We have come up with an interesting problem while doing a recent annual.  Was wondering if anyone might have some ideas?

 

Background:

 

We have a well built and well maintained Legacy that has been flying for about 2 years with just under 300 hrs on it. We are doing the (second) annual inspection and on the gear swing found that the nose gear retracts first, then the left main followed by the right main.  When the right main went up it did so it with a chatter or shudder, most noticeable, at first, with the inner gear door.  In other words, it went up but not smoothly like the other gear or as it has ALWAYS done in the past.

 

In an attempt to trouble shoot the problem we disconnected the inner gear door and checked for ease of movement, binding etc..  All was perfectly smooth with no binding or resistance of any kind.  We then retracted the gear without the inner door connected.  We still notice a consistent chatter in the right main AND in the inner gear door actuator cylinder, moving without the inner gear door attached.  We then took the sequencing valve out of the picture by using a piece of doweling pushed up on the sequencing valve as the main gear retracted (inner door was still disconnected) and now noticed a smooth operation of the gear and the inner door actuator.

 

We have checked that the sequencing valve makes good solid contact with the gear. We checked the up side hydro pressure and it was 1100 psi. We ran this problem by Lancair technical (Ross) and he suggested we bump up the hydro pressure to not more than 1,500 psi up to see if that made any difference.  We boosted it temporarily up to 1,425 psi  nd there were NO changes.

 

Does any one have an idea of what may be going on?  We have considered air in the system but with no leaks and the system operating for quite some time with no problems and many cycles, would air in the system still be a possibility?  How about the sequencing valve, seems pretty simple, they either work or they don't, could that be an issue? Since we have been involved in this problem the issue has been consistent, never intermittent, and never involved the other gear.

 

At this point ANY ideas or suggestions would be GREATLY appreciated.   

Erik

Legacy
N74FX