WITHDRAWN: TECHNICAL CONTENT COVERED IN CS-STAN, SUBPART B, CS-SC203
- Published
AI-generated summary of the official EASA document. Verify against the PDF before acting.
What to do
Operators should verify engine approval for Hjelmco Avgas 91/96 UL or 91/98 UL by consulting the latest engine type certificate holder instructions and confirm engine specifications have not been altered. They should check engine data plates and operating manuals for octane and temperature limits, label fuel caps appropriately, and for Lycoming engines, update manuals per Lycoming service instructions. No mandatory compliance deadline is specified.
Summary
EASA Safety Information Bulletin SIB No. 2010-31 informs owners and operators of aeroplanes powered by spark-ignited piston engines about the use of unleaded Hjelmco Avgas 91/96 UL and 91/98 UL fuels. These fuels meet certain military and ASTM standards and may be used in engines approved for these grades without additional aeroplane approval. The bulletin specifically references engine types such as Rotax, Lycoming, and Kalisz.
What changed
This bulletin introduces information regarding the use of unleaded Hjelmco Avgas 91/96 UL and 91/98 UL as alternatives to traditional leaded Avgas 100LL. It clarifies that these unleaded fuels have different properties, including lower octane ratings and lead content, and provides guidance on engine approvals and compatibility. The bulletin also highlights that use in non-approved engines may cause damage or failure.
Why it matters
This information is important for aviation professionals because it affects fuel selection and engine operation for piston-engine aeroplanes. Operators and maintenance organizations must ensure that engines are approved for these unleaded fuels to avoid potential engine damage or in-flight failures. Compliance with engine manufacturer instructions and fuel specifications is critical for safety and airworthiness.
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