Background The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to all MHI RJ Aviation ULC Model CL-600-2C10 (Regional Jet Series 700, 701 & 702), CL-600-2C11 (Regional Jet Series 550), CL-600-2D15 (Regional Jet Series 705), CL-600-2D24 (Regional Jet Series 900), and CL-600-2E25 (Regional Jet Series 1000) airplanes. The NPRM published in the Federal Register on March 3, 2023 (88 FR 13385). The NPRM was prompted by AD CF-2022-43, dated August 9, 2022, issued by Transport Canada, which is the aviation authority for Canada (referred to after this as the MCAI). The MCAI states that new airworthiness limitations have been developed. In the NPRM, the FAA proposed to require revising the existing maintenance or inspection program, as applicable, to incorporate new or more restrictive airworthiness limitations. The FAA is issuing this AD to address an unannunciated loss or low quantity of fire extinguishing agent in the engine and auxiliary power unit (APU) fire extinguishing bottles. This condition, if not corrected, could result in the inability to extinguish and suppress an engine or APU fire. You may examine the MCAI in the AD docket at regulations.gov under Docket No. FAA-2023-0422. Discussion of Final Airworthiness Directive Comments The FAA received comments from The Air Line Pilots Association, International (ALPA) who supported the NPRM without change. Conclusion This product has been approved by the aviation authority of another country and is approved for operation in the United States. Pursuant to the FAA's bilateral agreement with this State of Design Authority, it has notified the FAA of the unsafe condition described in the MCAI referenced above. The FAA reviewed the relevant data and determined that air safety requires adopting this AD as proposed. Accordingly, the FAA is issuing this AD to address the unsafe condition on this product. Except for minor editorial changes, this AD is adopted as proposed in the NPRM. None of the changes will increase the economic burden on any operator. Related Service Information Under 1 CFR Part 51 The FAA reviewed Task 26-20-00-101, "Visual Check of the Engine Fire Extinguishing bottle pressure gauge" and Task 26-20-00-102, "Visual Check of the APU Fire Extinguishing bottle pressure gauge," of Section 1, "Certification Maintenance Requirements," Subject 1-26, "Fire Protection," of the MHI RJ Model CL-600-2C10, CL-600-2C11, CL-600-2D15, CL-600-2D24, and CL-600-2E25 Series 550/700/705/900/1000 Airworthiness Limitations, Maintenance Requirements Manual-Part 2, Volume 1, CSP B-053, Revision 26, dated March 25, 2022. This service information specifies procedures for new airworthiness limitations for certification maintenance requirements. 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. Costs of Compliance The FAA estimates that this AD affects 606 airplanes of U.S. registry. The FAA estimates the following costs to comply with this AD: The FAA has determined that revising the maintenance or inspection program takes an average of 90 work-hours per operator, although the agency recognizes that this number may vary from operator to operator. Since operators incorporate maintenance or inspection program changes for their affected fleet(s), the FAA has determined that a per-operator estimate is more accurate than a per-airplane estimate. Therefore, the agency estimates the average total cost per operator to be $7,650 (90 work-hours × $85 per work-hour). 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, (2) Will not affect intrastate aviation in Alaska, and (3) Will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act. 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: 2023-10-03 MHI RJ Aviation ULC (Type Certificate Previously Held by Bombardier, Inc.): Amendment 39-22439; Docket No. FAA-2023-0422; Project Identifier MCAI-2022-01067-T. (a) Effective Date This airworthiness directive (AD) is effective July 11, 2023. (b) Affected ADs None. (c) Applicability This AD applies to all MHI RJ Aviation ULC (Type Certificate previously held by Bombardier, Inc.) Model CL-600-2C10 (Regional Jet Series 700, 701 & 702), CL-600-2C11 (Regional Jet Series 550), CL-600-2D15 (Regional Jet Series 705), CL-600-2D24 (Regional Jet Series 900) and CL-600-2E25 (Regional Jet Series 1000) airplanes, certificated in any category. (d) Subject Air Transport Association (ATA) of America Code 26, Fire Protection. (e) Reason This AD was prompted by a determination that new or more restrictive airworthiness limitations are necessary. The FAA is issuing this AD to address an unannunciated loss or low quantity of fire extinguishing agent in the engine and auxiliary power unit (APU) fire extinguishing bottles. The unsafe condition, if not corrected, may lead to the inability