Which hydraulic system can be pressurized by deploying the RAT in an emergency?

The blue hydraulic system is designed to be pressurized by the deployment of the Ram Air Turbine (RAT) during an emergency. The RAT is a crucial backup system that provides hydraulic pressure to the blue hydraulic system in the event of a primary hydraulic system failure.

In normal operation, the blue hydraulic system is powered by an electric motor pump. However, if there is a loss of electrical power or failure of the primary hydraulic system, the RAT can be deployed to generate emergency hydraulic pressure. This capability ensures that critical systems relying on the blue hydraulic system, such as the landing gear and some flight controls, remain operational under emergency conditions.

The other hydraulic systems operate differently. The green and yellow hydraulic systems have independent hydraulic sources and do not rely on the RAT for pressurization. Understanding the role of the RAT specifically highlights its importance within the blue hydraulic system in maintaining aircraft functionality during emergencies.