Auburntsts
Well Known Member
So, I have an IO-540-C which, IAW Lycoming SI 1070R, was certifed to use a minimum grade of 91/96 AVGAS (which is no longer available, at least in CONUS). I need to gen up the fuel tank placards (or possibly engrave the fuel caps -- haven't decided) and I'm wondering if I should just put down "100LL" or should I put "91 OCT MIN" or something similar in case by some miracle one of those unleaded, 90ish octane 100LL substitutes becomes a reality? Of course, this is more of an issue if I go the engraved route. What say the brain trust?
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