Broken screw found on the ground

[DC_Brasil]

Hello,

1990 Mooney M20J.

Just flew home from my annual and after I parked the plane and shutdown, a linesman at the ramp told me there was a screw on the ground, right under the exhaust. 

I cannot be sure it wasn't already there at the ramp but also, I want to know where it came from.

The screw looks broken and was kind of coated in some lubricant. It wasn't hot like it had fallen from the engine but it was warm to the touch (it's a sunny day and the ramp had no shadows).

I'm trying to get an A&P to come see the plane but wanted to check with the experts here if anyone would have a guess. I have an important work commitment so I couldn't stay at the airport and uncowl the engine to take a look around.

Any thoughts?

 

My guess is that, if this screw came from my plane, it could only have fallen from the nose gear area or somewhere over the RH cowl flap.

 

Thanks

[CCAS]

It looks a bit like a brake caliper bolt but not sure how it would have ended up near your nose wheel. It may not have been from your aircraft but you might want to take a look at your left and right main wheels to see if the calipers are missing any bolts (and are safety wired).  Otherwise if you still think it was deposited from your aircraft I’d remove the top and bottom cowlings and see if any of your engine accessories are missing mounting hardware. 

[PT20J]

You could measure the diameter and grip to determine the AN or MS part number for the bolt and then a search of the IPC will show where that bolt is used. 

[IvanP]

My suggestion is to remove the cowling and look for missing fasteners and possibly oil leak (looks like the bolt is covered in oil). Given the size and position it was found in - possibly cowl flap mechanism. Just a guess, though. Then again, it may not be from your plane. Cannot tell from the pictures for certain, but the break looks fresh.  

[ArtVandelay]

Given the bolt has a smooth section I would think it is used for a moving part, so brakes, engine cowl flaps, control arms (throttle, mixture, prop), landing gear, etc.

[skykrawler]

Should've asked what was parked there before.

That's a fairly large diameter bolt.   Not very many that size on a Mooney.

[MooneyMitch]

Possibly an exhaust flange bolt.  

[mhrivnak]

That generally looks like the size of several bolts that hold the nose gear assembly together. If your thumbs are about like mine, that could be something like an AN6-14 or AN6-15, both of which are used in the nose gear. Take a look at IPC section 32-20-00 for the diagram and a list of all the bolts in that area. I wouldn't put my head under there until either confirming that the critical bolts are all there or attaching a tail weight. You might consider sticking your phone between the gear doors and taking several pictures facing forward.

But also, wow that bolt has been through some trauma! There must be a story of how it got so scarred. Let us know if you figure out where it came from.

[N201MKTurbo]

It is a fine thread bolt, so it didn’t come from the engine. But it is very oily. Does your engine leak oil? Is your landing gear oily?

[Fritz1]

This is a rather large sheared off bolt, thorough inspection of engine and nose gear is in order before flying plane

[skykrawler]

5 hours ago, MooneyMitch said:

Possibly an exhaust flange bolt.  

Exhaust flanges are held on with nuts, not bolts.

[N201MKTurbo]

I’m voting for it’s not from the Mooney.

[Bartman]

That’s not Mooney. 

[MooneyMitch]

19 hours ago, skykrawler said:

Exhaust flanges are held on with nuts, not bolts.

Possibly I used the wrong word.............exhaust flange.  On my former Lycoming O-360 and IO-360, the exhaust headers from the cylinders were attached to the muffler tubes with  3 hole flanges [header and muffler], 3 bolts [such as the one shown in the photo], 3 tension springs, spacer washers and nuts w/cotter pins.  

As I look at the bolt photo further, yes, I agree the bolt does look too large to be one of the bolts for the exhaust joints.