AD 2021-26-22 Prompted By An Uncontained Failure Of An HPT Stage 2 Disk

The FAA is superseding Airworthiness Directive (AD) 2020-20-13 for certain General Electric Company (GE) CF6-80A and CF6-80C model turbofan engines.

AD 2020-20-13 required ultrasonic inspection (UI) of high-pressure turbine (HPT) stage 1 and stage 2 disks and replacement of any HPT stage 1 or stage 2 disk that fails the inspection. This AD was prompted by an uncontained failure of an HPT stage 2 disk and the manufacturer's subsequent determination to expand the population of affected HPT disks requiring UI inspection. This AD requires UI of HPT stage 1 and stage 2 disks and replacement of any HPT stage 1 or stage 2 disk that fails the inspection. This AD also expands the applicability to include an additional population of affected HPT stage 1 and 2 disks requiring UI inspection. The FAA is issuing this AD to address the unsafe condition on these products. This AD is effective March 14, 2022.

Supplementary Information: The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to supersede AD 2020-20-13, Amendment 39-21269 (85 FR 63193, October 7, 2020), (AD 2020-20-13). AD 2020-20-13 applied to certain GE CF6-80A, CF6-80A1, CF6-80A2, CF6-80A3, CF6-80C2A1, CF6-80C2A2, CF6-80C2A3, CF6-80C2A5, CF6-80C2A5F, CF6-80C2A8, CF6-80C2B1, CF6-80C2B1F, CF6-80C2B2, CF6-80C2B2F, CF6-80C2B4, CF6-80C2B4F, CF6-80C2B5F, CF6-80C2B6, CF6-80C2B6F, CF6-80C2B6FA, CF6-80C2B7F, CF6-80C2D1F, CF6-80C2L1F, and CF6-80C2K1F model turbofan engines. The NPRM published in the Federal Register on October 6, 2021 (86 FR 55545). The NPRM was prompted by an uncontained failure of an HPT stage 2 disk and the manufacturer's determination to expand the population of affected HPT disks requiring UI inspection.

After the FAA issued AD 2020-20-13, the manufacturer discovered an error in the service information and determined that the requirement to perform UI of affected HPT stage 1 and 2 disks should be expanded to include an additional population of HPT stage 1 and stage 2 disks. GE, therefore, revised its service information to include the additional affected HPT stage 1 and stage 2 disks. In the NPRM, the FAA proposed to continue to require UI of HPT stage 1 and stage 2 disks and replacement of any HPT stage 1 or stage 2 disk that fails the inspection. In the NPRM, the FAA also proposed to expand the applicability to include an additional population of affected HPT stage 1 and 2 disks.

FMI: www.regulations.gov