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]

I don't have a clue what would have happened in the back. I have always been attached by a harness while doing stuff like this. And you would have a centripetal forces coming into play.

Sorry redsnake I really don't know. We are into Nervier-stokes equations telling us what's going in..

The fin and rudder won't be broken off with a 90 deg bank if nothing else has happened. I suspect that the rudder is like that because the bottom pivot point has been removed when the fin came away.

 

[RedSnake]

For you if you are up for it ..
Since it is in swedish I made a translation.
Perhaps unnecessarily the feeling is probably evident anyway.

Nio Vackra Änglar

https://www.youtube.com/watch?v=ypClbq-LWp8&list=RDypClbq-LWp8&start_radio=1

We saw your courage to challenge.
Life and everything that came.
Nothing was too difficult.
No obstacle too high
To cope, to get up

A smile, take a leap
Jump, live life to the fullest

So free, so beautiful.
Your souls are with us

So free, so dear
Our nine beautiful angels

Oh, that the unthinkable happened
Think, everything can go so fast

In his arms he took you
Under the shadow of broad wings you have protection

So free, so dear
Our nine beautiful angels.

When sorrow and despair surround us
Are we close to each other

When the longing tears within us
Are we close to each other

When sadness and despair surround us.
Are we close to each other

When the longing tears within us
From nine beautiful angels

Heaven got, and we gave.
In our hearts you live on.

So free, so beautiful
Your souls are with us
So free, so dear
Our nine beautiful angels.

Best regard Anna

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

 

[LittleInch]

That's very touching.

I'm not sure quite where this thread is going at the moment but to add in a few observations from personal experience.

When you talk about "negative G" what this means for a bunch of people not strapped in to the plane is that you suddenly find yourself floating above the floor and unable to do anything about it without some sort of hand hold and even then the rest of your body is doing what it wants. Some people find themselves fending off the roof. Trust me it's a really strange feeling when it happens.

Then the plane suddenly meets you and gravity has returned. But you might be upside down or in a different part of the airplane from which you started. And someone else has landed on you. The jump pilots used to do it on the bigger aircraft every now and then for a bit of "fun" but it used to scare the living daylights out of most of us, especially when the door was closed.

But a stall or spin in that aircraft full of movable lumps of mass will not behave in the same manner as those videos.

Like Alistair says, we and you will never know for sure what exactly happened and the sequence of flight controls, aircraft movement or which bits fell off first and that's why the investigators work on probable cause.

Being that high for that long without oxygen I think has a big part to play in delayed reactions / bad judgement, but if this plane did actually stall / roll or spin then the weight distribution would change in an instant and to start with would be massively rear weight followed by massive front weight in a dive, but also if it was spinning would have been much harder to get out of with the weight now at the extremities. It seems from the altitude data that there was perhaps some form of attempt to get out of the dive they probably found themselves in but I think that's when parts of the plane started falling off and /or the pilot blacked off from positive G. I think it only takes a few seconds (5-10)? of 3-4G before you start to loose consciousness.

I do really hope you find what you're looking for and if we can help in any way please let us know.

LI

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[RedSnake]

• The aircraft then lands on the right side with a large oblique blow with increased lifting force and increased resistance as a result, which reduces the speed increase and the diving angle.
• The speed increases further, the rodder is overloaded and breaks off.

These statements do not come from SHK but from some older gentlemen who are dead set on giving SHK a real match.
I will not repeat their judgment about SHK and their job as it is not for me to say.

But compared to me who mostly feels frustrated because the investigation does not contain enough technical facts that I would need to be able to create a good enough picture of what can be understood so that I can move forward in my mourning work and do not really have any other agenda,
it's something completely different for these two gentlemen.

I have been talking to them at one or two occasions.
They have made a description of what they claim is 100% shore has happened, but I am 99 % sure that they are wrong on some points.
This is one of them.
But before I pass it on to them.
I would need a critical eye on this.
If you look at the picture of the rudder, is it possible that the damage occurred in what is described in these two statements?
That's my only question right now.

Best Regard Anna

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

 

[Alistair_Heaton]

There is issues with cyclic input of controls over loading ie if you do full left then full right then full left again etc then it will fail.

