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Dillon

Malaysian Flight 370

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Surely "tail down" requires a controlled landing attitude? With nobody controlling the plane, would it not just glide down? In other words, nose first?

Unmanned airplanes don't glide very well.  Took all the skill of a very experienced Capt. Sullenberger to drop his airplane onto the flat calm waters of the Hudson River.

A descending, out of fuel, airplane under control of auto pilot would likely see AP disconnect when it no longer met AP parameters such as speed / altitude etc

january

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If the plane ran out of fuel with everyone unconscious, it is highly unlikely that it suffered a "tail strike" impact with the ocean.

 

I disagree - if the aircraft AP was running VNAV or in ALT HOLD, it would have tried to maintain altitude as long as possible.  IF that altitude was low, and it's unlikely the aircraft engines would've have flamed out simultaneously, the aircraft would've lost power and possibly gradually descended until the other engine flamed out or until impact.  In this scenario, the aircraft angle of attack would've been higher than level flight IMO.  


2014-1-3_22-52-44-860.jpg

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Surely "tail down" requires a controlled landing attitude? With nobody controlling the plane, would it not just glide down? In other words, nose first?

If it was a 'controlled' ditching then it would be nose high on contact with the water. As there has been no wreckage or bodies it's difficult to say exactly where the a/c went down. It's quite possible everyone was strapped in and the a/c broke up on contact and sank so quickly no one could get out. i.e. they all drowned in their seats.


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Super VC10 into LOWI with PF3 at a cinema near you

https://www.youtube.com/watch?v=298UDyNmgUA

 

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It is possible it was soft landed and not out of fuel yet, due to the current search area being shorter compared to the original search area that was based on the distance it would fly until it ran out of fuel. They did change the original search area because it crashed sooner then originally thought.


Matthew Kane

 

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As there has been no wreckage or bodies it's difficult to say exactly where the a/c went down.

 

Bloomberg News reports Bluefin 21 has completed its 7th dive to the bottom with no apparent result.

8th dive underway, with now 50% of the target area covered.

One has to wonder if perhaps MH370 may be somewhere else?

january

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One has to wonder if perhaps MH370 may be somewhere else?

 

Bluefin is using a side scan sonar as its principle survey tool. I do not know what frequency that side scan is set to use, but I would assume 100 Khz. If you are not familiar with a SSS, think of it as a headlight that shines out a narrow beam of light. Any objects in front of that beam are "illuminated" and return a bit of that light. What gives definition to the object that is illuminated is the shadow that lies behind the object, where the return from beam is missing. Add digitization and processing and you get a 2 D plan view of the ocean bottom. More processing and manipulation and you can view a somewhat 3 D image.

 

See this image: http://www.l-3mps.com/Klein/image/gallery/gallery_new/DornierFullrez-350.jpg

 

http://www.l-3mps.com/Klein/image/gallery/gallery_new/gal_raa_new.jpg

 

The height off of the seafloor that Bluefin must hold is dependent on the frequency of the SSS and the speed of its travel. Bluefin appears to be plowing along at about the speed of a person walking or 3 to 4 knots. That means that greater resolution is possible with higher frequencies if they can get closer to the seafloor. 15,000 feet is just beyond Bluefin's normal maximum operating depth. That difference could be critical in "seeing" the debris field.

 

BUT... most importantly, detection of the debris field is subject to seafloor topography. If the aircraft debris fell into a valley, along the side of an escarpment, or in an area with substantial elevation changes in short distances, Bluefin could miss the field entirely.

 

Here is an article worth reading: http://defensetech.org/2014/04/18/navys-bluefin-21-drone-dives-for-mh370/

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Very informative- thanks Tom.

BBC News reports today that Bluefin 21 is now two-thirds completed of its search for MH370. Ninth mission to start Monday.

january

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 Re the possibility of MH370 being hit by a meteoroid- the following is from Discover magazine - June 2009 - in reference to the Air France crash in the south Atlantic and a detailed analysis of the possibility of a meteor hit.

 

"Anyway the meteor idea is not crazy, though not likely. The weather seems more likely to be at the root of the tragedy…but we may never know. One thing, though, is clear: if we keep flying big planes at high altitude, eventually one will get hit by a meteor."

 

The little that is known about MH370 seems to fit such a scenario. 

january

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The little that is known about MH370 seems to fit such a scenario.

