Kolavia A321 Crashes In Sinai / Egypt - Part 5

lightsaber · Sun Nov 08, 2015 3:00 am

Please continue discussion here:

Kolavia A321 Crashes In Sinai / Egypt - Part 4 (by jetblueguy22 Nov 4 2015 in Civil Aviation)

Please keep on topic and respectful of other users.

shortstack81 · Sun Nov 08, 2015 4:00 am

this was the last thing I typed in the previous thread. Recreating here:

of particular interest was when the FDR stopped: 04:13:20

FR24 data seems to indicate the event began at 04:13:15 and was over by 04:13:39

mandala499 · Sun Nov 08, 2015 4:07 am

If the FDR stopped at 4:13:20 and FR24 records ended up at 4:13:39, there are 2 possibilities:
1. Timestamp differences between FDR and FR24
2. Physical connections to the FDR stopped before the aircraft's Mode-S/ADS-B transceiver lost data feed and power.

By the way, any photos of the horizontal stabilizers and the rudder yet? How about the rear fuselage between the wing's rear edge and the last row of seats?

zeke · Sun Nov 08, 2015 4:19 am

Summary of what os known
Wreckage spread over a large area indicating in flight breakup, what caused the breakup is unknown
Autopilot was connected until the end of recording indicating the crew had no prior warning
A sound is heard on the CVR at the end, analysis of that sound is being made

777Jet · Sun Nov 08, 2015 4:28 am

Quoting zeke (Reply 3):
Summary of what os known

It is also known that ISIS *claimed* responsibility.

Here is an interesting article on ISIS at Sharm El Sheikh:

'ISIS infiltrate holiday destinations in Sharm El Sheikh'

http://www.express.co.uk/news/world/...liday-destinations-Sharm-El-Sheikh

"ISLAMIC State militants suspected of blowing up a Russian passenger plane have a network of insurgents working in bars, restaurants and hotels across Sharm El Sheikh.

The terror group also uses operatives employed at the airport, authorities in the Egyptian Red Sea resort fear."

2175301 · Sun Nov 08, 2015 4:48 am

Quoting shortstack81 (Reply 1):
If the FDR stopped at 4:13:20 and FR24 records ended up at 4:13:39, there are 2 possibilities:
1. Timestamp differences between FDR and FR24
2. Physical connections to the FDR stopped before the aircraft's Mode-S/ADS-B transceiver lost data feed and power.

I would expect that a timestamp difference would exist between two independent recording devices. I have no idea if it is normally within 5 seconds, 10 seconds, etc., or up to a minute.

Have a great day,

Backseater · Sun Nov 08, 2015 4:49 am

French news channel reports that for the third time ISIL (from Aleppo) has claimed responsibility for bringing the plane down.

Regarding the report in the British press that a Thomson flight had to evade a missile when approaching SSH last summer, here is the official Egyptian statement:
Ahramonline (excerpt)
Egyptian foreign ministry spokesman Ahmed Abu Zeid said on his Twitter account on Sarturday.

"The Incident involved GROUND-TO-GROUND fire exercise in military base few km off Sharm airport, no ground-to-air firing involved whatsoever.

"Egypt & UK [governments were] fully aware that [the] plane was in no danger. Airliners were previously informed of military exercise and instructed of procedures," Abu Zeid added.

SuseJ772 · Sun Nov 08, 2015 5:01 am

Quoting mandala499 (Reply 2):
By the way, any photos of the horizontal stabilizers and the rudder yet? How about the rear fuselage between the wing's rear edge and the last row of seats?

That is what I was asking in the first thread. That was what pointed me to a non-mechanical breakup right from the beginning. We had almost a "perfect outline" of a plane wings and forward. We had a very small part of the rear of the aircraft. But no evidence of anything in the 15-20 feet back from the wings to the very end of the tail.

Quoting 2175301 (Reply 5):
I would expect that a timestamp difference would exist between two independent recording devices. I have no idea if it is normally within 5 seconds, 10 seconds, etc., or up to a minute.

Especially since I doubt the FDR has a NIST sync. Maybe someone can detail how the FDR keeps in time sync. I have a pretty good sense of how FR24 keeps in sync given it is constantly connected to a NIST source.

BoeingVista · Sun Nov 08, 2015 5:53 am

Quoting mandala499 (Reply 2):
By the way, any photos of the horizontal stabilizers and the rudder yet?

Yes, I have seen pictures of at least one of the HS, maybe both but it was a few days ago they are not part of the widely circulated images for some reason.

