In the NPRM, the FAA proposed to continue to require the actions in AD 2023-21-10 and require expanding the applicability and inspecting the HS front spar web and center box internal area for discrepancies and accomplishing applicable corrective actions, as specified in EASA AD 2025-0110. 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-2026-3878.
The FAA received a comment from the Air Line Pilots Association, International (ALPA) who supported the NPRM without change.
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. 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.
EASA AD 2025-0110 specifies procedures for a one-time detailed inspection of the HS left-hand and right-hand leading edge lateral ribs, the box in between the center box upper panel, HS forward back-up fitting, and the HS front spar web and center box internal area for discrepancies (
i.e.,
any loose, missing, or incorrectly installed fasteners, any composite delamination, and any cracked fittings); and applicable corrective actions. Corrective actions include contacting the manufacturer for repair instructions if any discrepancy is detected during any inspection.
The FAA also reviewed ATR Service Bulletin ATR42-55-0020, Revision 03, dated January 31, 2025; ATR Service Bulletin ATR72-55-1013, Revision 03, dated January 31, 2025; ATR Service Bulletin ATR42-55-0025, dated February 3, 2025; and ATR Service Bulletin ATR72-55-1018, dated February 3, 2025. This material identifies the affected airplane serial numbers.
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.
The FAA estimates that this AD affects 16 airplanes of U.S. registry. The FAA estimates the following costs to comply with this AD:
The FAA has received no definitive data on which to base the cost estimates for the on-condition repairs specified in this AD.
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.
(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.
Accordingly, under the authority delegated to me by the Administrator, the FAA amends 
14 CFR part 39 as follows:
2. The FAA amends § 39.13 by:
a. Removing Airworthiness Directive (AD) 2023-21-10, Amendment 39-22582 ( 88 FR 83820, December 1, 2023); and
b. Adding the following new AD:
2026-16-07 ATR-GIE Avions de Transport Régional:
Amendment 39-23437; Docket No. FAA-2026-3878; Project Identifier MCAI-2025-00913-T.
(a) Effective Date
This airworthiness directive (AD) is effective September 18, 2026.
(b) Affected ADs
This AD replaces AD 2023-21-10, Amendment 39-22582 (88 FR 83820, December 1, 2023) (AD 2023-21-10).
(c) Applicability
This AD applies to ATR-GIE Avions de Transport Régional Model ATR42-500 and ATR72-212A airplanes, certificated in any category, as identified in ATR Service Bulletin ATR42-55-0020, Revision 03, dated January 31, 2025; ATR Service Bulletin ATR72-55-1013, Revision 03, dated January 31, 2025; ATR Service Bulletin ATR42-55-0025, dated February 3, 2025; or ATR Service Bulletin ATR72-55-1018, dated February 3, 2025; as applicable.
(d) Subject
Air Transport Association (ATA) of America Code 55, Stabilizers.
(e) Unsafe Condition
This AD was prompted by reports of loose fasteners and cracks in the horizontal stabilizer (HS) left- and right-hand leading edge lateral ribs, the box in between, the center box upper panel, and HS forward back-up fitting. This AD was also prompted by a determination that additional airplanes are affected by the unsafe condition, and that the HS front spar web and center box internal area also need to be inspected. The FAA is issuing this AD to address loose, missing, or incorrectly installed fasteners, composite delamination, and cracks in the HS. The unsafe condition, if not addressed, could result in reduced structural integrity of the airplane.
(f) Compliance
Comply with this AD within the compliance times specified, unless already done.
(g) Requirements
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, European Union Aviation Safety Agency (EASA) AD 2025-0110, dated May 14, 2025 (EASA AD 2025-0110).
(h) Exceptions to EASA AD 2025-0110
(1) Where the Groups definition for Group 3 airplanes in EASA AD 2025-0110 refers to “the SB2”, this AD requires replacing this text with “ATR Service Bulletin ATR42-55-0025, dated February 3, 2025; or ATR Service Bulletin ATR72-55-1018, dated February 3, 2025; as applicable”.
(2) Where EASA AD 2025-0110 refers to “06 July 2023 [the effective date of EASA AD 2023-0125],” this AD requires using January 5, 2024 (the effective date of AD 2023-21-10).
(3) Where EASA AD 2025-0110 refers to its effective date, this AD requires using the effective date of this AD.
(4) Where paragraph (2) of EASA AD 2025-0110 specifies if “any discrepancy as defined in the SB1 or the SB2, as applicable, is detected, before next flight, contact ATR for approved repair instructions and, within the compliance time identified therein, accomplish those instructions accordingly. If no compliance time for the repair is identified in those instructions, accomplish those instructions before next flight.”, this AD requires replacing that text with “any discrepancy other than cracking is detected, before next flight, contact ATR for approved repair instructions and, within the compliance time identified therein, accomplish those instructions accordingly, except if no compliance time for the repair is identified in those instructions, accomplish those instructions before next flight; and if any crack is detected, the crack must be repaired before further flight using a method approved by the Manager, International Validation Branch, FAA; or EASA; or ATR-GIE Avions de Transport Régional's EASA Design Organization Approval (DOA). If approved by the DOA, the approval must include the DOA-authorized signature.”
(5) This AD does not adopt the “Remarks” section of EASA AD 2025-0110.
(i) No Reporting Requirement
Although the material referenced in EASA AD 2025-0110 specifies to submit certain information to the manufacturer, this AD does not include that requirement.
(j) Additional AD Provisions
The following provisions also apply to this AD:
(1)
Alternative Methods of Compliance (AMOCs):
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 responsible Flight Standards 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 (k) of this AD and email to:
AMOC@faa.gov. Before using any approved AMOC, notify your appropriate principal inspector, or lacking a principal inspector, the manager of the responsible Flight Standards Office.
(2)
Contacting the Manufacturer:
For any requirement in this AD to obtain instructions from a manufacturer, the instructions must be accomplished using a method approved by the Manager, International Validation Branch, FAA; or EASA; or ATR-GIE Avions de Transport Régional's EASA DOA. If approved by the DOA, the approval must include the DOA-authorized signature.
(k) Additional Information
For more information about this AD, contact Christopher Spencer, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: 516-228-7332; email:
9-AVS-AIR-BACO-COS@faa.gov.
(l) 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 this AD specifies otherwise.
(i) ATR Service Bulletin ATR42-55-0020, Revision 03, dated January 31, 2025.
(ii) ATR Service Bulletin ATR42-55-0025, dated February 3, 2025.
(iii) ATR Service Bulletin ATR72-55-1013, Revision 03, dated January 31, 2025.
(iv) ATR Service Bulletin ATR72-55-1018, dated February 3, 2025.
(v) European Union Aviation Safety Agency (EASA) AD 2025-0110, dated May 14, 2025.
(3) For EASA material identified in this AD, contact EASA, Konrad-Adenauer-Ufer 3, 50668 Cologne, Germany; telephone +49 221 8999 000; email
ADs@easa.europa.eu.
You may find this material on the EASA website at
ad.easa.europa.eu.
(4) For ATR-GIE Avions de Transport Régional material identified in this AD, contact ATR-GIE Avions de Transport Régional, 1 Allée Pierre Nadot, 31712 Blagnac Cedex, France; telephone +33 (0) 5 62 21 62 21; fax +33 (0) 5 62 21 67 18; email
continued.airworthiness@atr aircraft.com;
website
atr-aircraft.com.
(5) You may view this material at the FAA, Airworthiness Products Section, Operational Safety Branch, 2200 South 216th St., Des Moines, WA. For information on the availability of this material at the FAA, call 206-231-3195.
(6) 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.