Background The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to certain Embraer Model EMB-505 airplanes. The NPRM was published in the Federal Register on November 18, 2025 (90 FR 51607). The NPRM was prompted by ANAC AD 2025-04-01, effective April 15, 2025 (ANAC AD 2025-04-01) (also referred to as the MCAI), issued by ANAC, which is the aviation authority for Brazil. The MCAI states that there is a possibility of some airplanes having invalid HS backlash test results due to the use of incorrect test procedures. The excessive backlash may result in an aeroelastic phenomenon exposing the surrounding structure and systems to unacceptable vibration levels and reduced controllability of the airplane. In the NPRM, the FAA proposed to require inspecting the airplane's LH and RH HS backlash and replacing, as applicable, the LH and RH hinge point attachment parts, the LH or RH pitch trim actuator rod-end attachment parts, and the pitch trim actuator. The FAA is issuing this AD to address the unsafe condition on these products. You may examine the MCAI in the AD docket at regulations.gov under Docket No. FAA-2025-3993. Discussion of Final Airworthiness Directive Comments The FAA received comments from the Citizens Rulemaking Alliance. The following presents the comments received on the NPRM and the FAA's response to each comment. Request To Justify Forgoing Notice and Comment The Citizens Rulemaking Alliance requested that the FAA provide its justification for finding good cause to bypass notice and comment procedures, reopen the comment period for at least 30 days, and delay enforcement of non-time critical provisions pending comment unless the risk analysis demonstrates a truly imminent hazard. The commenter asserted the FAA has not adequately justified use of the good cause exemption to bypass notice and comment and the 30-day delayed effective date. The FAA notes the comment was submitted in response to an NPRM for which the FAA provided a 45-day comment period. This final rule is effective 35 days after its publication in the Federal Register . Therefore, no change to this AD is necessary. Request To Make Incorporation by Reference (IBR) Materials Reasonably Available The Citizens Rulemaking Alliance stated that the FAA's current practices for IBR frequently fail to meet the legal and regulatory standards for reasonable availability. The commenter called on the FAA to guarantee that all IBR materials are easily and freely accessible to the public and affected parties for the duration of the comment period and to reopen the comment period for at least 30 days to accommodate this access. Furthermore, the commenter requested that, if the manufacturer will not consent to open posting of the IBR materials in the docket, the FAA should either obtain permission to post the materials or provide a detailed technical summary sufficient for meaningful comment. The FAA notes that ANAC AD 2025-04-01, which is incorporated by reference in this AD, is available to the public on the ANAC website at sistemas.anac.gov.br/certificacao/DA/DAE.asp, as explained in the preamble and regulatory text of the NPRM. This material was also posted in the AD docket upon publication of the NPRM. Therefore, the FAA did not change this AD as a result of this comment. Request To Consider Impact on Small Entities The Citizens Rulemaking Alliance requested that the FAA either provide the factual basis for its Regulatory Flexibility Act (RFA) certification that the AD will not have a significant economic impact on a substantial number of small entities or prepare an initial regulatory flexibility analysis and consider less burdensome alternatives for small operators. The commenter stated that the FAA should also reopen the comment period to allow comment on that analysis. FAA has considered the AD's impact on small businesses and provides the following factual basis for its RFA certification. The Regulatory Flexibility Act of 1980, Public Law 96-354, 94 Stat. 1164 (5 U.S.C. 601-612), as amended by the Small Business Regulatory Enforcement Fairness Act of 1996 (Pub. L. 104-121, 110 Stat. 857, Mar. 29, 1996) and the Small Business Jobs Act of 2010 (Pub. L. 111-240, 124 Stat. 2504, Sept. 27, 2010), requires Federal agencies to consider the effects of the regulatory action on small business and other small entities and to minimize any significant economic impact. The term "small entities" comprises small businesses and not-for-profit organizations that are independently owned and operated and are not dominant in their fields, and governmental jurisdictions with populations of less than 50,000. Small Entities to Which This AD Applies The FAA used the definition of small entities in the RFA for this analysis. The RFA defines small entities as small businesses, small governmental jurisdictions, or small organizations. In 5 U.S.C. 601(3), the RFA defines "small business" to have the same meaning as "small business concern" under section 3 of the Small Business Act. The Small Business Act authorizes the Small Business Administration (SBA) to define "small business" by issuing regulations. The SBA (2023) has established size standards for various types of economic activities, or industries, under the North American Industry Classification System (NAICS). These size standards generally define small businesses based on the number of employees or annual receipts. The SBA definition of a small business applies to the parent company and all affiliates as a single entity. The following table provides the SBA size standards for all industries with at least one entity impacted by this AD. Note that the FAA does not have entity data on 13 of the 41 affected airplanes, and those airplanes with missing entity data are excluded from this analysis. Small Business Size Standards NAICS code Description Size standard 237210 Land Subdivision $34.0 million. 