What type of lubrication does the APU lubricating system provide?

• A. Only splash lubrication
• B. Only pressurized lubrication
• C. Both pressurized and splash lubrication
• D. Only dry lubrication

Answer: (C)

The APU (Auxiliary Power Unit) lubricating system utilizes both pressurized and splash lubrication methods to ensure optimal function and protection of its internal components. In this system, pressurized lubrication is primarily responsible for delivering oil to critical engine parts under pressure, which is essential for reducing friction and wear during operation. This mechanism ensures that oil reaches bearings and other vital components where it is needed most.

Meanwhile, splash lubrication is utilized when certain components, such as pistons and gears, achieve movement within the lubrication reservoir. As these components move, they churn the oil, allowing them to receive lubrication naturally through the splashing effect. This dual approach enhances the overall reliability of the APU, ensuring that various operating conditions can be effectively managed.

The combination of both methods in the APU's lubrication system provides a comprehensive approach to protecting the engine. This combination is critical for maintaining the engine's operational integrity and preventing overheating or failure due to inadequate lubrication.