BREAKING NEWS: airliner missing within Egyptian FIR

[Bertie Bonkers]

Thanks to Sardak for the Hudson plane photo - very helpful in clarifying how the HS sits inside & illustrates what some are saying about how the HS movement should be limited by the beam below.

Also, thanks to triumph61 for the photo collection - makes it much easier to visualise the overall situation when the images are all together in one place.

[triumph61]

Here is a piece normaly located below Door 2L.
http://img5.fotos-hochladen.net/uploads/2l5marked8zcfdyilaw.jpg
http://img5.fotos-hochladen.net/uploads/lefta321manr7xis8z69.jpg

on the right side this piece is located
http://img5.fotos-hochladen.net/uploads/2r3markedpchiqd3voj.jpg
http://img5.fotos-hochladen.net/uploads/righta321tfz43qak6g.jpg

[triskele]

re excellent posts 2004/2026...port side top link fracture, stbd side bend and fracture. If the port hinge assy lost integrity first the HS would move violently down, but also rotate to the left, this could amputate the flight recorders. The slots whereby the HS is inserted would be unable to contain the released forces. The tailcone upper mount failures are different, but there appears little damage on the tailcone separation ring, which puzzles. It is possible the combined forces of a loose HV subsequently fracture the aft fuselage?

[Kulverstukas]

https://img-fotki.yandex.ru/get/6002/6154164.285/0_b260e_a68dc5f0_XL.jpg

https://img-fotki.yandex.ru/get/17917/6154164.285/0_b260f_c14f12f9_XL.jpg

[22/04]

Have to say that my view as to the likely cause is shifting towards a fuselage breach either because of a bomb or centre fuel tanks disruption - or the first causing the second.

I wonder whether the armchair experts here should not be giving at least equal attention to fuselage disruption as to the HS and VS, because as someone lese said, that discussion becomes an academic exercise if it was not the primary cause.

I hope also that we can more conciliatory towards Egypt- if this was a bomb (or perhaps even if it wasn't) it has had just the effect the terrorists wanted. If we are to show them that they won't win, we need, if Egypt allows us to, to help the Egyptian authorities correct any security breaches and help the Egyptian tourist industry to get back on track as soon as possible

[Wantion]

Kulver

Thanks for putting these two pics up together.....Interesting the metal X brace is missing..the hole is from the cable bundle ripped out that was attached to the X brace.

The fuel line? seems long .....disconnecting somewhere into the tail.

[G0ULI]

The photos posted by Kulverstukas appear to show four major attachment eyes for the rear section of the fuselage on the intact photo.

The photo from the crash site clearly show at least two of those attachment points have fractured and pulled out of the support frame at what would be the top surface while leaving the support frame relatively undistorted.

That would imply that the tail section broke away downwards in relation to the rest of the aircraft.

[Volume]

Triumph61, the burn/heating pattern you can see on that skin for me is consistent with fire on the inside on the ground, when thin skin heats up fastest.
I have never seen a frame/stringer reinforced (and chemically milled) skin with heat damage caused in flight, but I would assume it looks exactly the other way around, heat is best dissipated to airflow at the thin skin, because of that stringers and frames see the most severe heat and hence damage.

What we can agree for sure is heat damage from the inside, just below the floor. As the floor was destroyed at impact, it is hard to believe that it was a barrier for the fire on the ground...

[triumph61]

Around the Pieces on the Ground is no Burn Marks to see. Piece 2L is lying ~20m away from Fuselage, and the Burnmarks at the piece is Opposite from Fuselage
http://img5.fotos-hochladen.net/uploads/area1brhgaq7uwz.jpg
http://img5.fotos-hochladen.net/uploads/area2mn548wq30g.jpg

[A0283]

I would expect chemically milled skin and not a bonded or rivetted doubler.

What strikes me most is that you have severe fire damage at the grey lower part, and almost clean white upper parts of this panel. If you look at the panel from the inside it is shows the same. Not even soot.

The impression that i get is that the section either landed with the crown open (higher probability), or opened on or just after impact (lower probability). That then the fire started to consume the lower part of this section. And that at some stage the rescue teams may have used the white crane to drag this part out of the fire.

