How is this possible?

[Joe Larussa]

All I can say is what the hell. Landed yesterday with oil all over the place. Turns out the mag was loose. Engine overhauled 125 hours ago. Lost 1/2 quart of oil. You can't tell me there is no way to keep this from happening. Thoughts?

[mike_elliott]

2 minutes ago, Joe Larussa said:

All I can say is what the hell. Landed yesterday with oil all over the place. Turns out the mag was loose. Engine overhauled 125 hours ago. Lost 1/2 quart of oil. You can't tell me there is no way to keep this from happening. Thoughts?

You are lucky it wasn't worse. The lock washer must be changed each time the mag is ladjusted/removed, never reused. There is a sb on this to insure the correct clamping hardware etc is installed.  

[Mooneymite]

Good thing you landed when you did.  If the loss of oil didn't  get you, the loss of the mag would have.

Do you have the single mag?

[Joe Larussa]

13 minutes ago, bluehighwayflyer said:

Do you have a 201 with a dual mag?  If so I can tell you exactly how this happened. You were very lucky!

Yep I have the dual mag. How about safety wire? Although I've never seen safety wire on a nut. Must be a better way.

[Joe Larussa]

16 minutes ago, bluehighwayflyer said:

Do you have a 201 with a dual mag?  If so I can tell you exactly how this happened. You were very lucky!

Yes on both!

[1524J]

Not a bad idea to have a set of clamps as well. I got a set from Spruce in anticipation of pulling my mags. It took almost 6 weeks for them to arrive.

[jetdriven]

If you put the mag fully in the case and, use the new style clamps and use new star lock washers and torque down the nuts firmly the mag won't come loose.  Many mechanics haven't gotten the message and I frequently see loose mags on planes because they adjust the timing and retorque the nuts.  

Absolutely verify this, because it can kill you faster than any other maintenance item on the airplane. 

 

If if someone was shooting at me and I could only preflight one thing on a 201 it would be the mag clamps.

 

 

Edited March 19, 2016 by jetdriven

[carusoam]

Joe,

I'm glad you handled this as well as you did...

You are not the first person to experience this loose mag debacle.  That we cannot change.

You probably won't be the last either.  This is the part we can try to make a difference.

Consider updating the title of this thread.  Simple, right to the point, so others can Find it when they search, or read it when they come accross the title.

Try something like...   Loose dual magneto on my M20J, lost oil.

You may make a difference for the next Mooney pilot that comes along.

There are a couple of strange re-used pieces of hardware that get done but hide only for awhile...

Re-used star washers on a mag is one. (Byron covered the reason above)

Re-used exhaust clamps on a Bravo is the other.

You bought the plane after the OH or you had the engine OH'd?  When were the mags last retimed?

Best regards,

-a-

[Joe Larussa]

4 minutes ago, carusoam said:

Joe,

I'm glad you handled this as well as you did...

You are not the first person to experience this loose mag debacle.  That we cannot change.

You probably won't be the last either.  This is the part we can try to make a difference.

Consider updating the title of this thread.  Simple, right to the point, so others can Find it when they search, or read it when they come accross the title.

Try something like...   Loose dual magneto on my M20J, lost oil.

You may make a difference for the next Mooney pilot that comes along.

There are a couple of strange re-used pieces of hardware that get done but hide only for awhile...

Re-used star washers on a mag is one. (Byron covered the reason above)

Re-used exhaust clamps on a Bravo is the other.

You bought the plane after the OH or you had the engine OH'd?  When were the mags last retimed?

Best regards,

-a-

I had the engine overhauled about 120 hours ago. Thing is we had to swap out the fuel pump which is another story. The mechanic removed the mag to make the job easier. I don't know for sure if he replaced the washers or not. I just finished reading the service bulletin. Not sure if the mechanic today replaced the washers either but I'm not going to re-cowl until I know for sure!

[carusoam]

Good conversation to have with him.  It can be used as a learning experience or build a good relationship with your mechanic if it can be done properly. 

Not done properly, leaves you starting over with the next mechanic.

Best regards,

-a-

[Joe Larussa]

Okay how about double nutting the stud? Safety wire, locktite, duct tape,

chewing gum!

[bradp]

I found a loose mag after overhaul of said mag, where mag didn't come back right and was R&R'd again.  I imagine it was when they tried to re-time and re used the hardware.  

Torque values on those mag hold down nuts is not as high as you'd expect, but metal expands as it heats etc.  Over torquing those bolts is not good either.  Point is that - the washers serve a purpose as Byron stated.

Check those mags.   Go where the doctors have been...

Brad 

[PTK]

10 hours ago, Joe Larussa said:

All I can say is what the hell. Landed yesterday with oil all over the place. Turns out the mag was loose. Engine overhauled 125 hours ago. Lost 1/2 quart of oil. You can't tell me there is no way to keep this from happening. Thoughts?

http://www.lycoming.com/Portals/0/techpublications/serviceinstructions/SI%201508C%20%2802-10-2011%29/Dual%20Magneto%20Attachment.pdf

[Browncbr1]

When I bought my plane, I noticed one of the nuts holding the vacuum pump was loosening. So, I got my a&p to put those washers that bend up and have a hole for safety wire in addition to the star washer.  They seem to work well.  

https://m.aircraftspruce.com/catalog/topages/safetywirekits1.php?clickkey=200082

Edited March 19, 2016 by Browncbr1

[N201MKTurbo]

I wish our cowls came off easier so we could give everything a good shake before we go.