AA 587 this happened with.


To me that looks like the base of the rudder was attached to a different load structure and when the fin came off there was a fraction of a second while the fin travel sideways until the pivot point sheared off the bottom which bent the rudder out to the side.

 

[LittleInch]

There may be something either lost in translation here (literally) or it's not possible based on only two bullet points to figure out what they are talking about.

But as a guess are they meaning the plane was falling sideways in a slip / bank or that they think that the plane is falling in a dive, but at an angle?

Or falling like your picture from four posts above but basically right wing down and falling sideways / vertically down the page.

But 100% sure?? That is just not possible. IMHO. Sorry.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[RedSnake]

Unfortunately, I'm a bit gone too, they have not entered any timestamps, so I do not really know what they mean and where they are.
So I think they have to do without my feedback.

In any case, I will explain why I do not believe in this.
What they claim is that first the right wing fell off. (No comment).
Then the fin and the rudder fell off. (not true in my opinion)
Then the stabilizer /they have not specified which! / (Not true in my opinion).

And now I will explain why.

The fin / side rudder has been broken / demolished by the right stabilizer which has been broken loose from behind and forwards and then broken up against the fin and the side rudder.
This has also been confirmed by phone by SHK (not so easy to understand when reading the final report) and in the material survey report.
This has been stated there because the upper hinge on the side rudder is the only part of the plane that had a red base color, which is imprinted on the right stabilizer. On the rest of the plane, the base color is yellow.
My comment below.
It could have been the other way around, but both the fold up at the bottom of the fin and how it has become cracked like a V contradicts this and also the placement of the aircraft parts on the ground.

The location of the right outer wing is not confirmed in this image. According to SHK, everything else is correct.

Fena = Fin, Balanshorn = Counter wheigt, Höger =Right, Vänster = Left, Yttre = Outer

This is something I wrote and sent to SHK six months ago .. Before the final report came.

In the picture below the right rear bracket and its attachment, you can clearly see that the front bolt 1 was "lever" and released last.

What's a little puzzling is that it looks like it's been moving forward at the same time.
This can be seen in the fact that the holder 2 for the front bolt is pulled forward instead of straight up or to the right as it should have done in your scenario
Figure 46. Sequence of the breaks of the stabilizer and fin
and also that the rear bolt 3 is worn obliquely forward .
The only scenario I have found that explains this is that the entire stabilizer has been pushed up and forward at the same time.

I hope that I have managed to be a little clearer than the older gentlemen and that the translation has not become too crazy.
I have tried to correct it where it was obviously wrong.

Best Regards Anna

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

 

[Alistair_Heaton]

It more than likely was, we don't know the orientation of the aircraft when it happened or for that matter what direction it was going. The plane could very well have been travelling tail in the direction of travel.

You have to think what are they trying to do with these investigations.

Yes there is a remit to document what they think happened.

But the main remit it is to find the primary cause and find ways for preventing it happening again so the risk factor is below a certain fatality risk.

The understanding the precise failure mode during an inflight breakup may indicate that one or two aspects of the design are slightly out but cause absolutely no issues during normal operation or may require special attention to ensure no fatigue cracking is occurring.

But the main issue is they were operating outside CoG envelope, the main objective now to prevent anything similar happening again is to ensure that nobody else operates in such a manner.

If the plane had been inside limitations flying along and suddenly a wing fell off like what happened in Jamijarvi then the investigation would have been more focused on the engineering of the structure.


This case they had a perfectly serviceable relatively new aircraft which for some reason departed controlled flight with out any structural failure. Why?

C of G was outside limits... Why was it outside?

If you stop the error progression before the plane departs from controlled flight then you have improved flight safety.

Which is why I said earlier that getting to grips with the organisation aspects of operating a jump aircraft in Sweden will have a more far reaching long term effect than picking through a single aircraft type looking for design snags. There won't be any that are major regulation breaches anyway and even if they weren't there it wouldn't have changed what happened on the day with the aircraft being operated outside the CoG limits.

 

[RedSnake]

Yes I know ..
But as I said earlier, SHK has already given recommendations on this and I have no objections against any of them.

