Plane Crash in Egypt - 224 Dead

[HJ1an]

U.S. AND BRITISH OFFICIALS are now saying, at least tentatively, that an explosive device may have downed the Kogalymavia Airbus over the Sinai peninsula last weekend. The thinking is that the local Sinai affiliate of the Islamic State group, better known as ISIS, placed a bomb on board the A321 prior to its departure from the Red Sea resort of Sharm-el-Sheikh.

http://www.askthepilot.com/airbus-crash-in-egypt/

[jwocky]

@KL-666: I have to admit to my guilt, I used the word "impact" in lieu of a better one. As you know, I am no native speaker in English, so sometimes vocabulary leaves me just a blank to pull.

[jwocky]

Okay okay, the "bomb theory" ... I had a few minutes to read over what they say. Everything started with some guy in BBC who claimed, the plane broke up forward of the rear passenger door and therefore also forward of the pressure bulkhead. So he placed his theory on an explosive device forward of those points which means luggage compartment or in the passenger compartment above it.
Now, I haven't checked the credentials of this TV expert and not every TV expert or otherwise media expert is inherently inept in any subject, but one has to make one point clear here (and yes, I have my own experiences on that subject): The "experts" rarely have time to follow the latest news form five minutes ago somewhere posted, the journalists have their little helpers for that. So you are often confronted with some piece of info coming form the journalist and have to figure how it fits in what you know. The crux is, those last minute pieces of information are sometimes not correct because they come second or even third hand, are incomplete or the sources are more than dubious.

So I looked over the pictures once more. And if you look, the aft bulkhead, the pressure bulkhead, is intact. The tail part broke off after the bulkhead. Which places any hypothetical explosive device behind the bulkhead and that is a compartment, where no passenger would have had access. That's where the APU sits.
The other point in question is to me still the sink rate. 5000-6000 fps is not free fall, it is steep glide or descent. A plane that gets ripped in two pieces in 31,000 ft does three things:

- at least one of the aprts goes down with the usual gravitational acceleration of 9.81 m/s2. Which means, latest in the 3rd minute after the break up, this part is at roughly 8500fpm and 21,000 ft. The secedn curve would look for this part like a parable, not the constant linear descent we saw for example in FlightAware. The other part, the one with engines still running for a few seconds or even till the part hits the ground, would make some erratic changes of the descent rate, depending on the motions of this part around it's x, y and z axis. So it would be at one time 300ß fpm, at the next moment 7000 fpm then again only 4000 fpm for example. But over the fall, the numbers would increase as well, and so, in a system taking data only all few seconds, it would appear as a shallower parable, but also not as this straight linear descent from the radar trackers.

- Since the plane breaks up in high altitude, there are explosive decompression and two big holes, the one of the forward part at the end and the one at the rear part facing forward. The effects of explosive decompression would in split seconds suck everything lose out of those two big holes and rip seat out of their anchors and people out of their seats. The result would be a debris field like for example Lockerbie - big, almost elliptical in shape if you put it in a map with a spread of remains and debris basically determined by weight/surface rates of the objects in which realtive big but light objects like bodies have a higher probability to be found in the forward part of the debris field. What we have instead in this case is a relative discrete field and the passengers were according to the first reports, mostly still strapped in their seats. Additionally, some phots showed an almost linear spread of luggage pieces, which also indicate, the luggage compartment didn't break up high in the air (then luggage would be all over the place).

- The hull of the fuselage consists basically of relative thin aluminium sheets and a lot of isolation material in between. In case of explosive decompression due to a widely compromised hull, this construction disintegrates because the light weight isolation is also sucked out, the aluminun sheets collapse between the support spans and pieces break out of the frame. If yu look at the rear part in the photos, the remains of the cockpit and the rear end of the forward piece (the forward piece is almost the whole fuselage in this case), do you see any sqaure shape hull skin break outs? I don't.

