In most current systems the power is provided to the control actuators by high-pressure hydraulic systems. In fly-by-wire systems the valves, which control these systems, are activated by electrical signals. In power-by-wire systems, the power is carried to the actuators by electrical cables. These are lighter than hydraulic pipes, easier to install and maintain, and more reliable. Elements of the F-35 flight control system are power-by-wire. The actuators in such an electro-hydrostatic actuation (EHA) system are self-contained hydraulic devices, small closed-circuit hydraulic systems. The overall aim is towards more- or all-electric aircraft and an early example of the approach was the Avro Vulcan. Serious consideration was given to using the approach on the Airbus A380.