What does TFSC stand for?

• A. Thrust-specific fuel consumption – fuel used per hour
• B. Fuel consumption per unit of thrust per hour
• C. Thrust specific fuel consumption - fuel used per unit of thrust per hour
• D. Specific fuel consumption per hour per engine

Answer: (C)

TFSC stands for Thrust Specific Fuel Consumption. This metric shows how much fuel an engine uses to produce a set amount of thrust over a period of time. Put simply, it’s the fuel flow divided by the thrust, usually expressed as weight of fuel per hour per unit of thrust (for example lb/(hr·lbf) or kg/(h·kN)). A lower TSFC means the engine is more efficient because it delivers the same thrust with less fuel. The description that defines it as fuel used per unit of thrust per hour captures both the per-hour and per-thrust aspects. The other phrasings either omit the thrust factor or misstate the scope, so they’re less accurate.