2026-09-02: Turbine Engine Compressor Section

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: 2026-09-02 Pratt & Whitney RTX Corporation (Type Certificate Previously Held by Pratt & Whitney Division United Technologies Corporation): Amendment 39-23322; Docket No. FAA-2025-0923; Project Identifier AD-2024-00529-E. (a) Effective Date This airworthiness directive (AD) is effective June 26, 2026. (b) Affected ADs None. (c) Applicability This AD applies to certain Pratt & Whitney RTX Corporation (type certificate previously held by Pratt & Whitney Division United Technologies Corporation) (PW) Model PW4074, PW4074D, PW4077, PW4077D, PW4084D, PW4090, and PW4090-3 engines. (d) Subject Joint Aircraft System Component (JASC) Code 7250, Turbine Section; 7230, Turbine Engine Compressor Section. (e) Unsafe Condition This AD was prompted by an analysis of an event involving an International Aero Engines, LLC Model PW1127GA-JM engine, which experienced a high-pressure compressor (HPC) 7th-stage integrally bladed rotor separation that resulted in an aborted takeoff. The FAA is issuing this AD to prevent failure of the HPC 15th-stage disk, front turbine hub, high pressure turbine (HPT) 1st-stage air seal, and HPT 2nd-stage hub. The unsafe condition, if not addressed, could result in uncontained disk failure, release of high energy debris, damage to the engine, damage to the airplane, and possible loss of the airplane. (f) Compliance Comply with this AD within the compliance times specified, unless already done. (g) Required Actions (1) For HPT 1st-stage air seals with a serial number identified in table 1 to paragraph (g)(1) of this AD: At the next piece part opportunity after the effective date of this AD, remove the HPT 1st-stage air seal from service and replace with a part eligible for installation. Table 1 to Paragraph ( g )(1)-HPT 1st-Stage Air Seals Affected Serial Numbers Serial No. Part No. (P/N) CKLBME2702 50L663 CKLBME2703 50L663 CKLBME2704 50L663 CKLBME2705 50L663 CKLBME2711 50L663 CKLBMS8019 50L959 (2) At the next piece part opportunity after the effective date of this AD, and thereafter at every piece part opportunity, perform angle ultrasonic scan inspections (AUSIs) of the HPC 15th-stage disk, front turbine hub, HPT 1st-stage air seal, and HPT 2nd-stage hub for crack indications in accordance with the applicable service information specified in paragraph (g)(2)(i) through (iv) of this AD. (i) For HPC 15th-stage disks: Accomplishment Instructions, paragraph 4.A or 4.B., of PW Alert Service Bulletin (ASB) PW4G-112-A72-365, Revision No. 1, dated June 20, 2024. (ii) For front turbine hubs: Accomplishment Instructions, paragraph 4.A or 4.B., of PW ASB PW4G-112-A72-367, dated June 20, 2024. (iii) For HPT 1st-stage air seals: Accomplishment Instructions, paragraph 4.A or 4.B., of PW ASB PW4G-112-A72-366, dated June 20, 2024. (iv) For HPT 2nd-stage hubs: Accomplishment Instructions, paragraph 4.A or 4.B., of PW ASB PW4G-112-A72-368, dated June 20, 2024. (3) If during any inspection required by paragraph (g)(2) of this AD, any crack indication is found, before further flight, remove the part from service and replace with a part eligible for installation. (h) Definitions For the purposes of this AD: (1) A "piece part opportunity" is one of the conditions specified in paragraph (h)(1)(i) through (iv). (i) The HPC 15th-stage disk is removed from the engine and all blades are removed. (ii) The front turbine hub is removed