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

 

[RedSnake]

Type certificate holder: MT-Propeller Entwicklung GmbH
Type: MTV-9-B / 200-58

Operating time after inspection, hours 25

Loss of oil pressure : The propeller has spring return to low pitch/high RPM setting. SHK has confirmed this.
Which feels reasonable to me as the conditions should be better for emergency landings

The spline shaft couple between the prop shaft and gear box: SHK has controlled this by turning around the engine with what was left of the propeller blades if this is a good enough check I do not know..

2700 rpm is only for take of, 2500 rpm is max in all other flight conditions.

SHK had written that all motor controls were max forward. I do not know if the control of the propeller angle is considered a motor control, I should maybe ask about it?

Please explain OSG's ??

Best Regards Anna

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

 

[Alistair_Heaton]

OSG stands for over speed governor. Its so if the prop system fails the engine doesn't self destruct.

Yep that's a typical system for a none negative G system. It relies on gravity to take the oil back to the sump and it sits there until required. A scavenger system pumps it back into an accumulator which is pressurised which then gives you a period of time when everything stays working without gravity in effect. There is another closed loop system for the unlimited class of aerobatic aircraft but I don't know much about them.

As I said above I suspect they went negative G and the prop governor didn't have any oil to meter so the prop went full fine pitch and the rpm increased until the Engine governor started limiting fuel flow. This means the system was working correctly and as per design.

There are three motor controls. Power, fuel mixture and rpm. If they were all forward he had completed the flight upset memory items.

As for making sense of the rpms shown. I really haven't a clue what it would all do if the aircraft was going backwards or vastly out of normal AoA range of the prop. There are some very funny things happen with props with strange vectors of wind due gyroscopic effects. I just know that if something weird starts to happen you slam the power in a fast as you can which changes the velocity of the airflow through the prop which then alters the airflow angle and most of the time saves the day as long as you are pointing down a runway with enough room to get off again. IF you don't the aircraft may go sideways and one wing lift which I have never heard a sensible explanation for why that happens.

 

[RedSnake]

He had completed the flight upset memory items. Pleace explain, remember this is like greek to me ;-)

The report only talks about vertical accelerations that are referred to as positive.
When you write about 0 g or negative, do you mean deaccelerations or change of height upwards?
I think you have to explain to me in what situation negative g-forces arise?

/A

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

 

[Alistair_Heaton]

Memory items are procedures to complete from memory when action is required immediately with out reference to a checklist. The ones for upset are mixture and rpm up. The power lever depends on if you going fast or slow

Negative G is in relation to the aircraft axis. Ie positive G is when the force makes the pilot sit in their seat and feel heavier and negative is when they are lifted out of there straps.

The inflight breakup will be due to excessive positive G.

Engine prop control going funny only takes a fraction of a second of 0 or negative G for air to go into the lines and it takes 4-5 seconds for it to be pulled through and things back to normal.

Nobody has a clue what the flight attitudes were when they lost longitudinal stability and after that. So it might be all the readings they have are positive G but that's in earth reference. The plane may be inverted which would make them negative G for the engine oil system.

 

[zeusfaber]

Anna,

"Memory Items" are the most critical Emergency Actions listed in the Flight Reference Cards. We used to call them the "Boldface Actions" because of the way they are printed. Pilots need to memorise them, because they are the things they have to do straight away - after which they can take a minute to fish the cards out and find out what else they need to do.

"Flight Upset" essentially means that the aircraft has stopped flying the way the pilot told it to.

So Alistair is saying that the pilot appears to have done the things the instructions say he needed to have done first.

Straight and level flight is 1g. I think you're already familiar with the idea of >1g.

0g is what you experience if you push the nose over (sometimes called a "bunt") and fly some sort of parabolic Vomit-Comet manoeuvre making yourself weightless.

Negative g is what you get if you bunt even harder, but more commonly if you roll the aircraft over and fly inverted - at which point you find yourself hanging from the straps, all the rubbish in the cockpit transfers itself into the canopy and all the oil in the sump of the engine moves away from the scavenge pump inlet.

A.

(Edit: Just to note that Alistair posted as I as typing)

 

[Alistair_Heaton]

You said it far better than I, please continue interpreting what I have written.

To note the fuel system also needs a special system for negative G but it tends to last longer due to the fuel feed pipes being long and the flow rate being lower. But as soon as you go zero G there is nothing pushing the fuel into the inlet in the collector tank.

