What are the two types of lubrication systems used in gas turbine engines?

The correct choice identifies the two primary types of lubrication systems used in gas turbine engines: wet-sump and dry-sump systems.

In a wet-sump system, the oil is stored in a sump (or reservoir) that is usually situated at the bottom of the engine. This design allows the oil to be easily accessible and maintains a constant supply to the necessary components. It's a simpler and more compact system, commonly used in smaller engines where space and weight are at a premium.

On the other hand, a dry-sump system employs a separate tank for oil storage, which allows for better oil management and distribution throughout the engine. This system removes excess oil from the engine, preventing it from flooding the engine components and thereby sustaining lower weight and more efficient operation at high speeds or under extreme conditions. It is more complex but essential for larger, high-performance engines, ensuring consistent lubrication in various operational states.

Understanding the distinctions between these lubrication systems is crucial for gas turbine engine design and operation, as each serves different applications and can significantly influence engine performance and reliability.