Crack in elevator trailing edge

[JimB]

Looks to me like it's been there a while. Personally I wouldn't worry about it all. Use it to negotiate some off the price, stop drill it and go fly. 

On 12/13/2019 at 1:32 PM, MB65E said:

Flight Controls are the surfaces...

I repaired a rudder on an Extra at an Airshow per the manual. I was grilled later about 337’s etc by a few people including the Local FSDO....

A MedVac KingAir at 3am fired up in front of the hangar we were in and blew our airplane into another KingAir spinner. 

-Matt
 

Matt - That doesn't surprise me but that doesn't make them right. Of course I have no idea the extent of the repair you had to make on the rudder. 

I certainly wouldn't do a 337 for stop drilling a small crack on the trailing edge. 

[Alan Fox]

On 12/17/2019 at 12:07 AM, Adi said:

Hey folks, 
 

Thank you all for your advice and replies.
I got two more data points from different a&Ps who both said this is not a big issue, can be stop drilled but not an airworthiness issue.. so I went ahead with the plane. I'm now a Mooney owner!

Adi

Congrats , although I don't drink the "Koolaide" , I am an A&P with some Mooney experience , feel free to reach out for advice in the future... Regards

 

[Adi]

2 years later and after a successful thorough annual in 2020, the new shop I’ve taken it to this year squawked it as an airworthiness issue.

As I negotiate with them, does anyone have a reference to either a crack disqualifying an airplane from airworthiness altogether or the opposite? I’ve also heard a stop drill could require rebalancing or being considered a major alteration, any reference to that?

edit: I haven’t had anyone stop drill it nor has it progressed beyond what it looked like I’m the original post. 

edit2: I do apologise, @EricJ actually provided the reference when I originally posted the question: AC 43.13 Par. 4-59. That's still pretty scant unfortunately, I don't see any guidance there on what is acceptable and what is not. Maybe it's a judgement call?

[carusoam]

1 hour ago, Adi said:

, I don't see any guidance there on what is acceptable and what is not. Maybe it's a judgement call?

Skip this diatribe…  go directly to Doc’s post below…   

 

For background on the logic…. Read the diatribe written here….

i think you have hit on the issue…

In GA, we have a few resources of what is acceptable for repairs…

The two big ones are…

1) The maintenance manuals written by Mooney.

2) The standards of aircraft maintenance written by the FAA.   
 

3) If it isn’t in the manuals showing that it is acceptable… then it isn’t…. We have some damage that is known to be acceptable… a certain amount of fuel leak from a fuel tank is OK…. Because the manual says so…
 

When your mechanic can’t find the necessary guidance from there… he contacts the factory to discuss the repair with their engineering department…

The world kind of frowns making judgement calls on things that can kill you…

Example… if you have a crack in the sheet metal of a flight control….  To make it right again, probably removes the crack…

Metallurgists know that cracks can propagate, without any warning… leading to a tear….

A tear in an important flight control can lead to much bigger problems like flutter, or just a simple loss of control…

Stop drilling is often successful at stopping a crack in some less important area, like a gear door… they can be really effective… but not all stop drill holes are successful… and the crack reappears… and continues on… unabated….

 

So… from a pilots perspective… it looks like the bad situation could stay stable forever… why spend any money on it…?

From the engineer’s perspective…. That situation could change without warning…. Who wants to fly in a plane that may shed a flight control…?

 

Flight controls are kinda unique… they are extra light weight, and highly balanced… so they don’t get shed at high speeds…

Adding modifications to them requires careful engineering… for safe results…

The moment flutter occurs… the pilot is immediately in a bad place… with an unknown amount of time to make a change… the forces caused by flutter are destructive… compared to the strength of the hinges and controls…

 

Options for aileron repair are as simple as re-skinning, or replacement…

Skins are available from the factory… used flight controls are available from the big three Sanford and sons….

 

My apologies, I didn’t read the whole history… so I probably made some assumptions…

Got any current pics of what needs to be corrected?

Best regards,

-a-

[Guest]

46 minutes ago, Adi said:

2 years later and after a successful thorough annual in 2020, the new shop I’ve taken it to this year squawked it as an airworthiness issue.

As I negotiate with them, does anyone have a reference to either a crack disqualifying an airplane from airworthiness altogether or the opposite? I’ve also heard a stop drill could require rebalancing or being considered a major alteration, any reference to that?

edit: I haven’t had anyone stop drill it nor has it progressed beyond what it looked like I’m the original post. 

edit2: I do apologise, @EricJ actually provided the reference when I originally posted the question: AC 43.13 Par. 4-59. That's still pretty scant unfortunately, I don't see any guidance there on what is acceptable and what is not. Maybe it's a judgement call?

