EASA AD 2025-0022
Engine Fuel & Control — Fuel Control System — Additive Application
Summary
EASA Airworthiness Directive 2025-0022 is an official safety directive addressing the fuel control system of GE Aviation Czech M601, H75, H80, and H85 series engines. These engines are commonly installed on aircraft such as the Aircraft Industries L-410 and L-420, Air Tractor AT series, Allied Ag Cat G-164, Thrush Aircraft 510G and S-2R, Viking Air DHC-3 Otter, Zlin Z-37T, and PAC FU-24. The directive mandates the periodic application of a lubricity improver additive to the fuel control unit to prevent fuel deposit-related malfunctions.
What Changed
This new directive introduces a requirement for repetitive application of a lubricity improver additive to the fuel control units of the affected engines. It addresses reported incidents where fuel deposits caused delayed or no response of the fuel control unit to engine control lever inputs. The directive references GE Aviation Czech Alert Service Bulletin SB-000469 Revision 01 for detailed application instructions.
Why It Matters
This directive is critical for maintaining engine responsiveness and safe power control by preventing fuel deposit buildup in the fuel control unit. Operators and maintenance organizations must comply to avoid potential engine power control issues that could compromise flight safety. Compliance ensures continued airworthiness and adherence to European Union aviation safety regulations.
What To Do
Affected operators must apply the lubricity improver additive within 100 flight hours after 4 February 2025 and continue to apply it at intervals not exceeding 100 flight hours thereafter. The application must follow the procedures outlined in GE Aviation Czech Alert Service Bulletin SB-000469 Revision 01. No terminating action is provided, so ongoing compliance is required.