EASA AD 2026-0173-E
Engine Oil – Oil Pump – De-Pairing
Summary
EASA Airworthiness Directive 2026-0173-E is an emergency directive addressing RB211 Trent 800 series engines installed on aircraft such as the Boeing 777. It focuses on the oil pump components, specifically certain part numbers of oil pumps that have been identified as potentially unsafe. The directive mandates operational restrictions and maintenance actions to mitigate the risk of dual in-flight engine shutdowns.
What Changed
This new emergency airworthiness directive introduces a requirement to de-pair engines fitted with affected oil pump parts, ensuring that no aircraft operates with two engines having these non-serviceable parts installed simultaneously. It also allows replacement of affected parts with serviceable ones or engine swaps to comply with the de-pairing requirement. The directive is an interim measure pending further actions.
Why It Matters
This directive is critical for aviation professionals because it addresses a safety risk related to low oil pressure caused by oil pump input-coupling shear neck failures. Operators and maintenance organizations must ensure compliance to prevent potential dual engine shutdowns, which could severely impact flight safety and aircraft control. Compliance teams must update maintenance and operational procedures accordingly.
What To Do
From the effective date of 2026-09-08, operators must not fly aircraft with two engines installed that both have affected oil pump parts. They must either replace affected parts with serviceable ones, remove one affected engine, or follow the Rolls-Royce Alert NMSB RB211-79-AL441 instructions for de-pairing. Reinstallation of affected parts or engines is only allowed if rectified or replaced as specified in the directive.
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