from the engine and all blades are removed. (iii) The HPT 2nd-stage hub is removed from the engine and all blades are removed. (iv) The HPT 1st-stage air seal is fully disassembled from the engine. (2) A "part eligible for installation" is: (i) An HPC 15th-stage disk having P/N 51S115, 51S315, 55H615, or 56H015 that has passed the angle ultrasonic scan inspection (AUSI) required by paragraph (g)(2)(i) of this AD. (ii) An HPC 15th-stage disk having P/N 51S115 or 56H015 that has a certificate of conformance that shows compliance with Non-Destructive Inspection Procedure (NDIP)-1276. (iii) An HPC 15th-stage disk having P/N 51S315 or 55H615 that has a certificate of conformance that shows compliance with NDIP-1289. (iv) A front turbine hub having P/N 55L801 or 55L901 that has passed the AUSI required by paragraph (g)(2)(ii) of this AD. (v) A front turbine hub having P/N 55L801 that has a certificate of conformance that shows compliance with NDIP-1273. (vi) A front turbine hub having P/N 55L901 that has a certificate of conformance that shows compliance with NDIP-1288. (vii) An HPT 1st-stage air seal having P/N 50L663 or 50L959 that has passed the AUSI required by paragraph (g)(2)(iii) of this AD. (viii) An HPT 1st-stage air seal having P/N 50L663 that has a certificate of conformance that shows compliance with NDIP-1286. (ix) An HPT 1st-stage air seal having P/N 50L959 that has a certificate of conformance that shows compliance with NDIP-1287. (x) An HPT 2nd-stage hub having P/N 53L202 or 54L802 that has passed the AUSI required by paragraph (g)(2)(iv) of this AD. (xi) An HPT 2nd-stage hub having P/N 53L202 that has a certificate of conformance that shows compliance with NDIP-1274. (xii) An HPT 2nd-stage hub having P/N 54L802 that has a certificate of conformance that shows compliance with NDIP-1275. (xiii) Any HPC 15th-stage disk, front turbine hub, HPT 1st-stage air seal, or HPT 2nd-stage hub that is new, zero-time, and that has an FAA Form 8130-3 from the original equipment manufacturer for new production dated July 1, 2025, or later. (i) Optional Terminating Action-Airworthiness Limitations Section (ALS) Revision Revising the ALS of the existing engine manual and the operator's existing approved maintenance program or inspection program, as applicable, by incorporating the information in figure 1 to paragraph (i) of this AD, constitutes terminating action for the actions required by paragraphs (g)(1) through (3) of this AD. Figure 1 to Paragraph ( i )-ALS Additional Inspections Engine manuals P/N 51A345 and 51A751 B. Parts requiring inspection description CIR manual 51A750 inspection check-02 update to include Chapter/Section 05-10-00 PW4000 SERIES ENGINE MANUAL ENGINE-AIRWORTHINESS LIMITATIONS-TIME LIMITS P/N 51A345 Revision Date: 2025-02-01 TASK 05-10-01-990-004. 5. Critical Life Limited Part Inspection and Critical Part Inspection. P/N 51A751 Revision Date: 2025-07-01 TASK 05-10-01-990-007. 5. Critical Life Limited Part Inspection and Critical Part Inspection. Seal-Air, HPT 1st Stage TASK 72-52-19-200-001. 1. Non-Destructive Inspection-Stage 1 HPT Airseal H. Angle Ultrasonic Inspection (1) Do an Angle Ultrasonic Inspection for P/N 50L663 by NDIP-1286 and for P/N 50L959 by NDIP-1287. Chapter/Section 05-10-00 PW4000 SERIES ENGINE MANUAL ENGINE-AIRWORTHINESS LIMITATIONS-TIME LIMITS P/N 51A345 Revision Date: 2025-02-01 TASK 05-10-01-990-004. 5. Critical Life Limited Part Inspection and Critical Part Inspection. P/N 51A751 Revision Date: 2025-07-01 TASK 05-10-01-990-007. 