When you look at the AirAsia fuselage you see a flattened fuselage. So why is this one different. First difference is seawater vs rocky ground. Second difference is probably more of a rotation of the forward section and wing combination just before impact.

You might compare it to the IL76 coming down but with the rotation more planar (flat).

Would be interesting if others have another view of how you could connect these dots.

[slats11]

Test results from the swabs and scrapings of plane fragments to detect the presence of traces of explosives will at least take a week.

Really? I suspect someone if playing for time.

Several times I have been selected for such testing after passing through the metal detector / scanner. How come airport security can test me and my carry-on in 30 seconds.

Sure thats just one test, and they will be running thousands of samples. But "at least a week."

[RYFQB]

Revisiting the satellite images of 01 november (http://www.todayonline.com/sites/default/files/styles/photo_gallery_image_lightbox/public/photos/43_images/map_reuters.jpg) for some speculation... I'm pretty sure the piece at the top is the tail section. Cone at the center or left, HS (grey, no shadow) at the bottom, perhaps? "Tail", "left cone" and "HS" objects sit approximately 900, 750 and 1050 meters ENE (perpendicular) of the recorded path, respectively. The "tail" object ~200 m after recorded vertical speed went negative, and the "left cone" object ~200 m before same point, in the direction of travel.

If 11:25 is EET/Moscow time, then this was 08:25 UTC, at which point the sun would be at 160 degrees azimuth (SSE) and 43 degrees above the horizon, according to WolframAlpha.

[A0283]

The chairman of the investigation noted that Autopilot1 was engaged before the event, and remained so till the end of the recording.

I wonder what is considered to be the minimum time by commercial pilots to disengage the autopilot in a severe upset event. In two cases:
a. instinctive reaction,
b. fastest reaction time after fast analysis (in quite a few general (=not specifically A/P related) cases there is talk about 12 seconds...),

And do different airlines have different default (training) procedures? Do you go to the button on the stick or do you go to the buttons on the 'glareshield'. The first procedure makes it easier to have an instinctive reaction. The second requires more consideration, and automatically takes longer.

To this day pilot incapacitation has not been an item.

[HugD]

From the beginning we are guessing on the root cause of the following sequence of events. One of the first events in that sequece is the rupture of the cables to the flight recorders as the voice recorder only shows the beginnig of a more intensive noise. So we can assume a cause that from one instant to the next broke those cables. What could have that effect?

A failure of the structure thru fatigue or lack of maintenace is to expect when there are heavy flight manuvers, not under smooth conditions as the flight was close to reach FL320 at safe air speed. Engines probably running at less than 100%.

Weather conditions cavok, no known shear winds (guessing).

Then loss of control and brakeup of the fuselage, beginnig? with the tailsection into 3 parts and the ripp off of the outer parts of the stabilisor. all of this in the first seconds of the crash sequence.

What cause would explain this?

[funfly]

If the Autopilot was engaged then it doesn't matter what the pilots were doing as any 'flying' input from them would show on the flight recorders.
Unless you are suggesting that there was an event that they were unable to correct, in which case this would also have been shown in the flight recorders.
FF

[Flo121142]

Normally I don't comment on these threads, this times however I followed the thread a bit more closely. On thing I didn't see mentioned here before is that when the event happend the ACT was propably just becoming empty (total Fuel on Departure, around 21 tons according to the documents published by Metrojet, and the Wing+CWT Tank can take a total amount of around 19 tons), this might be somehow related. Does anybody know the pax load for the previous flights? I noted that they landed with 17 tons of fuel remaining on on flight, according to my calculations (and obviously depending on the MLW of the specific aircraft - there are several weight variants available to airlines) they should not be able to upload more that around 110-120 passengers on that flight...
RE: A0283 The autopilot is disconnected with the instintive button on the side stick. The button on the FCU is only used to engage the AP - a disconnection with the FCU button is a "involuntary disconnection" (according to Airbus) and not normally used. It would not take more that 2 or 3 seconds to reach for the stick and disconnect the AP. However in many non normal situation disconnecting the AP won't be the first action, as the AP is able to handle most malfunctions and removes a lot of workload from the crew in a potentially critical situation. But I guess in this case (rapidly developing unusual attitude) it propably was the first action (if the AP did not disconnect by itself anyway...)
RE: Funfly If you give a input on the sidestick (with enough force to overcome the lock) the AP will disconnect anyway...

