Definition
A refining process in which crude oil is heated and separated into different products based on their boiling points. As the heated crude vapor rises through a tall fractionating tower, it cools at different levels, and each component (or 'fraction') condenses back into liquid at the level matching its boiling point. Lighter products like aviation gasoline condense near the top; heavier products like diesel and lubricating oils condense lower down.
Plain English
Heating crude oil so it turns into vapor, then collecting different fuels and oils as the vapor cools at different heights inside a tall tower. Each type of fuel cools back into liquid at its own level, which is how they get separated.
Context Anchor
Seen in aircraft maintenance discussions about how petroleum products, including fuels and oils, are produced and separated.
Derivation
From Latin 'fractio' meaning 'a breaking,' and 'distillare' meaning 'to drip down.' Crude oil is broken into parts (fractions) by letting the vapors drip back down as they cool. The name describes exactly what happens inside the tower.
Why Pilots Care
Aviation fuels are specific fractions of crude oil with carefully controlled properties. Knowing fuel comes from a separation process helps pilots understand why grade, purity, and contamination matter so much.
Grounding Statement
When crude petroleum is heated, the lighter parts separate first, and the heavier parts need more heat before they separate.
Intuition Check
Fractional distillation does not mean the liquid is only partly distilled. It means the mixture is separated into fractions, or parts, based on the temperatures at which those parts vaporize and condense.
Example Sentence 1
Aviation gasoline is one of the lighter products produced by fractional distillation of crude oil.
Example Sentence 2
Maintenance technicians understand that the properties of aviation gasoline depend on the fractions collected during fractional distillation.