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MH17 down near Donetsk

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MH17 down near Donetsk

Old 14th Aug 2014, 11:58
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katSLF wrote:
Oh and another thing -- in decompressions where the plane remained intact and flyable, there always were PILOTS left to fly it and controls left to take their commands. Here the pilots and the avionics were the first to go.

This is not always the case. TWA800 and Hughes Airwest 709 remained in one piece while the cockpit was gone. In fact, the investigators of Pan Am 103 (lockerby) had poblems to explain why the rear section broke up in many pieces. So they said that broken cables gave last seconds imput etc during cockpit section separation. The 777 has no cable steering in that sense, so the steering surfaces would end in a locked beutral position.
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Old 14th Aug 2014, 12:22
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SAMPUBLIUS wrote
crude example- at 60 mph, put your hand out the window. face palm down like an airplane wing. Now twist palm 90 degrees so palm faces forward.

feel the difference ? Now multiply that force by 8 to 10 and thats for a small area of say 25 square inches. Now multiply that by say 800 for a approx body diameter closed tube into the ' wind "

In addition, plane losing control may dive or nose up or twist or turn

Forces above 3 to 4 g would exceed max design overload - ultimate - in a few seconds or less.


The concept of airodynamic drag is known to me. Don't forget that the pressure at 33000 feet is only 1/5th of ground pressure.

The lockerby report concluded also that the pressure on the back section even as an open tube would not cause the structure to fail.

In your terms: The issue is how the hand changed from horizontal to vertical.
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Old 14th Aug 2014, 13:11
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Blackbird69 said

The lockerby report concluded also that the pressure on the back section even as an open tube would not cause the structure to fail.
Simple pressure probably won't cause complete structural failure - though there are quite a few accidents where differential pressure has caused an ultimate failure of the aircraft or significant damage. Examples are

Turkish Airlines Flight 981 - lost cargo door
American Airline Flight 96 - lost cargo door

On similar major incidents to MH17, the disruptive event caused immediate separation of part of the aircraft and subsequent disintegration of the rest due to aerodynamic overloads.

PA-103 (Lockerbie)
TWA-800 ( US)

Incidentally, in both of the above incidents, the main part of the aircraft continued flying until ground impact or detachment of wings etc.

MH17 appears to have done the same thing with late detachment of the tail after loss of the cockpit and 1st class cabin early on.
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Old 14th Aug 2014, 14:26
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Mahatma Kote wrote:

Simple pressure probably won't cause complete structural failure - though there are quite a few accidents where differential pressure has caused an ultimate failure of the aircraft or significant damage. Examples are

Turkish Airlines Flight 981 - lost cargo door
American Airline Flight 96 - lost cargo door

These accident clearly came to my mind. But remember that regulations have changed after these accidents because the cabin floor of the DC-10 was considered too weak. Both planes stayed intact. AA 96 landed safely. For completeness I mention United Air 811, also landed safely, after loosing forward cargo door (And that is a large door).


Mahatma Kote wrote:
On similar major incidents to MH17, the disruptive event caused immediate separation of part of the aircraft and subsequent disintegration of the rest due to aerodynamic overloads.


This is suspected, but not explained - which is exactly my point.

Mahatma Kote wrote:
PA-103 (Lockerbie)
TWA-800 ( US)

Incidentally, in both of the above incidents, the main part of the aircraft continued flying until ground impact or detachment of wings etc.

MH17 appears to have done the same thing with late detachment of the tail after loss of the cockpit and 1st class cabin early on.

PA 103 main part disintegrated on high altitude.
TWA800 main part disintegrated on impact.

Clearly not the same. Only other plane to disintegrate on high altitude is china airlines 611. That took 10 - 15 s.