[jdd1]

Food for thought
We still have no confirmation of explosive use. Could a bomb really have caused the selective damage we are seeing?
One of the earliest declarations from the authorities said the accident was caused by an external source.
A bomb in the aft cargo hold may have caused the disintegration of the aft fuselage but why would it have forced out the HS taking the rudder with it, and cleanly ejecting the tail cone and APU leaving the rest of the empennage relatively intact. Apparently the ACTs didn't explode since the aft fuselage panel fragments are not burnt. Following the DC10 accident outside Paris on 3 March 1974 when the aft cargo hold door departed causing deformation of the floor panels and seizure of the controls the regulations were changed so that cabin decompression would not cause break-up, even with the loss of a cargo door. Also crack stoppers at the frames reduce disintegration. So unless it was a huge bomb I think it unlikely that the fuselage would have disintegrated. The PanAm 747 was an even older design than the DC10 so was more vulnerable.
A bomb under the HS would have destroyed the FDR and CVR which are located there and they are in pristine (paint) condition.
What could have caused such sideways moment as to:
- distort the forward fuselage in relation to the wing (see the debris pattern)
- cause the disintegration of the rear fuselage
- cause such gyroscopic forces as to break off the cantilevered part of the engine pylons including the front spar attachment fittings with the engines, and cause their break up?
With the wing leaking fuel from the engine fuel supply lines and possibly the pylon attachments could this explain the scorched fuselage panels and engine parts? The burning fuel supply lines would immediately cause a fire around the engine and eventually ignite the spray of fuel or vapor coming from the ruptured tanks?
The second part of the HS to be found had major damage to the outer half. Could whatever caused that damage have caused all the rest???????????,

[oldoberon]

Triumph61 we have both HS (external parts admittedly less of the right one) but you aren't showing that? we also have the majority of both wings.

am I misunderstanding the meaning of your pinky beige colouring?

[A0283]

If you give a input on the sidestick (with enough force to overcome the lock) the AP will disconnect anyway...

Would you estimate this as being in the 2-3 seconds reaction time range too?

[triumph61]

@A0283
The Piece 2L was not moved by white crane or person. You can see this Piece placed on this Pic. That Pic was the first what was published and you can see the Smoke.
http://img5.fotos-hochladen.net/uploads/wingmarketmyoxqlwvbn.jpg

[FDMII]

. . . .

To this day pilot incapacitation has not been an item.
A0283, Perhaps I am not following your thinking? For the A320/A330/A340 types flight control actions/inputs are protection-limited in Normal Law and would not cause the loss of the THS or the breakup of the aircraft. If the aircraft were in Direct Law with no such protections, it is doubtful that swift, full deflections of the sidestick would break anything

[Mudman]

RYFQB Revisiting the satellite images of 01 november (http://www.todayonline.com/sites/default/files/styles/photo_gallery_image_lightbox/public/photos/43_images/map_reuters.jpg) for some speculation... I'm pretty sure the piece at the top is the tail section. Cone at the center or left, HS (grey, no shadow) at the bottom, perhaps? "Tail", "left cone" and "HS" objects sit approximately 900, 750 and 1050 meters ENE (perpendicular) of the recorded path, respectively. The "tail" object ~200 m after recorded vertical speed went negative, and the "left cone" object ~200 m before same point, in the direction of travel.

If 11:25 is EET/Moscow time, then this was 08:25 UTC, at which point the sun would be at 160 degrees azimuth (SSE) and 43 degrees above the horizon, according to WolframAlpha.

