EASA AD US-2021-26-06
Engine - Transfer Gearbox Radial Gearshaft - Inspection / Replacement
Summary
Federal Register Volume 87, Number 7 Airworthiness Directive 2021-26-06 is a final rule issued by the FAA addressing certain General Electric Company GE90 model turbofan engines. It mandates inspection and possible replacement of the transfer gearbox (TGB) radial bevel gearshaft due to failures that caused two in-flight shutdowns. The directive applies to GE90-76B, GE90-85B, GE90-90B, GE90-94B, GE90-110B1, and GE90-115B engines with affected serial numbers.
What Changed
This new airworthiness directive introduces a requirement for a one-time visual inspection of the TGB radial gearshaft for burrs or rework on teeth chamfers and mandates replacement if defects are found. It clarifies the definition of an engine shop visit and excludes certain serial number ranges from inspection requirements. The AD also adds an interim action paragraph pending further investigation of additional affected gearshafts.
Why It Matters
This AD is critical for aviation professionals because it addresses a safety risk that could lead to engine failure and in-flight shutdowns. Operators and maintenance organizations must ensure compliance to prevent potential catastrophic engine malfunctions. The directive helps maintain airworthiness and operational safety of aircraft powered by affected GE90 engines.
What To Do
Operators of affected GE90 engines must perform a visual inspection of the TGB radial gearshaft at the next engine shop visit involving disassembly of the compressor discharge pressure seal joint. If defects are found, the gearshaft must be replaced before further flight. Compliance with this AD is mandatory by February 15, 2022.
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