[Hank]

Ever since I found a bolt inside my cowl, just laying in the bottom (didn't fly that day), that turned out to be an alternator mounting bolt, I always give it a good shake as well as checking belt tension. Can't check everything, just what I can reach. I also have two openings in top, the oil door and a second one on the other side--can't really reach anything, but at least I can look at both sides.

[carusoam]

When considering new ways to fasten important items to your engine.  Also consider the environment the fastener is working in.  (High vibration, temperature swings, expansion and contraction). Also consider what happens if a failure occurs with your new method...

---------------------

The instructions deliberately say... Stay on the path...

The instructions go out of the way to say how to stay on the path...

They also say when you have left the path....  (What not to do or reuse or substitute)

The path is a modern, time-proven method that is documented and widely broadcast and easy to find...

 

Why would anyone want to invent a new path?

What experience or training does one have to improve on the given path?

 

If you are considering a new path, also consider all the side effects that come with that decision.

If your mechanic doesn't have the latest version of the path or just doesn't follow the path, he isn't the right mechanic for you.

-----------------------

The path is 'use new star washers'

You have left the path if you re-use the old star washers or the wrong star washers the system will have an increased chance of failure.

 

If you are unsure if new star washers were used with proper torque, what are the choices of what to do next...?

 

Have you seen a bucket of used fasteners used as a tail tie down weight get used as a back-up supply of fasteners for a project?

This is an old tradition in many shops.  Find it in the bucket, clean it and install it.

 

To prove to yourself the value of a used star washer, just put a new one next to an old one.  If that doesn't work, tighten it down on a bolt with a nut.  The springiness and bite are different....

--------

just stuff that is PP observable.  Stay on the path...

Best regards,

-a-

 

[ArtVandelay]

My plane had a new engine installed in 96 by the "Plane Doctor", 81 hours later the right mag fell off in flight, with the internet these days, I would make sure everyone about it.

[N201MKTurbo]

It really boils down to using the correct torque. The lock washer is just the belt to the torque's suspenders. A properly torqued fastener will put a stress load on the nut's sliding surface that far exceeds the torque necessary to loosen it in any scenario of thermal expansion.  

I would say that in all cases when a mag falls off it was a failure of the mechanic to properly torque the nuts (or forgot to). The lock washers are just there to keep a loose nut from turning.

 

[neilpilot]

Suffered a loose mag on my M20E years ago  Observed oil on the nose gear a few hours after the annual, and then found the mag literally hanging loose.

That was the only MSC annual I had done in the 23 years I owned the E, and it was done at a MSC that has a very good reputation and that I returned to for the prebuy on my current C.

Moral of this story - even the best Mooney shop can screw up securing your mag.

[Browncbr1]

3 hours ago, Hank said:

Ever since I found a bolt inside my cowl, just laying in the bottom (didn't fly that day), that turned out to be an alternator mounting bolt, I always give it a good shake as well as checking belt tension. Can't check everything, just what I can reach. I also have two openings in top, the oil door and a second one on the other side--can't really reach anything, but at least I can look at both sides.

Yea, I decided to do the alternator conversion after a few times my GPS shut down on final for lack of voltage.  So, when we took the bottom cowl off, the generator just pretty much fell off. One bolt was holding it in and it was hand tight.     We were sure to use thick gauge safety wire on the plane power kit.  

[Guest]

3 hours ago, N201MKTurbo said:

It really boils down to using the correct torque. The lock washer is just the belt to the torque's suspenders. A properly torqued fastener will put a stress load on the nut's sliding surface that far exceeds the torque necessary to loosen it in any scenario of thermal expansion.  

I would say that in all cases when a mag falls off it was a failure of the mechanic to properly torque the nuts (or forgot to). The lock washers are just there to keep a loose nut from turning.

 

I agree fully, it also comes down to lack of care and training from a senior technician.  I train my apprentices to get the manual, find the table of limits and torque accordingly with a calibrated wrench.  While it takes a few minutes longer hopefully the lesson sticks.

On the dual magnetos we also add an old style Pal nut.

https://m.aircraftspruce.com/catalog/hapages/ms27151palnuts.php?clickkey=18692

I've also seen mags fall off due to incorrect magneto flange gaskets being installed.

Clarence

[carusoam]

Things I got from reading this thread again...

How this is possible:

1) Improperly re-used hardware.

2) Improperly torqued hardware.  Proper calibrated torque wrench is key.

3) Improper seal used.

4) Failure to follow the proper procedure, to completion.

5) Failure to detect the looseness of the part before flight. (Tough to do with a Mooney cowl.)

6) This can happen at high end maintenance shops where humans are involved.

7) When you find a fastener in the cowl, know that it came from somewhere.  It is best to find out where it came from.

8) Know that there is a worst doctor in the world, and somebody has an appointment to see him on Monday...

9) Adjusting this title may help the next Mooney pilot.

10) Input came from pro pilots, pro mechanics and other people with identical experience.

11) Mags have the dual abillities of being really bad.  Losing both engine oil and ignition as they come loose.

12) Other things that came loose in a similar fashion generator/alternator and vacuum pump.

13) Getting it right is a challenge.  Going one step further, Doc offered the Pal nuts.

That's a summary of what I think I read.  I am a PP working on my reading/writing skills.  Most of these ideas came from somebody else.

How's that?

Best regards,

-a-

[Hector]

Most critical hardware in my engine compartment get a torque stripe. I look for the torque stripes during my preflight inspection.

[Shadrach]

1 hour ago, Hector said:

Most critical hardware in my engine compartment get a torque stripe. I look for the torque stripes during my preflight inspection.

This is sound advice. I keep a tube mechanics lacquer in my tool box. We marked every bolt when we hung the engine. I'm sure his IA would mark it on request.