I started a google map to chart the debris field. Based on the satellite images and images from the ground this is what i have so far...

https://www.google.com/maps/d/edit?m...Vw&usp=sharing (https://www.google.com/maps/d/edit?mid=z2eN5R4TFUjU.kiBjTxg4RTVw&usp=sharing)

[Flo121142]

A0283, yes, but "overpowering" the AP would be unvoluntary disconnection as well, i.e. not a normal way to disconnect the AP. But I guess it should not take more than 2-3 sec (I don't know the exact force required, it might be in some maintenance manual, but I don't think its more than 3 or 5 kg or so...). But as others have said I think it highly impropable that some sort of incapacitation caused this event (the aircraft is protected,in normal law the only way to overload the aircraft would be through massive rudder inputs...)

[Kulverstukas]

https://img-fotki.yandex.ru/get/16129/6154164.285/0_b261b_eaa3a70f_orig

[Mauersegler]

Kulverstukas, you have the sides wrong paired, left/right right/left.

[Bertie Bonkers]

pics above

Good one Kulverstukas - that's exactly what I've just been looking at. I'm guessing the 'slots' in the tail cone separation ring(?) are where the lug of the HS centre projects out behind the pivot point. Looks like the lower tail cone attaching lugs have pulled off the end of their respective box sections and an area of frame is also missing directly above on each side - where the HS pivot mounting attaches to the lower part of the fuselage.

Also - looking just above the slot on the left side of the APU cone (where the top attachment of the HS pivot mounting would have been) is that just normal muck, or does that look like an area of sooting on an otherwise apparently fire-free tail cone?

[Kulverstukas]

Kulverstukas, you have the sides wrong paired, left/right right/left.

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.

[Bertie Bonkers]

The lower end of the HS pivot mounting let go on both sides and swang backward on the top attachment, breaking the frame of the separation ring and prising the APU cone away at the bottom?

Otherwise - the HS pivot somehow spontaneously let go both sides (appears totally implausible), dropped below the slot and the attaching lugs of the HS centre punched into the APU separation ring, to the same effect?

[Bertie Bonkers]

Low panels bears marks of hit from lower pinions.


'Pinions' - that's the word I was looking for.

[oldchina]

"I noted that they landed with 17 tons of fuel remaining on on flight"

Can you point us to where you see 17t ? That doesn't make any sense to me.

[CONSO]

#2036 (http://www.pprune.org/9176579-post2036.html) (permalink (http://www.pprune.org/rumours-news/569907-breaking-news-airliner-missing-within-egyptian-fir-102.html#post9176579))

Just a guess- since we have not seen any HS "wing box " structure- it may well be that that structure along with jackscrew attach points and surrounding ' skin' has been removed from wreckage after cutting out the CVR and FDR to show what was found almost immediately.

That would include some of the attach lugs/points of the VS- which are missing. Some of the 'damage' to surrounding parts as seen may be the result of on the ground dissassembly to load on truck(s)

As to the obvious bending -breaking off of HS near simultaneous- IMO that could be caused by simply breaking the jackscrew or its follower or its mounting points allowing the HS to move towards being a flat plate to the airstream. - evidenced by the pulling down of the fuselage ret he tension unzipping of upper half forward of the AFT door. What caused the breaking or slippage is yet to be determined

Until either the HS ' wing box ' is found or revealed- we have probably reached the practical end of a reasonable analysis-

Explosive residue is another issue re initiation and where in aircraft :ugh:

[Flo121142]

Oldchina, On the extracts from the Flightlog - its on Flightlog page 26916...it says remained 17000kgs, Uplift 3930kgs giving a total of 20930...it seems to be a case of rather extreme tankering as the rotation was DME-LED-SSH...

[matkat]

JDD1 the CVR and FDR are located in the cabin above the rear lavatory not under the HS.

[VNAV PATH]

http://nsa37.casimages.com/img/2015/11/10/15111005404614808.jpg (http://www.casimages.com/i/15111005404614808.jpg.html)

[Flo121142]

Vnav path, thats one with 7 tons (the accident flight), but there is also a previous one with 17t, page 26916...

[Bertie Bonkers]

Looking back at photos of the Hudson plane, it's possible to see pins connecting the two plates of the HS pivot hanger above and below. So once the HS goes down beyond a certain angle, the bottom edges of its attaching lugs will collide with the lower pins, twisting the hangers backward at the lower end and pushing onto the APU separation ring.

