What describes the dry sump lubrication system?

• A. Stores oil externally and uses scavenging pumps to return oil to the reservoir
• B. Recirculates oil within the crankcase
• C. Uses a submerged oil tank
• D. Relies on air lubrication

Answer: (A)

Dry sump lubrication stores oil in an external reservoir and uses scavenging pumps to return oil to that reservoir. In this setup, a pressure pump draws oil from the external tank and delivers it to the engine bearings, while scavenging pumps pull oil from the crankcase sump and pump it back to the external reservoir. This keeps the crankcase largely oil-free and ensures consistent oil supply even under hard acceleration, abrupt maneuvers, or inverted positions, which helps prevent oil starvation and reduces windage losses.

The other descriptions don’t fit because they imply keeping oil inside the crankcase (wet sump) or other arrangements not characteristic of a dry sump, such as an oil tank that’s submerged or relying on air lubrication.