The problem that the two older gentlemen have and the club is that they believe that SHK's conclusions are wrong.
They probably have different motives for this, I'm sure.
So we do not need to discuss the underlying motives for that again.

The older gentlemen believe that the accident was caused by the pilot fainting from lack of oxygen long before the plane made the left turn down.
They mean that there is no way the pilot shoulden't been able to handel the situation, clouds no clouds with the education he had if he been conscious, no matter how the plane was loaded etc.
They mean that the SHK has not clearly stated that this was the root cause and has not done there jobb when they have not come up with any recommendations for this.

The club says that the accident could not have happened because it was outside the CoG limits.
Because then this would have happened eight years ago.
They have flown with the same loading and probably worse than it was this day without problems.
From end report
Flight test
The type certificate holder has performed flight tests with a center of mass position at 1,703 mm, in other words close to the calculated mass center position at the door opening in the flight in question (1,694 mm).
The tests show that the stick force to increase the speed from a tuned position by 80 knots to 100 knots is only 0.2 daN.
Above 100 knots, the stability is divergent, which means that the speed increases without any forward pressure on the stick being required. No test of slowing down was performed.

I myself have seen a dozen movies from this plane where the CoG limits should have been even more outside the limits than is presented in this case.
It is my opinion that the club also believe that he fainted and that was the cause.

Although it is against my nature to make assumptions about things that cannot be proven should someone force me at gun point to choose between the two.
I would say that the reason for the accident was that he fainted.
The reason for this is, that if you look at it from a statistical point of view, skie diving aircrafts would fall down every single day in Sweden if CoG limits were the reason.
I have no idea how often it happens that pilots faints?
And it is also clear that it started to go wrong long before the plane turned / dived down to the left.

But there are two other things that may have affected the flight of the plane in addition to what is stated above.
My problem is still that some things around this, don´t feel sufficiently well investigated XOR possibly explained.

They have had two technical problems with the aircraft before the accident itself, if you do not include poorly welded items.
This is one of them.

Taken from the report.

Trim walk
According to information, a phenomenon has previously occurred in the aircraft with so-called trim walk.
At speeds around 120 knots, the trim wheel has started to rotate backwards by itself, which trims the front edge of the stabilizer down, with the effect that the aircraft's nose is raised.
During the technical examination, the jack screw was in the opposite position, with the leading edge of the stabilizer up, ie. in tuned position for the aircraft's nose down.

1.16 Special tests and examinations
The position of the screw was 90% towards the end position of the front edge of the stabilizer up, ie. for trimming the aircraft's nose down.
According to the type certificate holder, this position on the screw corresponds to a position on the stabilizer of 1.3 degrees leading edge up.

From type certificat

Nowhere in the final report is there any mention, that it was checked whether the plane at some point after reaching altitude had a speed of 120 knots?
I am not shore how mutch that would meen in km/h with wind correction and such?

And he wasn't fully trimmed out on the stabilizer.

Best regards A



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

 

[Alistair_Heaton]

I think there is a certain amount of arse covering going on and transfer of guilt feeling going on.....

I have seen this happening before its a triangle of people try to not be responsible in their own minds.

You can see it in the challenger report and several others. To this day there are managers that were involved in the launch release that still say it was the right decision.

Utter bollocks

Have a read of truth lies and o rings on the challenger disaster. The old boys will be on the management side of things.

 

[RedSnake]

I do not know if you mean management of the club?

In that case.
No, the older gentlemen have nothing to do with the club at all ..
One is a retired civil engineer in aeronautics, flight characteristics, former head of Applied Aerodynamics, at Saab
The other a former fighter pilot and military, F 5, and civilian flight instructor, Trafikflyghögskolan /
(The School of Transport), TFHS and he has writen a book named Principles of Flight

And thank you for enduring all my millions of questions.

Anna

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

 

[Alistair_Heaton]

I don't have a clue then what they are up to.

Both should know fine well that operating an aircraft outside the POH flight envelope puts you into unknown territory which the certification standards do not apply to.

I Strongly suggest you contact the Swedish pilots union about your concerns. Apart from anything else they will know all the main characters involved.

