thrust, and severe vibrations; these conditions will result in loss of control of the helicopter. Installing the modification is required to restore the full function of the helicopter and allow the safe usage of ballast weights. The FAA is mandating this fix because it is essential for ensuring the safety of all operations and to fully address the unsafe condition on these helicopters. 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 174 helicopters 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 Remove ballast weights from service .5 work-hour × $85 per hour = $43 $0 $43 $7,482 Modify ballast box 2.5 work-hours × $85 per hour = $213 300 513 89,262 Revise the RFM 1 work-hour × $85 per hour = $85 0 85 14,790 The FAA has included all known costs in its cost estimate. According to the manufacturer, however, some of the costs of this AD may be covered under warranty, thereby reducing the cost impact on affected operators. 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 2025-06-51, Amendment 39-23007 (90 FR 15310, April 10, 2025); and b. Adding the following new airworthiness directive: 2025-22-03 Bell Textron Canada Limited: Amendment 39-23181; Docket No. FAA-2025-3996; Project Identifier MCAI-2025-01201-R. (a) Effective Date This airworthiness directive (AD) is effective November 20, 2025. (b) Affected ADs This AD replaces AD 2025-06-51, Amendment 39-23007 (90 FR 15310, April 10, 2025). (c) Applicability This AD applies to Bell Textron Canada Limited Model 505 helicopters, certificated in any category, as identified in Transport Canada AD CF-2025-35, dated July 4, 2025 (Transport Canada AD CF-2025-35). (d) Subject Joint Aircraft System Component (JASC) Code 2500, Equipment/Furnishings. (e) Unsafe Condition This AD was prompted by deformation and improper pin engagement in the knuckles of the door hinge on the aft movable ballast box assembly, which could allow the ballast weights to escape the ballast box and strike the tail rotor assembly. The FAA is issuing this AD to prevent damage and departure of tail rotor blades, loss of tail rotor thrust, and severe vibrations. The unsafe condition, if not addressed, could result in loss of control of the helicopter. (f) Compliance Comply with this AD within the compliance times specified, unless already done. (g) Required Actions (1) Except as specified in paragraph (h) of this AD: Comply with all required actions and compliance times specified in, and in accordance with, Transport Canada AD CF-2025-35. (2) For this AD, the owner/operator (pilot) holding at least a private pilot certificate may revise the existing rotorcraft flight manual (RFM) for the helicopter by inserting the applicable flight manual supplement into the RFM and must enter compliance into the helicopter 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. (h) Exception to Transport Canada AD CF-2025-35 (1) Where Transport Canada AD CF-2025-35 refers to its effective date, this AD requires using the effective date of this AD. (2) Where Transport Canada AD CF-2025-35 refers to air time, this AD requires using hours time-in-service. (i) Special Flight Permits Special flight permits are prohibited. (j) Alternative Methods of Compliance (AMOCs) (1) 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 (k) of this AD and email to: AMOC@faa.gov. (2) 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. (k) Additional Information For more information about this AD, contact Kurt Ladendorf, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (817) 222-5254; email: kurt.d.ladendorf@faa.gov. (l) Material Incorporated by Reference (1) The Director of the Federal Register approved the incorporation by reference of the material listed in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51. (2) You must use this material as applicable to do the actions required by this AD, unless the AD specifies otherwise. (i) Transport Canada AD CF-2025-35, dated July 4, 2025. (ii) [Reserved] (3) For Transport Canada material identified in this AD, contact Transport Canada, Transport Canada National Aircraft Certification, 159 Cleopatra Drive, Nepean, Ontario K1A 0N5, Canada; phone: (888) 663-3639; email: TC.AirworthinessDirectives-Consignesdenavigabilite.TC@tc.gc.ca. You may view this material on the Transport Canada website at tc.canada.ca/en/aviation. (4) You may view this material at the FAA, Office of the Regional Counsel, Southwest Region, 10101 Hillwood Parkway, Room 6N-321, Fort Worth, TX 76177. For information on the availability of this material at the FAA, call (817) 222-5110. (5) You may view this material at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, visit www.archives.gov/federal-register/cfr/ibr-locations or email fr.inspection@nara.gov . Issued on October 31, 2025. Steven W. Thompson, Acting Deputy Director, Compliance & Airworthiness Division, Aircraft Certification Service.