Between the twisting of the hangers and the sudden downforce/drag, you suddenly have a whole lot of forces at work on the tail of the aircraft.

[Kulverstukas]

matkat

http://www.pprune.org/rumours-news/569907-breaking-news-airliner-missing-within-egyptian-fir-71.html#post9171991

[Mesoman]

barring a bomb, what structural failure (if any possible) would be required to cause an instantaneous catastrophic failure and departure of the tail.

A central fuel tank explosion would cause an instantaneous catastrophic failure. I don't know how that can be ruled out given what we know, although I presume actions taken after TWA800 have reduced its low likelihood to even lower.

[WNTT]

@mudman

I started a Google map to chart the debris field. Based on the satellite images and images from the ground this is what i have so far...

https://www.google.com/maps/d/edit?m...Vw&usp=sharing

I have been doing something similar in Google earth, a couple of comments

- i think that you last reliable location position could be added to, the flight radar 24 S data indicates that at 04:13:15 the data starts going nuts, at 30.149689 34.178521, this is just to the west of the debris field and could indicate the start of 'event'.
- based in photos i think that the most east wreckage (30.168889, 34.171111) is an engine. This is determined from emergency vehicles and other wreckage in the background of photos.

[Sober Lark]

Until either the HS ' wing box ' is found or revealed.


The desert is hardly a hostile topography for finding such pieces.

[Mauersegler]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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 (http://www.pprune.org/rumours-news/569907-breaking-news-airliner-missing-within-egyptian-fir-93.html#post9174686)

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]

Question. What if malefactor loosened or unscrew this links?

https://img-fotki.yandex.ru/get/3913/6154164.286/0_b261c_fcdbf642_orig

[Kulverstukas]

there is no impact damage to its' vertical edges.

There are. Two semicircular indentations at frame below longish oval holes for pivot.

[Control Eng]

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]

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]

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:

www.youtube.com/watch?v=P4eofrp9Ewo

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]

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]

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?

[fantom]

This is getting silly now; amateur stress analysts/ AAIB investigators/ whatever-theorists.

Let the real professionals do the theorising.

[Smott999]

Does it really take a week to analyze possible explosive traces, or is somebody buying time?
And if so why?
Who benefits from withholding a positive confirmation of bomb?

And who benefits from withholding knowledge of NO bomb? ( and I realize showing the negtive is much harder....)

[VNee]

Using an image from post 2049, we might be able to gain more understanding about the force(s) that broke the APU/tail cone section off the fuselage:

The mysterious hole seen in the APU fwd firewall appears to have been elongated by what seems to be a harness of Tefzel wires. That is to say, whatever forces were involved here were
strong enough to break the 4 mount points but not enough to rip this harness clean. Incredibly, that section had to remain attached for an amount of time while the hole was being distorted.

And for the critics, I consider my post to be 90% observation and 10% speculation.

http://i68.tinypic.com/i5nhgy.jpg

[CONSO]

#2078 (http://www.pprune.org/9176807-post2078.html) (permalink (http://www.pprune.org/rumours-news/569907-breaking-news-airliner-missing-within-egyptian-fir-104.html#post9176807))

The residue would be minimal- and in the airstream might be well dispersed- in addition the 'blast' and smoke would be minimal

AND pretty much limited to the sections/skins/and pieces like HS "wing" box we have not seen, but which must have been present when finding the CVR and FDR.
While there may be some residue on the pieces we have seen- it would not be obvious just from the photos available

Minimum shrapnel also :hmm:

[Chronus]

#2078 (http://www.pprune.org/9176807-post2078.html) (permalink (http://www.pprune.org/rumours-news/569907-breaking-news-airliner-missing-within-egyptian-fir-104.html#post9176807))

The residue would be minimal- and in the airstream might be well dispersed- in addition the 'blast' and smoke would be minimal

AND pretty much limited to the sections/skins/and pieces like HS "wing" box we have not seen, but which must have been present when finding the CVR and FDR.
While there may be some residue on the pieces we have seen- it would not be obvious just from the photos available

Minimum shrapnel also :hmm:

Cannot agree with above, for answers see Pan Am 103, in particular:

"DERA's Feraday and Dr. Thomas Hayes examined two strips of metal from AVE 4041, and found traces of pentaerythritol tetranitrate (PETN) and cyclotrimethylene trinitramine, components of Semtex-H, a high-performance plastic explosive manufactured in Pardubice, Czechoslovakia (now Czech Republic)"

Pan Am was also at 31000 feet and at similar speed when it was brought down.

