Skin Tear

[Charles K]

Greetings, 

Posting several pics with the hope of understanding what and when this damage would have occurred. 

BLUF, 81 M20J departed for annual flying total of five hours in VMC conditions at 4,500 MSL. At departure from home station no damage was noted, after checking in for service I departed and two days later received the discrepancy list with damage noted. This location is the aft upper section of the main cabin door if it wasn't obvious, key reference is the antenna and big opening of door. 

My questions are:

1) Did this happen in flight? If not, would you conduct a flight with this issue?

2) What would have caused this?

3) Repair method / recommendation?

Yes, I have my theory of what could have happened based of general observations and details of photos, but I don't want to sway a theory from this post. 

Thanks for the time and comments. 

[A64Pilot]

No idea how it could happen, cannot imagine in flight, as it’s peeled outside that seems to not indicate something from the outside like an overhead lift punctured it.

I’d fly it, but would probably put a piece of tape over it. As we have a tube steel structure I don’t think the thin skin is particularly structural. 

[slowflyin]

Looks like it was pried up.  Not sure what could have caused it but I can't imagine you wouldn't have noticed it while getting in or out of the AC.   As it's pried outwards it seems unlikely it was an inflight event.   

[N201MKTurbo]

It looks like a crack formed and the pointy flap formed by the crack started vibrating in the wind till it fractured and flew away.

You should stop drill that crack. 
 

You can patch it, or reskin it, which would be a lot of work.

[47U]

4 hours ago, Charles K said:

My questions are:

1) Did this happen in flight? If not, would you conduct a flight with this issue?

2) What would have caused this?

3) Repair method / recommendation?

Sorry this happened.

1.  Did not occur in flight.  Yes, I would put some speed tape over the top of it before flight.

2.  I think ‘someone’ egressing the cockpit caught a piece of clothing, a snap/button/tool on the skin.  Unintentional, but stuff happens.

3.  I don’t think I’d scab patch it… probably try for a flush repair, which will require a doubler under the skin.  Maybe, a 2” to 3” half circle?  I think the skin is pretty thin there (.025” 2024 T3 Clad), which wouldn’t normally be thick enough material to use countersunk rivets, but since it’s not structural, for aesthetics I might do it anyway.  Some careful fitting of the patch will be required so it lays flat agains the door frame.  And seal the seam against the door frame with some PRC or something that won’t work loose over time.  A flush patch would have less risk of getting caught on something again as opposed to a scab patch.  I think replacement of the entire skin panel would be overkill and really expensive.  If it’s the top skin, index 34, ugly.  If it’s the door post skin, index 35, maybe not so bad.

Forgive me for reposting your pics in a different orientation…

Edited Friday at 05:20 PM by 47U
Input the correct skin thickness/properties.

[Igor_U]

Good post by Four Seven Uniform. I think he's right, this could not happened due to vibration or aerodynamic forces in flight. I would think crack existed  for a while but IDK.

I am not sure how easy access is from the inside, to install the doubler. Tube structure is underneath and might be difficult to work this area. For sure, stop drill the crack and try to provide some pictures with interior removed. Good luck.

 

[WilliamR]

I've witnessed that exact same rip in the exact same place on a Mooney. The one I saw was due to something caught in the bottom on the door (think headset cord). Door was then closed on the cord which flexed the door to slip tight to the skin and maybe a little under. There was no issue or tightness closing the door. Door was a bit hard to openand was then forced open slightly and "pop", skin is ripped. It was clearly apparent the door was jammed a little only when trying to reopen. The pilot was surprised the skin ripped so easily rather than either the fuselage skin or the door just giving a little. 

Lots of ways to fix it given the non-structural nature. The repaired rip mocks the owner every time they are entering the cabin. 

William

[IvanP]

I do not think this happened in flight. Would be hard not to notice when you exited the aircraft. It seems more liklet that a tool or clothing got caught under the skin that may have been somewhat previouly comromised and the tear is the result. 

[EricJ]

+1 that a flush patch should be workable there.    Another benefit of owning a Mooney is that the skin around the cabin is not structural, so there is more freedom in repair technique.    Since that spot will be seen by anyone getting in/out, and since that area of the skin is all flush riveted, anyway, a flush patch would be a nice way to fix it if practical given the location.

I don't think what caused it matters at this point.
 

[Charles K]

All, 

Thanks for the great response. I agree with some comments about how something like this could happen. I wanted to ensure I was not off base in my thoughts about this subject, and yes, it will be repaired. It reminds me of this annual event every time I take a flight. 

I will say that a shop should never underestimate the knowledge or experience of an Owner or the attention to detail he/she has about the plane owned. 

