One may distinguish grades 100 and 100LL by

One may distinguish grades 100 and 100LL by

• A. Lead content and color
• B. Octane rating
• C. Viscosity
• D. Density

Answer: (A)

Distinguising aviation fuels in practice relies on additives and color, not just the numeric rating. The 100 grade and 100LL differ mainly in lead content, with LL standing for low lead, meaning less tetraethyl lead is used in 100LL than in older 100-grade fuels. To make misfueling less likely, fuels are color-coded — 100LL is given a distinct dye so ground crews can tell the fuels apart at a glance. The octane rating may be high for both fuels, so it doesn’t reliably differentiate them; viscosity and density aren’t practical identifiers the way the lead content and color are.

Distinguising aviation fuels in practice relies on additives and color, not just the numeric rating. The 100 grade and 100LL differ mainly in lead content, with LL standing for low lead, meaning less tetraethyl lead is used in 100LL than in older 100-grade fuels. To make misfueling less likely, fuels are color-coded — 100LL is given a distinct dye so ground crews can tell the fuels apart at a glance. The octane rating may be high for both fuels, so it doesn’t reliably differentiate them; viscosity and density aren’t practical identifiers the way the lead content and color are.