FAA Powerplant Written Practice Test

What advantage is provided by using a reduction gear box in a turbine engine?

1. It increases fuel consumption

2. It enables the proper speed for accessories

3. It enhances performance at high altitudes

4. It reduces overall engine weight

The correct answer is: It enables the proper speed for accessories

The use of a reduction gear box in a turbine engine primarily serves to enable the proper speed for accessories. In turbine engines, the main shaft spins at very high speeds, which can be unsuitable for driving various engine accessories like generators, fuel pumps, and hydraulic pumps that require a lower speed to operate efficiently. The reduction gear box effectively reduces the rotational speed of the engine's output from the turbine to a level that is appropriate for these accessories, ensuring that they function correctly without risk of damage or excessive wear due to being driven at too high a speed. This design allows for better integration of the engine and its components, optimizing performance and enhancing overall system reliability. The other choices do not accurately represent the primary purpose of the reduction gear box.