ELA Eclipse Undercarriage main landing gear collapse - Please inspect

[Abid]

Hi All:
On the French forum there was a report of ELA Eclipse undercarriage collapse on takeoff roll. Seems like it warrants an inspection for pre-mature fatigue in the landing gear for ELA owners starting at the hole for securing bolt. Better to order and change the landing gear by catching it now than have a flip over on the runway and lose a lot more $$ and possibly get hurt.
Fly safe.

This is Google translate from French:

"
This morning, before leaving for the weekend, I had a christening to perform at Lens-benifontzine. A stag party.

10:10 I take off from Arras.

10:25 I land in Lens.

10:41 I take off with my passenger.

11:15 I land, having made one more happy passenger.

11:21 it's time to head home to enjoy the Grandes Eaux de Versailles.

I taxi to threshold 21. I check the magnetos and announce that I'm lining up. The wind is in line for 15kt. I enter 21 and after a few metres, as I'm rolling and about to turn to line up, I hear a huge snap to my left, the gyro collapses and tilts to the left.

In an instant I found myself almost upside down.

2 seconds later, a smell of petrol invaded the cockpit. I switched off the pumps and the master and unlocked the canopy.

That's it! I've got my answer... is it possible to open the canopy in the event of a tip-over?

In 3 seconds I understood that it was impossible.

I then tried to break the plexus with my feet. I discover the capacity of deformation of this material which seemed so fragile...

It took 10 hammer blows to break through the plexus. A few good thrusts with both legs then shattered the whole thing. The whole thing only lasted a few seconds...

Fortunately, nothing caught fire.

I soon realised that it was the whole landing gear leg that had failed and not just the rim this time.

Petrol is spraying profusely from the vent pipe...

In the distance I see a crowd outside the aircraft hangar. After more than 5 minutes, the club secretary got into her car to come and see what was going on! Nobody else had moved!

She arrived while I was on the line with 191, who decided to close the field and send in the fire brigade.

3 fire engines arrived in 10 minutes.

The person in charge of the flights was furious... his pitch was closed!

The fire brigade had to cross the runways to put him back in place, while he decided to take off a plane for a first flight! A real cunt!

I managed to dissuade the firemen from carrying out a preventive spraying operation... all the electronics would have been out of order. A fireman doesn't skimp on resources... and when he can use his toys...

10 firemen then took care of getting the Gyro off the runway and onto the taxiway.

It then took us 4 hours, with the invaluable help of Sylvain (a multiaxis instructor from Arras who came to lend me a hand) and Frédéric Bastien, a Gyro instructor from Lens, to dismantle the remaining part of the landing gear leg and install a landing gear leg that Fred had in the corner (see SB on this subject).

The machine is sleeping tonight in a hangar in Lens.

I'll know on Monday whether my insurance (which I hesitated to renew in June!!) is good or not...

Dr Pascal is already on the case and ready to collect the injured man from his emergency department.

The main thing... no injuries"

 

[Aerofoam]

He's got a great dry sense of humor!!!!

 

[XXavier]

From 'La Voix du Nord'

 

[Strike]

NONon sembra essere l'unico modello ad aver avuto questo problema! L'ho avuto con un guasto al supporto del telaio delle gambe! Ma su un modello junior 09, ecco perché adesso non uso queste gambe in Ergal!!
Sul mio modello Ela 07 ho cambiato completamente il sistema!

 

[Andino]

Shame! Am relieved there were no injuries. Hadn't ELA shown some previous structural weaknesses?

 

[Sv.grainne]

NONon sembra essere l'unico modello ad aver avuto questo problema! L'ho avuto con un guasto al supporto del telaio delle gambe! Ma su un modello junior 09, ecco perché adesso non uso queste gambe in Ergal!!
Sul mio modello Ela 07 ho cambiato completamente il sistema!

Strike: Can you get the model number on the fan that is on the radiator?

Bobby

 

[Chook]

Classic metal fatigue lines emanating from the bolt through the undercarriage spar!

And his notation - "I soon realised that it was the whole landing gear leg that had failed and not just the rim this time."

Regards.............Chook.

 

[Abid]

Shame! Am relieved there were no injuries. Hadn't ELA shown some previous structural weaknesses?

Yes 3 accidents where the tail boom broke off in flight. But that wasn’t on the Eclipse. French authorities determined it was because how they did the welding there.
Also the composite blades they make I have seen two sets here in Florida with starting of cracks on them. Have to inspect each year carefully.

 

[Abid]

Classic metal fatigue lines emanating from the bolt through the undercarriage spar!

And his notation - "I soon realised that it was the whole landing gear leg that had failed and not just the rim this time."

