got a dent in my nose gear truss. Opinions?

[Herlihy Brother]

10 hours ago, rbridges said:

Thanks. I figured as much. I was most concerned about any legality issues if it exceeded the 1/32".  Since it doesn't, I'll just have to be more wary in the future. 

Of course the other thing is that that dimple's presence has  annoyed me for the past 20 years. the Fact that it is there, and that it may be technically unairworthy, and that the FBO would not take responsibility.  Maybe it's past the 32nd, maybe not. No IA has noticed but its constantly in the back of my mind and in my face every time I am down there checking for additional damage from subsequent fbo visits. As if we don't have enough other useless worries cluttering up our minds.  I'd pay $2,500 to just have that memory go away and not ever think about such a trivial annoyance ever again.  It's like fbo ptsd and I hope it doesn't happen to you.

[Hank]

9 hours ago, Bravoman said:

Rob, What you complaining about. You make more than that in 20 minutes with one patient! 

 

9 hours ago, Bravoman said:

Rob, What you complaining about. You make more than that in 20 minutes with one patient! 

Cause he's just the CEO, and still has to answer to CFO 'Shel!     

[rbridges]

3 hours ago, Herlihy Brother said:

Of course the other thing is that that dimple's presence has  annoyed me for the past 20 years. the Fact that it is there, and that it may be technically unairworthy, and that the FBO would not take responsibility.  Maybe it's past the 32nd, maybe not. No IA has noticed but its constantly in the back of my mind and in my face every time I am down there checking for additional damage from subsequent fbo visits. As if we don't have enough other useless worries cluttering up our minds.  I'd pay $2,500 to just have that memory go away and not ever think about such a trivial annoyance ever again.  It's like fbo ptsd and I hope it doesn't happen to you.

exactly.  I'd go fix it if I knew it wouldn't happen again, but with my luck, it would happen the day after I get it repaired.  

[DonMuncy]

Years ago, I had conversations with a couple of very well known Mooney gurus, who said that over the years they had seen pretty severe dents in the nose gear truss, that did not cause any problems. At that time the Mooney factory had no specification for allowable damage to it. Then somebody got all upset and started asking Mooney what that spec was. Eventually, just to get them to shut up, someone at the factory came up with the 1/32 inch limit, which has been the word ever since. 

[ArtVandelay]

In my limited experience, metal stuff tends to fail at bends, welds or because of corrosion.


Tom

[Captnmack]

Technically there is NO legal requirement to replace or repair Truss for such a small dent. I asked a well know Mooney Service Center about dents and was told unless it’s really bad then just monitor.

[mike_elliott]

8 minutes ago, Captnmack said:

Technically there is NO legal requirement to replace or repair Truss for such a small dent. I asked a well know Mooney Service Center about dents and was told unless it’s really bad then just monitor.

hummm...contrary to what Mooney and Dmax says. 1/32" dent or greater = unairworthy. This one had a bit more than 1/32"

[EricJ]

42 minutes ago, Captnmack said:

Technically there is NO legal requirement to replace or repair Truss for such a small dent. I asked a well know Mooney Service Center about dents and was told unless it’s really bad then just monitor.

Check your Service Manual.   The J model SM says 1/32" dent maximum towing damage on the nose leg assembly.   The SM is gospel.   I don't know whether that's in the F model SM or not.   I suspect it is.

[Mark89114]

1 hour ago, mike_elliott said:

hummm...contrary to what Mooney and Dmax says. 1/32" dent or greater = unairworthy. This one had a bit more than 1/32"

But it didn’t fail at the dents.....

[mike_elliott]

But it didn’t fail at the dents.....

Yea, it didn't have time to. It failed a few feet into a taxi after being abused.

Sent from my Pixel 2 XL using Tapatalk

[PT20J]

1 hour ago, bluehighwayflyer said:

We have replaced the nose gear truss in our C three times now since my dad purchased her in 1982.  All at our own expense and one time even when our FBO moved her so they could do repairs to our private t-hangar.   Causation wise this is a very tough nut to crack when you are dealing with the vast majority of people.  The average guy or girl  has no idea whatsoever of Mooney turning limits.  

Jim

When you replaced them, did you install the retrofit kit with the turning stops?

[Gagarin]

I would just leave it alone, it does not look that bad. I splitted in half 1/2" piece of rubber hose an wrapped around the tubing to prevent tubing direct contact to avoid dinging it when the plane is towed by a truck. Any time you leave the plane at an FBO you are risking a ding.

Edited October 11, 2019 by Gagarin

[bradp]

I adopted taking pics of the truss before and after I use an FBO on a trip. That way there can’t be doubt if it’s dibged. 

