EASA AD 2023-0119
Engine Fuel & Control — Hydromechanical Units — Replacement
Summary
EASA Airworthiness Directive 2023-0119 is an airworthiness directive addressing Rolls-Royce Trent 1000 series engines, specifically targeting the hydromechanical units (HMU) with part number G5040HMU01. The directive mandates replacement or repair of affected HMUs to prevent fuel flow reduction caused by wear in the combining spill-valve (CSV) assembly. This AD applies to all serial numbers of Trent 1000-AE3 through Trent 1000-R3 engines.
What Changed
EASA Airworthiness Directive 2023-0119 introduces engine flight hour (EFH) limits for the replacement of affected hydromechanical units and prohibits installation of HMUs that have exceeded these limits without CSV replacement. It requires operators to replace or repair the HMU before exceeding specified EFH thresholds and allows modification of engines per Rolls-Royce service bulletins as an acceptable compliance method.
Why It Matters
This directive is critical for aviation professionals because wear in the HMU's combining spill-valve can reduce fuel flow output, potentially causing thrust reduction and reduced aircraft control. Operators, maintenance organizations, and compliance teams must ensure affected parts are replaced or repaired within the specified EFH limits to maintain engine reliability and safety. Non-compliance could lead to unsafe operating conditions and regulatory penalties.
What To Do
Operators of Trent 1000 engines with affected HMUs must replace or repair these parts before exceeding 6,000 EFH or within 30 days after 26 June 2023, whichever is later, and before 4,500 EFH by 1 October 2024. Installation of affected parts exceeding EFH limits without CSV replacement is prohibited. Compliance can be achieved by following Rolls-Royce Alert NMSB TRENT 1000 73-AK733 and Service Bulletin TRENT 1000 73-K891 instructions.
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