Regards.............Chook.

Yes that is what will happen when you drill a hole in Aluminum that deep which isn’t smooth or not reamed. a life limit of say a 1000 hours probably is a good number on a round spring leaf of Aluminum. Taking off on grass which isn’t smooth can accelerate the fatigue. In this case though it is the jagged edges of an improperly drilled bolt hole that created premature fatigue. The hole is drilled in steps and then no reamer was used to smooth it out. A loose fit hole allowing slight movement equals premature fatigue.

That notation indicates that may be he had a rim of the wheel sue at some point or is it a translation thing.

 

[Aerofoam]

I can't believe they would design it with a hole in that structure.....

 

[Grodou]

That notation indicates that may be he had a rim of the wheel sue at some point or is it a translation thing.

On that specific machine, unproper bolts had been used on the rim before purchase.
3 of them broke at the same time during attempted take off. Luckily no other damage resulted.

 

[Abid]

On that specific machine, unproper bolts had been used on the rim before purchase.
3 of them broke at the same time during attempted take off. Luckily no other damage resulted.

View attachment 1158827

Was this rim on the same side as the landing gear that broke now? That could have caused damage in that bolt hole when the rim came off. That damage then started the fatigue because it was not caught in a proper thorough inspection before.

 

[Abid]

I can't believe they would design it with a hole in that structure.....

Nothing wrong with a hole in the structure. That is how many undercarriage landing gears are secured in aircraft but it is a hole that cannot be allowed to be loose. The movement there starts fatigue and accelerates quickly. That hole has to be properly drilled, reamed with a good reamer and have a snug fit for the bolt. Bolt should be a Cadmium plated bolt like an AN bolt. Regular metric industrial hardware would be zinc plated and that would start corrosion in bare (non Anodized) Aluminum contact and that can also accelerate fatigue. Cadmium and Aluminum have much less propensity to start corrosion than zinc and Aluminum. For this particular area, something as small as that matters. In other areas it may not be a huge deal. Cadmium's galvanic characteristics are compatible with Aluminum

 

[Gyro Technic]

In this case though it is the jagged edges of an improperly drilled bolt hole that created premature fatigue. The hole is drilled in steps and then no reamer was used to smooth it out.

Abid,
As you know, normally I don't comment much on any threads...
I agree about everything regarding this as a design flaw.
But come on now!

Unless you have much more info on this than the rest of us...

There is no way you can tell the surface finish of the inside of that hole, let alone the machining process they used to create it, just by that one photo.

A broken mirror has jagged edges!

I just thought this was a bit stretch.....

Denis

 

[Grodou]

Was this rim on the same side as the landing gear that broke now?

Same side indeed.
As suggested the owner, examination of the right side leg will probably tell us a bit more about condition/drilling/wear of that bar.

 

[Aerofoam]

Nothing wrong with a hole in the structure. That is how many undercarriage landing gears are secured in aircraft but it is a hole that cannot be allowed to be loose. The movement there starts fatigue and accelerates quickly. That hole has to be properly drilled, reamed with a good reamer and have a snug fit for the bolt. Bolt should be a Cadmium plated bolt like an AN bolt. Regular metric industrial hardware would be zinc plated and that would start corrosion in bare (non Anodized) Aluminum contact and that can also accelerate fatigue. Cadmium and Aluminum have much less propensity to start corrosion than zinc and Aluminum. For this particular area, something as small as that matters. In other areas it may not be a huge deal. Cadmium's galvanic characteristics are compatible with Aluminum

No disrespect, it is probably within the realm of acceptability(barely) But I beg to differ:
The first problem is using aluminum as a spring..............
Even if it is over sized enough for the task, it will then be heavy to the point of, Why didn't I use much thinner steel alloys
in the first place?
Second problem (Referring to the first problem) Why the $%## would you drill a hole through aluminum at one of the already present
stress risers????? I don't care how smooth the bore is, or how radiused the entry was, I would avoid that like the plague.
BTW the hole looks to be off center by at least .062", maybe intentional?
Maybe the other issues exacerbated the failure, but it shouldn't be that close to the brink of disaster in the first place.
I like enough margin of error to not cause a cascading failure if one item has issues....

Pillow blocks?, Chromo tube?, DOM tube?, Multi point?... any number of techniques could be used that would end up stronger without a weight
penalty... Look at the flimsy AC structure, I have not heard of a rampant set of failures......(except where holes were drilled...)

There is nothing earth shaking, or new here, why tempt failure?

 

[Strike]

Strike: Puoi ottenere il numero di modello sulla ventola che si trova sul radiatore?

