HP

ekellyie

Could someone explain to me what hydraulic pressure is in an aircraft ?

ChicaneAuto

The control surfaces on large aircraft are usually operated by hydraulic rams like on diggers etc, these contain oil that is held at pressure.
The system works on differential pressure which means simply to extend the ram, the pressure behind it must be higher than the pressure infront of it and the opposite is true to retract the ram. If there is a leak hydraulic pressure will be partially or fully lost and the contol surfaces on that circuit will become less effective or inoperable.
For this reason it is important to have and instrument to keep tabs on the hydraulic pressure in the aircraft.

Mr Benevolent

ekellyie wrote: »

Could someone explain to me what hydraulic pressure is in an aircraft ?

Think of a cars hydraulic power steering. When the engine is turned on it's easy to move the steering wheel. With the engine turned off it becomes horribly heavy. That's what hydraulic pressure does.

Stovepipe

Hi there
Hydraulic pressure is used to raise and lower the undercarriage, operate airbrakes, spoilers, thrust reversers and apply brakes. Older smaller public transport categhory aircraft still use steel cables or rods to move the control surfaces.

regards
Stovepipe

Bearcat

Hydraulic pressure is very important on airbus aircraft:D

Skuxx

Aircraft hydraulics operate at 3000psi. Airbus' have 3 systems, yellow, green and blue.
Engine 1 powers a pump which runs the green system, engine 2 powers the pump for the yellow system. Both can also by powerd by electrical pumps on the ground. The blue system is pressurised by an electric pump only, or the RAT in an emergency situation.
The power transfer unit (PTU) can transfer power between the yellow and green systems, but can't transfer hydraulic fluid between the systems.