What happens when the HYD PUMPS switches are placed in the ON position?

• A. The pump pressure is cut off from the hydraulic system
• B. The depressurization valve in the engine-driven pump is de-energized
• C. The hydraulic system becomes overpressurized
• D. The electric motor-driven pump is activated

Answer: (B)

When the hydraulic pumps switches are placed in the ON position, the correct action is that the depressurization valve in the engine-driven pump is de-energized. This process is critical in the functioning of hydraulic systems, as it allows hydraulic fluid to flow into the system under pressure.

In hydraulic systems, the engine-driven pump is equipped with a depressurization valve that helps manage the pressure within the system. When the pump switches are turned ON, this valve must be de-energized to allow the pump to function properly, enabling the hydraulic fluid to pressurize and circulate through the system as needed for operations such as braking, actuation, and other hydraulic functions.

Having the pump switches in the ON position allows the hydraulic system to be energized and ready for operation, ensuring that components that rely on hydraulic pressure can function effectively. This makes it an essential aspect of hydraulic systems in various applications, particularly in aviation and heavy machinery.