What action does the RAT AUTO switch perform on the Emergency Panel?

The RAT AUTO switch on the Emergency Panel serves an essential function in managing the aircraft's emergency power system. When the switch is in the automatic position, it enables the deployment of the Ram Air Turbine (RAT) under specific emergency conditions, such as when both engines fail, and normal electrical sources are unavailable.

By selecting the option that prohibits automatic RAT deployment, the operator effectively ensures that the RAT can only be deployed manually when deemed necessary. This provides an additional layer of control, allowing the flight crew to assess the situation before allowing the RAT to deploy automatically, which could occur without pilot intervention in a fully automatic state.

The other options do not accurately reflect the function of the switch—resetting the system or isolating power does not align with its designed purpose, which is to manage deployment behavior rather than system reset or power isolation. Understanding the RAT AUTO switch's role helps ensure that pilots can operate the emergency systems effectively during critical situations.