Definition
The metal spouts at the end of a fuel hose that are inserted into an aircraft's fuel tank opening to deliver fuel during refueling. Aviation fuel filler nozzles are sized and sometimes shaped differently for avgas and jet fuel to help prevent misfueling.
Plain English
The end piece of the fuel hose that goes into the tank opening when the airplane is being refueled.
Context Anchor
You encounter fuel filler nozzles during refueling, preflight planning, and any discussion of preventing the wrong fuel from being put into an aircraft.
Derivation
“Fuel” comes from an old word meaning material for a fire. “Filler” means something used to fill an empty space. “Nozzle” originally referred to a small projecting nose or spout. Together, the term points to the spout used to fill the airplane with fuel.
Why Pilots Care
Correct nozzles prevent spills, contamination, and damage to the filler neck while ensuring the right fuel reaches the tanks.
Intuition Check
Do not confuse fuel filler nozzles with engine fuel nozzles. Fuel filler nozzles are used to put fuel into the airplane’s tanks; engine fuel nozzles are part of some engine systems and deliver fuel inside the engine.
Example Sentence 1
The line crew used the smaller fuel filler nozzle marked for 100LL to top off the wing tanks.
Example Sentence 2
Always confirm fuel type and nozzle fit before connecting the fuel filler nozzle to the aircraft.