True that commercial planes have an independant hydraulic reservoir, usable when the others don't work?

Question

True that commercial planes have an independant hydraulic reservoir, usable when the others don't work?

Answer 1

most planes, especially commercial/ big ones all have multiple redundancies.

for a given system, there is at least 2 sets of it in case if one fails. most likely 3 or 4.

the independent hydraulic reservoir/pump is, like a back up. it is used to keep hydraulic pressure up long enough to get the plane safely on the ground.

Answer 2

All commerical aircraft have more than one hydraulic system, and some more than 2. Each system is completly independent of each other, other then the cylinders, and a shuttle valve prevents fluid from leaking if one system is in/op.

All hydraulic systems use a resivor to hold fluid, where it pulls fluid and then dumps back in. An accumulator absorbs any shock in the system from constant pressure changes.

What your referrering to is a nitrogen tank , that if both systems lose the means to create flow in the system can release its charge that will allow for the limited  use of hydraic system for landing and braking.

There is also other ways such as a ram air turbine that can be release provide the means to move hyrdalic fluid.

These will only work in a closed circuit system, if there is any leaks, broken lines, that single system is in/op but the built in renducy will usually make it a non issue until safely on the ground. However,but none of these will work if all 3 systems are in/op, thats what happend in the Dc-10 in Sioux City IA, when a turbine fan sliced through all three lines, in 3 independent systems.,

Answer 3

I think what you are asking is whether there is a reserve supply of fluid to the hydraulic pumps in the case of a leak. Most reservoirs have a stand-pipe which supplies the main hydraulic pumps. So if there is a leak in the system and fluid is lost only half the fluid from the reservoir is pumped overboard. The EMDP (electric motor driven pump) gets its supply from the bottom of the reservoir giving a last minute supply to critical systems to land the aircraft. So it is not really an independant reservoir but a reservoir within a reservoir. This still depends on aircraft type.

Answer 4

The plane I fly has three independent hydraulic reservoirs.

In addition, there is an accumulator that stores fluid under pressure to help in manual landing gear extension, and two accumulators that store fluid under pressure for braking.

Answer 5

Generally all commercial ac, that presently use a local hydraulic system will have more than one pump/reservoir.  Redundancy is mandated and all the major flight controls will have back up systems.

newer designs using high frequency electric power, use several separate systems distributed throughout the ac.  smaller pump/tanks where they are needed (at the aelerons, elevators, rudder, slats/flaps, etc.)  even the ECS system will have separate motors .  The advantage is that its easier to route smaller wires than it is to route larger hydraulic lines.

and the controls can be electronic.

Answer 6

depending on the ac you could have up to 3,, the only one i ever heard that lost all was a united dc-10 which had an engine go and severed all hydraulics,, they made a d**n good shot at landing from cruiseing altitude to sioux falls just by useing the throttles more left more right, and just as it landed it flipped .. i credit the pilots for comeing up with the idea to do this for saving as many people as they did.. there is a video of it im sure on utube...

Answer 7

most commercial