Document

Airworthiness Directives; Textron Aviation Inc. Airplanes

The FAA is adopting a new airworthiness directive (AD) for certain Textron Aviation Inc. (Textron) Model B300 and B300C airplanes. This AD was prompted by the manufacturer's rev...

Department of Transportation
Federal Aviation Administration
  1. 14 CFR Part 39
  2. [Docket No. FAA-2026-7223; Project Identifier AD-2026-00329-A; Amendment 39-23417; AD 2026-15-05]
  3. RIN 2120-AA64

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Final rule; request for comments.

SUMMARY:

The FAA is adopting a new airworthiness directive (AD) for certain Textron Aviation Inc. (Textron) Model B300 and B300C airplanes. This AD was prompted by the manufacturer's revision of the airworthiness limitations manual (ALM) to introduce revised inspection intervals to detect cracks in the wing spar or wing supporting structure. This AD requires revising the Airworthiness Limitations section (ALS) of the existing aircraft maintenance manual (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.

DATES:

This AD is effective August 10, 2026.

The Director of the Federal Register approved the incorporation by reference of a certain publication listed in this AD as of August 10, 2026.

The FAA must receive comments on this AD by September 8, 2026.

ADDRESSES:

You may send comments, using the procedures found in 14 CFR 11.43 and 11.45, by any of the following methods:

  • Federal eRulemaking Portal: Go to regulations.gov. Follow the instructions for submitting comments.
  • Fax: (202) 493-2251.
  • Mail: U.S. Department of Transportation, Docket Operations, M-91, West Building Fifth Floor, Room W58-213, 1200 New Jersey Avenue SE, Washington, DC 20590.
  • Hand Delivery: Deliver to Mail address above between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

AD Docket: You may examine the AD docket at regulations.gov under Docket No. FAA-2026-7223; 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 street address for Docket Operations is listed above.

Material Incorporated by Reference:

  • For Textron material identified in this AD, contact Textron, One Cessna Blvd., Wichita, KS 67215; phone: (316) 517-9355; email:; website: txtav.com.
  • You may view this material at the FAA, Airworthiness Products Section, Operational Safety Branch, 1100 Main, Kansas City, MO 64105. For information on the availability of this material at the FAA, call (817) 222-5110. It is also available atregulations.gov under Docket No. FAA-2026-7223.

FOR FURTHER INFORMATION CONTACT:

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

SUPPLEMENTARY INFORMATION:

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-2026-7223; Project Identifier AD-2026-00329-A” 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 ( printed page 46707) 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 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 was notified by Textron that the existing ALM of the ICA for Textron Model B300 and B300C airplanes contained incorrect wing inspection intervals for airplanes that are certified to or operating at a 16,500 pound (lb.) maximum takeoff weight (MTOW). As a result, Textron has revised the existing Model B300 and B300C structural inspection and repair manual (SIRM) and ALM to separate the wing inspection criteria and intervals between airplanes that are certified to or operating at a 15,000 lb. MTOW and those that are certified to or operating at a 16,500 MTOW. The new and updated inspection criteria are based upon the airplane operating hours. The FAA is issuing this AD to prevent undetected cracks in the wing or wing supporting structure. The unsafe condition, if not addressed, could result in reduced structural integrity and consequent wing separation from the fuselage in flight.

FAA's Determination

The FAA is issuing this AD because the agency determined the unsafe condition described previously is likely to exist or develop in other products of the same type design.

Material Incorporated by Reference Under 1 CFR Part 51

The FAA reviewed Textron Mandatory Service Letter MTL-57-04, Revision 1, dated March 27, 2025. This material specifies information about the new and updated wing inspection criteria for Model B300 and B300C airplanes within the SIRM and ALM based upon the airplane operating hours. 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.

AD Requirements

This AD requires 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 intervals specified in the material already described.

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 the existing incorrect wing inspection intervals need to be revised to detect any crack that could develop in the wing spar or wing supporting structure due to differences in operators' mission profiles (airplanes operating at a 16,500 lb. MTOW). Current FAA data indicate that a number of airplanes are past the revised inspection intervals specified in this AD. Cracks in the wing spar or wing supporting structure could result in reduced structural integrity and consequent wing separation from the fuselage in flight. 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 113 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-hours × $85 per hour = $85 $0 $85 $9,605

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: ( printed page 46708)

(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.

[Amended]

2. The FAA amends § 39.13 by adding the following new airworthiness directive:

2026-15-05 Textron Aviation Inc.: Amendment 39-23417; Docket No. FAA-2026-7223; Project Identifier AD-2026-00329-A.

(a) Effective Date

This airworthiness directive (AD) is effective August 10, 2026.

(b) Affected ADs

None.

(c) Applicability

This AD applies to Textron Aviation Inc. Model B300 and B300C airplanes, certificated in any category, identified in Textron Mandatory Service Letter MTL-57-04, Revision 1, dated March 27, 2025, including airplanes identified in paragraphs (c)(1) through (3) of this AD, except for any airplane that has had a wing evaluation performed by Textron Aviation Special Missions and been issued a serial number specific aircraft limitations manual and structural inspection and repair manual supplements.

(1) Model B300 airplanes (heavy weight) having Kit 130-4402 installed (effective for serial numbers (S/Ns) FL-91, FL-381, FL-383, FL-387, FL-391 and on).

(2) Model B300 (heavy weight) and B300C (non-extended range) airplanes having Kit 130-4030 installed (effective for S/Ns FL-381, FL-383 and on, and FM-12 and on).

