Definition
An aviation maintenance term referring to fuel drawn directly from an aircraft's fuel tank, typically through a sump drain or sampling port, for the purpose of inspection, contamination checking, or testing. Fuel taken from the tank is used to verify grade, color, and the absence of water or sediment before flight.
Plain English
Fuel that is taken straight from the airplane's tank — usually a small sample drained out so it can be checked for water, dirt, or the wrong type of fuel before flying.
Context Anchor
Seen in fuel-system descriptions, diagrams, maintenance explanations, and cockpit discussions about where the engine’s fuel supply is coming from.
Why Pilots Care
Sampling fuel from the tank is one of the most basic and important preflight checks. Water, sediment, or the wrong fuel grade in the tank can cause engine failure. Catching contamination on the ground is the whole point of taking a sample.
Intuition Check
Do not assume this means all fuel in the tank is available to the engine. It means fuel is being supplied from the tank through the correct path to the engine.
Example Sentence 1
During preflight, the pilot drained a small amount of fuel from the tank into a clear sampler to check for water.
Example Sentence 2
During the engine run-up, the pilot verified steady fuel from the tank by watching the pressure gauge.