Bobby

Strike: Puoi ottenere il numero di modello sulla ventola che si trova sul radiatore?

Bobby

CCertainly

 

[Abid]

No disrespect, it is probably within the realm of acceptability(barely) But I beg to differ:
The first problem is using aluminum as a spring..............
Even if it is over sized enough for the task, it will then be heavy to the point of, Why didn't I use much thinner steel alloys
in the first place?
Second problem (Referring to the first problem) Why the $%## would you drill a hole through aluminum at one of the already present
stress risers????? I don't care how smooth the bore is, or how radiused the entry was, I would avoid that like the plague.
BTW the hole looks to be off center by at least .062", maybe intentional?
Maybe the other issues exacerbated the failure, but it shouldn't be that close to the brink of disaster in the first place.
I like enough margin of error to not cause a cascading failure if one item has issues....

Pillow blocks?, Chromo tube?, DOM tube?, Multi point?... any number of techniques could be used that would end up stronger without a weight
penalty... Look at the flimsy AC structure, I have not heard of a rampant set of failures......(except where holes were drilled...)

There is nothing earth shaking, or new here, why tempt failure?

Aluminum as a spring leaf? Do you know how many airplanes use Aluminum leaf springs?
Try this just for a sample

Grove Landing Gear

Same for even the axles. Tons of them use Machined Aluminum axles. Grove, Matco, Cleveland and so on.
And no. You cannot get the strength from Steel alloys at the same weight as 7075-T6 Aluminum. Ain't ever going to happen. 7075-T6 Aluminum for the same strength is going to be 45% of the weight of Steel alloy. The safety factor applied in such Aluminum applications is supposed to be 2x as opposed to 1.5x. This is to keep fatigue life in check.
Now if your engineering is crap, your manufacturing engineering is crap, then yes you are going to have junk in = junk out. That isn't the fault of the material. That is the fault of an engineer not knowing how to engineer for the given material.
Why would you drill a hole through Aluminum. To secure the landing gear in its bracket of course. You know so many rotors whose hub bar is made of solid Aluminum with holes in the hub bar to bolt clamping plates to clamp to blades. Dominator (Dragon Wings), GyroTechnic, Averso, and tons of others. By this logic all of these are wrong. No they aren't wrong. They are just done properly and inspected for torque and tightness every year. You may not care about the bore not being smooth but Physics does care. A loose uneven hole creates movement and movement creates fatigue. Simple as that. The assembly needs to act as one unit between landing gear leg and its securing/supporting structure. Tubes do not make a great landing gear. Leaf springs are solid and usually machined from bigger to smaller radius to behave properly as landing undercarriage.
I agree there is nothing earth shattering here but I think you are completely off base in your assumptions.
In this particular case if there was a previous incident as was said with rims coming off because of wrong bolts being used, then it is very likely that in that incident that landing gear took a lot of abuse and that hole became damaged and no one bothered to inspect and check it and fix it. A simple fix would be to redrill and ream and upsize the hole and use an Aluminum bushing pressed in to bring it back to bolt size. That would have halted the problem with a proper bolt torque and stop the movement of the landing gear inside the bracket and thus stopping the accelerated fatigue cycle. A proper A&P mechanic or an engineer would know to do that. An end user or a car mechanic who just wrenches and knows nothing else, won't.

 

[Sv.grainne]

CCertainly

Grazie

 

[Abid]

Abid,
As you know, normally I don't comment much on any threads...
I agree about everything regarding this as a design flaw.
But come on now!

Unless you have much more info on this than the rest of us...

There is no way you can tell the surface finish of the inside of that hole, let alone the machining process they used to create it, just by that one photo.

A broken mirror has jagged edges!

I just thought this was a bit stretch.....

Denis

Well you can see the fatigue though correct. It is clear as the blue sky in that picture. Unless this landing gear has seen over 2000 hours and many cycles, that fatigue only has one cause. Movement. Movement would not happen if the bolt was tight and secured.
I do not think this is design flaw necessarily. It may be but we don't have enough info to say that. This model did pass German BUT certification which does require dead drop tests and a safety factor. I think this is a manufacturing flaw or if this is the same side where people are saying the rim came off during ground roll for takeoff, then it is a flaw created from that incident without being properly checked and caught back then and made worse with further usage. So that we are clear, I am not prepared to say this is a design flaw but I am prepared to say it is good to inspect this area. If you have things like rims coming off, then inspection shouldn't just stop at the rim and axle. Many end users always seem to fall in this trap. You really ought to inspect the whole assembly and in a gyro even the frame. Load paths go through the whole structure right into the mast.