What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

LRI needle does not rest on peg

McFly

Well Known Member
I removed the wing inspection plate to which my LRI pitot is attached plate for condition inspection.

The LRI needle used to rest on the peg when was the plane stationary. Now the needle floats off of the peg in the middle of the red arch.

The LRI seems to function normally. I cannot say perfectly though since I have not done any stalls while watching the LRI.

I don?t remember the LRI pitot get banged or abused when the panel was off, so it is a bit of a mystery why this has happened. Is there anyway to reset the needle so that it pegs again? Thanks
 
I removed the wing inspection plate to which my LRI pitot is attached plate for condition inspection.

The LRI needle used to rest on the peg when was the plane stationary. Now the needle floats off of the peg in the middle of the red arch.

The LRI seems to function normally. I cannot say perfectly though since I have not done any stalls while watching the LRI.

I don’t remember the LRI pitot get banged or abused when the panel was off, so it is a bit of a mystery why this has happened. Is there anyway to reset the needle so that it pegs again? Thanks

Hugh, I suspect one of the probe tubes is obstructed (probably the "Hi" line) and the gauge is registering residual pressure in the line. Could a line have gotten kinked when you removed the inspection plate?
 
Hugh, I suspect one of the probe tubes is obstructed (probably the "Hi" line) and the gauge is registering residual pressure in the line. Could a line have gotten kinked when you removed the inspection plate?

Thanks Sam. I guess it?s possible but it seems unlikely. The needle moved freely in flight and pegs in the green arch.

I will disconnect the lines in the back of the instrument and see if it relieves any residual pressure.
 
Thanks Sam. I guess it?s possible but it seems unlikely. The needle moved freely in flight and pegs in the green arch.

I will disconnect the lines in the back of the instrument and see if it relieves any residual pressure.

Sounds like a plan, that will indicate whether you have a probe/line problem or gauge problem. I don't know how to reset the needle but the fact it went goofy when you moved the probe would lead us to believe the gauge is ok.
 
Update: success - sort of

I unhooked the hoses but no joy. The needle still floated above the peg.

I removed the gauge from the panel to see what I could see. One curious thing was that when loosening one of the mounting nuts, the threaded rod that mounts the gauge to the panel came loose and unthreaded from the back of the gauge.

I removed the back of gauge which revealed a rubber diaphram with a nut in the center. When I pulled the nut, the needle showed lift. When I pushed the nut the needle moved closer to the peg but I was afraid to put too much pressure on it. There did not look any user servicable parts and I was not ready to cut it open so I put it back together.

When mounting the gauge back to the panel and tightening the mounting nuts on the threaded rod, the needle moved closer to the peg as I tightened the nuts:D I was able to get the needle against the peg without over torqing the nut:)

I guess the threaded rod had been working loose and the needle came off the peg. This probably happened before I loosened the inspection plate, I just never noticed it:eek:

I took a quick flight and verified that the LRI works correctly. We have a low deck so I could not verify the accuracy through stalls.

Hugh
 
Back
Top