238220 Plumbing, Heating, and Air-Conditioning Contractors $19.0 million. 314910 Textile Bag and Canvas Mills 500 employees. 332311 Prefabricated Metal Building and Component Manufacturing 750 employees. 339112 Surgical and Medical Instrument Manufacturing 1,000 employees. 441110 New Car Dealers 200 employees. 481211 Nonscheduled Air Transport 1,500 employees. 484121 General Freight Trucking, Long Distance, Truckload $34.0 million. 523991 Trust, Fiduciary and Custody Activities $47.0 million. 531110 Lessors of Residential Buildings and Dwellings $34.0 million. 541714 Research and Development in Biotechnology (except Nanobiotechnology) 1,000 employees. To identify small entities, the FAA first identified the primary NAICS of the entity or parent company, and then used data from different sources ( e.g., company annual reports, Bureau of Transportation Statistics) to determine whether the entity meets the applicable size standard. The FAA provides the estimated number of small entities affected by this AD: Estimated Number of Small Entities Category Number of entities Number of affected airplanes Number of small entities Percent small entities Land Subdivision 1 1 1 100 Plumbing, Heating, and Air-Conditioning Contractors 1 1 1 100 Textile Bag and Canvas Mills 1 1 1 100 Prefabricated Metal Building and Component Manufacturing 1 1 1 100 Surgical and Medical Instrument Manufacturing 1 8 1 100 New Car Dealers 1 1 1 100 Nonscheduled Air Transport 4 9 2 50 General Freight Trucking, Long Distance, Truckload 1 1 0 0 Trust, Fiduciary and Custody Activities 1 3 1 100 Lessors of Residential Buildings and Dwellings 1 1 1 100 Research and Development in Biotechnology (except Nanobiotechnology) 1 1 1 100 Total 14 28 11 79 Projected Reporting, Recordkeeping, and Other Compliance Requirements FAA estimates affected entities will incur an inspection cost of $1,360. Based upon the results of the inspection, operators could incur up to five conditional repair costs. If an operator were to incur all repair and inspection costs, FAA estimates each operator would incur $14,950 per airplane. However, according to the manufacturer, all of the costs of this AD may be covered under warranty, thereby reducing the cost impact on affected entities. The FAA analyzes the cost of inspections and all repair costs over the two-year analysis period for each small entity. The following table provides the estimated compliance costs at a 7 percent annualized discount rate by each NAICS industry. Average Revenue and Cost of Compliance per Small Entity Category Annual revenue Low-case annualized cost (7% discount rate) Average Percent of revenue High-case annualized cost (7% discount rate) Average Percent of revenue Land Subdivision $3,470,000 $657 0.02 $7,222 0.21 Lessors of Residential Buildings and Dwellings 18,280,000 703 0.00 7,728 0.04 New Car Dealers 520,000 703 0.14 7,728 1.49 Nonscheduled Air Transport 12,928,355 680 0.01 7,475 0.06 Plumbing, Heating, and Air-Conditioning Contractors 196,890 703 0.36 7,728 3.92 Prefabricated Metal Building and Component Manufacturing 24,340,000 703 0.00 7,728 0.03 Research and Development in Biotechnology (except Nanobiotechnology) 31,600,000 703 0.00 7,728 0.02 Surgical and Medical Instrument Manufacturing 610,000,000 5,486 0.00 60,306 0.01 Textile Bag and Canvas Mills 12,600,000 703 0.01 7,728 0.06 Trust, Fiduciary and Custody Activities 15,850,000 1,971 0.01 21,667 0.14 Significant Alternatives Considered The FAA evaluated the alternative of not promulgating this AD but ultimately deemed that this alternative would create a significant safety hazard. The FAA is issuing this AD to address the unsafe condition for certain Embraer Model EMB-505 airplanes, ensuring a level of safety that the alternative of no action could not provide. RFA Conclusions Based on average compliance costs, the FAA has determined that the financial impacts of this AD are not disproportionate to small entities. The FAA did not change this AD as a result of this comment. Request To Comply With the Paperwork Reduction Act (PRA) The Citizens Rulemaking Alliance requested that the FAA revise the proposed AD to comply with the PRA if reporting is required or remove any reporting provisions until PRA requirements are satisfied. The FAA notes that paragraph (i) of this AD specifies that this AD does not require reporting. If an AD were to