BREAKING NEWS: airliner missing within Egyptian FIR
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I don't want to get involved in this, but just thought I'd point out one thing if I might. If the HS is ever free to move about it's pivot point (ie sans jackscrew) it will align itself with the oncoming air (weathervaning), not slam to one or the other stop. It's takes the path of least resisitence. 
Sorry.
Depends whether aeroD CofP is ahead of or behind remaining pivot point.
Been there, seen that. Thats why Im Wilyflier.
Edges of fuselage clearance holes unlikely to act as movement stops .
The only proper stops I can see on construction photos is that blobby thing on the end of the jackscrew.....Plus the mounting for the screw motor and Jesus! nut at the top.
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Center fuel tank explosion?
n in-flight explosion at FL310 resulting in a fireball cannot be due to structural failure. It must either be a bomb, or involve an engine explosion puncturing fuel tanks.
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That might be the case but it will be of more concern if this was a structural failure.
To some extent we can take precautions against outsiders taking action even though these actions may only be to reassure passengers and to make it more difficult for the perpetrators. Structure failures would reflect on the airworthiness of a lot of aircraft currently in service with far more repercussions.
FF
To some extent we can take precautions against outsiders taking action even though these actions may only be to reassure passengers and to make it more difficult for the perpetrators. Structure failures would reflect on the airworthiness of a lot of aircraft currently in service with far more repercussions.
FF
The Horizontal Stabilizer and rudder broke off. It would appear that only one half of the HS has been found and it shows extreme structural failure breaking upward without apparent impact damage from aircraft structures. This is a failure most aircraft engineers would say was close to impossible to envisage even if there had been a bomb in the rear of the aircraft. I think I am right in saying that there is not a case of a 321 crash where the horizontal stabilizer has broken away cleanly at its attachment point.
We will be living with terrorist bombs on aircraft for decades to come and there are ways of ensuring security. But we also need to ensure that there is no problem with maintenance or airframe design that might cause this type of breakup. So the investigators really need to find the other HS and show how and why they broke off the aircraft.
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Possible sequence?
I'm also puzzled as the damage to the HS/VS, a possible explanation would be:
-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.
-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.
Last edited by Mauersegler; 8th Nov 2015 at 16:34. Reason: "departs" replaces "goes down"
If a fuel/air explosion in the CWT or ACT was found to be the cause, the fallout wouldn't bear thinking about - both from the airworthiness point of view (all Airbus narrow-bodies grounded?) and politically (large quantities of international humble pie being eaten).
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For what it is worth from today's NYPost
“The indications and analysis so far of the sound on the black box indicate it was a bomb,” said the Egyptian investigation team member, who asked not to be named due to sensitivities. “We are 90 percent sure it was a bomb.”
Interesting quote from Tim Clark:
“What happened in Sharm al-Sheikh last week, and to a lesser extent with the … (Germanwings) aircraft, are game changers for our industry,” Emirates Airlines President Tim Clark said, referring to the crash of a Germanwings airliner in the French Alps in March, believed crashed deliberately by its co-pilot.
“They have to be addressed at industry level because no doubt the countries — U.S., Europe — I would think will make some fairly stringent, draconian demands on the way aviation works with security,” he said at the Dubai Airshow.
Interesting quote from Tim Clark:
“What happened in Sharm al-Sheikh last week, and to a lesser extent with the … (Germanwings) aircraft, are game changers for our industry,” Emirates Airlines President Tim Clark said, referring to the crash of a Germanwings airliner in the French Alps in March, believed crashed deliberately by its co-pilot.
“They have to be addressed at industry level because no doubt the countries — U.S., Europe — I would think will make some fairly stringent, draconian demands on the way aviation works with security,” he said at the Dubai Airshow.
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What it wasn't
After 1800 posts is a lot of certainty by posters had emerged, yet the current set of posted conclusions are significantly divided in direct opposition. A lot of certainty is going to eventually be proven wrong. What we do know so far as possibilities, though less so as probabilities:
The ‘event’ may have been of long (20+ seconds) or short (3 seconds) duration.
Primary cause may or may not have been an onboard explosion, missile strike, mechanical failure, or fatigue failure.
Explosion may or may not have been a bomb, missile, battery+, or other, and may not have, by itself, been sufficient to cause the results, meaning more than one item combined to produce an explosive effect, intentionally or by happenstance.
An intentional 'bomb'-- pyro or non pyro—may have been loaded by happenstance, or placed very intentionally at a very specific location for a very specific reason.
