by Captain Joe
This video will give you an insight into the hydraulic and fly-by-wire system of the Airbus A320 family.
Very often you can see the tail rudder of an Airbus pointing into the right direction once parked at the gate and shutdown engines.
The ailerons and rudders are primarily powered by three independent hydraulic system, which provide pressure to the actuators.
Once you shutdown the engines the hydraulic pressure drops cause the pressure is generated by a hydraulic gearbox connected to the main engines.
Once the pressure is lost, the weight of the ailerons press the cylinders of the actuators inward, making the ailerons look like as if the are hanging down.
The massive tail rudder is also unpressurised and turn either left or right, depending on the wind direction.
This is just a little insight in to the fly-by-wire and hydraulic system, I will explain both systems in much more detail in future videos.