2026-16-12: Horizontal stabilizer structure; Horizontal stabilizer miscellaneous structure; Vertical stabilizer structure

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: a. Removing Airworthiness Directive 2024-16-06, Amendment 39-22812 (89 FR 67267, August 20, 2024); and b. Adding the following new airworthiness directive: 2026-16-12 Air Tractor, Inc.: Amendment 39-23442; Docket No. FAA-2026-7236; Project Identifier AD-2026-00543-A. (a) Effective Date This airworthiness directive (AD) is effective August 31, 2026. (b) Affected ADs This AD replaces AD 2024-16-06, Amendment 39-22812 (89 FR 67267, August 20, 2024) (AD 2024-16-06). (c) Applicability This AD applies to Air Tractor, Inc. Model AT-802 and AT-802A airplanes, all serial numbers, certificated in any category, that have Wipaire, Inc. Supplemental Type Certificate (STC) No. SA01795CH installed. (d) Subject Joint Aircraft System Component (JASC) Code 5510, Horizontal stabilizer structure; 5511 Horizontal stabilizer, Spar/Rib; 5514, Horizontal stabilizer miscellaneous structure; 5530, Vertical stabilizer structure. (e) Unsafe Condition This AD was prompted by additional reports of cracks where the vertical fin structural support brace mounts to the horizontal stabilizer spar. The FAA is issuing this AD to prevent structural failure of the horizontal stabilizer spars. The unsafe condition, if not addressed, could result in structural failure of the horizontal tail with consequent loss of control of the airplane. (f) Compliance Comply with this AD within the compliance times specified, unless already done. (g) Required Actions Retained From AD 2024-16-06 (1) Within 7 days after the effective date of September 4, 2024 (effective date of 2024-16-06) or before the airplane accumulates 110 hours time-in-service (TIS) after installation of STC No. SA01795CH, whichever occurs later, and thereafter at intervals not to exceed 110 hours TIS until the airplane is modified as required by paragraph (g)(3) of this AD, inspect the left and right horizontal stabilizer spars for cracks in accordance with Steps 1 through 9 of the Work Instructions-Inspection, Method 1 in Wipaire, Inc. Service Letter 253, Revision D, dated July 3, 2024 (Wipaire SL 253D). (2) If any crack is found in a horizontal stabilizer spar during any inspection required by paragraph (g)(1) of this AD, or if any crack, elongated hole, or corrosion is found in a horizontal stabilizer spar during any inspection required by paragraph (h) of this AD, before further flight, replace the horizontal stabilizer spar. (3) Within 300 hours TIS or 12 months after the effective date of September 4, 2024 (effective date of 2024-16-06), whichever occurs first, install bathtub fittings (Service Kit 1012347-01 or 1012347-02) in accordance with Steps 1 through 10 of the Work Instructions-Install Bathtub Fittings in Wipaire SL 253D except where Step 2 specifies that to be eligible for reinstallation, finlet mount weldments must include the welded gussets shown in figure 8 of Wipaire SL 253D, that constraint is not required by this AD. If any spars were previously modified by installing 7D1-4399 Revision L or earlier, regardless of condition, those spars must be replaced at the same time the bathtub fittings kit is installed. (h) Required Actions Retained From AD 2024-16-06 With New Service Material Within 110 hours TIS after installing the bathtub fittings and thereafter at intervals not to exceed 110 hours TIS, inspect the horizontal stabilizer spars for cracks, elongated holes, and corrosion in accordance with Steps 1, 2, 4, 5, 6, 9, and 10 of the Work Instructions-Inspection, Method 2 in Wipaire, Inc. Service Letter 253, Revision H, dated July 27, 2026. (i) Required Actions New to This AD Within 50 hours TIS or 7 days after the effective date of this AD, whichever occurs later, and thereafter at intervals not to exceed 50 hours TIS, inspect right and left horizontal stabilizer spars in the tail, at the strut brace mount locations for cracks in accordance with Steps 1 through 9 of the Work Instructions in Wipaire, Inc. Service Letter 277, Revision C, dated July 27, 2026. If any crack is found, before further flight, replace the horizontal stabilizer spar. (j) Reporting Requirement Within 5 days after each inspection required by paragraphs (g)(1), (h), and (i) of this AD or within 5 days after the effective date of this AD, whichever occurs later, report the information listed in paragraphs (j)(1) through (9) of this AD to ccb-cos@faa.gov. Report this information regardless of whether cracks are found. (1) Model, engine configuration (with horsepower limits), and propeller type; (2) Serial number and N number; (3) Total hours TIS on airframe; (4) Total hours TIS operated with floats, if known; (5) STC configuration and total hours with STC installed; (6) Crack location (right or left, upper/lower caps inboard/outboard hole); (7) Crack size; (8) Photos of cracks found, if available; and (9) Any additional operator/mechanic comments. (k) Credit for Previous Actions (1) You may take credit for any inspection required by paragraph (h) of this AD if, before the effective date of this AD, you complied with Wipaire, Inc. Service Letter 253, Revision D, dated July 3, 2024. (2) You may take credit for the initial inspection required by paragraph (i) of this AD if, before the effective date of this AD, you complied with Wipaire, Inc. Service Letter 277, Revision A, dated February 11, 2026, or Wipaire, Inc. Service Letter 277, Revision B, dated June 18, 2026. (l) 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 Certification Branch, send it to the attention of the person identified in paragraph (m)(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. (m) Additional Information (1) For more information about this AD, contact John Emery, Aviation Safety Engineer, FAA, 1801 S Airport Road, Wichita, KS 67209; phone: (847) 294-7122; email: john.emery@faa.gov . (2) Material identified in this AD that is not incorporated by reference is available at the address specified in paragraph (n)(5) of this AD. (n) Material Incorporated by Reference (1) The Director of the Federal Register approved the incorporation by reference (IBR) 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. (3) The following material was approved for IBR on August 31, 2026. (i) Wipaire, Inc. Service Letter 253, Revision H, dated July 27, 2026. (ii) Wipaire, Inc. Service Letter 277, Revision C, dated July 27, 2026. (4) The following material was approved for IBR on September 4, 2024 (89 FR 67267, August 20, 2024). (i) Wipaire, Inc. Service Letter 253, Revision D, dated July 3, 2024. (ii) [Reserved] (5) For Wipaire, Inc. material identified in this AD, contact Wipaire, Inc., 1700 Henry Avenue, Fleming Field (KSGS), South St. Paul, MN 55075; phone: (651) 451-1205; email: customerservice@wipaire.com; website: wipaire.com . (6) 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. (7) 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 August 11, 2026. Steven W. Thompson, Acting Deputy Director, Compliance & Airworthiness Division, Aircraft Certification Service. [FR Doc. 2026-16672 Filed 8-13-26; 8:45 am]BILLING CODE 4910-13-P