EASA AD 2025-0155: Fuel — Fuel Pump Set and Drainer Assembly / Copper Sealing — Replacement | RegNotify

Airworthiness DirectiveEASA AD 2025-0155

Fuel — Fuel Pump Set and Drainer Assembly / Copper Sealing — Replacement

Published: Jul 21, 2025
Effective: Jul 28, 2025

Stemme Ag S12

AI-generated summary of the official EASA document. Verify against the PDF before acting.

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.

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.

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