Edit: LHS HS I think

[Edited 2015-11-07 22:37:14]

[Edited 2015-11-07 22:38:16]

WIederling · Sun Nov 08, 2015 8:56 am

Quoting suseJ772 (Reply 7):
Especially since I doubt the FDR has a NIST sync.

GPS is a 4 DoF location service x,y,z and T as in time. there is a slight disparity between UTC based time services and the GPS time. For one there are no leap seconds in GPS.
A logging device does not have to be in sync with some time source or other. Fully sufficient to log a time source (even if only the PPS signal from a GPS unit ) together with all the other signal sources.

mandala499 · Sun Nov 08, 2015 9:26 am

Quoting BoeingVista (Reply 8):
Edit: LHS HS I think

Yes, I've seen that one. Still trying to "decipher" what it's saying...
But then, I came across this (first time I've seen it from this angle)... Looks like another clean cut along structural lines that's typical (but doesn't mean it has to be) of metal fatigue.

Looks like the part between the stabilizer and the APU exhaust cone.

So we have this, part behind where the stabilizer joins the fuselage, and the part in front. Both the 2 parts have clean cut lines along structural lines. Yet, we're still missing the the lower part of the fuselage and where the stabilizer joins the fuselage, and the rudder.

Bomb theorists can talk about bombs all they want but these parts, literally "stinks" of structural failure due to fatige.

We just need more parts to say yes or no to it...

Airbus747 · Sun Nov 08, 2015 9:39 am

Britons trained in Syria with an "electronics background" might have helped to construct the bomb that brought down the Russian jet, according to reports this morning. [...] "Chatter" picked up by GCHQ reportedly featured jihadists with London and Birmingham accents celebrating in Egypt after the explosion.
http://www.independent.ie/world-news...about-blowing-up-jet-34179911.html

I think this is the first report that goes more into detail about what the reported "chatter" was about. Interesting that it was Britons... maybe that's why the UK was among the first to act.

BoeingVista · Sun Nov 08, 2015 9:44 am

Quoting mandala499 (Reply 10):
Looks like the part between the stabilizer and the APU exhaust cone.

Yup sems to be, also I believe that I see the rear of the APU still in there as that has been a point of conjecture.

Quoting mandala499 (Reply 10):
But then, I came across this (first time I've seen it from this angle)... Looks like another clean cut along structural lines that's typical (but doesn't mean it has to be) of metal fatigue.

Well no, what it tells you is that the structural joint is the weakest part of the combined structure and failed first.

Quoting mandala499 (Reply 2):
How about the rear fuselage between the wing's rear edge and the last row of seats?

The top of the fuse has possibly been spotted, its unpeeled and upside down, unpealing from the bottom would support the bomb theory.

This video more or less explains how the majority of wreakage came to be arranged in such close proximity.

http://www.youtube.com/watch?v=MOnsIGcZS-M

[Edited 2015-11-08 01:55:15]

cedarjet · Sun Nov 08, 2015 9:47 am

Surely if it was a bomb we would know by now — such a device would leave a chemical signature that is unmistakable. I remember after PA103 went down in Scotland in 1988 we knew within a day or two. Now it's been a week since Metrojet and all we have are some idiots on a website and a "loud noise" on the CVR. Well there's idiots everywhere and as for the explosion, well, no-one's denying the plane crashed.

Btw the repair to the tail strike took THREE MONTHS, that is a serious amount of repair.

Thunderboltdrgn · Sun Nov 08, 2015 9:56 am

Quoting cedarjet (Reply 13):
Btw the repair to the tail strike took THREE MONTHS, that is a serious amount of repair.

I thought it was said in the previous thread that the damaged section wasn't repaired but replaced?

lancelot07 · Sun Nov 08, 2015 10:06 am

Quoting mandala499 (Reply 10):
Looks like another clean cut along structural lines that's typical (but doesn't mean it has to be) of metal fatigue.

Clean cut yes, but if think it would be strange to have rupture due to fatigue in 2 independent locations. One would assume stress is mostly gone when one location breaks.
Anyway, cracks due to fatigue show very distinctive marks and should be fairly easy to identify.

Quote:
Well no, what it tells you is that the structural joint is the weakest part of the combined structure and failed first.

[Edited 2015-11-08 02:08:09]

Scorpio · Sun Nov 08, 2015 10:06 am

Quoting mandala499 (Reply 10):
Yes, I've seen that one. Still trying to "decipher" what it's saying...
But then, I came across this (first time I've seen it from this angle)... Looks like another clean cut along structural lines that's typical (but doesn't mean it has to be) of metal fatigue.

Looks like the part between the stabilizer and the APU exhaust cone.

