FAA Powerplant Written Practice Test

The term "burnishing of crankshaft bearings" refers to:

1. Breaking in new bearings

2. Removing dirt

3. Ensuring they are lubricated

4. Seating the bearings

The correct answer is: Seating the bearings

The term "burnishing of crankshaft bearings" specifically relates to the process of seating the bearings. Burnishing refers to a method in which the surface finish of the bearings is enhanced through a controlled rubbing action. This action helps the bearing surfaces to conform to one another, ensuring a proper fit and reducing the likelihood of future wear or damage. During this process, as the crankshaft and bearings are used under operational conditions, the surfaces undergo a slight smoothing which allows for improved contact and distribution of loads. This ensures that the bearings remain seated appropriately, which is critical for maintaining overall engine efficiency and preventing issues that may arise from improper alignment or surface irregularities. The context surrounding the other options clarifies why they do not accurately describe the burnishing process. Breaking in new bearings involves running the engine to allow the bearings to adapt to their seating surfaces, but it is a broader process that encompasses functions beyond just burnishing. Removing dirt is an important maintenance activity but does not pertain to the burnishing of the bearings. Ensuring they are lubricated is crucial for preventing wear, yet it does not relate directly to the seating action implied by burnishing. Thus, seating the bearings is the most precise definition of this term.