Unless, since then technology in armaments and explosives have advanced to a capability of manufacturing bombs that on detonation leave no residual trace whatsoever, it would be a certain bet it will be found.

[Lonewolf_50]

Russian communications intercepted by U.S. intelligence agencies showed Russia believed the plane that crashed in Sinai, Egypt, on Oct. 31 was brought down by a bomb, U.S. sources familiar with the matter said on Monday I really wish these "sources" would shut the hell up. Then again, this really does not make the Intel folks look good. "We heard the Russians talking about it, therefore we think it was a bomb, so we told them, in effect feeding them their own work as our 'intel assistance'" isn't what I'd call exceptional Intel work. :ugh:

I expect that this might be a purposeful leak used as a smokescreen. Actually, I hope it is or my worries on who is guarding the zoo in the Intel world will have increased. :mad:

As noted above, all this talking around the problem has hit the Egyptian tourist industry in the chest with a spike. Not good.

[Kulverstukas]

Chronus, if you know where to look, make analysis will be piece of cake. Otherwise, you must collect samples from any suspicious part and lab test them until you found what you looking for. It's also answers question "why two weeks" - not because each test is slow, but because there is a looooot of samples.

[BigaC]

Smot911

"Does it really take a week to analyze possible explosive traces, or is somebody buying time?"

Lockerbie: they found PETN and other tracks after a week.
UTA-772: a week or more (investigation in France).
https://en.wikipedia.org/wiki/UTA_Flight_772

IIRC in both cases investigators also found the parts of timer.
Both cases require hundreds of soldiers to collect all possible parts, in second case investigation says they collect 15 tons of debris to check the explosive traces.

However, despite we are in 2015 the basic components of explosives are the same (like PETN). There are more sophisticated explosives, but hardly available for terrorists I think.

Anyway, there is a list if someone want search similarities or differences.
https://en.wikipedia.org/wiki/Timeline_of_airliner_bombing_attacks

[CONSO]

#2081 (http://www.pprune.org/9176841-post2081.html) (permalink (http://www.pprune.org/rumours-news/569907-breaking-news-airliner-missing-within-egyptian-fir-105.html#post9176841))
Cannot agree with above, for answers see Pan Am 103, in particular:


Note i didn't say NO residue - just that obvious signs like shrapnel and smoke would be mostly on the parts we have not seen.
And if chem residue in small quantities ( as compared to a suitcase style bomb or one in a container ) is still present on the pieces left for photos- it would not be obvious from the photos.

Unfortunately , everyone thinks of an explosive leaving a major size flash and smoke as in pearl harbor or similar- or blowing the whole plane apart, etc

And if many parts/sections b must be examined - it does take time

[edmundronald]

Explosives leave residue. Hence:

Residue ==> confirmed explosive device. ==> set loose the terror cops.
No residue ==> no explosive.
No explosive ==> probable mechanical failure. ==> set loose the airframe inspectors.

Edmund

[Chronus]

Chronus, if you know where to look, make analysis will be piece of cake. Otherwise, you must collect samples from any suspicious part and lab test them until you found what you looking for. It's also answers question "why two weeks" - not because each test is slow, but because there is a looooot of samples.

Not uttered a word about pieces of cake. Air crash investigation is a painstaking
task, am sure that with such a landmark event, not a single piece of stone will be left unturned, let alone the wreckage that lays scattered on that stone and rock strewn desert.

[sarabande]

Prada
that pivot point pic is v useful, thanks.


I am slightly confused, being more used to tiny simple planes. If I am wrong please enlighten me.

The jackscrew is the means of trimming the HS +/- by small increments, and would not be able to rapidly change the AofA of the HSs. The bottom bracket or trunnion of the JS must be linked in some way to the main pivot bearings further aft, otherwise the HSs could not articulate.

