EASA SIB 2019-08: Safran Aerosystems Flight Crew Oxygen Masks — Clogging of Ceramic Valves

What to do

Operators of aircraft equipped with the affected Safran Aerosystems oxygen regulator mask assemblies should perform a one-time inspection and replace the regulator main casing if necessary, following the instructions in Zodiac Aerotechnics Service Bulletin MF10-20-35-330. Flight crews should be informed about the risks and advised to breathe calmly if initial breathing difficulties occur. There are no mandatory compliance deadlines as this bulletin provides recommendations only.

Summary

EASA Safety Information Bulletin 2019-08 is a safety information bulletin addressing the clogging of ceramic pilot valve seats in Safran Aerosystems flight crew oxygen regulator mask assemblies, specifically part numbers MF10-05-11 and MF20-534. These assemblies are installed on Airbus aircraft. The bulletin informs operators about breathing difficulties caused by partially clogged ceramic valves and provides guidance on inspection and replacement procedures.

What changed

This bulletin introduces awareness of a potential issue with the ceramic pilot valve seats in certain Safran Aerosystems oxygen masks that may cause delayed oxygen supply. It references Zodiac Aerotechnics Service Bulletin MF10-20-35-330, which provides instructions for inspection and replacement of the regulator main casing if necessary. The bulletin clarifies that the issue does not currently warrant mandatory Airworthiness Directive action.

Why it matters

This information is important for aviation professionals because partially clogged oxygen regulator valves can increase pilot workload and potentially reduce aircraft control during critical situations such as smoke presence or cabin decompression. Operators and maintenance teams need to be aware of the risk to ensure flight crew safety and maintain proper oxygen system functionality. Understanding this issue helps in proactive maintenance and crew training to mitigate operational risks.