KL-666 said something interesting: The parts are laying bottom-up in the photos. But still, the cockpit part and the part with the pressure bulkhead look to me almost perfectly rounded. Now, if a body hits the ground at high speed, and be the angle as shallow as 2 degrees only, I would expect deformation. It's often harder to see if the plane parts are bottom-down because the lower side of planes is constructed a little flatter in many models, but in this case, the rounder upper side is on the ground. A similair effect happens on the wings. At high speed, the leading edges would hit any obstacle with enormous force and therefore not only cause the wings to break off but also to deform. The wings broke off but I don't see too much general deformation. That makes me think, the speed of the forward part was relative low at the time it reached the ground and since this big piece of the plane is still together, it hit nose forward, not down, kind of belly landing style. The problem is, I saw what appears to be always the same wing in several photos but not the other one or parts of it. If I am not mistaken, it was always the right wing. So where is the left one? To flip over the bigger part of the plane without totally deforming all the remaining bigger parts of the fuselage, the speed had to be low, one wing had to strike ground or an obstacle and partially disintegrate in the process and then, the other wing could break off underside up, slide a bit around and comes to a halt gearbox up.

Bottom line is: I see nothing, that makes me really think bomb. I can be wrong, of course, but to prove, there was a bomb, we would have to wait for lab results on chemical residue on the debris. A good lab can determine, whether there was a bomb explosion and what explosive was used by the burn residue but that takes a little time and since those "officials" speaking of bombs can't have those results yet, they can't know for sure. Technically impossible. Thus, they do the same thing as everybody, they speculate. Only their speculations will always include a political convenience element.

[HOM001]

Well, the Russians and Egyptians seem to agree with you jwocky.
https://www.washingtonpost.com/world/ru ... story.html

[HJ1an]

Well from the aerial view it would seem like the wreck pancaked into the ground while spinning slowly. I did not look through the entire wreck field, and have no idea where the tail is relative to the main parts, but I am assuming based on other images that the tail landed quite a distance away from the main wreck. Interestingly enough, I didn't see the elevators in that tail section, although that's just my own observations. It could very well be a few feet away and just wasn't in the picture. I haven't checked the images as much as you guys because I get upset seeing them too much.

The fact that it didn't fall as fast could be attributed to the wings, which are still attached. I am reminded of a video I saw years ago of a US UAV that lost control and went into a vertical spin. It actually pancaked into the ground at a very low speed. Of course in this case, with the tail gone, the immediate nose down and spin would probably tear out the engine pods, and without those weighing it down it might just go into such a tumble, eventually hitting the ground upside down.

[HJ1an]

Oh, wait. Based on the altitude charts, the it actually went upwards sharply at the last moment. Or at least the part that was recording this information went sharply upwards . I didn't realize this before. Now I don't know what to think.

[KL-666]

Please people, try to understand that ads-b data is NOT suitable for inspecting a period of seconds. It is probably accurate over a mean period of minutes. The reason for this is that minimal and incomplete data is sent. The rest is calculated together with previous transmissions. This way a reasonable accurate trajectory over a longer period can be calculated. But individual transmissions mean nothing. Looking at them will show you mad unintelligible spikes. Sadly these spikes are drawn in newspapers as actual data. But afterwards they are always proven as not having happened. (Ads-b data is used by Flightradar24 which is most likely the source of this graph in the Washington Post)

Of the crash site i think the area of the main part will be the least interesting. Sure there was fire, but i believe as a result of tumbling down. Torn of engines can cause a good fuel leak.

The tail part is a few km away, so it fell off somewhere in flight. The big question is: Where is the horizontal stabilizer? Is it close to the tail section, so it came off during the free fall of that section? Or is it far from the tail section, so it came off first and is part of the cause?

Has anyone seen an accurate map of where all the parts came down?

Kind regards Vincent

[jwocky]

Not yet and I can't find any wide angle pictures to figure the position of the parts to each other out on myself. So, as usual, the real interesting details are not in the media.

[legoboyvdlp]

Shall we start a fund to buy you a ticket to Sharm?

[MIG29pilot]

How much of the tail is gone?