What happens when blue (100LL) and red (80) fuel are mixed?

When blue 100LL aviation fuel and red 80 octane fuel are mixed, the resultant mixture typically appears brown. This is due to the different dyes that are used to color the fuels: the blue dye in 100LL and the red dye in 80 octane fuel. When combined, these dyes interact in such a way that the mixture yields a brown coloration. This color change is an important factor for pilots and other personnel to consider, as it indicates the presence of different fuel types, which can be critical for safety and operational reasons. Proper fuel identification is essential to ensure that the correct type of fuel is being used in aircraft, thus preventing potential engine issues or failures.