EASA AD US-2025-25-07
Turbine Engine - High-Pressure Turbine (HPT) Stage 1 and HPT Stage 2 Disks - Replacement
Summary
The Federal Aviation Administration's Airworthiness Directive 2025-25-07 addresses certain General Electric Company Model GE90-90B, GE90-94B, GE90-110B1, and GE90-115B engines. It requires replacement of specific high-pressure turbine (HPT) stage 1 and stage 2 disks suspected to contain iron inclusion in the powder metal material. This directive aims to prevent premature fracture and uncontained failure of these turbine disks.
What Changed
This new airworthiness directive introduces mandatory replacement of affected HPT stage 1 and stage 2 disks identified by part and serial numbers. It updates part numbers for certain disks based on comments from GE Aerospace and incorporates GE Service Bulletin 72-0926, Revision 01, dated December 22, 2023. The directive sets compliance deadlines including immediate replacement before further flight for certain disks and replacement at next piece-part exposure or specified cycle limits for others.
Why It Matters
This directive is critical for aviation professionals to ensure engine safety and prevent uncontained engine failures that could cause damage to aircraft and risk to flight safety. Operators and maintenance organizations must track affected parts and comply with replacement schedules to maintain airworthiness. Compliance helps avoid unexpected engine failures and potential operational disruptions.
What To Do
Operators of aircraft with affected GE90 engine models must identify if installed HPT stage 1 or stage 2 disks match the listed part and serial numbers. Disks identified in the directive must be replaced before further flight or within specified cycle limits and piece-part exposures. A grace period of up to 50 flight cycles is allowed for certain stage 1 disks exceeding 4,650 cycles since new as of the effective date. Replacement parts must be eligible for installation as defined in the directive.