Isn't this simply the entire tailcone subassembly? See https://www.youtube.com/watch?v=kLtnsTgQdgk at 1:44. Seems to be a perfect match. Also, is this part really susceptible to metal fatigue as much as the rest of the fuselage? After all, it's located behind the rear pressure bulkhead and so doesn't go through the pressurisation cycles. If the HS is blown backward because of an explosion (bomb or rear bulkhead failure) wouldn't one expect the tailcone to break away in exactly this fashion?

F9Animal · Sun Nov 08, 2015 10:50 am

Quoting cedarjet (Reply 13):
Surely if it was a bomb we would know by now — such a device would leave a chemical signature that is unmistakable. I remember after PA103 went down in Scotland in 1988 we knew within a day or two. Now it's been a week since Metrojet and all we have are some idiots on a website and a "loud noise" on the CVR. Well there's idiots everywhere and as for the explosion, well, no-one's denying the plane crashed.

Actually, how can we be certain that we would know by now? Scotland and PA 103 involved investigators that were very open, and didn't hesitate to hold news conferences. It was pretty much a cooperation of countries.

This incident involves 2 countries that are hesitant, very secret, and have much at stake if it turns out to be a bomb.

Anyways, watching the memorial service on CNN. Those poor people on that flight.

MD11Engineer · Sun Nov 08, 2015 10:58 am

Quoting cedarjet (Reply 13):
Surely if it was a bomb we would know by now — such a device would leave a chemical signature that is unmistakable. I remember after PA103 went down in Scotland in 1988 we knew within a day or two. Now it's been a week since Metrojet and all we have are some idiots on a website and a "loud noise" on the CVR. Well there's idiots everywhere and as for the explosion, well, no-one's denying the plane crashed.

Btw the repair to the tail strike took THREE MONTHS, that is a serious amount of repair.

If it was an explosive based on nitrogen. Other explosives leave other or no residue. Chlorate based explosives would leave ordinary salt, but salt in clothes at a beach resort isquite common.
Peroxide based explosives would leave practically no traces (decomposing into water and carbon dioxide).
Most commercial and military explosives are nitrogen based, as these are often the strongest and safest to handle compounds. More exotic explosives, as used by terrorists because they can be made from chemicals available in household goods shops, hardware and paint shops or pharmacies, are often quite temperamental and equally dangerous to the person making them.

As for diving cylinders, while there is a lot of scuba diving going on at Sharm-El-Sheik and Hurgada (being the closest destinations reachable from Europe with coral reefs), most divers only bring their wetsuits, buoyancy jackets, masks, fins and snorkel, plus their own regulators and dive computers (meaning the stuff one's life depends on and, due to hygienic reasons, the stuff which touches the body) and rent the heavy items like air tanks and lead weights on site, as the surcharges for extra luggage would be extraorbitant.

Jan

Unflug · Sun Nov 08, 2015 11:05 am

Quoting mandala499 (Reply 10):
Bomb theorists can talk about bombs all they want but these parts, literally "stinks" of structural failure due to fatige.

Possibly could be both, couldn't it? Structural failure coming from fatigue as well as stress - whichever reason, including a bomb?

Or this:

Quoting Scorpio (Reply 16):
If the HS is blown backward because of an explosion (bomb or rear bulkhead failure) wouldn't one expect the tailcone to break away in exactly this fashion?

Unflug · Sun Nov 08, 2015 11:18 am

quoting prebennorholm from last thread:

"Ayman al-Muqaddam, head of a team of experts looking into one of Egypt's worst air disasters, said his team, including experts from Egypt, Russia, France, Germany and Ireland, was considering "all possible scenarios for the cause of the accident" but had not yet reached any conclusion. He said structural fatigue, a fuel explosion and even lithium batteries carried by passengers could be a cause."

Have a look at the end. Sure lithium batteries can catch fire, and depending on the circumstances it can spell real danger for an aircraft. But a lithium battery cannot blow a plane apart in a split second.

Mr. Muqaddam is head of the investigation. How can there be a head of investigation with such a total lack of knowledge of physics? This is really worrying!!! How can that happen? Is it an Egyptian stunt to try and salvage what can be salvaged of their tourist industry? While at the same time assuming that the rest of the world are idiots?

I think that's a bit harsh. To me it sounds perfectly OK to look at every scenario thinkable (no matter how improbable at first glance), and then check each of these scenarios. That includes a fire caused by lithium batteries. I'm quite confident Mr. Muqaddam will come to the same conclusion, unless the investigation team has other information we do not know of. He wasn't saying that lithium batteries are a probable cause in this case, he just said that they are looking at everything...

zeke · Sun Nov 08, 2015 11:21 am

Quoting mandala499 (Reply 10):
But then, I came across this (first time I've seen it from this angle)... Looks like another clean cut along structural lines that's typical (but doesn't mean it has to be) of metal fatigue.