[DonMuncy]

43 minutes ago, Gagarin said:

I would just leave it alone, it does not look that bad. I splitted in half 1/2" piece of rubber hose an wrapped around the tubing to prevent tubing direct contact to avoid dinging it when the plane is towed by a truck. Any time you leave the plane at an FBO you are risking a ding.

When I first started working on this problem, I was astounded with how small a space there was between the steering horn and the tube it bumps. If you put a hose in there, I am surprised you have any turning radius left. 

[Gagarin]

Just now, DonMuncy said:

When I first started working on this problem, I was astounded with how small a space there was between the steering horn and the tube it bumps. If you put a hose in there, I am surprised you have any turning radius left. 

On a tight turn the hose material compress allowing the wheel to turn without denting the tube, 

[carusoam]

Clearly the dent measurement isn’t saying the tube will fail where the dent is...

the amount of force put on the system to allow the dent is what is being measured... that force is tearing apart the rest of the welds...

It shows up nicely as a visual indicator that something bad has happened...

So... if you get a dent... measure if you like... but definitely consider the rest of the damage that can have occurred... all the way through the system...

PP thoughts only, not a mechanic...

Best regards,

-a-

[Mooneymite]

4 hours ago, carusoam said:

Clearly the dent measurement isn’t saying the tube will fail where the dent is...

-a-

Tha FAA's Aircraft Inspection and Repair manual has a large section on repair of dented tubing.  Is the 1/32" dent limit a Mooney limitation specific to the nose truss, or is it derived from the FAA's guidance?

Is it in fact a "limitation", or is it "guidance"?

https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC_43.13-1B_w-chg1.pdf

[carusoam]

Typically...

Our first line of defense for approved maintenance and inspection procedures for our Mooneys comes from the Mooney Maintenance Manuals...

How the maintenance manuals get written and approved is the next level higher...

That puts my PP skills two levels too low to know the answer for sure. 

 

The cool part of flying a certified aircraft... All these docs are in place before the plane gets certified....

The cool part of having a Mooney... these procedures have a well established history of keeping our planes flying...

The unfortunate part... some of the procedures in the MMs are pretty minimal... and can be hard to get improvements for...

 

Best regards,

-a-

[RogueOne]

My opinion doesn’t matter, but since you asked: I would fly that truss with zero concern.

[Mooneymite]

56 minutes ago, carusoam said:

...

The cool part of flying a certified aircraft... All these docs are in place before the plane gets certified.......

-a-

Well, there are sometimes "gaps" in what the manufacturer tells us.  The Boeinig MAX is a good example.

Did you see where Boeing operators just got surprised by the "Pickle Fork AD"?

Really, these things evolve from the users.....

[mike_elliott]

Robert, unfortunately, flying it with zero concern will not fix it, nor make it airworthy again. Mooney's engineering dept has determined, be it right or wrong, that 1/32" dent or greater, the part is unairworthy. As much as the internet of engineers here would like it to be ok, it is not ok to fly an unairworthy plane. 

This isnt my opinion, this is Mooney's. Just being the messenger to prevent you from drinking the koolaid of bad advice. Consider getting it fixed, your plane will be sellable, flyable and insurable again.

[Mooneymite]

9 minutes ago, RogueOne said:

My opinion doesn’t matter, but since you asked: I would fly that truss with zero concern.

And I agree with you generally.  My truss was "at limits" when I bought it 21 years ago.  It still is.  We check it every year.  However, at this point I am questioning the 1/32 "limit".  Where did it come from, is it accurate? 

Ultimate question:  At what depth/severity does the dent become too much?

[RogueOne]

Just now, Mooneymite said:

And I agree with you generally.  My truss was "at limits" when I bought it 21 years ago.  It still is.  We check it every year.  However, at this point I am questioning the 1/32 "limit".  Where did it come from, is it accurate? 

Ultimate question:  At what depth/severity does the dent become too much?

When it is beyond 1/32”.  At least you can measure that with a straight edge and a piece of safety wire.  How about your tail bolts.  How “scientific” is that measurement?  Help me out Engineers.  What tool is used on that assessment?

[RogueOne]

3 minutes ago, Mooneymite said:

And I agree with you generally.  My truss was "at limits" when I bought it 21 years ago.  It still is.  We check it every year.  However, at this point I am questioning the 1/32 "limit".  Where did it come from, is it accurate? 

Ultimate question:  At what depth/severity does the dent become too much?

Damn.  I was hoping for total agreement since he used a razor blade and a 1/32” safety wire wouldn’t fit...Oh well.  

 

[mike_elliott]

2 minutes ago, RogueOne said:

Damn.  I was hoping for total agreement since he used a razor blade and a 1/32” safety wire wouldn’t fit...Oh well.  

 

my bad, i missed it was less than the 1/32" spec of unairworthy.. Fly that sucker...