Differences between TWA800 and PA103:
TWA800: 18000 feet, no damage to engines or tail during separation.
PA 103: 31000 feet. During separation the front section folded to the right and hit the nr 3 engine, which was detached. Also debris damaged both horizontal stabilizers.
One strange thing about the break up is that 3 of the landing gears and wheel wells and the aft cargo hold stayed together. Strange because the 747 likes to break just after the body landing gear wheel well (SQ0600, klm tenerife and others).

From MH17 evidence so far it looks most likely that the missile exploded in front of the left side of the cockpit. It caused the aircraft skin to blacken and deform by the blast, next to numerous holes in the skin, probably all cockpit windows destroyed, killing crew and ravaging avionics. Result decompression (doubt if this is explosive decompression. Calculations show so far it still took several seconds before cabin pressure was gone).

And then what?
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Old 14th Aug 2014, 16:33
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Originally Posted by Green Guard
any news or rumors about...when the red boxes will be read out and published ?
The team's efforts will initially focus on the report of preliminary findings, which the Dutch Safety Board aims to publish in a few weeks' time.
Dutch Safety Board | Investigations & Publication | Investigation crash MH17, 17 July 2014
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Old 15th Aug 2014, 13:47
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By blackbird69: "Result decompression (doubt if this is explosive decompression. Calculations show so far it still took several seconds before cabin pressure was gone)."
Where are you getting this from? Doesn't make sense to me and at the moment there doesn't seem to be enough information to do these "calculations"?!
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Old 15th Aug 2014, 18:47
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The shrapnel is preceded by a blast wave travelling around say mach 4. This is very high pressure, so for a moment there is higher pressure outside, so it doesn't decompress. Then the wave passes, it decompresses by rolling and curling back the panels along the perforations. It does not need to be explosive to rip up the cabin, because of the shrapnel holes. Twisting, banking, awing, diving, parts ripping of, port engine ingesting its own fan.... a lot of G forces in a lot of directions it was never designed for ....enough to break along ALL the section join lines. Fast or slow,who really will ever know? but there's only 2 or 3 seconds difference between the two speeds, so its moot.
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Old 15th Aug 2014, 20:20
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If you want to see what happens when a SAM explodes near an aircraft look at this clip.

Nike Missile Destroys B-29 Bomber | Military.com

around 2.10 the missile hits. The destruction is immediate and the aircraft rotation tells its own story.
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Old 16th Aug 2014, 05:19
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777 cable steering

The 777 has no cable steering in that sense,
Not quite true. The 777 while normally FBW does have minimal cable backup for minimally suffficient flight control when everything else goes bonkers. But in this case, cables would not have made much difference re the final result .
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Old 17th Aug 2014, 15:46
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@blackbird69:
Thanks. In the investigation of Korean 007 they did actually use such calculations to estimate initial damage to the fuselage! wikipedia/KE007
It would seem MH17 took more of a direct hit and initial damage would have been greater? Comparable to that in other similar major decompression accidents ?
Either way the plane was probably doomed after the initial hit and we will have to wait for the investigation to know a bit more.
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Old 18th Aug 2014, 23:34
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1978 wrote:
Thanks. In the investigation of Korean 007 they did actually use such calculations to estimate initial damage to the fuselage! wikipedia/KE007
It would seem MH17 took more of a direct hit and initial damage would have been greater? Comparable to that in other similar major decompression accidents ?


KAL007 was hit by a R-98 AAM, 40 kg fragmentation. The surface of the hole(s) is surprisingly small. Maybe it hit the cabin after the pressure bulkhead.

MH17 was hit by a larger warhead. The cockpit was immediately evacuated, and there could have been large stress on the two bulkheads between cockpit and cabin.
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Old 18th Aug 2014, 23:47
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anonymousdefender wrote

Quote:
LE MISSILE A EXPLOSÉ DERRIÈRE LE SIÈGE 5A
Fow anyone who dont know french what talking about this source?
If something hit a plane near seat No 5A then Seeker and Fuse can continue fly after detonation of warhead (which hit by multiple strike elements a cabin).
Then it another fact about launch site Snezhnoe.


