Definition
Airport ground staff employed by a fixed-base operator (FBO) or fueling service who handle aircraft on the ramp, including fueling, oil servicing, towing, parking, tie-down, and basic exterior care.
Plain English
The people on the ramp who fuel your airplane, move it, park it, and help you with ground services before and after you fly.
Context Anchor
Seen during preflight, refueling, oil servicing, and other ground operations at an airport or fixed-base operator.
Derivation
The word 'line' in airport use refers to the flight line — the area of the ramp where aircraft are parked and serviced. 'Line service' therefore means the work done on the flight line, and the personnel are the people who do it.
Why Pilots Care
Incorrect fuel grade, contamination, or improper oil servicing can cause engine failure; pilots must confirm actions with line service personnel before flight.
Intuition Check
“Line” does not mean people standing in a row. Here it means the flight line, the airport area where aircraft are parked and serviced.
Example Sentence 1
After landing, the pilot taxied to the FBO and asked line service personnel to top off both tanks with 100LL.
Example Sentence 2
Always watch line service personnel sump the fuel strainer to confirm no water is present.