Large and speedy increments or decrements of the HS are generated by the elevators on the trailing edge.

If the JS- for whatever reason - becomes detached, the HSs will align (as you suggest) with the immediate airflow at the tail, and the trimming effect will be lost.

Would loss of the jackscrew (and hence taking away of trim) result in the PF making a quick reaction to re-trim using the elevators, and could this cause a full scale deflection + or- of the HS, unmoderated or even jammed by the broken JS ?

I'm trying to work out the consequences of a single point of failure loss of the JS.

[papershuffler]

Question. What if malefactor ...?

I've been pondering similar for the last few days.

An explosive or mechanical device wasn't even needed. Just access to the aircraft for someone with a couple of tools and a basic knowledge of flight dynamics (and/or directed by someone who had more advanced knowledge). The aircraft was on the ground for 12 hours, possibly unsecured. Various acts* of mechanical sabotage could have taken place in that time.

In my eyes, sabotage undetectable to the naked eye or sniffer dogs could be far more dangerous than explosives.

However, why did nothing happen until that particular altitude? If the airframe was seriously compromised, wouldn't something have happened/been detected earlier, even just an erroneous sensor reading or vibration? Would it have even left the ground?


*public forum - unsure whether we want to discuss exact details here?

[Bertie Bonkers]

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

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.

I take your point re this. As I'm seeing it up to now, the HS goes down, the lower edge of the HS pivot attaching lug striking the connecting pin/bolt/casting which connects the two halves of the 'sandwich'. This causes the pivot mounting to twist around the HS pivot, with aerodrag on the HS causing the lower pinion to push backward onto the APU cone, twisting the lower supporting frame with it. What you then have is the length of the pivot mount sandwich prising away the APU cone at the lower end below the slot, the two halves of the sandwich exerting equal force on the inner and out edges of the APU cone surround frame on both sides.

The key to why the surround doesn't distort could be in the alignment of the cone attachment lugs at the top - they are vertical - so as the pivot mounts force out the lugs at the bottom, the top end opens up like a hinge.

Having said all that though...

[thcrozier]

How it could be done speculation is unwise in my opinion. It rarely seems to be moderated out, and many of us probably learned enough in high school chemistry to come up with numerous vectors.

With a forum as widely read as PPRuNe, participants should assume that at least some viewers have less than noble intentions, and exercise appropriate discretion.

Far back in this thread I posted one such speculation, not quite the full recipe but enough to make further research simple. Within a few minutes someone else (thank you whoever you were) suggested it might not be such a good idea for the reasons stated above.

My post now reads "Deleted by author."

[vovachan]

Apparently field tests for the most common explosives found nothing so they are testing now for homemade\exotics.

Which begs the question why would ISIS do that, aren't there plenty of commercial/military explosives available in the Sinai already.

[thcrozier]

A little study on devices used in the past should help you understand.

[oldoberon]

Jdamnation http://www.pprune.org/rumours-news/569907-breaking-news-airliner-missing-within-egyptian-fir-104.html#post9176759

Two ways to do that are risky

a) go out to aircraft alone - risky someone may question why or caught on cctv
b) have it in pocket whilst loading (or unloading bay), you may get detected with it or placing it.

If a bomb in that compartment it was almost certainly in baggage, enough reports that scanning was inept at best.

Thinking ahead:-

I am ony aware of 1 bomb that was placed in an aircraft (toilet) as opposed in passenger luggage (inc cabin)

If this were to turn out to be the scenario, the question of on ground aircraft security arises, to the best of my knowledge no external hatches or doors are lockable perhaps they will need to be made secure in some way.

Remembering the reactions to 911 will we see something along these lines.

Aircraft having a alarm system like a shop set by crew on leaving, can only be reset from flight deck which is locked, so access not prevented but is known.

Perhaps an extra ad hoc cabin crew member who does not leave until cleaning, refuelling, cleaning, baggage unloading is complete is complete, same person would have to be there prior to main crew to give access to catering and refuelling (if not done earlier), sort of like a junior crewchief.

[Bertie Bonkers]

Apparently field tests for the most common explosives found nothing so they are testing now for homemade\exotics.

