SESKStuff Everyone Should Know
SESK: Stuff Everyone Should Know · sesk.info/pilot-fuel-next-higher-grade

If your engine's recommended fuel grade is not available, what should you use?

The next higher grade, never a lower one.

  1. The next lower grade
  2. Automotive gasoline of any grade
  3. The next higher grade ✔

Why: A lower grade can push cylinder head and oil temperatures past normal and cause detonation. The FAA says to use the next higher grade as a substitute and never a grade lower than recommended.

Huh, didn't know that: 100LL avgas is dyed blue, and the newer 100VLL is also blue and virtually indistinguishable from it.

The dad joke
Why did the airplane get blue fuel? It was feeling a little low-lead.
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Sources

  1. FAA Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C), Chapter 7 https://www.faa.gov/regulations_policies/handbooks_manuals/aviation/faa-h-8083-25c.pdf

Test yourself in the game

Flying & DronesFor weight and balance, how much does one gallon of avgas weigh?Flying & DronesFlying VFR by day, how much fuel must remain after reaching your first planned landing?Flying & DronesFlying VFR at night, what minimum fuel reserve does an airplane need after the first planned landing?

That's stuff everyone should know.