EASA AD 2025-0155
Fuel — Fuel Pump Set and Drainer Assembly / Copper Sealing — Replacement
Summary
EASA Airworthiness Directive 2025-0155 is issued for Stemme S12 powered sailplanes, addressing a fuel leak issue related to the fuel pump set and drainer assembly copper sealing rings. The directive mandates replacement of the affected copper sealing rings with improved FKM (Viton®) sealing rings to ensure continued airworthiness and safety of these aircraft.
What Changed
This new Airworthiness Directive introduces a mandatory replacement of copper sealing rings (P/N D7603-12016-CU) in specific fuel pump and drainer assembly locations with improved FKM (Viton®) sealing rings (P/N 831984). It also prohibits installation of the affected copper sealing rings on any affected location from the effective date.
Why It Matters
This directive is critical for aviation professionals as it addresses reported fuel leaks that could lead to fire hazards in Stemme S12 powered sailplanes. Operators and maintenance organizations must comply to prevent potential safety risks and ensure regulatory compliance, avoiding grounding or operational restrictions.
What To Do
Operators of Stemme S12 powered sailplanes with affected copper sealing rings must replace these parts with the improved sealing rings before the next flight after detecting a fuel leak or within 100 flight hours from 28 July 2025. Additionally, no affected copper sealing rings may be installed on any aircraft from the effective date onward.