If you do aerobatics or spins in fixed pitched prop aircraft its relatively easy to get the engine to cut out through lack of fuel. But the suction effect of the engine usually pulls fuel through and recovers quicker than the oil system would.

 

[RedSnake]

The recorded sound file indicates that the engine ran, at least until 07:24

The reson I am asking about the diffrenses in motor/propeller RPM:s is that there are a couple of older gentleman who claims that they can look at altitude curves and speed. And then say for 100% sure that the plane was never steered or the engine values ​​were never changed by anyone after the plane turned left at 07:00. and that everything you see is just because the plane flew where it wanted?!??

But if the propeller control lever was pushed max forward, as one of the motor controlls stated in the SHK:s report.
That it is wrong right there because you need pass by a gate on the propeller control lever to get to 2700 rpm instead of normal max 2500 rpm and before the left turn the motor rpm was around 2350 rpm.

Anna

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

 

[Alistair_Heaton]

There is no way of knowing what went on.

If I was having control issues and the stall warner was beeping I would have everything at max as well.

Those are GPS ground speeds so wind will have an effect as well. But that's in the 55-65 knts range which is very slow even with a 30 knt head wind.

 

[RedSnake]

SHK had calculated the flight speed to about 70 knots.
"The calculations show that during the last moment before the aircraft lost altitude from 13,600 feet, the speed was below 70 knots and decreasing"
But they used data from the airport's transponder system.
They say that the military radar data shown above that is also from the report is less accurate ?!

You might think that if you are going to be able to shoot down some enemy aircrafts, you should have better radar system than everyone else?!?

Wind data from other commercial flights
The following information has been obtained from the registration of flight data from a commercial aircraft that was approaching from the south and landing at Umeå Airport shortly before the accident.
Flight level 130 - wind, 351 degrees, 27 knots, temperature -9 ° C
Flight level 136 - wind, 352 degrees, 30 knots, temperature -10 ° C
Flight level 140 - wind, 351 degrees, 31 knots, temperature -11 ° C.

Can you expect 0 G or negative G at a stall or spinn etc. ?
Or as in this picture taken from SHK's report as an expamle on how they reasoned and calculated?

Anna


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

 

[Alistair_Heaton]

Not so much in a stall but in a spin and recovery you can get everything from negative through to wings fall off positive G.

They haven't taught spinning for years to PPL's or CPL's in Europe because it was killing more people in training than it was saving so they teach them slow flight and sin avoidance.

While your in a spin there is actually very little load on the aircraft because all flight surfaces apart from the rudder are fully stalled. In gliders we used to spin them down through cloud because there was zero chance of you hitting a gust and breaking the wings.

The problem occurs during recovery for a normal spin mode like you have pictured above you remove the power, neutralise the elevator and ailerons and then apply rudder in the opposite direction to the spin. The rotation rate may initially increase and then when you feel pressure on the elevator some types your told to slowly apply forward pressure others you don't. This then un-stalls all the flight surfaces. Now if you have rammed the control forward at the point the elevator un stalls you will get a colossal sudden nose down input which will give you negative G. You now have an aircraft which is pointed directly at the ground +- 15 degs accelerating at 10 m/s/s. You then have to get the nose back to straight and level before your speed goes over Vne. Which requires you to pull back on the controls. Which is usually when people over stress the airframe and the wings come off as you have a picture of.

But that is only one spin mode, there are others depending on how you enter the spin. It can also be what's called inverted so the canopy is the opposite side to the one pictured.

I know the basics about the mode I have described and know there are other modes which you may not be able to fly out of. But the whole dynamics of spins is test pilot stuff and way way above my knowledge base.

Now I have a bit of a issue, I wanted to post a video of spin instruction in a Cessna 150 and a video of the spin in a piper PA38 which is what I used to teach spinning in. C150 which is the most docile spinner our there away from gliders. And they didn't let it go into a fully developed spin. And the PA38 which is a high rotation handful to get out of a spin. Just a bit concerned it might traumatise you.

 

[RedSnake]

I thought that this part of the audio file could possibly show that he followed the spin instruction, but it could also be the governor who regulates the rpm, but that when the plane flattens out, the jumpers come flying from behind and the controls are pushed forward to max. Many but here ...

