Ram Air Turbine

Ram Air Turbine (RAT) is a small turbine that can be deployed into the airstream from the aircraft fuselage or wing root to generate emergency hydraulic pressure and/or electrical power in the event of a total engine failure or loss of all normal power sources. Once deployed, it cannot be retracted in flight.

• Deploys automatically when both engines flame out or all generators fail
• Provides enough power for essential flight instruments and minimum hydraulics for flight controls
• Powers the aircraft during emergency descent to a landing — critical for fly-by-wire aircraft
• Famous use: Gimli Glider (1983) and US Airways Flight 1549 (2009, Hudson River)