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-   -   BREAKING NEWS: airliner missing within Egyptian FIR (https://www.pprune.org/rumours-news/569907-breaking-news-airliner-missing-within-egyptian-fir.html)

Mauersegler 10th Nov 2015 16:11


It doesn't matter. What I want to points is: top panel and holes for center pivots seems undamaged. Low panels bears marks of hit from lower pinions.

It means that HS leading edge travels down much more than allowed.
Not my intention to start a war here ;) , but I see that in another way. The attachment points (all 4) are gone, the two at the bottom third were clearly teared away, some material point forwards/outwards. Not like it was compressed at these locations. With them is the X-structure also gone.
For me this is more like the APU/tail cone was teared away. Edit: or other parts teared away, but not knocking, at least more tension than compression.

http://i65.tinypic.com/2d9qsl1.jpg


http://i63.tinypic.com/mbk76b.jpg


http://i66.tinypic.com/mmvatz.jpg

Prada 10th Nov 2015 16:12

ACT
 
So there must have been at least one ACT tank.

If it ruptured at initial event and spilled fuel and vapors into cabin, it is a good explanation why only backward seats were scorched.
Pieces from that tank are yet to be seen.

http://www.keri.ee/crash/keskpaak.jpg

Kulverstukas 10th Nov 2015 16:18

Mauersegler just down the holes for center lugs circular bendings are clearly seen. Teared our "ears" are lower. I see it like this (thanks for picture)

https://pbs.twimg.com/media/CTXeqs8XAAAjjpO.jpg:large


Now it's time for some crazy guess...

1) Some person who was allowed in by corrupted security, visit plane overnight and placed something at the top of center of HS.
2) Let's us assume it was not bomb, but some mechanical device, thus troubles with identifying case of disaster.
3) Device pushed HS down at the end of climb
4) APU cone separated, as shown above, broken fuel line spill some kerosene, electric sparks ignite central tank.

A0283 10th Nov 2015 16:22

@FDMII and FLO
 
Thanks for responding. Clear answers.

I take smaller steps though. Information gathering stage for this subject and certainly not trying to get to conclusions now myself. Let me try to rephrase my question.

We have two pilots who are capable and have the plane on AP1 in climb/cruise. All quiet and running normal.

Suddenly, there is, we assume, a rather violent event ... duration, not known yet, but most expect that it was (very) short ... hope recorders will answer that.

What are some of the options they have:

a. They both freeze,

b. They don't know, and subconsciously wait for more information or to get better orientation, or consciously 'they decide to sit on their hands'.

c. They discuss, think they know and decide:
c1 ... but don't have the time to act as events progress and they ran out of time,
c2 ... consciously decide to leave the plane in control,
c3 ... take action that can only be found using the recorders,

d. events are running so violent and/or fast that there is no time or suitable environment to think anymore, and/or action is not possible anymore (G-forces or ...),

We only know that they did not take action that in one way or another (see your posts) that disengaged the AP. And, neither did the plane hand over control back to the pilots based on its analysis of event(s) !!

All these options can be mapped on a timescale. So I want to try to get a feel and understand how much time they had available for a number of elements in these options. The shorter and the more violent the events the more precise the timing has to be in order to do a proper analysis.

ironbutt57 10th Nov 2015 16:28

that's the scenario I see as well Kulverstukas...now whether a stripped out nut on the stab (a la Alaska MD-80) caused this, or something exploded causing this to occur is the question

tubby linton 10th Nov 2015 16:31

Would somebody please repost the link to the techlog pages published by the airline .Local rumour in HESH is that this aircraft was often tech, but they may be trying to deflect the bomb theory as it is seriously damaging their economy.

G0ULI 10th Nov 2015 16:38

Speculation
 
If the tail horizontal stabilisers had deflected fully upwards instead of down, the nose of the aircraft would have dropped and with the engines set to climb power, the aircraft could enter a mach stall.

Aerodynamic forces once the aircraft broke the sound barrier could be sufficient to tear the aircraft apart, or at least separate the tail section. The sonic boom would sound like a bomb explosion. At lower altitude the remaining fuselage and engines enter a flat spin, causing the engines to tear from the wings and leaking fuel to ignite.

The FBW protection systems would normally operate to prevent a pilot performing such a manouver, but not necessarily if there was a sudden failure in the tail horizontal stabilisers.

Of course the stabiliser might have flipped down first and then fully upward, which would generate the same general effect.

Mauersegler 10th Nov 2015 16:44

Thanks Kulverstukas,
while I think it could have happened that HS pointed downwards at a time and broke the tail assembly (in my opinion the HS could also break the tail pointing upwards, it could have oscillated anyway), I don't see the compression damage (I try looking at other pictures too). Also with this explanation the damage to the VS remains unexplained and also why the jack screw failed at first.