 

Except that a strike of an aircraft at altitude would not explain the absence of sea surface evidence - in fact, it would argue that it should be all over the place. Remember TWA 800? It was an explosion (you pick your favorite cause) and it left a surface debris field that was breathtaking, albeit closer to shore. Never the less, had a mid-air strike occurred, there would have been sea surface evidence of it IMHO.

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Remember TWA 800? It was an explosion (you pick your favorite cause) and it left a surface debris field that was breathtaking,

 

 Yes - quite true for TWA 800, which blew up while airborne. 

But suppose a meteoroid the size of a bullet (or smaller) went thru the equipment bay and a fuel tank without physically exploding & destroying the aircraft. 

 

The result might be instant depressurization, loss of all instrumentation and a jet of flaming JP4 as the fuel was instantly sucked out by the atmosphere at FL350. This latter was reported at the time by a worker on an oil platform offshore from Vietnam in the S China Sea, who thought it was a plane going down.

 

In this scenario, the crew would don masks and likely attempt to turn back toward Kuala Lumpur for an emerg landing. They would be relying solely on the mag compass- probably in a dark cockpit with no com capability- all instrumentation having been destroyed in the equipment bay. Easy to get lost out over the Andaman Sea. A last ditch try might be to unsuccessfully use one's own cellphone to contact ground. 

 

Being totally lost at night over the ocean with NO instrumentation, would explain the strange course plotted by satellite. Perhaps the idea may have been the old tactic of travelling in a straight line until you find something you can identify. At some point emerg oxygen would run out and all souls aboard would die IF the aircraft was at altitude.

How its final moments evolved without the 777 breaking up on contact with the sea, is for someone else to rationalize.

But then again, this "Flying Dutchman", may yet be found to be somewhere else.

january

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Yes - quite true for TWA 800, which blew up while airborne.

 

Well, I can't top your imagination, that is for sure. However, have you ever witnessed explosive decompression? It ain't pretty and I doubt that a "clean" decent without debris would result.

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However, have you ever witnessed explosive decompression? It ain't pretty and I doubt that a "clean" decent without debris would result.

 

Only seen on TV-  as in a chamber teaching students use of oxy masks in the event of sudden decomp. Done by perforation of a diaphragm in wall of the chamber.

----------------

Consider however that the hole could be very small- perhaps size of a BB pellet..

At a meteoroid speed of say 40+ km/second, it could punch a very nice and small hole, leading to non explosive decomp. In other words a big leak rather than explosion! 

Scientists at U of Adelaide estimate that earth intercepts DAILY about 19,000 meteoroids weighing over 3.5 oz.

(apparently, most burn up in the denser atmosphere below 40,000 ft - Wilbur & Orville were most likely not especially concerned by THAT risk!)

january

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If one want to have a "serious" discussion about an extremely unlikely event such as a meteorite impact, then it opens up the door to all and every unlikely theory.  Maybe rats chewed through the wiring bundles.  Maybe a deadly snake got loose on the flight deck, stung the pilots, and then the strange flight path was the result of involuntary muscle spasms.  Maybe they hit a large Indonesian Bullfrog that had been taken skyward by a waterspout.  All of these things are equally plausible, and for the sake of argument, could actually be what happened! But, clearly, January, you seem to be convinced that the meteorite thing must be what happened, based on little more than it's novelty, but what I'm saying is that it stretches the discussion into the realm of ridiculous speculation of unlikelihoods.


 

At a meteoroid speed of say 40+ km/second, it could punch a very nice and small hole, leading to non explosive decomp. In other words a big leak rather than explosion! 

 

 

I doubt a small hole would hardly cause anything to happen to the cabin altitude, unless it ripped open and became a much bigger hole.  The outflow valve would just close a tiny bit. 

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If one want to have a "serious" discussion about an extremely unlikely event such as a meteorite impact,

You just said the magic phrase- "an extremely unlikely event" !!!

Remember the truism- If something CAN happen, sooner or later it will !

One would sure hope that the investigators of MH370 will not ignore possibilities that are "unlikely".

january

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Well, I agree on the premise that whatever happened to MH370 is the result of an extremely unlikely event, and probably even an unlikely chain of unlikely events, as most accidents are.  I just don't understand why you're pressing the meteorite case so hard, as if it's the best working theory so far.   There is nothing to even hint that that's the cause of all this, so why spend so much time concentrating on this, instead of the possiblity of deadly black tarantulas?

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