5. Critical Life Limited Part Inspection and Critical Part Inspection. Hub, Turbine Front Assembly (1st Stage) TASK 72-52-05-200-001. 1. Non-Destructive Inspection-Turbine Front Hub (Stage 1)-H. Angle Ultrasonic Inspection (1) Do an Angle Ultrasonic Inspection for Assembly P/N 55L221 or Detail P/N 55L801 by NDIP-1273 and for Assembly P/N 55L521 or Detail P/N 55L901 by NDIP-1288. Chapter/Section 05-10-00 PW4000 SERIES ENGINE MANUAL ENGINE-AIRWORTHINESS LIMITATIONS-TIME LIMITS P/N 51A345 Revision Date: 2025-02-01 TASK 05-10-01-990-004. 5. Critical Life Limited Part Inspection and Critical Part Inspection. P/N 51A751 Revision Date: 2025-07-01 TASK 05-10-01-990-007. 5. Critical Life Limited Part Inspection and Critical Part Inspection. Hub, Turbine Rear Assembly (2nd Stage) TASK 72-52-06-200-001. 1. Non-Destructive Inspection-Turbine Intermediate Hub (Stage 2)-H. Angle Ultrasonic Inspection (1) Do an Angle Ultrasonic Inspection for Assembly P/N 53L232 and Detail P/N 53L202 by NDIP-1274 and for Assembly P/N 54L932 and Detail P/N 54L802 by NDIP-1275. Chapter/Section 05-10-00 PW4000 SERIES ENGINE MANUAL ENGINE-AIRWORTHINESS LIMITATIONS-TIME LIMITS P/N 51A345 Revision Date: 2025-02-01 TASK 05-10-01-990-004. 5. Critical Life Limited Part Inspection and Critical Part Inspection. P/N 51A751 Revision Date: 2025-07-01 TASK 05-10-01-990-007. 5. Critical Life Limited Part Inspection and Critical Part Inspection. HPC Disk 15th Stage TASK 72-35-92-200-001. 1. Non-Destructive Inspection-HPC Disk 15th Stage-H. Angle Ultrasonic Inspection (1) Do an Angle Ultrasonic Inspection for P/N 55H615 and P/N 51S315 by NDIP-1289. TASK 72-35-92-200-001-A. 1. Non-Destructive Inspection-HPC Disk 15th Stage-I. Angle Ultrasonic Inspection (1) Do an Angle Ultrasonic Inspection for P/N 56H015 and P/N 51S115 by NDIP-1276. (j) Alternative Methods of Compliance (AMOCs) (1) The Manager, AIR-520 Continued Operational Safety 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 AIR-520 Continued Operational Safety Branch, send it to the attention of the person identified in paragraph (k) of this AD. Information may be emailed 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. (k) Additional Information For more information about this AD, contact Molly Sturgis, Aviation Safety Engineer, FAA, 2200 South 216th Street, Des Moines, WA 98198; phone: (562) 627-5373; email: molly.a.sturgis@faa.gov. (l) 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 the actions required by this AD, unless the AD specifies otherwise. (i) Pratt & Whitney RTX Corporation (PW) Alert Service Bulletin (ASB) PW4G-112-A72-365, Revision No. 1, dated June 20, 2024. (ii) PW ASB PW4G-112-A72-366, dated June 20, 2024. (iii) PW ASB PW4G-112-A72-367, dated June 20, 2024. (iv) PW ASB PW4G-112-A72-368, dated June 20, 2024. (3) For PW material identified in this AD, contact PW, 400 Main Street, East Hartford, CT 06118; phone: (800) 565-0140; email: help24@prattwhitney.com; website: connect.prattwhitney.com. (4) You may view this material at the FAA, Airworthiness Products Section, Operational Safety Branch, 1200 District Avenue, Burlington, MA 01803. 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 fr.inspection@nara.gov. Issued on May 20, 2026. Lona C. Saccomando, Acting Deputy Director, Integrated Certificate Management Division, Aircraft Certification Service. [FR Doc. 2026-10360 Filed 5-21-26; 8:45 am]BILLING CODE 4910-13-P