require reporting, the preamble of the AD would include a paragraph titled "Paperwork Reduction Act" that would provide the applicable OMB control number, required PRA statements, and the estimated time to collect the required information (burden). Any costs associated with the reporting requirement would be included in the Costs of Compliance section in the preamble of the AD. Therefore, the FAA did not change this AD as a result of this comment. Conclusion 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 reviewed the relevant data, considered any comments received, and determined that air safety requires adopting this AD as proposed. Accordingly, the FAA is issuing this AD to address the unsafe condition on these products. This AD is adopted as proposed in the NPRM. Material Incorporated by Reference Under 1 CFR Part 51 The FAA reviewed ANAC AD 2025-04-01, which specifies procedures for inspecting the LH and RH HS backlash for correct values, and replacing, as applicable, the LH and RH hinge point attachment parts, the LH or RH pitch trim actuator rod-end attachment parts, and the pitch trim actuator. 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. Differences Between This AD and the MCAI The material specified in ANAC AD 2025-04-01 allows the use of alternative or similar parts in place of the ones specified in the kits, provided these alternative or similar parts are approved by Embraer, but this AD requires approval from either the Manager, International Validation Branch, FAA; ANAC; or ANAC's authorized Designee. If approved by the ANAC Designee, the approval must include the Designee's authorized signature. Costs of Compliance The FAA estimates that this AD affects 41 airplanes of U.S. registry. The FAA estimates the following costs to comply with this AD: Estimated Compliance Costs Action Labor hours Labor cost 1 Parts cost Cost per airplane Total cost to U.S. operators Required: Inspection 16 $1,360 $0 $1,360 $55,760 Conditional: Replace horizontal to vertical stabilizers LH hinge point attachment parts 17 1,445 300 1,745 71,545 Conditional: Replace horizontal to vertical stabilizers RH hinge point attachment parts 17 1,445 350 1,795 73,595 Conditional: Replace RH pitch trim actuator rod-end attachment parts 16 1,360 400 1,760 72,160 Conditional: Replace LH pitch trim actuator rod-end attachment parts 16 1,360 400 1,760 72,160 Conditional: Replace pitch trim actuator 18 1,530 5,000 6,530 267,730 Low-Case Cost 2 1,360 55,760 High-Case Cost 3 14,950 612,950 1 FAA estimated operators will incur $85 in costs per labor hour, which is the weighted average fiscal year (FY) 2026 fully loaded wage of an aircraft mechanic ($69.85) working 60% of the labor hours and a general and operations manager ($108.15) working 40% of the labor hours. The FAA estimated these wages by taking the average of the FY 2024 Bureau of Labor Statistics (BLS) air transportation industry average wage for aircraft mechanics and general and operations managers (See: Occupational Employment and Wage Statistics Query System, BLS (May 2024), data.bls.gov/oes/ ); multiplying each wage by a fringe benefit factor of 1.42 (See: Employer Cost for Employee Compensation-December 2024, BLS (2024), bls.gov/news.release/archives/ecec_03142025.pdf ); and adjusting these 2024 wages to 2026 dollars using an implicit Gross Domestic Product (GDP) Price Deflator of 2.8% (See: Gross Domestic Product: Implicit Price Deflator, FRED (2026) fred.stlouisfed.org/series/GDPDEF ). 2 The low-case cost assumes each airplane incurs only inspection costs. 3 The high-case cost assumes each airplane incurs inspection and all conditional repair costs. Over a two-year analysis period, the FAA estimates operators will incur an inspection cost of $1,360. Based upon the results of the inspection, operators could incur five conditional repair costs. If an operator were to incur all inspection and repair costs, the FAA estimates each operator would incur $14,950 per airplane. The FAA cannot estimate the number of conditional repairs each operator would need to undertake, but the cost of an inspection ($1,360) and the cost of an inspection and all conditional repairs ($14,950) represent the low-case and high-case costs per affected airplane. FAA recognizes that operators might incur additional costs, such as airplane downtime. However, FAA anticipates this AD will not trigger any downtime costs because the requirements of this AD can be performed during regularly scheduled maintenance. The FAA uses a two-year analysis period for estimating the annualized costs of this AD. Upon this AD's promulgation, all Group 1 airplanes must be inspected within 12 months or 750 flight hours, and all Group 2 airplanes must be inspected within 24 months or 1,000 flight hours. In this analysis, FAA assumes all Group 1 costs will be incurred in year 1, and all Group 2 costs will be incurred in year 2. The following tables display the annual AD compliance costs and summarize the AD's quantified and unquantified benefits and costs. Annual Compliance Costs Year Affected airplanes Low-case cost High-case cost 1 27 $36,720 $403,650 