EASA 66/ assignment help needed from the pro's.
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Joined: Apr 2006
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From: Queenstown New Zealand
EASA 66/ assignment help needed from the pro's.
Hey guys. I'm currently doing an assignment on the hydraulic system of a Boeing 757. The following question seems vauge. wondered if anyone would agree:
Q: The pilot reported in the technical log defect column as follows: "number one hydraulic system showing low pressure. vibration felt through airframe. Pressure indication fluctuates between 100 and 1000psi.
[B]Describe the procedure you would follow to isolate then rectify the fault?[B]
Seems to lack in information to me, I would assume the aircraft was in normal flight when the fault arised. This i guess would indicate the EDP was vaulty, not the ACMP. yet the gears must still be turning (hence vibrations and pressure fluctuations). I thought maybe one of the EDP pump gears had shattered, or excessive bearing wear, putting the pump out of ballance, resulting in the vibrations.
Does anyone else have experience with this fault? would my diagnosis seem reasonable? If the EDP was faulty, swould the whole unit be replaced, or just the faulty bearing/gear?
regards to all,
Toby.
Q: The pilot reported in the technical log defect column as follows: "number one hydraulic system showing low pressure. vibration felt through airframe. Pressure indication fluctuates between 100 and 1000psi.
[B]Describe the procedure you would follow to isolate then rectify the fault?[B]
Seems to lack in information to me, I would assume the aircraft was in normal flight when the fault arised. This i guess would indicate the EDP was vaulty, not the ACMP. yet the gears must still be turning (hence vibrations and pressure fluctuations). I thought maybe one of the EDP pump gears had shattered, or excessive bearing wear, putting the pump out of ballance, resulting in the vibrations.
Does anyone else have experience with this fault? would my diagnosis seem reasonable? If the EDP was faulty, swould the whole unit be replaced, or just the faulty bearing/gear?
regards to all,
Toby.
Last edited by Toby Gee; 13th January 2007 at 13:36.
Joined: Dec 2006
Posts: 236
Likes: 1
From: belgium
I would say exactly the same. Except I've never seen a broken edp causing vibrations. Maybe the vibrations come from a quick up and down movement of the pressure, resulting in some control surface flutter? (eg some spoilers on left system only?)
Joined: Dec 2006
Posts: 236
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From: belgium
If cavitation can indeed cause vibrations, I wouldn't search further for an explanation.
Joined: May 2005
Posts: 58
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From: in your mind
Always go to Maint Manual. First i would check the case drain filter for material, if any found replace the pump. Then check pump press filter for contamination. Sounds like the compensator cartridge has failed for the flight controls