to extinguish and suppress an engine or APU fire. (f) Compliance Comply with this AD within the compliance times specified, unless already done. (g) Maintenance or Inspection Program Revision Within 60 days after the effective date of this AD, revise the existing maintenance or inspection program, as applicable, to incorporate the information specified in Task 26-20-00-101, "Visual Check of the Engine Fire Extinguishing bottle pressure gauge" and Task 26-20-00-102, "Visual Check of the APU Fire Extinguishing bottle pressure gauge," of Section 1, "Certification Maintenance Requirements," Subject 1-26, "Fire Protection," of the MHI RJ Model CL-600-2C10, CL-600-2C11, CL-600-2D15, CL-600-2D24, and CL-600-2E25 Series 550/700/705/900/1000 Airworthiness Limitations, Maintenance Requirements Manual (MRM)-Part 2, Volume 1, CSP B-053, Revision 26, dated March 25, 2022 (Task 26-20-00-101 and Task 26-20-00-102 of the MRM-Part 2, Revision 26). The initial compliance time for doing the tasks is at the phase-in time specified in Task 26-20-00-101 and Task 26-20-00-102 of the MRM-Part 2, Revision 26, or within 60 days after the effective date of this AD, whichever occurs later. (h) No Alternative Actions or Intervals After the existing maintenance or inspection program has been revised as required by paragraph (g) of this AD, no alternative actions ( e.g., inspections) or intervals may be used unless the actions or intervals, are approved as an alternative method of compliance (AMOC) in accordance with the procedures specified in paragraph (i)(1) of this AD. (i) Other FAA AD Provisions The following provisions also apply to this AD: (1) Alternative Methods of Compliance (AMOCs): The Manager, New York ACO 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 ATTN: Program Manager, Continuing Operational Safety, FAA, New York ACO Branch, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; telephone 516-228-7300. Before using any approved AMOC, notify your appropriate principal inspector, or lacking a principal inspector, the manager of the responsible Flight Standards Office. (2) Contacting the Manufacturer: For any requirement in this AD to obtain instructions from a manufacturer, the instructions must be accomplished using a method approved by the Manager, New York ACO Branch, FAA; or Transport Canada; or MHI RJ Aviation ULC's Transport Canada Design Approval Organization (DAO). If approved by the DAO, the approval must include the DAO-authorized signature. (j) Additional Information (1) Refer to Transport Canada AD CF-2022-43, dated August 9, 2022, for related information. This Transport Canada AD may be found in the AD docket at regulations.gov under Docket No. FAA-2023-0422. (2) For more information about this AD, contact Joseph Catanzaro, Aerospace Engineer, Airframe and Propulsion Section, FAA, New York ACO Branch, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; telephone 516-228-7300; email 9-avs-nyaco-cos@faa.gov . (k) Material Incorporated by Reference (1) The Director of the Federal Register approved the incorporation by reference of the service information listed in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51. (2) You must use this service information as applicable to do the actions required by this AD, unless this AD specifies otherwise. (i) Task 26-20-00-101, "Visual Check of the Engine Fire Extinguishing bottle pressure gauge" and Task 26-20-00-102, "Visual Check of the APU Fire Extinguishing bottle pressure gauge," of Section 1, "Certification Maintenance Requirements," Subject 1-26, "Fire Protection," of the MHI RJ Model CL-600-2C10, CL-600-2C11, CL-600-2D15, CL-600-2D24, and CL-600-2E25 Series 550/700/705/900/1000 Airworthiness Limitations, Maintenance Requirements Manual-Part 2, Volume 1, CSP B-053, Revision 26, dated March 25, 2022. (ii) [Reserved]. (3) For service information identified in this AD, contact MHI RJ Aviation Group, Customer Response Center, 3655 Ave. des Grandes-Tourelles, Suite 110, Boisbriand, Québec J7H 0E2 Canada; North America toll-free telephone 833-990-7272 or direct-dial telephone 450-990-7272; fax 514-855-8501; email thd.crj@mhirj.com ; website mhirj.com . (4) You may view this service information at the FAA, Airworthiness Products Section, Operational Safety Branch, 2200 South 216th St., Des Moines, WA. For information on the availability of this material at the FAA, call 206-231-3195. (5) You may view this service information that is incorporated by reference at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, email fr.inspection@nara.gov, or go to: www.archives.gov/federal-register/cfr/ibr-locations.html . Issued on May 12, 2023. Michael Linegang, Acting Director, Compliance & Airworthiness Division, Aircraft Certification Service.