New start material strenght calculation for operating horn from crashed plane. Part 2 4

[RedSnake]

Can anyone help me check if this calculation works so far?
There are so many conversions between different units ..
The calculation is made by a free software but I assume that their calculation models are correct.

My own assumption is that the elevator is heavier at the front edge as there are hinges made of MIL 1430 N and since the lever and its attachment also are , there are also steel details on the other side and the rest is aluminum.
I have chosen to see it as a simple bar to begin with.

And the calculation is made to check which load the fixed joint must withstand for the elevator's own weight.

I intend to present it in steps so if I got something wrong I can adjust it before the next step.
If it's okay with you people?

Best regards Anna

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

 

[Alistair_Heaton]

You would do that down to about 30ft in the stuff I fly. The light aircraft down to 10ft or less. But we are 50 tons plus. I start taking power off at 100ft and it all comes off at 20-30ft. Light aircraft its as the nose goes through the horizon.

 

[RedSnake]

I will tell you something about Swedish mumms.
My mother wanted to invite me to lunch to day, a Christmas plate that she was going to pick up from the pensioners' association, because it's Corona times and they can not meet and eat together.
This morning I called and said I could not come as I was a little snotty and sneezing so it is not allowed.
She thought I would probably be better at noon?!?.
It does not matter I said, I have no idea if it is a cold or corona.
Then at one a clock the doorbell rings, and it is my mother who comes to leave the Christmas plate to me that she has picked up and she cannot keep her distance.
What to do ??
I know she does it because she is kind and caring, at the same time I get so angry when she does not understand that she should stay away.
It's not like I was going to starve to death, if she had not come ... SIGH
That is Swedish mothers in a nutshell for you.

/A


“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

 

[RedSnake]

Can you come up with another way to break the elevator horn towards the maximum stop up?
It would need a drag force of more than 5100 N on the elevator surface for it, speed 180 knots.
Other than if the plane falls backwards with the tail down and the elevator out 90 degrees against the direction of fall.
And that would need a fall of 190 m.
Or in a clockwise roll, but then the plane must have rolled at least 7 revolutions / second.
Does not even feel reasonable. ??

Best regards A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

 

[waross]

Has this been considered?:
The elevator was ripped from the plane by aerodynamic force.
The remaining attachment was by the horn and linkage.
The horn broke off last.
Was the break in line with the normal force on the horn or was it at random as would be the case if it was the sole remaining link with the aircraft?
Sorry for the inexpert input but I have been wondering this for many posts now.
Inconclusive?
Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[RedSnake]

Sorry for the inexpert input but I have been wondering this for many posts now.

No problem for me, ask whatever you want.

Yes, in one way or another so is aerodynamic forces XOR G-forces involved.
Just need to prove/convince myself that the bad welding didn't make things worse.
The remaining attachment was by the horn and linkage.
The horn broke off last.
That is what SHK claimed in our last conversation, but it is not possible.
Because the stabilizer had been broken loose from behind and forward and then up against the fin.

The wrinkles, dents and braken skin in the front of the vertical stabilizer indicate that the stabilizer had been pushed to the left,
A dent on the top side of the RH elevator together with signs of red coloured steel primer was found close to the indentation. Possible parts having this primer in the close surroundings could only be seen on the upper rudder hinge,

This would not have been physically possible, if the horn haden't been broken of first.
In addition, the material report has come to the following conclusion.

Examination of elevator hinge RH side. Measuring of the elevator travel up and down relative to stabilizer showed: Up :::: 54 °, (allowable limit 15 ° ± 0,5 °). Down :::: 68 °, (allowable limit 19 ° ± 0,5 °).

I have a hard time believing that this would have happened after the stabilizer and the elevator had separated from the plane.

Visual inspection of the corner welds indicated areas of severe lack of fusion in the
longitudinal and the circular part of the weld. This was confirmed using radiographic
examination. LOF is regarded as critical and is normally not accepted in any welding class. The weld defect will reduce the load carrying ability and the stiffness of the elevator
operating horn.

Bad weld

Figure 28. The lack of fusion defect extended more than 10 mm. Effective weld penetration is here reduced to 10 -50 %.
The fracture had started in a weld defect of the corner weld. The fracture mode was overload in tension transverse to the welding direction.
No signs of fatigue were evident.

Best regards A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

 

[RedSnake]

I guess it could have been broken loose by the stabilizer when it started to break up forward, it has a larger surface on which the force can act.
The elevator is more flexible until it ends up against one of the stops.
But the way the balance horn had been torn loose is also very strange.
They did not find it until 4 months after this material report was written.

The balancing weights were mounted in the outer part of the elevator using eight blind rivets. The remaining blind rivet heads on the RH side were examined. It was concluded that none of the blind rivets had failed but the rivet heads had expanded the rivet mounting holes and thus caused the weight to separate. Besides the eight rivets the balancing weight is mounted using a screw in the turning centre. This screw did not fail but it still holds a small part separated balancing weight. No signs of fatigue fracture were visible.


Some force should be needed for that. But it's just the angle that make it feels weird.

Someone said that they used the same weights in the balance horn as when balancing car tires.

Well maybe I have misunderstood, but Alisair I got the impression that you were an airplane technician/mechanic before?

So what would happen if a weight fell loose while flying and then lying and rattling around in there?

I have not seen that SHK has writen anything about having examined the balance horn at all after they found it.
Mayby I should ask about this...

/A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

 

[Alistair_Heaton]

https://www.instagram.com/p/BqiBTuygS55/

I have been looking for videos of other aircraft having wing failures to see what the dynamics are like.

My gut feel is it might have been going backwards at some point.

Found this one.