A fire in the aft hold so far cannot be ruled out as primary or located with certainty in the event sequence.
HS failure, tail section parting, aft fuselage parting, and any of the three HS support points may each have been primary in sequence.
HS shearing off may have been up, or down, or multiple ups and downs of high or low frequency….and the HS or support structure may have been previously compromised by chemical or mechanical action.
Loss of any of the three HS support points dooms the airframe and frees the HS to large movements in response to both positive and negative loads. The range of possible sequences of resulting actions of the loss of one of the HS pivots in an AC departing normal flight attitudes have not yet been argued and there is as yet no consensus.
It is generally deemed to be in the best interests of the public and of the investigation that the public including Pprune should not know all that is known.
Of note:
Engine pylons are weaker against abrupt yaw than abrupt pitch loads.
Maximum accelerations in pitch or yaw by an intact airframe will be lower than accelerations by an incomplete airframe.
A missile strike does not always result in a warhead explosion. Especially if the warhead explosive has been removed.
“Smoke” in the video may have been added not to enhance an effect but to obscure something, like the absence of smoke, or to misdirect from something else. If you can refrain from laughing, ask why that might be done. One reason might an absence of explosive fingerprint.
The list or people, organizations, political entities, government agencies, and governments who/which for a wide variety of perhaps extremely bizarre reasons known only to themselves might want to “down” a very specific or just some random airliner to leverage some very large political rock is very very long, with most of them probably thinking in terms of a false flag operation rather than advertising their name.
The ‘event’ may have been of long (20+ seconds) or short (3 seconds) duration.
Primary cause may or may not have been an onboard explosion, missile strike, mechanical failure, or fatigue failure.
Explosion may or may not have been a bomb, missile, battery+, or other, and may not have, by itself, been sufficient to cause the results, meaning more than one item combined to produce an explosive effect, intentionally or by happenstance.
An intentional 'bomb'-- pyro or non pyro—may have been loaded by happenstance, or placed very intentionally at a very specific location for a very specific reason.
A fire in the aft hold so far cannot be ruled out as primary or located with certainty in the event sequence.
HS failure, tail section parting, aft fuselage parting, and any of the three HS support points may each have been primary in sequence.
HS shearing off may have been up, or down, or multiple ups and downs of high or low frequency….and the HS or support structure may have been previously compromised by chemical or mechanical action.
Loss of any of the three HS support points dooms the airframe and frees the HS to large movements in response to both positive and negative loads. The range of possible sequences of resulting actions of the loss of one of the HS pivots in an AC departing normal flight attitudes have not yet been argued and there is as yet no consensus.
It is generally deemed to be in the best interests of the public and of the investigation that the public including Pprune should not know all that is known.
Of note:
Engine pylons are weaker against abrupt yaw than abrupt pitch loads.
Maximum accelerations in pitch or yaw by an intact airframe will be lower than accelerations by an incomplete airframe.
A missile strike does not always result in a warhead explosion. Especially if the warhead explosive has been removed.
“Smoke” in the video may have been added not to enhance an effect but to obscure something, like the absence of smoke, or to misdirect from something else. If you can refrain from laughing, ask why that might be done. One reason might an absence of explosive fingerprint.
The list or people, organizations, political entities, government agencies, and governments who/which for a wide variety of perhaps extremely bizarre reasons known only to themselves might want to “down” a very specific or just some random airliner to leverage some very large political rock is very very long, with most of them probably thinking in terms of a false flag operation rather than advertising their name.
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I can make some summarizing again if you don't mind.
1) I'm sure investigators, contrary to pprune detectives, has all photos of all parts of plane and some of them have plenty of time to look at them at site and even touch them with their own hands. So there is no "mystery" of lost part of HS and VS (for them, or we will know).
2) We cant beat them in game "look we found some suspicious holes, it's a bomb!" so if there was clear evidence of explosion it will be found and nailed already.
3) There is no clear evidence of the way relaxed security at SSH make bomb planting possible or we already will read about suspects arrested.
4) All other "clues", such as sat surveillance, phone intercepts etc. are too weak to make case strong enough to pinpoint it. They can however add flavors after it will be solved through other means.
Major mess organized in Egypt by other countries in my opinion can be not directly driven by any proof but by the fear that in current conditions - even if this was not terrorist case - bombing can be easily made. For example, if you found that your jewelry was stolen, you will check locks and latches and repair them immediately, asking somebody to guard your house till you will go to hardware store, even if most probable case was that your housemaid stole them.