That is to be expected when the loads on the structure exceed the design loads plus the safety factor. One would expect it to fail along joins. The tailcone would normally be subjected to very light loads, if it were ejected from the rest of the fuselage at high speed I would see it being exposed to air loads that would cause failure.

Quoting mandala499 (Reply 10):
Bomb theorists can talk about bombs all they want but these parts, literally "stinks" of structural failure due to fatige. We just need more parts to say yes or no to it...

You dont need an explosive to initiate structural failure. On the previous thread I made the comment that the pressure inside the aircraft is like a dam wall, all you need to do is put a crack in the dam wall, and the water pressure will do the rest. Aside from explosives, "dangerous goods" such as gallium and acids if spilled in a fuselage can weaken to a point where the loads on the airframe can result in structural failure, likewise a fire can weaken a structure and the pressure differential can do the rest.

eielef · Sun Nov 08, 2015 11:57 am

No Mossad intelligence done yet in the area? If someone really knows what's going on in the Sinai Peninsula that must be Israel. And they should have very capable technology and technicians to check what happened that day at that time. They offered help, but so far I couldn't find any information given by Israel yet.

directorguy · Sun Nov 08, 2015 12:32 pm

Quoting eielef (Reply 22):

The last thing Egypt will allow is Mossad intelligence in the Sinai. Having them directly involved would be a very sensitive issue and hell would break loose if news of that got out.

FredrikHAD · Sun Nov 08, 2015 12:38 pm

Quoting 2175301 (Reply 5):
I would expect that a timestamp difference would exist between two independent recording devices. I have no idea if it is normally within 5 seconds, 10 seconds, etc., or up to a minute.

In networking installations, you either sync with NTP, Network Time Protocol, against external time servers (widely available for free on the Internet), or a GPS receiver designed to only extract the timestamp from the satellites. GPS is generally classified as one of the best time sources available along with atomic (cesium, rubidium) clocks or other radio clocks (designated Stratum 0 in the NTP terminology).

Since the GPS timestamp is available in the aircraft, I'd be surprised if the FDR and ADS-B systems are not synced to it, which would give sub-millisecond deviation from the "real" time. In a networking environment, you can have ms precision without investing a single dime, and given the importance of time sync in all troubleshooting/investigations, I find that crucial, both in avaiation and networking.

/Fredrik

mandala499 · Sun Nov 08, 2015 12:59 pm

Quoting zeke (Reply 21):
You dont need an explosive to initiate structural failure.

Exactly!

Quoting Scorpio (Reply 16):
After all, it's located behind the rear pressure bulkhead and so doesn't go through the pressurisation cycles. If the HS is blown backward because of an explosion (bomb or rear bulkhead failure) wouldn't one expect the tailcone to break away in exactly this fashion?

That's what I was thinking when I wrote my previous reply. Where on earth is the other horizontal stabilizer and it's joint assembly...

Just curious...

ltbewr · Sun Nov 08, 2015 1:13 pm

Quoting eielef (Reply 22):
No Mossad intelligence done yet in the area? If someone really knows what's going on in the Sinai Peninsula that must be Israel. And they should have very capable technology and technicians to check what happened that day at that time. They offered help, but so far I couldn't find any information given by Israel yet

I suspect that any intel from Israel being kept very quiet to the public but likely has been shared with the UK, USA and Russia and used by them in their reactions to this loss.

OMP777X · Sun Nov 08, 2015 1:46 pm

Reports now have quoted an Egyptian official who is part of the investigation as saying they're 90% sure a bomb caused the break up at cruise. Other reports have another investigator claiming 99.99% certainty. What they're basing this on is the sound of the explosion on the CVR. What I wonder is can they even say with that much certainty that it was in fact a bomb solely based on a CVR recording that has been examined for only several days?
http://mobile.reuters.com/article/idUSKCN0SX07D20151108

Best,

OMP777X

Kaiarahi · Sun Nov 08, 2015 1:54 pm

Despite all the prattling on here about intelligence, ISIS, etc, let's not forget that an investigation has only one objective.

Convention on International Civil Aviation, Annex 13, article 3.1

"The sole objective of the investigation of an accident or incident shall be the prevention of accidents and incidents. It is not the purpose of this activity to apportion blame or liability."