(3) Model B300 (increased gross weight with extended-range fuel tank) airplanes having Kit 130-4014 (effective for S/Ns FL-1 and on and FM-1 and on).

(d) Subject

Joint Aircraft System Component (JASC) Code 5700, Wing Structure.

(e) Unsafe Condition

This AD was prompted by the manufacturer's revision of the structural inspection and repair manual to introduce more restrictive inspection intervals for airplanes that are certified to or operating at a 16,500 pound (lb.) maximum takeoff weight (MTOW). The FAA is issuing this AD to prevent undetected cracks in the wing or wing supporting structure. The unsafe condition, if not addressed, could result in reduced structural integrity and consequent wing separation from the fuselage in flight.

(f) Compliance

Comply with this AD within the compliance times specified, unless already done.

(g) Required Actions

At the applicable compliance time specified in paragraphs (g)(1) through (3) of this AD, revise the Limitations Section of the existing aircraft maintenance manual or instructions for continued airworthiness and the existing maintenance or inspection program, as applicable, by incorporating the information identified in table 1 to paragraph (g) of this AD.

(1) For airplanes that are certified to or operating at 16,500 lb. MTOW and with 3,800 hours total time-in-service (TTIS) or less: Before accumulating 3,800 hours TTIS or within 25 hours time-in-service (TIS) or 30 days after the effective date of this AD, whichever occurs later.

(2) For airplanes that are certified to or operating at 16,500 lb. MTOW and with between 3,801 and 7,400 TTIS: Within 200 hours TIS or 6 months, whichever occurs first after the effective date of this AD.

(3) For airplanes that are certified to or operating at 16,500 lb. MTOW and with more than 7,401 hours TTIS: Within 25 hours TIS or 30 days, whichever occurs first after the effective date of this AD.

Table 1 to Paragraph ( g )—Revised Scheduled Component Replacement Time Limits

Task No. Component Interval
57-00-00-9602 Wing to Fuselage Attach Angles (FL-1 through FL-175, FL-177; FM-1 through FM-9; unless Kit 101-1202-0001 is installed) 16,500 MTOW airplanes, replace every 2,500 hours.
57-00-00-9603 Wing to Fuselage Attach Angles (FL-176, FL-178 and after; FM-10 and after; and prior airplanes with Kit 101-1202-0001 installed) 16,500 MTOW airplanes, replace every 29,200 hours.
57-20-01-9600 Outboard Wing Structure (FL-1 through FL-125; FM-1 through FM-8; unless 101-110085-1 and -2 spar caps are installed) 16,500 MTOW airplanes, replace every 6,500 hours.
There are no life limitation inspection tasks associated with the wing center section Wing Center Section (FL-126 and after; FM-9 and after; and prior airplanes with Kit 101-1200-0001 installed) The life is not limited provided the inspection programs defined in the listed maintenance manuals and the replacement schedule for the items listed below have been adhered to for continued airworthiness. King Air Series Structural Inspection and Repair Manual, P/N 98-39006, Revision D6. • Chapter 57-18-02 Super King Air Model B300/B300C Maintenance Manual, P/N 130-590031-11. • Chapter 5 • Chapter 57 Super King Air Model B300/B300C Fusion Maintenance Manual, P/N 434-590169-0009. • Chapter 5 • Chapter 57
( printed page 46709)
There are no life limitation inspection tasks associated with the outboard wing structure. Outboard Wing Structure (FL-126 and after; FM-9 and after; and prior airplanes with 101-110085-1 and -2 spar caps installed) The life is not limited provided the inspection programs defined in the listed maintenance manuals and the replacement schedule for the items listed below have been adhered to for continued airworthiness. King Air Series Structural Inspection and Repair Manual, P/N 98-39006, Revision D6. • Chapter 57-18-02 Super King Air Model B300/B300C Maintenance Manual, P/N 130-590031-11. • Chapter 5 • Chapter 57 Super King Air Model B300/B300C Fusion Maintenance Manual, P/N 434-590169-0009. • Chapter 5 • Chapter 57

Note 1 to paragraph (g): Additional guidance for accomplishing the actions required by this AD can be found in Textron Super King Air B300/B300C Airworthiness Limitations Manual 130-590031-211G, Revision G0, dated April 29, 2026.

(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: .

(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: .

(2) Material identified in this AD that is not incorporated by reference is available at the address specified in paragraph (k)(3) of this AD.

(k) 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) Textron Mandatory Service Letter MTL-57-04, Revision 1, dated March 27, 2025.

(ii) [Reserved]

(3) For Textron material identified in this AD, contact Textron, One Cessna Blvd., Wichita, KS, 67215; phone: (316) 517-9355; email: ; website: txtav.com.

(4) You may view this material at the FAA, Airworthiness Products Section, Operational Safety Branch, 1100 Main, Kansas City, MO 64105. 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 .

Issued on July 16, 2026.

Steven W. Thompson,

Acting Deputy Director, Compliance & Airworthiness Division, Aircraft Certification Service.

[FR Doc. 2026-15006 Filed 7-23-26; 8:45 am]

BILLING CODE 4910-13-P

Legal Citation

Federal Register Citation

Use this for formal legal and research references to the published document.

91 FR 46706

Web Citation

Suggested Web Citation

Use this when citing the archival web version of the document.

“Airworthiness Directives; Textron Aviation Inc. Airplanes,” thefederalregister.org (July 24, 2026), https://thefederalregister.org/documents/2026-15006/airworthiness-directives-textron-aviation-inc-airplanes.