Definition
A fuel system arrangement that allows fuel from a tank on one side of the aircraft to be fed to an engine or system on the opposite side. It is selected by the pilot using a cross-feed valve to balance fuel load between tanks or to keep an engine running when its normal-side tank is unusable.
Plain English
A switch or valve setting that lets the pilot draw fuel from the left tank to feed the right engine, or vice versa, instead of each side feeding only itself.
Context Anchor
Seen in fuel system descriptions, checklists, and emergency procedures, especially in multi-engine airplanes.
Derivation
‘Cross’ meaning across or from one side to the other, and ‘feed’ meaning to supply. Together: supplying fuel across the aircraft from one side to the other.
Why Pilots Care
Enables fuel balancing between tanks and keeps an engine running if its own tank runs low or is damaged.
Intuition Check
Do not assume fuel cross-feed automatically balances the tanks. It means fuel is being supplied across the normal tank-to-engine path, and the pilot must use it according to the aircraft’s procedures.
Example Sentence 1
After losing the right boost pump, the pilot selected cross-feed so the right engine could draw fuel from the left tank.
Example Sentence 2
During an engine failure drill, the instructor demonstrated how fuel cross-feed could keep the remaining engine supplied from either tank.