In what circumstances is the ram air turbine (RAT) deployed?

The ram air turbine (RAT) is an emergency device designed to provide hydraulic and electrical power to essential systems when the aircraft experiences an electrical system failure. In this particular scenario, the RAT is deployed when the aircraft's normal power sources become unavailable, ensuring the pilot can maintain control and operate critical systems, such as flight controls and navigation instruments.

In event of an electrical failure, the RAT harnesses the airflow through the open turbine, converting it into mechanical energy, which is then transformed into electrical power. This is crucial for maintaining aircraft operation and safety during critical situations.

Other circumstances such as normal operations for efficiency, during landing, or at cruising altitude do not involve the deployment of the RAT as these occasions typically rely on standard power systems and do not require the backup functions that the RAT provides. Thus, the only appropriate situation for the RAT’s activation is during an electrical system failure for emergency power.