AD 2026-14-10 ACTIVE

The FAA is adopting a new airworthiness directive (AD) for certain Textron Aviation Inc., Model 408 airplanes. This AD was prompted by the manufacturer's revision of the aircraft maintenance manual (AMM) to add a detailed inspection for the horizontal stabilizer spar, and change the airplane serial effectivity for the vertical stabilizer spar detailed inspection. This AD requires revising the Airworthiness Limitations Section (ALS) of the existing AMM or instructions for continued airworthiness (ICA) and the existing approved maintenance or inspection program, as applicable. The FAA is issuing this AD to address the unsafe condition on these products.

Final rule.

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 adding the following new airworthiness directive: 2026-14-10 Textron Aviation Inc.: Amendment 39-23411; Docket No. FAA-2026-7217; Project Identifier AD-2025-01364-A. (a) Effective Date This airworthiness directive (AD) is effective August 18, 2026. (b) Affected ADs None. (c) Applicability This AD applies to Textron Aviation Inc. Model 408 airplanes, serial numbers -0012 through -0051, certificated in any category. (d) Subject Joint Aircraft System Component (JASC) Code 5530, Vertical Stabilizer Structure; 5510, Horizontal Stabilizer Structure. (e) Unsafe Condition This AD was prompted by the manufacturer's revision of the aircraft maintenance manual (AMM) to introduce a detailed inspection for the horizontal stabilizer spar, and a change to the airplane serial effectivity for the vertical stabilizer spar detailed inspection. The FAA is issuing this AD to detect and address cracks in the horizontal and vertical stabilizers forward and aft spars. The unsafe condition, if not addressed, could result in reduced structural integrity of the airplane or reduced controllability of the airplane with possible loss of control of the airplane. (f) Compliance Comply with this AD within the compliance times specified, unless already done. (g) Airworthiness Limitations Section (ALS) Revision Within 150 hours time-in-service or 12 months after the effective date of this AD, whichever occurs first: Revise the ALS of the existing AMM or instructions for continued airworthiness and the existing approved maintenance or inspection program, as applicable, by incorporating the information identified in table 1 to paragraph (g) of this AD. Table 1 to Paragraph ( g )-Revised Model 408 Airworthiness Limitation Tasks Task number Task title Interval Inspection document Zone Serial effectivity 55-10-00-221 Horizontal Stabilizer Spar Detailed Inspection 1600 flight hours 4-12-MB 351, 352 -0012 through -0040. 55-30-00-221 Vertical Stabilizer Spar Detailed Inspection 1600 flight hours 4-12-MB 341, 342, 343 -0012 through -0051. Note 1 to paragraph (g): Additional guidance for accomplishing the actions required by this AD can be found in Textron Aviation Inc. Service Letter SL408-04-01, dated December 8, 2025. (h) Provisions for Alternative Actions and Intervals After the action required by paragraph (g) of this AD has been performed, no alternative actions and associated thresholds and intervals are allowed unless they are approved as specified in the provisions of paragraph (i) of this AD. (i) Alternative Methods of Compliance (AMOCs) (1) The Manager, Central Certification 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 Central Certification Branch, send it to the attention of the person identified in paragraph (j)(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. (j) Additional Information (1) For more information about this AD, contact Soban Saeed, Aviation Safety Engineer, FAA, 1801 South Airport Road, Wichita, KS 67209; phone: (316) 946-4123; email: CCB-COS@faa.gov. (2) For material identified in this AD that is not incorporated by reference, contact Textron Aviation Inc., P.O. Box 7706, Wichita, KS 67277; phone: (316) 517-6215; email: citationpubs@txtav.com; website: ww2.txtav.com/technicalpublications/. (k) Material Incorporated by Reference None. Issued on July 9, 2026. Steven W. Thompson, Acting Deputy Director, Compliance & Airworthiness Division, Aircraft Certification Service. [FR Doc. 2026-14109 Filed 7-13-26; 8:45 am]BILLING CODE 4910-13-P