[A64Pilot]

I think I would roll a piece of say .032 to match any curve, then coming from the inside use  structural adhesive to adhere the patch clamping the two together, then once the adhesive had set a little body putty ought to make the repair invisible and a good painter could I believe make it look like it never happened.

You could dimple and flush rivet shaving the rivet heads and make it invisible too, but I’m not that good, I had a guy who worked for me that was, I could take a pic of my 140 fuselage where I removed two stupid big venturi’s and he patched those holes and paint covered the patches.

[IvanP]

I hope that the shop will own up to the fact that the damage ocurred while the aircraft was in their custody and the repair will be on ther dime.  

[laytonl]

I’ve seen this happen to another Mooney before.  The aluminum was torn when a mechanic was removing the front seats and the seat frame snagged the aluminum. I don’t remember how it was repaired.  Lee

[ArtVandelay]

Any chance this was old damage and previously repaired with some bondo and it failed? The one picture looks like this might be the case.

[Charles K]

10 hours ago, laytonl said:

I’ve seen this happen to another Mooney before.  The aluminum was torn when a mechanic removed the front seats and the seat frame snagged the aluminum. I don’t remember how it was repaired.  Lee

That was my first thought. I know things happen, and I am not trying to assign blame, but I do not want to pay for carelessness. 

[Charles K]

On 3/7/2025 at 9:17 AM, N201MKTurbo said:

It looks like a crack formed and the pointy flap formed by the crack started vibrating in the wind till it fractured and flew away.

You should stop drill that crack. 
 

You can patch it, or reskin it, which would be a lot of work.

The only reason I would say not in flight is there are paint flakes under the flap; the parasitic drag would have prevented that. 

[Charles K]

13 hours ago, IvanP said:

I hope that the shop will own up to the fact that the damage ocurred while the aircraft was in their custody and the repair will be on ther dime.  

We shall see when the bill comes, as of now, there is no owning up, just repairs and continuing on with avionics updates. 

[Charles K]

15 hours ago, EricJ said:

+1 that a flush patch should be workable there.    Another benefit of owning a Mooney is that the skin around the cabin is not structural, so there is more freedom in repair technique.    Since that spot will be seen by anyone getting in/out, and since that area of the skin is all flush riveted, anyway, a flush patch would be a nice way to fix it if practical given the location.

I don't think what caused it matters at this point.
 

Correct, the damage is done, and I just want things corrected, there will be a flush patch applied, followed by some paint.

[Yetti]

I would inspect the door carefully in that area for scratches and such.   That might provide clues.    The "scratch" in the one pic looks like it might be the initial start of things.   it is a bit longer than the break.   And it could just be that this is a stress point between the door frame and skin.    Aluminum can only be worked for so long before it tears.

[MikeOH]

7 hours ago, ArtVandelay said:

Any chance this was old damage and previously repaired with some bondo and it failed? The one picture looks like this might be the case.

Good observation. Looks like all kinds of build-up of some material other than thin aluminum skin.

[Charles K]

10 minutes ago, MikeOH said:

Good observation. Looks like all kinds of build-up of some material other than thin aluminum skin.

Not that I'm tracking, can't really stop by the shop as it's not close by so at the mercy of shop sending any updated pics.

[MikeOH]

Just now, Charles K said:

Not that I'm tracking, can't really stop by the shop as it's not close by so at the mercy of shop sending any updated pics.

You should just ask them if it looks like it’s been repaired before. JMO

[Charles K]

22 minutes ago, Yetti said:

I would inspect the door carefully in that area for scratches and such.   That might provide clues.    The "scratch" in the one pic looks like it might be the initial start of things.   it is a bit longer than the break.   And it could just be that this is a stress point between the door frame and skin.    Aluminum can only be worked for so long before it tears.

Being told that this is common as the doors are not great in Mooney's. Funny thing is prior to the flight to shop I treated the door seal and noticed no damage. I did receive a picture of the seal with chaffing but did not 100% inspect the plane at dropping off. I'm over it, just want it fixed lol. 

[Charles K]

1 minute ago, MikeOH said:

You should just ask them if it looks like it’s been repaired before. JMO

I'll just let it slide at this point; there was a tone in the conversation that I de-escalated to the point of me telling them I was not blaming, just inquiring how this would happen and me not seeing it.

[PT20J]

I would check the door fit. Over time, the hinge wears and gets some slop and the door can sag and when you open and close the door, the door and fuselage skins can touch in this area. When you latch the door, it will pull this edge forward and there will be a gap. When you unlatch the door, the skins can touch and then when the door is opened it could catch the fuselage skin if it’s not flush.