 

[waross]

Thank you very much for taking the time to explain this to me Anna.
I appreciate the amount of work and time you put into your reply.I have one other question;
Are there travel stops on the elevator itself, either up or down, or do the stops bear on the horn.
I have looked at the diagrams and pictures but I can't be sure.
Thanks
Yours
Bill

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[RedSnake]

This is from a document I sent to SHK in July, 2 months before the final report came.
Not so far of, from your video I would say.. ..
But SHK says that this altitude increase at 12:07:22 is not correct?!? :-(
It also comes shortly after the speed goes through the roof, on the sound film, 3000 rpm, max for the engine is 2700rpm.

Best regards A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

 

[RedSnake]

The only stopps are on the horn (lever).. The bult is stopp down and the bracket for stopp up, I do not know if it is the right word here so I say stirrup then you know what I mean. ;-)

Best regards A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

 

[Alistair_Heaton]

The engine will have two max rpm's one prop governor related and one engine governor related which will be higher.

I have thought about this a few times, maybe you should keep an eye on the SHK website for any jobs coming up... From memory they don't just do aviation.

That diagram showing the sequence is the way I visualise things happening as well.

 

[RedSnake]

The engine will have two max rpm's one prop governor related and one engine governor related which will be higher.
Okey the prop governor has "two" rpms. 2700 rpm for take of that can only be jused, pasing a gate with the lever. Normal propeller rpm is 2500. I guess the enging being a boxer engine with injection and turbo can come up at much higher rpms if it was not limited.

I have thought about this a few times, maybe you should keep an eye on the SHK website for any jobs coming up... From memory they don't just do aviation.
The first time I had a skype conversation with them, it was the investigation leader and the pilot who made the reference flights, it sounded almost like they had intended to offer me a job. LOL
My feeling since a few months back is that they are too competent and too homogeneous as a group, the same background and age.
Maybe they would need someone who thinks outside the box and can ask all the stupid questions, stir up the pot a bit
But I'm not good at calculations and that kind of stuff.
I only see things like pictures and figures and connections in my head.
And it becomes insanely difficult to explain to others how I have arrived at things when it is not possible to get it down on a piece of paper.

That diagram showing the sequence is the way I visualise things happening as well.
Not the way the two older gents thinks it happened, one became quit annoyed at me when I tried to explain why I did not agree.
I can be without that.
I have no problem taking a discussion with someone and agreeing that we do not agree, but when someone just gets angry and annoyed when you say something then I can be without it.
Maybe I'm a little sensitive right now too ..
Normally I would get really pissed off if something like that happened, but now it just makes me sad.

Best regrds A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

 

[Alistair_Heaton]

Just your ability with diagrams would be an asset. You never know its worth considering once a bit of time has gone by. The worst thing they can say is no.

I am always very wary of old blokes in aviation who press an off mainstream opinion. Over the years I have learned that there is some other issue which may be personal or political which is the main driving force and you usually only find out the real reason in a pub or years later or when they pass away. There is often decades of history involved. The shutting down of others opinions through aggression is usually a sure fire pointer that something is going on which you don't know about. There is still feuds going on in the UK after Kegworth accident and investigation. And to make matters worse that accident is one of the mainstream training case studies for pilots round the world. I suspect there will be similar feeling in the Netherlands about Tenerife 747 accident.

SHK did an excellent job with the SAS Q400 gear issues but the final finding that it was colossal flaws with SAS maint standards and QA did not go down very well locally. It cost SAS an awful lot of money to sort that one out including a lot of compensation to Bombardier. I know some Swedish considered them traitors for keeping on pushing and eventually finding what they did and the resulting loss of face and money cost to close the subject down.

 

[RedSnake]

Yes, I feel that at least one person at SHK has had his own agenda here which he has pushed quite hard.
I have only had to deal with him once and received the same treatment from him as from one of the two older gentlemen, who do not work and never has worked at SHK.
The head of investigations at SHK has been very good and I have nothing bad to say about him, one of the few people I have met who is very unpretentious.
I do not disagree with the SHK:s recomendations.
But it just feels that not attention has been made to things that acyually can be investigeted, most thing can never get claryfied since there is no black box for example.

This is the qvalifications of the head of investigations.

/A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

 

[RedSnake]

Just your ability with diagrams would be an asset. You never know its worth considering once a bit of time has gone by. The worst thing they can say is no.
True they actualy changed a diagram becaus I "complained" it was the CoG diagrams ;-)
But than I might have to move to Stockholm and I am actually more of a country girl..

As in this actually Swedish song recorded by Blackmore's Night .. Highland.

https://www.youtube.com/watch?v=Mg77ASfpJHI

and the original One more Time. Higland

https://www.youtube.com/watch?v=6Nl8Ws6pj3M&list=RD6Nl8Ws6pj3M&start_radio=1&t=0

This is actually also a Swedish song..

https://www.youtube.com/watch?v=emdFpbGWZkE

BS A


“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

 

[Alistair_Heaton]

I think the UK ones commute and the ones away from farnborough do Tuesday to Thursday and work from home Mon and Fri.

 

[RedSnake]

I think the UK ones commute and the ones away from farnborough do Tuesday to Thursday and work from home Mon and Fri.
Do you meen the ones working as flight engineers in London or?

/A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

 

[Alistair_Heaton]

They are not based in London.

 

[RedSnake]

Okey sorry..... sade/smile.. wasn't clear on what you were referring to.
Having problems reading between the lines to day ;-)
So should I take pick? Farnborough, Hampshire? Farnborough, Berkshire? or Farnborough, Warwickshire?

/A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

 

[Alistair_Heaton]

Farnborough
Farnborough, UK

https://maps.app.goo.gl/FxSQgWyCB1shiL6e7

That's there hanger I think. The q400 SIM is the other side of the runway at flight safety