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How can a plane be crashed vertically without breaking up beforehand due to aerodynamic forces?

here

I reckon the only way to do it in a 777 would be to fly slowly, say 200kt, at low level, say 300ft, and do a very fast 90 degree bank and a spiral dive.

Administrator
Shoreham EGKA, United Kingdom

A few airliners are said to have gone supersonic without breaking up so I don’t see why the vertical entry should be particularly difficult. I’m sceptical that the fuselage wouldn’t break up as it hit the water though. I can’t read most of the document.

Any reasonable person would assume the best way to avoid this would be to land flat, as slowly as possible, even if that’s not the case. So unless a hijacker was a world-class physicist I don’t see why they would choose to do this. I suppose they could have other motives such as oblivion within the briefest possible moment.

Yes – the PDF seems corrupted. I found a good version of it (the usual technique of googling on an unusual phrase from it, in double quotes) and have put it here together with the movies referred to in the document (which are dropbox links so sure to vanish eventually).

It does seem amazing that they reckon the deceleration during the water entry could be only 6g. I am not a mathematician but it does seem to have been done impressively well.

(give the above stuff another 4hrs to upload)

Administrator
Shoreham EGKA, United Kingdom

Concerning MH370, it is hard to believe that not one shred of the airplane has been found …

FAA A&P/IA
LFPN

I haven’t read/viewed it all yet, but it looks interesting, thanks for posting.

It does seem amazing that they reckon the deceleration during the water entry could be only 6g. I am not a mathematician but it does seem to have been done impressively well.

The 6G is ball-park plausible: it will bring a 170 kt object to rest in about 60m, which is roughly the length of the aircraft.

And as they go on to say: “But the magnitude of decelerations could be far greater if the speed at ditching is large.”

White Waltham EGLM, United Kingdom

While it’s an interesting theory – it is only a theory. One of many. I am very sure that they simply have ot found the plane because the ocean is too big and the plane is too small. A 777 is not even a “needle in a haystack”, it’s smaller than a grain of dust in a gigantic ocean ..

Flyer59 wrote:

A 777 is not even a “needle in a haystack”, it’s smaller than a grain of dust in a gigantic ocean ..

True, but after enough time, some bits are bound to be found floating or washed on shore.

FAA A&P/IA
LFPN

Eventually, one day, a piece, or more, will be found. Reminds me of the huge German freighter “Munich” that one day disappeared in the Atlantic Ocean – almost without a trace. I think that only some life vests and one lifeboat were found. And that was a +250 meter ship!

Reminds me of the huge German freighter “Munich” that one day disappeared in the Atlantic Ocean – almost without a trace. I think that only some life vests and one lifeboat were found. And that was a +250 meter ship!

I recall seeing a TV documentary where it said that every year some dozen(s) of freighters disappear without trace. There is a particular class of bulk carrier which tends to break in half in rough seas and sinks within seconds. With 3rd World crews, it doesn’t make the news, and there is no money in searching for them, it was claimed. The hulls on the old ones are 20mm and rust takes 0.5mm per year. A few years ago I spoke to somebody in the industry and he said this really is a problem.

The 6G is ball-park plausible: it will bring a 170 kt object to rest in about 60m, which is roughly the length of the aircraft.

The bit I struggle with is that you would still surely get a disintegration of the hull, and something would come floating out. But maybe not, and these people clearly put a lot of thought into that.

Anyway, it’s clearly impossible at the end of a Vne++ spiral dive, which is what you would get if both engines flame out due to lack of fuel. The autopilot disconnects when the 2nd one runs out, AIUI. But if the pilot (or whoever it was) wanted the plane to not be found, this appears to be a viable explanation.

Administrator
Shoreham EGKA, United Kingdom

I think they argue it the other way round:

If there is no debris, and if our theory is the reason, then the vertical dive version is the most likely. (Bayes’ Theroem, more or less).

I have absolutely no idea what happened to MH370, but my gut feel also says there was (or even is) some floating debris, we just haven’t looked in the right place yet.

And whatever the cause, it clearly happens so seldom that we are unlikely to even imagine it before we get some more evidence.

Last Edited by DavidS at 14 Jun 16:12
White Waltham EGLM, United Kingdom
28 Posts
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