Deanger · Sun Nov 08, 2015 2:59 pm

Quoting cedarjet (Reply 13):

Quoting cedarjet (Reply 13):

Surely if it was a bomb we would know by now — such a device would leave a chemical signature that is unmistakable. I remember after PA103 went down in Scotland in 1988 we knew within a day or two.

Many differences

1) Countries involved

2) Placement of bomb on aircraft - if indeed it was a bomb on the flight it appears to have been placed near the back, on a airplane that had a history of a tail strike - which would immediately engender a longer and more discriminating process.
As opposed to where the bomb went off on flight 103

3) Entirely new generation of explosives. And kinds of 'attacks'. Shoes, clothing, liquids, etc.

4) I believe "Bomb" was in fact widely reported in the press around day 3 - there was just more pushback on places like this than in 1983.

5) Passengers/Airline targeted. What I mean by this isn't that other nations aren't targets of terror - we've seen that now. But if this were a plane of British Holiday-goers or American travelers then I speculate people would be a little quicker to embrace the 'deliberate act' - because these nations have been routinely singled out by dozens of groups

6) Value of fast reporting in 2015. Everyone wants to be first, so we all are conditioned to be (rightfully) cautious about trusting the media.

7) Strategic value of fast reporting in this case. If indeed it was a bomb that involved airport penetration then the last thing you would want to do is come out and say you know that. You would absolutely dole out that info in such a way as to not limit your ability to gather intel on this network. indeed, for all we know, they found very tell-tale information almost instantly, and kept their mouths shut so they could gather Signals Intelligence on the group that did it on the days that followed.

eielef · Sun Nov 08, 2015 3:49 pm

I have no ideas of explosives, but how big must be a bomb for bringing down a plane? Off course it depends on where the bomb is situated, and this is, mostly, randomly done by cargo handling people. For instance, if there was a bomb in the luggage of a passenger, that will go to the cargo area of the plane together with all other passenger bags. But there are many bags, so it'll mostly go to the place where it fits (sometimes inside a container, sometimes just on the plane).
Second, if the bomb was send by air-mail, it wouldn't be together with the passenger bags, but on a area of mail (in the cargo area of a plane).
And thirdly, there is always space left in the plane for some spare parts, some of them as big as a tire. It could have been placed there.

In this third scenario, I think some airport employee could have putted a bomb, which has tragically detonated costing the life of all on board.
So: how safe are our skies?
We are not allowed to carry liquids (like a can of coke) nor a sewing kit (because its considered dangerous), but an airport employee might have left a bomb on the cargo area of a plane?

I was asked this week if I wasn't afraid of flying in Russia. My answer was: the chances of this happening again (in my case were two short domestic flights) are none. But I'm wondering if I'm wrong...

MD11Engineer · Sun Nov 08, 2015 4:16 pm

Quoting eielef (Reply 30):
I have no ideas of explosives, but how big must be a bomb for bringing down a plane? Off course it depends on where the bomb is situated, and this is, mostly, randomly done by cargo handling people. For instance, if there was a bomb in the luggage of a passenger, that will go to the cargo area of the plane together with all other passenger bags. But there are many bags, so it'll mostly go to the place where it fits (sometimes inside a container, sometimes just on the plane).

A few hundred gramms of a high explosive are more than enough. The bomb that brought down the PanAm jumbo over Lockerbie were about 200 gramms of explosives. The old 200 gramm TNT blocks used by German army engineers were about the same size and shape as a bar of soap. TNT also looks like the cheap yellow soap used for washing clothes.
In the right place a charge of as little as 50 gramms can be enough. You have to think of a pre-stressed pressure vessel and suddenly there is a pressure wave running through it at three times the speed of sound. IIRC from my blasting courses, a 120 gramm stick of the commercial dynamite-like explosive (Ammon-Gelit 2 resp. Gelamon 2) we used for most applications would turn into about two cubic metres of gas within milliseconds.

Quoting eielef (Reply 30):
Second, if the bomb was send by air-mail, it wouldn't be together with the passenger bags, but on a area of mail (in the cargo area of a plane).
And thirdly, there is always space left in the plane for some spare parts, some of them as big as a tire. It could have been placed there.

With airmail and cargo the sender will usually not know which aircraft the cargo goes on. Also, in most places airmail and cargo are being either searched with dogs, x-rayed, put into flight simulation vacuum chambers or left for a few days. Of course, this is Egypt. If passengers got offered to bypass security for 20 dollars, a cargo shipment can also bypass security.