2 14 19,040 209,300 Total 41 55,760 612,950 Summary of Benefits and Costs Qualitative Benefits - This AD addresses an unsafe condition. The unsafe condition, if not addressed, could result in unacceptable vibration levels and reduced controllability of the airplane. Qualitative Costs - Airplane downtime. Quantified Costs Undiscounted 7% 3% 7% 3% Industry Costs Present Value Annualized Low-Case Cost $55,760 $50,948 $53,598 $28,179 $28,011 High-Case Cost 612,950 560,054 589,179 309,761 307,911 The FAA has included all known costs in its cost estimates. According to the manufacturer, however, all 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, (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: 2026-10-18 Embraer S.A.: Amendment 39-23358; Docket No. FAA-2025-3993; Project Identifier MCAI-2025-00630-A. (a) Effective Date This airworthiness directive (AD) is effective July 6, 2026. (b) Affected ADs None. (c) Applicability This AD applies to Embraer S.A. Model EMB-505 airplanes, as identified in Agência Nacional de Aviação Civil (ANAC) AD 2025-04-01, effective April 15, 2025 (ANAC AD 2025-04-01), certificated in any category. (d) Subject Joint Aircraft System Component (JASC) Code 2700, Flight Control System. (e) Unsafe Condition This AD was prompted by the discovery that some airplanes may have invalid horizontal stabilizer (HS) backlash test results due to incorrect procedures being performed. The FAA is issuing this AD to address the unsafe condition. The unsafe condition, if not addressed, could result in unacceptable vibration levels and reduced controllability of the airplane. (f) Compliance Comply with this AD within the compliance times specified, unless already done. (g) Required Actions Except as specified in paragraphs (h) and (i) of this AD: Comply with all required actions and compliance times specified in, and in accordance with, ANAC AD 2025-04-01. (h) Exceptions to ANAC AD 2025-04-01 (1) Where ANAC AD 2025-04-01 refers to its effective date, this AD requires using the effective date of this AD for both Group 1 and Group 2 airplanes. (2) Where the material specified in ANAC AD 2025-04-01 allows the use of alternative or similar parts in place of the ones specified in the kits, provided these alternative or similar parts are approved by Embraer, this AD requires approval from either the Manager, International Validation Branch, FAA; ANAC; or ANAC's authorized Designee. If approved by the ANAC Designee, the approval must include the Designee's authorized signature. (3) Where ANAC AD 2025-04-01 refers to removal and replacement of attachment parts and pitch trim actuators in paragraphs (b)(1), (c)(1), (d)(1), (d)(2), (e)(1), (e)(2), and (f)(1), this AD specifies accomplishing the removal and replacement in these paragraphs in accordance with the appropriate procedures contained in the material referenced in ANAC AD 2025-04-01. (4) Where the material referenced in ANAC AD 2025-04-01 specifies discarding parts, this AD requires removing those parts from service. (5) This AD does not adopt paragraph (h) of ANAC AD 2025-04-01. (i) No Reporting Requirement Although the material referenced in ANAC AD 2025-04-01 specifies to submit information to the manufacturer, this AD does not require that action. (j) Credit for Previous Actions This paragraph provides credit for the actions required by paragraph (g) of this AD, if those actions were performed before the effective date of this AD using Embraer Service Bulletin No. 505-27-0034, dated September 19, 2024; or Embraer Service Bulletin No. 505-27-0034, Revision 01, dated October 4, 2024. (k) 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 (l)(1) 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. (l) Additional Information (1) For more information about this AD, contact Jim Rutherford, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (816) 329-4165; email: jim.rutherford@faa.gov. (2) For Embraer material identified in this AD that is not incorporated by reference, contact Embraer S.A., Technical Publications Avenida Brigadeiro Faria Lima, 2170, São Jose dos Campos-SP, Brazil; phone: +551239275852; email: distrib@embraer.com.br; website: https://www.flyembraer.com/irj/portal. (m) 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) Agência Nacional de Aviação Civil (ANAC) AD 2025-04-01, effective April 15, 2025. (ii) [Reserved] (3) For ANAC material identified in this AD, contact ANAC, Continuing Airworthiness Technical Branch (GTAC), Rua Doutor Orlando Feirabend Filho, 230-Centro Empresarial Aquarius-Torre B-Andares 14 a 18, Parque Residencial Aquarius, CEP 12.246-190-São José dos Campos-SP, Brazil; phone: 55 (12) 3203-6600; email: pac@anac.gov.br; website: anac.gov.br/en/. You may find this material on the ANAC website at sistemas.anac.gov.br/certificacao/DA/DAE.asp. (4) You may view this material at the FAA, Airworthiness Products Section, Operational Safety Branch, 901 Locust, Kansas City, MO 64106. 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 May 18, 2026. Steven W. Thompson, Acting Deputy Director, Compliance & Airworthiness Division, Aircraft Certification Service.