The J model manual doesn’t allow or forbid repairs to flight controls.  It does say to check balance after repairs etc.  To me it infers that you can repair it per the AC43-13. 

Many Mooney airframes have similar damage and seem to fly on with no issues at all.

Clarence

[PT20J]

You could ask Mooney: technicalsupport@mooney.com

[A64Pilot]

I my opinion as an A&P I/A, if someone wanted to argue it was a safety issue, then I’d stop drill it. stop drilling will not require rebalancing as only a tiny, bit of metal (weight) is removed, I mean insignificant, stop drilling is the most conservative response, takes seconds, of course fo be super conservative any stop drilling should be reamed to remove any stress risers, another minute of work.

If I wanted to be super, super anal about it I’d make an entry that the crack needs to be checked for growth at every pre-flight as that adds no burden to the pilot, and surely your doing that anyway.

Problem is, is that safety is a sacred cow, once that flag is flown it’s tough to overcome.

I do not consider it a safety issue myself.

Oh and removing weight from the trailing edge of a flight control moves the CB forward which increases its resistance to flutter, but no scale I have ever used could possibly measure that tiny bit of metal removed from a stop drill hole.

Edited August 25, 2021 by A64Pilot

[Adi]

The Director of Maintenance came back to me and said that after some consultation, he's OK with the stop drill.

(Side note - I didn't know it had already been stop drilled - whoever did it did a neat job, apparently it's filled with silicone.)

Thanks all for your input. Very interesting to learn what your guys' thought processes are about where to look for info about what's allowed/not allowed, and what is a safety issue and what is not.

[carusoam]

11 hours ago, Adi said:

The Director of Maintenance came back to me and said that after some consultation, he's OK with the stop drill.

(Side note - I didn't know it had already been stop drilled - whoever did it did a neat job, apparently it's filled with silicone.)

Thanks all for your input. Very interesting to learn what your guys' thought processes are about where to look for info about what's allowed/not allowed, and what is a safety issue and what is not.

Hang out here long enough…. You will be giving guidance to the next new guys that show up with similar questions…. 
 

You have a great question….  It is hard to find a question that hasn’t been asked already…

Some answers came from people that used experience from outside of aviation…. They may be pilots, but at work they are engineers and scientists or mechanics that work on industrial machines….

Some answers get you halfway to where you want to go… and another MSer fills in the rest of the details…

 

You know when you have asked a tough question… When doc arrives and posts drawings and part numbers from a Mooney manual…

For interesting reading… find that reference / airplane maintenance circular…. There aren’t that many pages in a book that covers Everything…  and it’s free from the FAA…  

Best regards,

-a-

[PT20J]

22 hours ago, Adi said:

The Director of Maintenance came back to me and said that after some consultation, he's OK with the stop drill.

(Side note - I didn't know it had already been stop drilled - whoever did it did a neat job, apparently it's filled with silicone.)

Thanks all for your input. Very interesting to learn what your guys' thought processes are about where to look for info about what's allowed/not allowed, and what is a safety issue and what is not.

Glad this worked out. Many gray areas regarding airworthiness are left to discretion of the IA. In my experience, you want the most experienced one you can get because they generally are more comfortable with the gray areas. But still, some are more nit picky. Looks like you found a more experienced person to make the IA comfortable. The reason I suggested contacting the factory is because Mooney is the final authority for their airplanes and whatever they say gives the IA the technical data to make the repair, or let it go. The IA's ass is covered, so to speak.

Skip

[Bartman]

18 hours ago, carusoam said:

Hang out here long enough…. You will be giving guidance to the next new guys that show up with similar questions…. 
 

You have a great question….  It is hard to find a question that hasn’t been asked already…

Some answers came from people that used experience from outside of aviation…. They may be pilots, but at work they are engineers and scientists or mechanics that work on industrial machines….

Some answers get you halfway to where you want to go… and another MSer fills in the rest of the details…

 

You know when you have asked a tough question… When doc arrives and posts drawings and part numbers from a Mooney manual…

For interesting reading… find that reference / airplane maintenance circular…. There aren’t that many pages in a book that covers Everything…  and it’s free from the FAA…  

Best regards,

-a-

In other words I think -a- just said...

MooneySpace is one collective brain. 

[carusoam]

The collective power of MS is Awesome….

Some people are here nearly every day…

Others check in once each week….

A few only come by when they have a question….

Everyone has valuable experience to share….

They may not know the answer, or where to find it…

Somebody will often supply guidance on where to go and who to ask… or an example of the same situation… or a hint to the fact there is a similar situation out there….

 

Go MS!

Best regards,

-a-