Definition
A spring-loaded valve at the low point of the fuel strainer that allows the pilot to draw a small sample of fuel from the system during preflight. It is used to check for water, sediment, and the correct fuel grade by color, and to confirm that fuel is reaching the strainer.
Plain English
A small valve under the airplane that lets you take a fuel sample from the strainer before flight, so you can check that the fuel is clean and the right type.
Context Anchor
You encounter it during the preflight inspection of the fuel system, usually when sampling fuel before the first flight of the day or after refueling.
Derivation
Strainer' filters out particles; 'quick drain' refers to the valve design that opens with a brief push and closes again on its own, allowing a fast sample without tools.
Why Pilots Care
Allows visual detection of water or sediment that could cause engine failure if left undetected.
Intuition Check
Do not think of the fuel strainer quick drain as a way to empty the fuel system. Its normal use is to release a small sample so contamination can be found and removed.
Example Sentence 1
During preflight, the pilot held a clear sampling cup under the fuel strainer quick drain and pressed the valve to check for water in the fuel.
Example Sentence 2
After refueling from an unfamiliar source the pilot drained additional fuel through the fuel strainer quick drain to confirm cleanliness.