FAA Powerplant Written Practice Test

What is the primary function of the crankcase in an aircraft engine?

1. Providing airflow to the engine

2. Holding the fuel system

3. Containing crankshaft bearings and cylinder pads

4. Servicing the electrical components

The correct answer is: Containing crankshaft bearings and cylinder pads

The primary function of the crankcase in an aircraft engine is to contain the crankshaft bearings and cylinder pads. The crankcase serves as a vital structural component that houses the engine's internal components, specifically those related to the crankshaft's operation. It provides support and alignment for the crankshaft and ensures that the bearings are adequately lubricated and protected from external contaminants. Additionally, the crankcase plays a crucial role in maintaining the integrity of the engine by serving as a sealed housing that prevents oil leaks and accommodates the various forces generated during the engine operation. The design of the crankcase also contributes to the engine's weight, balance, and overall efficiency. In contrast, the other options do not accurately reflect the primary function of the crankcase. While airflow to the engine, holding fuel systems, and servicing electrical components are important aspects of an aircraft engine's operation, they fall under the responsibilities of other engine components, not the crankcase itself.