Definition
A cockpit-mounted valve control used to choose which fuel tank feeds the engine. Typical positions include LEFT, RIGHT, BOTH, and OFF, depending on the airplane's fuel system design.
Plain English
The knob or lever in the cockpit that decides which fuel tank the engine is drawing fuel from, or shuts the fuel off entirely.
Context Anchor
You check the tank selector before starting the engine, including before hand propping, so the engine has fuel from the intended tank.
Why Pilots Care
Correct tank selection maintains continuous fuel flow, prevents engine stoppage from an empty tank, and avoids fuel imbalance or contamination.
Intuition Check
Do not think of the tank selector as a fuel gauge. It does not show how much fuel is in a tank; it controls which tank the engine is drawing fuel from.
Example Sentence 1
Before hand propping the airplane, the pilot confirmed the tank selector was set to BOTH and the mixture was at idle cutoff.
Example Sentence 2
In cruise the pilot moved the tank selector to the right tank to balance fuel levels after the left tank ran lower.