FAA Powerplant Written Practice Test

Which of the following is an indication of proper piston ring seating?

1. High compression readings on all cylinders.

2. Lower oil consumption.

3. No air escaping from the crankcase during checks.

4. All of the above.

The correct answer is: All of the above.

The correct choice is comprehensive because all the indicators listed contribute to the understanding of proper piston ring seating. High compression readings on all cylinders are crucial because they signify that the rings are effectively sealing the combustion chamber. This means that the combustion gases are not escaping into the crankcase or leaking past the rings, which enhances engine performance and efficiency. Lower oil consumption is another essential indicator of effective ring seating. When the rings are properly seated, they maintain a better seal, allowing the engine to utilize less oil. This is important for ensuring that the oil remains where it is needed for lubrication and cooling rather than burning off in the combustion process. The absence of air escaping from the crankcase during checks is another sign that the piston rings are sealing well. Properly seated rings restrict the passage of gases from the combustion area back into the crankcase, which is critical for maintaining the correct pressure and function within the engine. In summary, each of these factors—high compression readings, lower oil consumption, and no air escaping from the crankcase—indicates that the piston rings have seated correctly. Hence, selecting all of the above reflects a comprehensive understanding of how proper ring seating impacts engine performance and efficiency.