To be Honest, I have probably turned off my emotions to be able to handle the situation, not a good thing I know.
I think I work a bit like a pressure relief valve that relieves a little now and then.
One reason I think for this is that I know that my partner was in the area of ​​the plane that had quit normal G forces for most of the time and only high ones under short moments and was the least damaged of all on the plane, perhaps together with the pilot.
It actually looked like he was lying in a pile of rubbish sleeping.
I just hope he was knocked unconscious when the plane turned left, one minute is a long time when you know you are going to die.
But I've had to deal with a lot of things in my life so I know I can handle most things, so upload the film, it's okay with me I can handle it.

But thanks for asking and that you are thinking about my well being.

Anna

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

 

[Alistair_Heaton]

Right here is a training video in the C150 by a very good instructor in my opinion. The plane is quiet docile and if you can see the Airspeed indicator they get nowhere near Vne. Hieght loss will be about 700 to 1000ft. The lady makes a very good what we call patter of whats going on. BUt she has to cheat to get the plane into a spin by inducing yaw.

https://youtu.be/4KEm-hf2Uvs

This next one is from a PA38 which I used to teach them in. Looks to me like a nicely executed spin number of rotations is controlled and under 3 you can see the initial spin up as rudder goes in. Height loss about 1500f. And he won;t have required rudder input to start it spinning.

https://youtu.be/bPMGkpQ0-X8

This next one if it was a plane out of a school I was instructing at and I was made aware of. I would not be happy with and words would be said. The pilot had roll input to try and flick it into the spin with one wing stalling more completely before the other which made it go flat and they didn't start the recovery as soon as the first rotation had finished or maybe they did but the attempt to flick spin it required more rotations for the rudder to bite. Which delayed the exit and lost alot of altitude in the process. I wouldn't be surprised if they lost 3000ft in that one.

https://youtu.be/tHFW2LLfx98

So between those three you can see the differences and the required reaction time to deal with things.

 

[RedSnake]

The pilot had flown Cessna 172, Cessna 172S, Piper PA-28,Cessna 182, Diamond DA40, GA8-TC 320.
The last competence check (PC) was in a Piper PA-28.

/A

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

 

[Alistair_Heaton]

none of those aircraft would be normally be used for spin training. I think you can spin the C172 on paper but nobody does. Its a 4 seater expensive machine which is more suited to cross country.

The rest of them are the same, intentional spins prohibited.

Spin training was going out of fashion in 2004. It wasn't compulsory for PPL's then and we only did it on request but if the student didn't want to then we didn't I think in 2010 they removed it completely and the only required spin training was in the flight instructors course. But you they weren't allowed to to teach it only demonstrate a recovery in case a student screwed up a stall.

But honestly before that there were several fatalities every year doing spin training. And some times it was years between anyone actually crashing because of spinning it outside training. And since they stopped training it there have been no increase in fatalities due to spinning in.

That statement is made about an aircraft inside the normal CoG envelope. And not with full power on.

 

[RedSnake]

This a film of the GA8.
But I think it is made by the company, so it might be a bit to their advantage, but here they only show "stall"

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

/A

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

 

[berkshire]

Boy things have changed , in the UK training on gliders, I was required by my instructor to demonstrate a two turn spin and recovery from the top of the launch in a Ka7 before I could go solo. That was 1969 and launch height was 1600 feet.
B.E.

You are judged not by what you know, but by what you can do.

 

[Alistair_Heaton]

Gliders still do spin training, to be honest I personally think that the UK gliding syllabus produces a more developed thinking pilot than the EASA PPL and CPl course. The CPL is more geared these days to go instantly into a 737 or airbus multi crew environment. Not into the self sufficient single crew GA scene.

CofG has a huge effect on an aircraft as does power setting.

With singles there is large variation of yaw induced because its single engine due power setting.

I really don't know what effect it will have or how marked during the stall or spin because I have never flown an aircraft out of rear CofG. I have flown then out of forward Cofg but that makes them more stable and just heavier in the flare.

 

[RedSnake]

Please help ...

• 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.

If this was true, would the rodder then be broken like a V to the right side of the plane ??

Best Regards Anna


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

 

[waross]

During the initial loss of control, where might the divers be?
Once the plane went nose down,could the divers be thrown into the cockpit adding to the nose down forces?
Could they have made a circuit of the cabin: Up, forward and then back aft?

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

 

[RedSnake]

Probably, it is at least my picture. It is physically possible.

But what I would like to know is, if it is possible for the fin or side rudder to be broken off to the right side of the plane?
Like his?

If the plane flies on it's right side "that is banking 90 degrees" forward and down like this??

Best regards Anna

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