The seat plan of malaysian Airlines 777-200 can be found here:
SeatGuru Seat Map Malaysia Airlines Boeing 777-200 (772)

Seat 5A is on the first row after the L2 door.
https://www.flickr.com/photos/jeroen...57645908125941
This is the L2 door including one window after it. No sign of missile impact here.

I don't know why PM thinks the missile entered here. The only reason I can imagine is that the forward section including cockpit has a length just very close to this door. This piece of wreckage is puzzling because it is bend so severely especially near the floor, that I suspect the forward section folded here to the left before it broke away.

So far for the 5A missile hit
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Old 19th Aug 2014, 01:25
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Is the seat number written on the actual seat??

I never understood where Paris Match got the Seat 5A from. They WERE on the scene before the bodies were removed, and saw a badly injured woman;s body, still in her seat, from the business class setion. But I don't know where they get 5A from.
The section in the image you linked has 3 or 4 small holes high up in the roof area, about level with the front edge of the door (visible in other images). Nothing else. The bending you see happened on ground impact.

The section in front of that door is missing, or fell flat and is covered in other debris. It is not possible to guess at what shrapnel damage is on it. But going on what is on the cockpit, this are must have received some damage, too, and people sitting near here may have been hit. This would be rows 1 to 4.
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Old 19th Aug 2014, 10:51
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What is the exact status of the wreckage, have the crash investigators been able to visit regularly, have any key bits of wreckage been removed and secured (ie the cockpit area).

if not is anyone there 24/7 observing/securing the various sites, it seems to have gone very quiet.
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Old 19th Aug 2014, 11:02
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It's a war zone.

Latest map:
http://mediarnbo.org/wp-content/uplo...4/08/19-08.jpg
Red explosion icons - battlezones;
Orange explosion with broken plane icon - the crash site.
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Old 19th Aug 2014, 13:37
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Ta yep a war zone, but that still doesn't tell me if anyone has taken responsibility to secure the crash sites.
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Old 19th Aug 2014, 15:55
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Isn´t it time to get some press release from the Netherlands?
Preliminary autopsy results (shrapnel found in bodies)?
Preliminary seat asignment of the bodies recovered and missing?
Preliminary CVR analysis?
Preliminary ATC recording analysis?

Are there really no facts available by now to base further discussion on?
Compared to other accidents there is a lot of silence currently.
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Old 19th Aug 2014, 16:00
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Compared to other accidents there is a lot of silence currently.
Since this must be a criminal investigation as well as a crash investigation, I would say that there are very good reasons to keep things out of the public domain for the present at least.
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Old 19th Aug 2014, 17:40
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Compared to other accidents there is a lot of silence currently.
Generally, early information releases during crash investigations are either to:
a) indicate that the initial findings are that there is not an unsafe condition that could affect other aircraft or
b) there is a potential unsafe condition and they recommend steps to alleviate the safety concerns (inspections, etc.)
In this case, there is pretty universal agreement that the airplane was shot down. So there isn't much justification for early information release simply to alleviate potential safety concerns.
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Old 19th Aug 2014, 18:39
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The recovery teams with the sniffer dogs had to go, there was no point sticking round, as there was to much fighting in the area. They hope they got a piece of everyone but they know there's some who may never be found.
The plan was to send investigators after the recovery was done. They haven't said, but if they had any sense they would have picked up and kept smaller pieces that looked potentially useful.

I had a picture last week of the burn field where the engines fell. The 8 - 12 inches fine broken small rubble they were standing on has been cleared, and they're on almost bare earth now. Guess the farmer wants his field back. Maybe they're dumping the bits into big drums, for lack of anything better to do, then they can be shipped back.

That port engine is worth bringing back. It is the most likely piece to have collected shrapnel that would still be there. In thinner bits it would have gone through and fallen out. They only need 1 or 2 to analyse. It is no likely to show who pushed the button .
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