Jan

MOW · Sun Nov 08, 2015 4:20 pm

Quoting eielef (Reply 30):
I was asked this week if I wasn't afraid of flying in Russia. My answer was: the chances of this happening again (in my case were two short domestic flights) are none. But I'm wondering if I'm wrong

It's absolutely safe. Just don't forget to wake up the lady who's behind the x-ray machine screen at the security check point. Or to report to a supervisor about another security lady who's OK to let that guy to keep the big can of shaving foam with him, because she 'loves scruffy men'

BoeingVista · Sun Nov 08, 2015 4:26 pm

Quoting MD11Engineer (Reply 31):
A few hundred gramms of a high explosive are more than enough. The bomb that brought down the PanAm jumbo over Lockerbie were about 200 gramms of explosives. The old 200 gramm TNT blocks used by German army engineers were about the same size and shape as a bar of soap. TNT also looks like the cheap yellow soap used for washing clothes.

Also lets not forget that this plane had auxiliary fuel tanks fitted in the rear cargo hold making the situation even more volitile.

JetBuddy · Sun Nov 08, 2015 5:02 pm

Quoting MD11Engineer (Reply 31):
A few hundred gramms of a high explosive are more than enough. The bomb that brought down the PanAm jumbo over Lockerbie were about 200 gramms of explosives. The old 200 gramm TNT blocks used by German army engineers were about the same size and shape as a bar of soap. TNT also looks like the cheap yellow soap used for washing clothes.
In the right place a charge of as little as 50 gramms can be enough. You have to think of a pre-stressed pressure vessel and suddenly there is a pressure wave running through it at three times the speed of sound. IIRC from my blasting courses, a 120 gramm stick of the commercial dynamite-like explosive (Ammon-Gelit 2 resp. Gelamon 2) we used for most applications would turn into about two cubic metres of gas within milliseconds.

Yep. I suspect a small charge tore a hole in the pressure vessel in some manner, causing things to be sucked out of the cabin. Complete panic. Also explains the terrible fact that the baby was found 33 km before the rest of the debris. The small hole then gradually expands until the whole tail rips off. Sounds really bad.

slvrblt · Sun Nov 08, 2015 5:24 pm

Quoting ltbewr (Reply 26):
I suspect that any intel from Israel being kept very quiet to the public but likely has been shared with the UK, USA and Russia and used by them in their reactions to this loss.

Agree, and certainly goes without saying. In this day and age I suspect there's very little that goes uncaptured - by someone - somewhere. And if you're an entity that's more than usually interested (CIA, Mossad) then there's probably more known than can be reasonably disclosed.

ltbewr · Sun Nov 08, 2015 5:32 pm

Quoting BoeingVista (Reply 33):
Also lets not forget that this plane had auxiliary fuel tanks fitted in the rear cargo hold making the situation even more volitile.

Is that true and can be verified ?

Quoting JetBuddy (Reply 34):
Quoting MD11Engineer (Reply 31):
A few hundred gramms of a high explosive are more than enough. The bomb that brought down the PanAm jumbo over Lockerbie were about 200 gramms of explosives. The old 200 gramm TNT blocks used by German army engineers were about the same size and shape as a bar of soap. TNT also looks like the cheap yellow soap used for washing clothes.
In the right place a charge of as little as 50 gramms can be enough. You have to think of a pre-stressed pressure vessel and suddenly there is a pressure wave running through it at three times the speed of sound. IIRC from my blasting courses, a 120 gramm stick of the commercial dynamite-like explosive (Ammon-Gelit 2 resp. Gelamon 2) we used for most applications would turn into about two cubic metres of gas within milliseconds.

Yep. I suspect a small charge tore a hole in the pressure vessel in some manner, causing things to be sucked out of the cabin. Complete panic. Also explains the terrible fact that the baby was found 33 km before the rest of the debris. The small hole then gradually expands until the whole tail rips off. Sounds really bad.

It definitely wouldn't take much explosive material for bomb to take down an aircraft, with good placement. With PA 103, it was by dumb luck and no double checks as transferred luggage in a Cadette/radio player in checked baggage. In this case, more likely here was a baggage handler or mechanic would know where to place it to assure mass destruction. It could have put into someone's checked bag, and intentionally placed in a critical place. I am quite sure it would be easy to bring in a glob of high density explosives material and a detonator and or timer hidden in some way and not subject to inspections of airside staff.

solarflyer22 · Sun Nov 08, 2015 5:42 pm

Quoting cedarjet (Reply 13):
Btw the repair to the tail strike took THREE MONTHS, that is a serious amount of repair.

For structural damage being repaired by Airbus France, that's not a long time. It was probably just queued waiting.

Quoting cedarjet (Reply 13):
I thought it was said in the previous thread that the damaged section wasn't repaired but replaced?

I didn't read that but seems like it would be even less likely to be fatigue then.

