Definition
A fuel system configuration in a multi-engine airplane in which fuel from a tank on one side of the airplane is routed across to feed an engine on the opposite side. It is selected using the crossfeed valve and is used to manage fuel imbalance between left and right tanks, or to keep an engine running after a fuel system problem on its own side.
Plain English
A setting that lets one engine drink fuel from the tank on the other side of the airplane, instead of from its own side.
Context Anchor
Seen in multiengine airplane fuel-system procedures, especially when managing fuel balance or handling an engine or fuel-supply problem.
Derivation
From 'cross' (across) and 'feed' (to supply with fuel). The name describes exactly what it does: feeding an engine from across the airplane.
Why Pilots Care
Prevents fuel imbalance that could create uneven wing weight and handling problems, and allows continued engine operation if one tank runs low.
Intuition Check
Crossfeed mode does not usually mean fuel is being moved from one tank into another tank. It means fuel is being routed across the airplane so an engine can use fuel from the opposite side.
Example Sentence 1
After securing the left engine, the pilot selected crossfeed mode so the right engine could draw from the left tank and burn down the remaining fuel.
Example Sentence 2
After the left tank quantity dropped, the crew selected crossfeed mode so the left engine could draw from the right wing tank.