My opinion as already posted:

-explosive event (decompression due to skin failure and/or bomb) detach fuselage skin directly in front of VS, that goes up to the VS increasing the load instantly over the design limits, VS crumbles it basis, deforming the attachment of the jackscrew assembly, this would go forward, pulling the HS upwards (or jackscrew break free with similar consequences).
-This put the AC in a nose down attitude instantly, bending the engine pylons upwards and probably detaching the APU/tail cone.
-The HS exceeds the design limits also, breaking in the left side and departing.
-The remaining HS departs with the underside of fuselage probably still attached and also maybe the jackscrew assembly.
-The remaining tail fuselage becomes detached later maybe under aerodynamic and or rotational forces.

qd2015 10th Nov 2015 16:52

Kulverstukas - I like that idea.
I'm a long-time lurker, but I posted (maybe early Sunday) something that I think didn't get approved, that I suspected Sabotage rather than a bomb.

I was just looking at all the postings "from the outside". I have no professional expertise.

The Mods have a hard job, The S/N ratio - especially from new posters - must be horrendous!

Prada 10th Nov 2015 17:13

look at pivot point
 
Dear friends!

If jackscrew was suddenly disconnected, then HS would have just followed wind direction. Meaning HS became neutral and useless.
It would have initiated immediate nose dive.

More of the wing area is located after pivoting point, thats the point.

http://www.keri.ee/crash/pivot.png

Kulverstukas 10th Nov 2015 17:20

Prada, my theory is that jackscrew disconnection was combined with something forced HS to ultimate pitch position, HS pivot assembly breakage and it moved clockwise (on pic from my post) around top link.

UPD, from private messages: I trying to marry idea of HS sudden travel outside of allowed margins with instant stop of FDR. I assume that IF there was NO traces of strange tings on the records, any things like huge pitch/dive deviation BEFORE FDR cables separation is strongly unlikely. So I think that event which caused HS travel was synchronized with separation of FDR cables.

Control Eng 10th Nov 2015 17:55


Originally Posted by Kulverstukas (Post 9176646)
Mauersegler just down the holes for center lugs circular bendings are clearly seen. Teared our "ears" are lower. I see it like this (thanks for picture) ....

Any speculation at failure or interference with the HS/VS falls at the first hurdle.

It is clear from the tail cone that it detached prior to the HS as there is no impact damage to its' vertical edges.

http://s11.postimg.org/6s53ng26b/Tail_cone.png

The HS pivot assembly is situated approximately equi-distant from the lower and upper attachment lugs of the tail cone.

Those lugs were ripped out by the force that detached the tail cone.

If that force was due to impact by the HS and/or pivot assembly, it is inconceivable that the frame would not be totally distorted.

MikeJ65 10th Nov 2015 17:56

I have not heard any discussion of the ripple marks aft of the 4L door. This was the first picture I could track down, although I know I've seen some better ones. link

To me, this can only be caused by a pressure event. I believe that these marks are just forward of the RPB. That means that the vertical split is right at the RPB and the outwardly ruptured skin just aft of the rippled skin would be aft of the RPB. To me, this indicates that the RPB gave way while there was still significant cabin pressure and was most likely the location of the initial depressurization.

Of course that still doesn't establish the root cause, but RPB failures are more than capable of taking out the HS and VS and have done so in past accidents. It could still be a planted explosive device or just the more mundane metal fatigue.

Comments?

Kulverstukas 10th Nov 2015 17:59

Question. What if malefactor loosened or unscrew this links?

https://img-fotki.yandex.ru/get/3913..._fcdbf642_orig

Kulverstukas 10th Nov 2015 18:06


there is no impact damage to its' vertical edges.
There are. Two semicircular indentations at frame below longish oval holes for pivot.

Control Eng 10th Nov 2015 18:06


Originally Posted by Kulverstukas (Post 9176743)
Question. What if malefactor loosened or unscrew this links?

How could that cause the tail cone to detach?

At best the rear of the fuselage might distort slightly.

Kulverstukas 10th Nov 2015 18:13


At best the rear of the fuselage might distort slightly.
Why fuselage? They work on stretching, not compression, thus not allowing HS pivot assembly travel outward.

jdamnation 10th Nov 2015 18:16

Bulk hold door
 
Been watching this thread from post one so thought I would finally register toady and make a contribution.

I was wondering if there there was any evidence to support the planting of an explosive device in the rear most cargo bay - bulk.

The bulk cargo hatch is unique in that the door for it opens inwards so the outer part of the hatch locks up against the cargo ceiling / pax floor, the curve of which, whilst in it's locked / open position, might just be big enough to hide a device that would be impossible to see when the door was open when loading. People would not be in bulk with the door closed.

There is a nice video of A320 bulk door ops here:



To me it seems to be in the right place, and is one of the more 'reachable' hatches on the A/C.

I can't help feeling that if there had been a bomb on board it would need to have been in this area....

JD

Control Eng 10th Nov 2015 18:19


Originally Posted by Kulverstukas (Post 9176747)
There are. Two semicircular indentations at frame below longish oval holes for pivot.

There is minimal distortion in the x-plane - do you believe there was some impact from the side?

Control Eng 10th Nov 2015 18:24


Originally Posted by Kulverstukas (Post 9176754)
Why fuselage? They work on stretching, not compression, thus not allowing HS pivot assembly travel outward.

If the pivot assembly moved outwards, would you not expect anything attached to it to move also?


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