by the pilot extending ground spoilers.

by the pilot selecting idle reverse thrust.

when the pilot does not lower the nose wheel to the ground.

by pilot action.

3 and 4.

1 and 3.

1 and 2.

2 and 4.

cool the hydraulic fluid and serve as a main pressure source for normal operation.

cool the hydraulic fluid and serve as a limited alternate source of pressure.

damp pressure fluctuations and serve as a limited alternate source of pressure.

damp pressure fluctuations and serve as a main pressure source for normal operation.

The aircraft will roll and yaw to the side where the flaps are extended.

The aircraft will roll and yaw to the side where the flaps are not extended.

The aircraft will roll to the side where the flaps are not extended and yaw to the direction of the wing with extended flaps.

The aircraft will roll to the side where the flaps are extended and yaw to the same direction

of the roll.

shut down systems that are overloaded.

reduce pump loads.

switch hydraulically operated units to the most appropriate pressure supply.

guard systems against overpressure

is powered in one direction only by hydraulic power, the return movement being under another force.

ravels one direction under one application of hydraulic power and in the opposite direction under a second

is a one shot actuator used for emergency systems only.

cannot be used for variable position operations as it is designed to lock in the extremities of travel.

 synthetic or vegetable oil.

mineral or vegetable oil

mineral oil or water and glycol.

synthetic or mineral oil.

In that case some fuel tanks remain empty during the whole flight, which stresses the aeroplanes structure inan unacceptable wav.

The lifetime of the fatigue sensitive parts has been based on a determined load spectrum.

Long haul aeroplanes often consume too much fuel on short haul flights.

The procedures and checklists for this kind of aeroplanes will take too much time.