Quoting mandala499 (Reply 10):
Bomb theorists can talk about bombs all they want but these parts, literally "stinks" of structural failure due to fatige.

It doesn't. I've been up front a center with planes under repair and you realize pretty quickly the skin is just a wrapper around the body. The internal frame is very sturdy.

The plane wasn't under a high G load at the time. It's just reaching FL33 with 1G and suddenly the fatigue just blows out the back? The pock marking on the door interior isn't a good sign either.

The fatigue wouldn't be hard to identify for investigators either. They'd see the metal cracking and shearing pretty quickly.

The aux fuel tanks in the back (if they were installed) are def worth investigating imo.

Quoting eielef (Reply 30):
I have no ideas of explosives, but how big must be a bomb for bringing down a plane? Off course it depends on

Not big. I'd probably design blow out panels to release the pressure. Might save the plane if something detonates.

RedChili · Sun Nov 08, 2015 5:42 pm

Quoting eielef (Reply 30):
Second, if the bomb was send by air-mail, it wouldn't be together with the passenger bags, but on a area of mail (in the cargo area of a plane).

In this case, we can safely rule out airmail and cargo. A charter flight normally does not carry mail and cargo, and I suspect that the flow of mail from Sinai to Petersburg is anyway quite miniscule.
.

MD11Engineer · Sun Nov 08, 2015 5:54 pm

Quoting JetBuddy (Reply 34):
Yep. I suspect a small charge tore a hole in the pressure vessel in some manner, causing things to be sucked out of the cabin. Complete panic. Also explains the terrible fact that the baby was found 33 km before the rest of the debris. The small hole then gradually expands until the whole tail rips off. Sounds really bad.

No, I rather think that the explosion ripped open part of the fuselage skin and caused cracks, and the airloads did the rest. The tail ripped off and the forward part of the fuselage with the wings, now very nose heavy, dived to earth.
You have to understand that the acting of a high explosive is very much like a sledge hammer. The explosive molecules don't get their activation energy to start their decomposition through heat, but through mechanical shock through a pressure wave running through the explosive at multiple times the speed of sound (in PETN or RDX up to 8000 meters per second). The resulting gases leave the explosive at the same speed. They hit everything around it, including the air like a massive hammer blow.
Let's put it like this:
Put 500 gramms of black powder, a typical low explosive, on a brick and light it. There will be a hiss, a flash and lots of smoke. The brick will be scorched, but else not damaged. If you put the black powder into a container, it will burn (a bit faster as the pressure and temperature increases) and eventually the gas pressure will cause the container to burst.

Take 50 gramms of a high explosive, e.g. PETN and detonate it on top of a brick, with no cover, there will be a sharp crack, like a whip, and the brick will be smashed to bits.

https://www.youtube.com/watch?v=eMYEPQ_5eHw

(Semtex 1A is a plastic explosive using PETN as the explosive content and some rubber / wax compounds to turn the white powder of PETN into something like modelling clay).

Jan

eielef · Sun Nov 08, 2015 8:35 pm

Quoting MD11Engineer (Reply 39):
Take 50 gramms of a high explosive, e.g. PETN and detonate it on top of a brick, with no cover, there will be a sharp crack, like a whip, and the brick will be smashed to bits.

https://www.youtube.com/watch?v=eMYEPQ_5eHw

Was there any chance that an explosive like this was between the luggage or the cargo of this plane?
If a crack like the one shown on the video was done to the fuselage at FL330 I think, because of the des-presurization, it can bring the plane down. But it does matter where it is situated. If it was inside a piece of luggage, which is between many others, inside some times a sealed container, it may create damage between the luggage but I don't think it can bring the plane down.
Plus, as seen in the video, we need some fire to light it up. Maybe an electronic detonator. Will it be easy to get it through security? I don't believe Egypt is a country when you can brive someone for 20USD. Maybe it could happen in Somalia, or Libya, or Sudan, but Egypt, and specially the three main airports (CAI, HRG and SSH) i think they are stricter with its personal. But there is so much sophistication with bombs, that i'm surprised that this PETN can cause so much damage. If a terrorist traveling with a child carries it, security personal at the airport could believe it's Play-Doh (children modelling clay) and maybe they can allow the passenger to board the plane! He might have a lighter for his cigarettes and a potential catastrophe could happen...

pvjin · Sun Nov 08, 2015 8:57 pm

Quoting eielef (Reply 40):
Plus, as seen in the video, we need some fire to light it up. Maybe an electronic detonator. Will it be easy to get it through security? I don't believe Egypt is a country when you can brive someone for 20USD. Maybe it could happen in Somalia, or Libya, or Sudan, but Egypt, and specially the three main airports (CAI, HRG and SSH) i think they are stricter with its personal.

