EASA AD 2023-0113
Engine Fuel & Control — Hydromechanical Units — Replacement
Summary
EASA Airworthiness Directive 2023-0113 is an airworthiness directive addressing Rolls-Royce Trent 1000 series engines, specifically targeting the hydromechanical units (HMU) with certain part numbers. The directive mandates replacement or repair of affected HMUs due to wear found in the combining spill valve (CSV) assembly, which can reduce fuel flow and potentially lead to thrust reduction and reduced aircraft control.
What Changed
This new regulation introduces mandatory replacement of affected hydromechanical units before exceeding specified engine flight hour limits and prohibits installation of HMUs that have exceeded these limits without CSV replacement. It also requires removal of certain HMUs by the end of 2028 unless the CSV has been replaced according to specified service bulletins.
Why It Matters
This directive is critical for operators and maintenance organizations to prevent thrust loss caused by wear in the HMU's combining spill valve, ensuring continued safe engine performance. Compliance helps avoid potential in-flight control issues and maintains regulatory airworthiness standards. Maintenance and compliance teams must track engine flight hours closely to meet replacement deadlines.
What To Do
Operators must replace affected HMUs before they exceed the engine flight hour limits specified in the directive, with deadlines starting from 15 June 2023 and tightening by 1 January 2025. Installation of HMUs is only allowed if they are serviceable as defined by the AD. Additionally, all affected HMUs with serial numbers SHV06-001 to SHV18-999 must be removed by 31 December 2028 unless CSV replacement is confirmed.
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