Any idea what this is for?

[BDPetersen]

Opening up for first annual on my "C", I find this piece of tubing slipped over the structural member along the LH nose gear well (note the fuel pump for orientation). It is slit/cut away along its length and secured by three hose clamps. The contained structural member is viewable through the slit with a mirror and is intact, so my initial panic that it was some kind of crutch repair was relieved. Additionally, there is a similar but shorter version of this on the RH side. Other than some kind of chaffe protection, the IA and I haven't figured out the purpose, and they are so well installed we are reluctant to remove. Who knows?

[ArtVandelay]

I'm going to ask obvious ?, did you check the logs?

[N601RX]

I would remove them and make sure there is no surprises behind them.

[N201MKTurbo]

If there is a problem with the tube it should be welded according to AC43-13-1B. It has extensive instructions about how to repair damaged tubing.

[BDPetersen]

No damage apparent. Only work in that area was nose gear truss 20 (or was it 30) years ago. This piece Seems to have existed for quite some time. Will remove and take a look. Was hoping for a common explanation. But . . .

[cliffy]

Have you removed it and looked to see if the tube inside has any deformations or kinks ?  How about evidence of rusty areas cleaned but deeper than allowed? What is the material of the outside tubing?

[carusoam]

The down side of leaving it there is it's abillity to keep moisture against the tubes that can rust.

I don't think I have seen that before..

Questions that come to mind...  Is it there to protect the tube from something?  Or to protect something from the tube?

Best regards,

-a-

[Yetti]

Is that safety wire securing the hose clamps?   Is that deformation on the larger hole in the stringer?  Has it ever been gear upped?  Is that corrosion below the large hole below the tubing to the right of the middle hose clamp?

[Yetti]

Where is the other master cylinder?

[BDPetersen]

Sigh. I hoped someone would say " Oh that's done all the time." But apparently it's not. So that meant a trip inside the tubing.

Removing the nicely safety wired hose clamps, one half of the wrap-around tube fell off revealing the structural tube within in pristine condition (sorry photos don't do it justice.) The other half oh the wrap-around remained wedged between the structural tube and the nose wheel well skin. That leaves me with the assumption the purpose of the wrap-around was a chaffe/buffer for some reason between the two pieces. I'm hoping someone has a better theory.

To recap, everything else is in normal condition. No rust, corrosion, dents, cracks or missing parts.

[Yetti]

looks like it was glued on.  ballast weights? Preemptive protection for a gear up?

[HRM]

Something flaky this way comes...

[BDPetersen]

Dunno. No glue involved. Just seems to be a rather well made prophylactic wrap of the structure that has been in place for a long time. I only wish that several large denomination silver certificates had been wrapped inside.

[Yetti]

hard attach points for 500lb bombs

[Hector]

Obviously a splint to allow the cracked original tube time to heal itself.....

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[BDPetersen]

Apparently it worked. Somewhere there's an A&P who had an idea and went to some trouble to do this. I suppose without it I will loose 10 kts and pick up a loud buzzing noise.

[Conrad]

Perhaps it has less to do with flight and more to do with maintenance. If the same mechanic was performing annuals for many years, perhaps they realized that there was some recurring action they could perform more easily if they weren't worried about damaging that tube?

[Conrad]

I notice that there is some kind of scraping against the cover that is lengthwise and irregular. In flight vibrations would be highly regular, which leads me to think that it's caused by a person using a tool. Notice there are some slight bits of paint missing just beyond either end of the cover, however paint is completely intact outside this area.

[DAVIDWH]

Might be worth while to check a few annual maint. logs and place a few phone calls. Often the same shops will annual the same plane for years,

 may not take too long.

Checked in with Donald Trump and after I convinced him you are not a loser, he really wants you to make that M20C great again.

Best,

DH

[Yetti]

I am still wondering about the safety wire.  Seems like you would want to drill the heads of the screws and then tie the three of them together.

[Alan Fox]

2 hours ago, Yetti said:

I am still wondering about the safety wire.  Seems like you would want to drill the heads of the screws and then tie the three of them together.

Common practice to safety wire clamps... I do it all the time...

[BDPetersen]

Good luck with that. It's all history now, anyway.

[takair]

Were you able to remove the inner half of the tube?  Is it possible that someone accidentally drilled holes in the tube when replacing or repairing the nose gear door hinge?  Might be hard to spot or even filled in?  It's just odd...

[MB65E]

Its to protect the factory tube from long pointy sheet metal screws when installing the left cover there. (They should be type-b tin merman screws...but) 

There are a few other spots in the belly where a long screw would chafe the factory tubes. 

Cool!! It wipe it all down with corrosion X and go another 20 years!

-Matt

[BDPetersen]

At last a plausible explanation. I don't see any nearby screws, however. Both halves are off. Have my Corrosion-X equipment standing by to do the rest of the plane. Might as well do as you suggest.