Which begs the question why would ISIS do that, aren't there plenty of commercial/military explosives available in the Sinai already.

And would you not actively seek to leave a trace to show you did it?

[Pontius Navigator]

Vovochan, simple. Common known explosives are detectable by equipment so designed to detect them. This is true of any detection system, they are reactive.

The shoe bomber evaded detection. The liquid limit again came in after first use
Making phones and laptops power up was yet another.

Now I know two common similar objects could be designed to by pass security ONCE. I know another common item that could be redesigned for several purposes but still pass the scanners.

And a friend showed me another common item that 99% carry but is lethal in trained hands.

These devices are so far undetected but are never the less known about.

[Control Eng]

I take your point re this. As I'm seeing it up to now, the HS goes down, the lower edge of the HS pivot attaching lug striking the connecting pin/bolt/casting which connects the two halves of the 'sandwich'. This causes the pivot mounting to twist around the HS pivot, with aerodrag on the HS causing the lower pinion to push backward onto the APU cone, twisting the lower supporting frame with it. What you then have is the length of the pivot mount sandwich prising away the APU cone at the lower end below the slot, the two halves of the sandwich exerting equal force on the inner and out edges of the APU cone surround frame on both sides.

The key to why the surround doesn't distort could be in the alignment of the cone attachment lugs at the top - they are vertical - so as the pivot mounts force out the lugs at the bottom, the top end opens up like a hinge.

Having said all that though...

Simple mechanics of levers - if you apply a force half way along a lever to exert a force at the end of a lever, then the original force has to be twice the magnitude.

The resultant force ripped the mountings out of the framework and twice the force did not distort the framework - no!

The whole 'loss of HS control' theory is a non starter without tail cone damage in this area.

[framer]

Aircraft having a alarm system like a shop set by crew on leaving, can only be reset from flight deck which is locked, so access not prevented but is known.

Perhaps an extra ad hoc cabin crew member who does not leave until cleaning, refuelling, cleaning, baggage unloading is complete is complete, same person would have to be there prior to main crew to give access to catering and refuelling (if not done earlier), sort of like a junior crewchief.
Non of that prevents a baggage handler simply leaving their smart phone in the hold as they finish up their job.

[sopwithnz]

One possibility is the group who originally claimed to have destroyed the AC was clear they would not be announcing how it was accomplished for some time, if ever. This is the 'terror' part of 'terrorism'.

And please stop posting ideas -- don't let your egos answer instead of your wisdom. :sad::eek::ugh:

[CONSO]

#2106 (http://www.pprune.org/9177036-post2106.html) (permalink (http://www.pprune.org/rumours-news/569907-breaking-news-airliner-missing-within-egyptian-fir-106.html#post9177036))- looks like that drawing following re lever action has been deleted --- but I'l' leave the following comment anyway

Yo -- The apu tail cone is NOT a primary structure and is held on to the HS pivot framework by essentially 4 lugs.
The plane would fly without the tail cone in place as it is maijnly an aero fairing designed to reduce drag and provide an exit for APU exhaust.

Look closely at the HS wingbox and pivot loactions and the surrounding fairly bulky frame- possibly a forging. The JS reaction is at the top " plate " between the pivot frame and the rear PB.

Note that we have yet to see the pivot points, the surrounding HS 'frame"( forging ) and the attached jack screw mechanisms.

While the leverage principle is basically valid, the identification of the cone " frame" as part of the pivot frame is incorrect. :oh:

I've yet to find a good- reasonable pic of the apu tailcone - or any of the HS reaction frame other than factory pics

[PPRuNe Towers]

An unedifying period which has led to competitive speculation and polite bickering amongst the technocats. (Spelling intentional) Numeracy is of no use when someone is baffled by IAS at altitude versus groundspeed and makes the content laughable to the intended audience for this forum.

Until there's some actual information the thread takes a rest. SOP in previous disasters and effective with those simply determined to type because there's no fresh data. Rehashing and circular arguments serve no purpose at all.

Please don't even try starting spinoff threads. If you are twitching at the keyboard with news hit the 'Contact Us' caption at the bottom right of the page.

Rob