 

[RedSnake]

My biggest concern right now is that I can not figure things out myself purely "mathematically / physically" it is frustrating and it makes me feel "stupid" :-(
I know this is not my area of ​​expertise so I have no reason to feel that way but it does not help much right now.

/A

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

 

[Alistair_Heaton]

When Naiver-stokes equations are involved you will never get an explicit answer. When you work with none linear you get used to the fact that your answer will never be right. And that's said as someone who used ot work with metal. How the hell the CFD people managed to keep a straight face when they presented there analysis to this day I don't understand. The Mooney-Rivlin peeps must have been on class A drugs with some of the shite they were trying to impress us with. Put CFD together with teh Mooney boys and the whole exercise was ripe for lunch time drinking.

The whole thing is nonlinear as hell. Geometry and materials.

There is a valid argument about hypoxia but the be honest he was a young lad and had done more than a few flights before and didn't get hit. And a load of older blokes regularly do the same profiles and some of them will be smokers.

But again it comes down to operation control. In The UK the jump pilot would have had to be on pure O2 above 10 000. Why is the Swedish parachute association not requiring all jump pilots above 10k to be on o2?

 

[RedSnake]

I do not know :-(

Seems to be a real soup ..

Requirements for the use of extra oxygen in accordance with current regulations
According to NCO.SPEC.110 (f) of Commission Regulation (EU) No 965/2012, the master shall ensure that mission specialists and crew members continuously use extra oxygen whenever he or she determines that the lack of oxygen at the height of the intended flight may lead to reduced capacity of crew members. or adversely affect contract specialists.
If the master is unable to determine how the lack of oxygen may affect those on board, he or she must ensure that mission specialists and crew members continuously use extra oxygen whenever the cabin height exceeds 10,000 feet for more than 30 minutes and whenever the cabin height exceeds 13,000 feet.

However, NCO.SPEC.PAR.115 states that the requirement to use extra oxygen gas does not apply to crew members other than the master, nor to mission specialists performing tasks essential to the specialized task when the cabin height exceeds 13,000 feet during a period not exceeding 6 minutes, or exceeding 15,000 feet for a period not exceeding 3 minutes.

I think that's what the 2 older gentlemen want to achieve and are fighting about.

Do you know what Skum Tomtar are?

/A

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

 

[Alistair_Heaton]

No but that sounds like gobbled gook bollocks.

No club is going to provide O2 if there is even a hint they have an excuse not to.

Btw it won't have caused the accident, just may have prevented it escalating from an incident to an accident.

 

[RedSnake]

No but that sounds like gobbled gook bollocks.

Is it a Scottish specialty? I get the beginning and the end .. if I put it together, I can only guess, but I think I got the general picture.
LOL
Do you mean the EU directives or the Skum Tomtarna?

Sometimes it helps to see things from a different angle.

That's about how it is at work right now ..
I have more than twice as much competence and experience as the rest of my colleagues, including all the technicians that I have to service and "teach" at work.
It feels like I have not done anything else in the last 15 years.
Has been full of averting all the disasters they are coming up with.

I once said to the only boss I had who actually knew the job as well, that I was thinking about taking a sabbatical year and doing something entirely different.
Kind of digging for dinosaur bones in Patagonia or feeding orphaned koals in Australia or something like that.
Then he said
- You know what Anna if you do, you will never come back.
and I answered
-Probably not ..

Right now it feels just like that ... or more..

/A

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

 

[RedSnake]

No, but it might have saved someone's life.
If they had said that he was caught in a down wind after passing over the cloud and that it was a comulus cloud that was about to become a cumulus nibus cloud, I would have believed it.
And do not ask why, I do not understand it myself.

Can you explain how to calculate the real speed if you only know the speed in relation to the ground?
Is it hard ?

/A

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

 

[Alistair_Heaton]

Not really you just find out what the wind was and you have two sides of a vector triangle the wind direction/speed and the ground speed/direction the last side of the triangle is the aircraft speed and heading . Finding out the wind is usually the problem but they got that off a near by aircraft who's flight management system works it out and records it.

 

[RedSnake]

Good morning .. and thanks!

And the direction is degrees with 0 as north, then clockwise ??

/A

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