Definition
A measure of an engine's fuel efficiency expressed as the amount of fuel burned per unit of power produced over time. For turboprop engines it is typically given as pounds of fuel per shaft horsepower per hour (lb/shp/hr); for jet engines it is given as pounds of fuel per pound of thrust per hour (lb/lbf/hr). A lower number means the engine produces more power for each pound of fuel burned.
Plain English
How much fuel an engine burns to produce a set amount of power for one hour. The smaller the number, the more efficient the engine.
Context Anchor
Seen in turboprop engine discussions, performance planning, and comparisons of engine efficiency at different power settings.
Derivation
"Specific" here comes from the Latin specificus, meaning "of a particular kind" — in engineering it signals a value measured per unit of something else (in this case, per unit of power). So "specific fuel consumption" literally means fuel consumption measured against a specific output, not total fuel burn.
Why Pilots Care
Lower values mean better fuel efficiency, directly affecting range, endurance, and operating costs on long flights.
Analogy
It is similar to comparing fuel mileage in a car, but turned toward engine work instead of road distance. For specific fuel consumption, lower is better because the engine is using less fuel to make the same power.
Intuition Check
Do not read “specific” as just “exact” or “detailed.” Here it means fuel use measured per unit of engine power, so it is not the same as total fuel burn.
Example Sentence 1
The PT6A turboprop's low specific fuel consumption is one reason it remains popular for regional and utility aircraft.
Example Sentence 2
Comparing specific fuel consumption helps select the most efficient engine for a given mission.