AD 2023-26-07 Airworthiness Directives; General Electric Company Engines

Models named: GE90-90B, GE90-94B. Read the applicability below — it usually turns on serial or part numbers too.

This AD applies to General Electric Company (GE) Model GE90-90B and GE90-94B engines with interstage HPT seals listed in Table 1 to Paragraph (c) of this AD and GE90-110B1 and GE90-115B engines with an installed high-pressure turbine (HPT) stage 1 disk, HPT stage 2 disk, forward HPT rotor seal, or stages 7-9 compressor rotor spool part number (P/N) and serial number (S/N) identified in Table 1 to Paragraph (c) of this AD, or identified in Paragraph 4. APPENDIX—A, Tables 1, 2, or 3, of GE GE90-100 Service Bulletin (SB) 72-0914, dated January 25, 2023 (GE90-100 SB 72-0914). Table 1 to Paragraph (c)—Affected HPT Stage 1 and Stage 2 Disks, and Interstage HPT Seals ER23JA24.021 Note 1 to paragraph (c): Part numbers and serial numbers for affected HPT stage 1 disks, HPT stage 2 disks, and interstage HPT seals are also listed in GE GE90-100 Service Bulletin (SB) 72-0904 R00, dated May 25, 2022; GE GE90-100 SB 72-0911 R01, dated September 21, 2022; and GE GE90 SB 72-1223, dated January 25, 2023.

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

At the applicable times specified in paragraphs (g)(1) through (6) of this AD, remove each affected HPT stage 1 disk, HPT stage 2 disk, forward HPT rotor seal, interstage HPT seal, and stages 7-9 compressor rotor spool from service and replace with a part eligible for installation. (1) For HPT stage 1 disks, before further flight. (2) For HPT stage 2 disks with a part number and serial number identified in Paragraph 4. APPENDIX—A, Table 1 of GE90-100 SB 72-0914, at the next piece part exposure or before exceeding 3,500 cycles since new (CSN), whichever occurs first. (3) For HPT stage 2 disks with a part number and serial number identified in Table 1 to paragraph (c) of this AD, before further flight. (4) For forward HPT rotor seals with a part number and serial number identified in Paragraph 4. APPENDIX—A, Table 3 of GE90-100 SB 72-0914, at the next piece part exposure or before exceeding 14,200 CSN, whichever occurs first. (5) For interstage HPT seals, at the next piece part exposure or before exceeding 12,600 CSN, whichever occurs first. (6) For stages 7-9 compressor rotor spools, at the next piece part exposure or before exceeding the cyclic removal thresholds identified in Paragraph 4. APPENDIX—A, Table 2 of GE90-100 SB 72-0914, whichever occurs first.

This AD was prompted by a manufacturer investigation that revealed certain HPT stage 1 disks, HPT stage 2 disks, forward HPT rotor seals, interstage HPT seals, and stages 7-9 compressor rotor spools were manufactured from powder metal material suspected to contain iron inclusion. The FAA is issuing this AD to prevent premature fracture and subsequent uncontained failure. The unsafe condition, if not addressed, could result in uncontained debris release, damage to the engine, and damage to the airplane.

None.