Hydraulic system A

[ibrahimzahid]

Hello friends

Is there any one hydraulic specialist who knows the reasons of increasing level of hydraulic system "A" after every flight upto 10% and becomes 100% after few flights without decreasing of pneumatic pressure in any accumulator attached to hydraulic system "A"?

ya hyd level in resrvior. but its not hyd its air in hyd but I m confused from where its entering in the system.

[MVSGas]

Are you talking about the hydraulic fluid level in the reservoir?

[MVSGas]

What makes you so certain that it is air? I seen the behavior for years on different aircraft, but for the most part, as long as you bleed the system regularly is should not affect anything. I think it could be crossbleed form ISA. I haven't trouble shoot hydraulics in so long anything I say is pure speculation. I know is a dumb question, but what have you found in the FI?

[jamesdasapb]

You may approach the problem like this:
1. Check the hydraulic fluid for contamination. Check if it's 100% hydraulic fluid. Could be fuel entrainment.
2. Reservice the Hydraulic A system to correct level when the system has cooled down.
3. Service the B system to correct level when the system has cooled down.
4. On next engine start, check the levels of both A & B reservoirs when reservoirs are pressurized. Note the readings.
5. After engine shut down, check the levels when reservoirs are pressurized. Note the readings.
6. Dump the pressure of both A and B reservoirs and check the levels.
7. If there is a rise in the A reservoir level and drop in B reservoir level, there is a cross flow from System B to System A. Fluid can be transferred via one of the the ISA. There is a fault code for this in the 29FI.
8. Lastly, check what was the last maintenance done on the A system hydraulics.

Rgds

James Das
jamesdas.apb@gmail.com

[jamesdasapb]

One last point is to reservice the pneumatic accumulators of the A system reservoir and A system Flight control accumulator.
1. How to reservice?. Release the air in the accumulators and check if there is Hyd fluid coming out. If yes, then replace the accumulator.
2. If no, then write to LM Aero and ask for assistance.

By the way where are you stationed?

James Das

[ibrahimzahid]

What makes you so certain that it is air? I seen the behavior for years on different aircraft, but for the most part, as long as you bleed the system regularly is should not affect anything. I think it could be crossbleed form ISA. I haven't trouble shoot hydraulics in so long anything I say is pure speculation. I know is a dumb question, but what have you found in the FI?

Thanks a lot sir.

As you say that you've seen this behavior for years I'm observing also same
But bleeding regularly is not possible however bleeding each and every time after maintenance is strictly observing
I also observe and note many times that there is no change in sys B so chance of cross bleed is not happening.

Anyhow thanks for reply

[ibrahimzahid]

Sir I have done most of the things you suggested.

Please guide me more if something special comes in your mind.
As all these things I am doing again and again but fail to permanently remove it.
Or to stop it from happening again and again so fast.

Thanks a lot