Maybe not for 20USD, but what about 20 000? ISIS doesn't lack money:

http://www.businessinsider.com/isis-...ichest-terrorist-group-2014-8?IR=T

Besides, who says there couldn't have been an ISIS sympathizer among the airport personnel? Even if there wasn't it's really not very realistic to believe airport security anywhere would be that effective, and based on information available Sharm El Sheikh certainly wasn't even up to western security standards.

lancelot07 · Sun Nov 08, 2015 9:08 pm

Quoting eielef (Reply 40):
Was there any chance that an explosive like this was between the luggage or the cargo of this plane?

Cargo - no. As far as we know, the plane did not carry any cargo. But luggage is a prime suspect.

Quoting eielef (Reply 40):
If it was inside a piece of luggage, which is between many others, inside some times a sealed container, it may create damage between the luggage but I don't think it can bring the plane down.

A normal container will not help. You would need a specially reinforced container that can contain or at least signifikantly dampen an explosion - if the bomb was inside and not in the galley, the lavatory or some other space.

Quoting eielef (Reply 40):
Will it be easy to get it through security? I don't believe Egypt is a country when you can brive someone for 20USD. Maybe it could happen in Somalia, or Libya, or Sudan, but Egypt, and specially the three main airports (CAI, HRG and SSH) i think they are stricter with its personal.

You will need a detonator, yes. A good old time bomb will do.
There are reports from passengers that they were offered to bypass security controls for a little bakshish. But it is highly unlikely that a passenger smuggled the bomb on board (Russians and Westerners don't usually bomb their own plane), it is far more likely that one of the staff at the airport did it. (Arabs are well known lovers of bombs, happens almost daily on the ground in some ME-country)

solarflyer22 · Sun Nov 08, 2015 9:09 pm

CNN reporting US officials are 99% certain it was a bomb that broke apart the plane.

http://www.cnn.com/2015/11/08/middle...plane-crash-egypt-sinai/index.html

GlenP · Sun Nov 08, 2015 9:18 pm

One only needs to remember that the FBI was certain TWA 800 was brought down by a bomb, & that proved to be wide of the mark.

The problem is that every item being reported by the news agencies today appears to be coming from either anonymous sources or agencies that are not directly connected to the investigation.

Following yesterday's briefing, by the head of the investigating committee changed from, basically, we're still investigating many possible causes but here are some of the things we've learned so far, such as the noise on the CVR, became, it's almost certainly a bomb, when reported on the BBC news.

a318 · Sun Nov 08, 2015 10:01 pm

is there a possibility that this could have been loaded into the catering at the rear of the aircraft? Not sure how this flight is catered - lots of charter companies load all catering on in the originating city, but perhaps they received more in Egypt?

RedChili · Sun Nov 08, 2015 11:50 pm

Quoting eielef (Reply 40):
If a terrorist traveling with a child carries it, security personal at the airport could believe it's Play-Doh (children modelling clay) and maybe they can allow the passenger to board the plane!

It was a charter plane, with Russian package tourists that had been on a vacation in Sharm, and they were on their way back home. Very, very unlikely that any of the passengers were behind the suspected bomb.

shortstack81 · Mon Nov 09, 2015 1:35 am

I'm kind of with mandala499 here. I don't discount the bomb but it would not surprise me at all if metal fatigue caused this disaster.

BoeingVista · Mon Nov 09, 2015 1:52 am

Quoting ltbewr (Reply 36):
Is that true and can be verified ?

Metrojet's maintenence program shows that MSN 663, EI-ETJ had ACT fitted, quite possible if near empty and breached it could became another exploding pressure vessel maybe accounting for the tail apparantly being popped off.

2175301 · Mon Nov 09, 2015 2:59 am

Quoting eielef (Reply 40):
If it was inside a piece of luggage, which is between many others, inside some times a sealed container, it may create damage between the luggage but I don't think it can bring the plane down.

PanAm 103's bomb was in a piece of luggage, and by volume was about the size of 3 golf balls squished together. The 747 almost instantly broke into 5 major pieces according to radar tracking.

So, a fairly small bomb inside luggage most certainly can bring a modern airliner down. My personal estimate (I used to work with C4 frequently) is that about a half of a golf ball amount of modern plastic explosive (RDX or PETN based) is enough to do crash an aircraft unless is is perfectly placed in the airplane such that it is in the middle of a very large volume (like the center of the cabin). Even that might do the trick if there is any noticeable fatigue.

Have a great day,

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