EASA AD 2025-0233
Engine — High-Pressure Compressor / Mini-Disc Anti-Rotation Block — Inspection / Modification
Summary
EASA Airworthiness Directive 2025-0233 is an official directive addressing the inspection and modification of the high-pressure compressor mini-disc anti-rotation block in Rolls-Royce Trent 1000 engines installed on Boeing 787 aircraft. It applies to Trent 1000-A, -AE, -C, -CE, -D, -E, -G, and -H engine variants with specific service bulletins embodied, excluding those with a particular production modification. The directive mandates inspections and a design modification to ensure engine safety and reliability.
What Changed
EASA Airworthiness Directive 2025-0233 supersedes the previous AD 2024-0122 and introduces a mandatory modification involving a revised bolting arrangement and updated components at the high-pressure compressor rotor shaft interface. This modification eliminates the unsafe condition of potential part release within the compressor assembly, replacing the prior requirement for repetitive inspections with a terminating design change.
Why It Matters
This directive is critical for aviation professionals because it addresses a safety risk that could lead to structural failures in critical engine parts, potentially affecting aircraft operation and safety. Operators and maintenance organizations must comply to prevent in-service failures and ensure continued airworthiness. The modification reduces the need for frequent inspections, improving operational efficiency and reliability.
What To Do
Operators must perform borescope inspections of the high-pressure compressor rear drum and rotor disc cavities within 800 engine flight cycles after 12 July 2024 and continue at 800 EFC intervals until the modification is completed. If any missing or loose parts are found, the engine must be removed from service and repaired per Rolls-Royce instructions before return to service. The mandatory engine modification must be completed within 67 months of 6 November 2025, which will terminate the inspection requirements.