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Hello-  one of our aircraft, at #2 prop, I always find atmospheric sump empty that means I don't find any touch of Hyd with Dipstick when SVC propeller. On the other hand pressurized sump remain full. It is very confusing for me. 

Any one can tell me why this happen?

What is other best and easy way to check Hyd level except atmospheric sump?

Thanks

 

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Hi there, 

I guess you dont have any hydraulics on your dipstick coz the level is probably lower than the dipstick or its not fully inserted. The presence of hydraulic within the pressurized sump may not mean that there is adequate hydraulics required. There is another dipstick to measure the levels within the atmospheric sump and you can probably use that to gauge whether the amounts are right. Correctly, you should service the sump till you have just a bit of oil on the dipstick from the atmospheric sump.

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On ‎7‎/‎26‎/‎2019 at 8:57 AM, pmostafiz said:

Hello-  one of our aircraft, at #2 prop, I always find atmospheric sump empty that means I don't find any touch of Hyd with Dipstick when SVC propeller. On the other hand pressurized sump remain full. It is very confusing for me. 

Any one can tell me why this happen?

What is other best and easy way to check Hyd level except atmospheric sump?

Thanks

 

It is likely your orifice cups are clogged, preventing proper filling of the barrel assembly, and therefore your atmospheric sump

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51 minutes ago, Lkuest said:

It is likely your orifice cups are clogged, preventing proper filling of the barrel assembly, and therefore your atmospheric sump

Hi Lkuest- Hope you are fine. Do you have any suggestions to solve it. Will this create any problem in near future if orifice cups remain clogged?. I meant rpm or torque fluctuations. 

Is there any other way to check Hyd level with pressurized sump?

Thanks

 

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If the orifice cups are clogged, you will never be able to accurately check servicing, as the pressurized sump may always show good, but at the expense of the atmospheric sump. The atmospheric sump is allegedly the most accurate location, so if it's inaccurate, it will always lie to you. You should check your tech data for how to clean the orifice cups. The only other option is to replace the pitchlock regulator, preferably with one that was recently overhauled to guarantee the cups are clean. One indication the orifice cups are clogged is that, when you check the pressurized sump after 2 minutes, the fluid fills up and overflows. This is due to the pitchlock regulator keeping the fluid pressurized in the system instead of draining the fluid into the barrel like it's supposed to.

Be careful of those who tell you only the pressurized sump is required for an accurate fluid check. This comes from the idea that the pressurized sump dipstick actually gives you a quantity, and the atmospheric sump is only a go/no-go. The only thing the pressurized sump dipstick tells you is how much fluid is in the pressurized sump, who's job is to force-feed the pumps sending the fluid out to the valvehousing. The atmospheric sump dipstick tells you how much is in the barrel AND atmospheric sump. If there's nothing on the atmospheric dipstick, you have no idea how much is in the barrel, and that can be dangerous.

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