AMP - Aviation Maintenance Technician Powerplant Practice Exam

What does "specific fuel consumption" (SFC) measure?

1. The total fuel usage during entirety of a flight

2. The efficiency in pounds of fuel burned per hour per horsepower

3. The total miles per gallon achieved by an engine

4. The amount of fuel pressure generated by a fuel pump

The correct answer is: The efficiency in pounds of fuel burned per hour per horsepower

Specific fuel consumption (SFC) is a critical measure used to evaluate the efficiency of an engine in terms of fuel usage. It is expressed as the amount of fuel consumed per unit of power produced over a specified period, typically in pounds of fuel burned per hour per horsepower. This measurement allows engineers and technicians to assess how effectively an engine converts fuel into usable power, highlighting its performance characteristics and efficiency under various operating conditions. In aviation, understanding SFC is essential because it directly influences operational costs and overall aircraft performance. A lower SFC indicates that the engine is able to produce more power with less fuel, which is advantageous for reducing fuel expenses and maximizing range. In contrast, the other options do not accurately define specific fuel consumption. For instance, measuring the total fuel usage during a flight would not provide insight into the engine's efficiency relative to its power output. Similarly, the total miles per gallon achieved by an engine is more indicative of the vehicle's overall fuel efficiency rather than the SFC specific to the engine alone. Additionally, the amount of fuel pressure generated by a fuel pump pertains to fuel system functionality and not to the concept of fuel consumption efficiency.