Shoulder Harness Mounting, is this normal?

[SoMooney]

Hey everyone,

 

Thanks advance for your help. We removed the interior of my 67F this past week to replace the windows and found the shoulder harness mounted to the tubing as seen in the photos. Its some pretty thin strapping wrapped around the tube. My A&P isnt a mooney guy but was pretty concerned about it. Seems pretty hokey to me too. This isnt legit is it? Does anyone have images of how it supposed to be done? 

 

Thanks

 

[kerry]

It's the way I've always seen it done.

[SoMooney]

Really? It just doesn't seem like it would be strong enough. Any idea if this is STC'd or is this the "minor change" i read about on the web?

[kerry]

My understanding is it's legal as long as the airframe is not altered.  Only a log book entry is required and signed by a A&P.

[SoMooney]

Thanks Kerry! Anyone else done it any other way?

[kerry]

I did mine differently but that's another story.  If you search this site you'll see pictures that look just like yours.

[Shadrach]

Whoa, the technique is legit, but I'm not sure about the hardware. I just installed belts in mine a few years back and they came with a pressed steel bracket that was a first class PIA to get around the roll cage. This looks like someone subbed in steel strap for ease of installation. I'm not saying it is not legit, but it does not look like the hardware that came with my Alpha aviation/amsafe kit. What do the logs say about installation?

[Ron McBride]

When I installed my shoulder harness, it came with a steel bracket, was a pita to install.   Special bolts come with the installation.   Yours looks like plumbing strapping.   I doubt that it is strong enough.

 

Ron

[SoMooney]

Thanks again guys. So it seems we shoudl replace it with teh alpha kit that has these

 

http://aircraftproducts.wicksaircraft.com/item/line-clamps/clamp-loop/ms27405-6

[1964-M20E]

I would say no.

I do not have the clamp with me but it is much like an Adel camp but more robust. 

[SoMooney]

Shadrach, i went through the logs and didnt see it, all though I could have missed it or It could be buried in on of the entries by an A&P with horrible handwriting. Ill look again with a beer ha.

[Yetti]

Thanks again guys. So it seems we shoudl replace it with teh alpha kit that has these

 

http://aircraftproducts.wicksaircraft.com/item/line-clamps/clamp-loop/ms27405-6

That is the one that come with the am safe kit.   I was not a fan of the mechanics of the install.  If you need it, the clamp is going to be rotating around the tube and put a weird angle,  But it is about the same size as a the bolts that hold the motor mount to the airframe.  And if you need it that much the airframe may not be reusable anyways.

[Guest]

Thanks again guys. So it seems we shoudl replace it with teh alpha kit that has these

 

http://aircraftproducts.wicksaircraft.com/item/line-clamps/clamp-loop/ms27405-6

This is a more correct mounting. The piece of metal on yours looks like galvanized sheet metal.

Later model Mooney's have a steel bracket welded to the tube.

Clarence

[Shadrach]

Thanks again guys. So it seems we shoudl replace it with teh alpha kit that has these

http://aircraftproducts.wicksaircraft.com/item/line-clamps/clamp-loop/ms27405-6

That's what the ALPHA/Amsafe Kit came with. Whoever does the install needs to be very careful; it's really easy to to crack the left rear side window during installation.

[jetdriven]

That's totally pipe strapping. Similar to the fire sleeve I saw the other day held on with zip ties.

[HRM]

That is not the correct clamp.

I know the correct one intimately.

It is green, pressed metal, possibly Ti, and was fabricated by Satan in Hell.

I was tempted to do what someone did with yours, but the thought of failure at a crucial time made me press on and do it right.

[mike_elliott]

That is the one that come with the am safe kit.   I was not a fan of the mechanics of the install.  If you need it, the clamp is going to be rotating around the tube and put a weird angle,  But it is about the same size as a the bolts that hold the motor mount to the airframe.  And if you need it that much the airframe may not be reusable anyways.

Ribs and clavicle  will break before that clamp fails. Trust me. 

[Hank]

The Voice of Experience, Mike! Sure glad it was installed in that plane, or the results would have been more tragic.

But are you saying that the homemade-looking clamp in THIS plane is satisfactory? Your post is unclear on this, as there is debate about that particular point.

[MB65E]

I installed mine with a steel adel clamp. In the spec it said tinsel strength was near equal to the bolt. It's much easier to install that the steel MS clamp from Wicks due to the thinness and the coushion is thinner than the MS21919 clamp. One needs to be careful because most/all of the MS21919 clamps are aluminum.

I'm thankful everyone is now aware of the safety improvement the belts offer.

-Matt

[mike_elliott]

The Voice of Experience, Mike! Sure glad it was installed in that plane, or the results would have been more tragic.

But are you saying that the homemade-looking clamp in THIS plane is satisfactory? Your post is unclear on this, as there is debate about that particular point.

 

Personally, I would immediately change out the clamp in this picture to the one that was supplied with the shoulder belts and tested with them. That is a known, this homemade looking clamp is not. Yep they are a pain in the butt to install, but very doable. I have installed them in my former F model. The plane  I was in (1991 Bravo) had factory shoulder belts, but I am sure it was clamped to the steel frame the same way.

[SoMooney]

thanks...again!

 

We are definitely going to change them out. As for the difficulty of snaking them between the tubing and the aluminum body, will it be any easier now that we have the windows out?

[Yetti]

A little bit.  The trick is to open them up with two screw drivers and then work the angles, you close them with channel locks as they go around the tube.  The passenger is easier.  Once you get good at it you will be done.  Some blue scotch tape with an open end wrench will hold the nut while you put it all together.

[cmkep]

Just installed shoulder harness in my 64 M20E last fall. Purchased the kits from Alpha Aviation. The clamp kit was $35. for both sides. Comes with all the bolts, washers and spacer so that it all fits. Was a pain to install. There was no good place to get the clamp under the aluminum and around the tube. My widows survived but needed some re-sealing when I was done. What ever bracket you use, my understanding is that the mount needs to be engineered or tested to hold 800lb. It can deform but not fail. The aircraft structure is allowed to fail at that load so do not test it on your aircraft. Call Alpha, they have lots of information.

[Shadrach]

I did mine on a cool fall day and ended up with a crack propigating from one of the window fasteners.  My advice to anyone is to wait for warm weather. Side window are probably less likely to crack at >80df.

[Yetti]

If you read the instructions, they say to start high with the clamp to get it around the tube, then side it down.  on the pilot this requires removing some screws that hold the skin on and bending the skin tab out.