1) I'm sure investigators, contrary to pprune detectives, has all photos of all parts of plane and some of them have plenty of time to look at them at site and even touch them with their own hands. So there is no "mystery" of lost part of HS and VS (for them, or we will know).
2) We cant beat them in game "look we found some suspicious holes, it's a bomb!" so if there was clear evidence of explosion it will be found and nailed already.
3) There is no clear evidence of the way relaxed security at SSH make bomb planting possible or we already will read about suspects arrested.
4) All other "clues", such as sat surveillance, phone intercepts etc. are too weak to make case strong enough to pinpoint it. They can however add flavors after it will be solved through other means.
Major mess organized in Egypt by other countries in my opinion can be not directly driven by any proof but by the fear that in current conditions - even if this was not terrorist case - bombing can be easily made. For example, if you found that your jewelry was stolen, you will check locks and latches and repair them immediately, asking somebody to guard your house till you will go to hardware store, even if most probable case was that your housemaid stole them.
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HS second pic
Kulver, Thanks so much for your continuing supply of photos. Your last HS pic at 1790 shows a LOT of leading edge damage not previously visible. The damage is generalized along the visible length (as it would be by a large flying skin section), and not an impact at a single point.
Would posters who have suggested a failure of the left HS tip upward agree that the LE damage in this pic would have probably decreased the strength of the left of HS and increased the probability of the line of failure at the HS center sections as observed? Absent any pic so far of the right HS, how would LE damage to it impact a proposed sequence of events?
Would posters who have suggested a failure of the left HS tip upward agree that the LE damage in this pic would have probably decreased the strength of the left of HS and increased the probability of the line of failure at the HS center sections as observed? Absent any pic so far of the right HS, how would LE damage to it impact a proposed sequence of events?
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Your last HS pic at 1790 shows a LOT of leading edge damage not previously visible.
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@ Leightman 957
That is the LEFT HS and we are seeing the top surface. The damage is to the trailing edge, probably caused by elevator flutter. But yes, it could have contributed to the weakening of the structure.
Kulver, thanks for the contribution, once again the first new information after so many pages of circular arguments.
Edit: wow, a few of us jumped on this quiet fast, 3 comments to the same extent before I finished typing
That is the LEFT HS and we are seeing the top surface. The damage is to the trailing edge, probably caused by elevator flutter. But yes, it could have contributed to the weakening of the structure.
Kulver, thanks for the contribution, once again the first new information after so many pages of circular arguments.
Edit: wow, a few of us jumped on this quiet fast, 3 comments to the same extent before I finished typing
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Thanks for the new picture Kulverstukas,
(edit: yes, we see the upper side of HS -left side- and the elevator is torn off, the leading edge is ok, see the other picture here http://cdn.aviaforum.ru/images/2015/...22868c7e21.jpg)
looks like it was suddenly put in the wrong angle... that and a smashed VS...
As pprune conclusion was it's left wing of HS, for me it looks more like elevator was torn off.
looks like it was suddenly put in the wrong angle... that and a smashed VS...
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thank you Kulverstukas
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This is an outstanding thread, a credit to PPrune but there are two kinds of posts I've mostly skipped over. The first kind are the "picture analysis" posts which seem to be a separate subject to me. The second type of posts I discount are the ones that propose that if the front joint of the HS were to disengage the HS would flop to 90° to the flight path. I don't have a picture of a ready to install 321 HS but if someone can find such a picture I'm sure it will show that about 2/3rds of the surface area is behind the pivot point. Thus MD80 fanatic is correct in his statement that the HS would align itself with the wind direction in case of loss of the front connection.
It is possible that when the tail section separated from the rest of the plane the VS caught the 280kt (IAS) wind blast and overpowered the HS effects and caused the HS to snap from leading edge down to leading edge up (or even back and forth) and imposed destructive loads. But that can only be a theory for now.
A second point that has been bothering me a bit is all the finger pointing at ISIS. The Russians have been very busy for the last few weeks bombing Al Nustra front positions (read: Al Quida), so they are more likely to be the group with a grudge against Russia.
Again: great thread!
It is possible that when the tail section separated from the rest of the plane the VS caught the 280kt (IAS) wind blast and overpowered the HS effects and caused the HS to snap from leading edge down to leading edge up (or even back and forth) and imposed destructive loads. But that can only be a theory for now.
A second point that has been bothering me a bit is all the finger pointing at ISIS. The Russians have been very busy for the last few weeks bombing Al Nustra front positions (read: Al Quida), so they are more likely to be the group with a grudge against Russia.
Again: great thread!