Final answer:
The aviation gasoline dyed blue is grade 100LL, which indicates it is a low-lead fuel primarily used in small piston-engine aircraft.
Step-by-step explanation:
The grade of aviation gasoline that is dyed blue is known as 100LL (low lead). This specific grade is the most commonly used aviation gasoline in small piston-engine aircraft. The blue dye is added to provide a visual method to differentiate it from other types of aviation fuels and to avoid the possibility of using the wrong type of fuel, which could be potentially hazardous.
Aviation gasoline grades are determined by their octane rating, which indicates the fuel's ability to resist knocking or pre-ignition, a critical factor in aviation engines.