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 Textron Aviation Inc., Model 408 airplanes. The NPRM was published in the Federal Register on April 29, 2026 (91 FR 23023). The NPRM was prompted by a report from Textron Aviation Inc., that an undetected crack could develop in the horizontal and vertical stabilizers forward and aft spars on certain Model 408 airplanes due to a quality escape from the supplier during manufacturing. The NPRM was further prompted by the manufacturer's revision of the AMM to introduce a detailed inspection for the horizontal stabilizer spar, and a revision to the airplane serial effectivity for the vertical stabilizer spar detailed inspection. In the NPRM, the FAA proposed to require revising the ALS of the existing AMM or ICA and the existing approved maintenance or inspection program, as applicable. The unsafe condition, if not addressed, could result in reduced structural integrity of the airplane or reduced controllability of the airplane with possible loss of control of the airplane. The FAA is issuing this AD to address the unsafe condition on these products. Discussion of Final Airworthiness Directive Comments The FAA received no comments on the NPRM or on the determination of the costs. Conclusion 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. 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. Costs of Compliance The FAA estimates that this AD affects 28 airplanes 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 Revise the ALS 1 work-hour × $85 per hour = $85 $0 $85 $2,380 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: 2026-14-10 Textron Aviation Inc.: Amendment 39-23411; Docket No. FAA-2026-7217; Project Identifier AD-2025-01364-A. (a) Effective Date This airworthiness directive (AD) is effective August 18, 2026. (b) Affected ADs None. (c) Applicability This AD applies to Textron Aviation Inc. Model 408 airplanes, serial numbers -0012 through -0051, certificated in any category. (d) Subject Joint Aircraft System Component (JASC) Code 5530, Vertical Stabilizer Structure; 5510, Horizontal Stabilizer Structure. (e) Unsafe Condition This AD was prompted by the manufacturer's revision of the aircraft maintenance manual (AMM) to introduce a detailed inspection for the horizontal stabilizer spar, and a change to the airplane serial effectivity for the vertical stabilizer spar detailed inspection. The FAA is issuing this AD to detect and address cracks in the horizontal and vertical stabilizers forward and aft spars. The unsafe condition, if not addressed, could result in reduced structural integrity of the airplane or reduced controllability of the airplane with possible loss of control of the airplane. (f) Compliance Comply with this AD within the compliance times specified, unless already done. (g) Airworthiness Limitations Section (ALS) Revision Within 150 hours time-in-service or 12 months after the effective date of this AD, whichever occurs first: Revise the ALS of the existing AMM or instructions for continued airworthiness and the existing approved maintenance or inspection program, as applicable, by incorporating the information identified in table 1 to paragraph (g) of this AD. Table 1 to Paragraph ( g )-Revised Model 408 Airworthiness Limitation Tasks Task number Task title Interval Inspection document Zone Serial effectivity 55-10-00-221 Horizontal Stabilizer Spar Detailed Inspection 1600 flight hours 4-12-MB 351, 352 -0012 through -0040. 55-30-00-221 Vertical Stabilizer Spar Detailed Inspection 1600 flight hours 4-12-MB 341, 342, 343 -0012 through -0051. Note 1 to paragraph (g): Additional guidance for accomplishing the actions required by this AD can be found in Textron Aviation Inc. Service Letter SL408-04-01, dated December 8, 2025. (h) Provisions for Alternative Actions and Intervals After the action required by paragraph (g) of this AD has been performed, no alternative actions and associated thresholds and intervals are allowed unless they are approved as specified in the provisions of paragraph (i) of this AD. (i) Alternative Methods of Compliance (AMOCs) (1) The Manager, Central Certification 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 Central Certification Branch, send it to the attention of the person identified in paragraph (j)(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. (j) Additional Information (1) For more information about this AD, contact Soban Saeed, Aviation Safety Engineer, FAA, 1801 South Airport Road, Wichita, KS 67209; phone: (316) 946-4123; email: CCB-COS@faa.gov. (2) For material identified in this AD that is not incorporated by reference, contact Textron Aviation Inc., P.O. Box 7706, Wichita, KS 67277; phone: (316) 517-6215; email: citationpubs@txtav.com; website: ww2.txtav.com/technicalpublications/. (k) Material Incorporated by Reference None. Issued on July 9, 2026. Steven W. Thompson, Acting Deputy Director, Compliance & Airworthiness Division, Aircraft Certification Service.

AD Docket: You may examine the AD docket at regulations.gov under Docket No. FAA-2026-7217; 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, any comments received, and other information. The address for Docket Operations is U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590.

Soban Saeed, Aviation Safety Engineer, FAA, 1801 South Airport Road, Wichita, KS 67209; phone: (316) 946-4123; email: CCB-COS@faa.gov.