Proposed Rules. Notice of proposed rulemaking (NPRM)

Agency: Federal Aviation Administration (FAA), DOT
Action: Notice of proposed rulemaking (NPRM)
Citation: FR Doc. 2026-08322 · RIN 2120-AA64 · Docket No. FAA-2026-3870; Project Identifier AD-2025-01364-A · 14 CFR 39

Summary

The FAA proposes to adopt a new airworthiness directive (AD) for certain Textron Aviation, Inc., Model 408 airplanes. This proposed 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 proposed AD would require 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 proposing this AD to address the unsafe condition on these products.

Dates

The FAA must receive comments on this proposed AD by June 15, 2026.

Supplementary Information

Comments Invited The FAA invites you to send any written relevant data, views, or arguments about this proposal. Send your comments using a method listed under the ADDRESSES section. Include “Docket No. FAA-2026-3870; Project Identifier AD-2025-01364-A” at the beginning of your comments. The most helpful comments reference a specific portion of the proposal, explain the reason for any recommended change, and include supporting data. The FAA will consider all comments received by the closing date and may revise this proposal 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 NPRM. 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 NPRM 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 NPRM, 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 NPRM. Submissions containing CBI should be sent to Soban Saeed, Aviation Safety Engineer, FAA, 1801 South Airport Road, Wichita, KS 67209. 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 received 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. As a result, Textron Aviation, Inc. issued revised limitations to the existing Model 408 AMM inspection program that require addition of a horizontal stabilizer spar detailed inspection and a revision to the airplane serial effectivity for the vertical stabilizer spar detailed inspection. The FAA is proposing 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. FAA's Determination The FAA is issuing this NPRM after determining that the unsafe condition described previously is likely to exist or develop on other products of the same type design. Proposed AD Requirements in This NPRM This proposed AD would require revising the ALS of the existing AMM or ICA and the existing approved maintenance or inspection program, as applicable, by incorporating the actions and associated thresholds and intervals specified in table 1 to paragraph (g) of this proposed AD. Costs of Compliance The FAA estimates that this AD, if adopted as proposed, would affect 28 airplanes of U.S. registry. The FAA estimates the following costs to comply with this proposed 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 The FAA determined that this proposed AD would not have federalism implications under Executive Order 13132. This proposed AD would 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 this proposed regulation: (1) Is not a “significant regulatory action” under Executive Order 12866, (2) Would not affect intrastate aviation in Alaska, and (3) Would 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 Proposed Amendment Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 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: Textron Aviation Inc.: Docket No. FAA-2026-3870; Project Identifier AD-2025-01364-A. (a) Comments Due Date The FAA must receive comments on this airworthiness directive (AD) by June 15, 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 change 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 No. 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 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 April 24, 2026. Steven W. Thompson, Acting Deputy Director, Compliance & Airworthiness Division, Aircraft Certification Service. [FR Doc. 2026-08322 Filed 4-28-26; 8:45 am]