Twenty passengers on missing flight 370 worked for Freescale Semiconductors

[EEVblog]

What if................
they flew so low (under radar) and made a belly landing on the sea, so no crash just plain landing on the sea, would there still be debris or would it just sink to the ocean floor?

Well, that's actually a possibility if the auto-pilot ghost plane theory is true.
I'm of the understanding that an autopiloted plane will do a half decent job to keep a plane in the air as the fuel runs out in each engine, sacrificing height for speed to keep it going until it eventually glides into the ocean?

[Wytnucls]

While that is true, the speed will be close to 180kts, with no slats or flaps extended, at a glide angle of 3 degrees or more. So the impact would still be severe and the plane would break up.

[Codemonkey]

According to a 777 pilot on the pprune forums, he ran that scenario on a simulator which resulted in the autopilot disengaging when power was lost after both engines cut out and before the RAT could kick in. The plane then performed a series of "phugoid" oscillations (nose down till speed picked up, followed by the nose raising for a while until speed died down. He suggested it was very unlikely that the plane would have landed smoothly, rather he implied that the rate of descent during the downward parts of the oscillation was such that disintegration would be inevitable on impact with the water.

(500+ pages of some really interesting postings from pilots, and crap from conspiracy theorist nut jobs can be found here http://www.pprune.org/rumours-news/535538-malaysian-airlines-mh370-contact-lost.html )

[Wytnucls]

We don't know if it was, but if the APU had been started during the initial emergency, the autopilot might not drop out.

[HackedFridgeMagnet]

Why doesn't the auto pilot attempt a smooth landing?

Like the Hudson River birdstrike landing.

[Wytnucls]

Because it needs an ILS runway guidance and the autopilot has to be set in auto land mode. It may not even engage in that mode, with reduced electrical power, when the engines are off.
Many system conditions have to be fulfilled first and that's not going to happen with a 250 ton glider over the sea.

[rollatorwieltje]

Why doesn't the auto pilot attempt a smooth landing?

Like the Hudson River birdstrike landing.

That was flown manually, and it was a textbook ditching under perfect conditions. But even that severely damaged the plane. It sank within a day.

Be aware that the touchdown speed of these airplanes is well above 200kmh, even if you do it smoothly the deceleration and stress on the airframe will be huge. Hitting a wave would be like hitting a brick wall.

[HackedFridgeMagnet]

I can understand that it would currently be nigh impossible, but it does seem like something to aim for.

I mean why use power to try to keep a plane up till the last second, that is eventually going to fail at some stage anyway.
When you could save a bit of that energy, you have power if you have autopilot, and get the landing speed and angle of attack as nears possible to optimum as you approach the sea.

Then hope for the best. (ps excuse my ignorance on this subject.)

[mikeselectricstuff]

What if................
they flew so low (under radar) and made a belly landing on the sea, so no crash just plain landing on the sea, would there still be debris or would it just sink to the ocean floor?

I suspect the stall speed is high enough that the margin between "belly landing" and "flip over and break up" is vanishingly small. Water is not much different to concrete at any significant speed.
And if it had made a belly landing and stayed intact, would it have ever sunk?
 

[pickle9000]

I wonder why they didn't sent in HMS Echo to do a sonar sweep first, to get at least a broad picture of what is down there, then send the sub.

The Echo was searching around the Chinese signal, as was the sub.

[pickle9000]

Bluefin cycle

The submarine takes 24 hours to complete each mission: two hours to dive to the bottom, 16 hours to search the seafloor, two hours to return to the surface, and four hours to download the data.

Oil slick

Here is a map, the oil slick is said to be 5.5km North of the last ping detected.

[Towger]

So, now we have discovered that the water is over 4,500m deep and the Bluefin 21 may have been damaged.
What's next in the arsenal of tools? 

BTW, I see the Glomar Explorer is back operation, am sure TerraHertz can fill us in on its capabilities 

[Wytnucls]

There is very little oil on an aeroplane. Some 20 liters per engine and some 50 liters of hydraulic fluid. Fuel tanks would have been close to empty. Most of it would have dissipated by now, unfortunately.

[pickle9000]

- I was thinking hydraulic fluid. If nothing else the proximity is correct.

- The bluefin just did a "return to surface" because it passed it's depth limit setpoint. It's capable of another 150+ meters according to the US Military. Even if it was damaged they have another one on site.

[Towger]

I assume the Bluefin is set to track the sea floor at a preprogrammed height.
Any idea what that is? I assume it is easy to raise it, at the cost of range / resolution.

[pickle9000]

50 meters above seabed.

[Towger]

If the deep areas are random valleys, I assume it could be programmed not to exceed 4500 and keep going, mapping their locations for later investigation.

[pickle9000]

My understanding is that the US military (who owns the device) is willing to allow it go another 150 meters deep if needed and that will still allow a small safety margin.

The first day was probably more of a systems check than anything. Having the unit come up early is probably good from that point of view.

I would be interested to see what the initial search pattern will be. Will they make a north south run up the middle looking for a field and perhaps an east west? You would think that would be the quickest. To cover the entire search area should be 25-30 days. Much less if debris is found.

[SeanB]

Probably they will do a drunkards walk and survey patches in an area then move to another random point in the search area, that way they can use side scan sonar during the move to get a more detailed image of the sea floor and possibly detect interesting areas to search later. They will likely find any large pieces along with a lot of dropped containers and other rocky outcroppings.

[PedroDaGr8]

This does not inspire confidence, note the power supply.

Here is the actual news story, the reporter shown at the end looks totally lost. There are two vids on the page the one I am referring to is half way down and is names what's inside a black box.

http://time.com/50937/black-box-signal-australia-malaysia-airlines/

Here is the confidence builder. It's about 30 seconds in. Dave recognize the brandname?

Csb time: about two years ago receiving at work opened up a box and inside was a "black box" that looked exactly like that one. Turns out UPS screwed up and delivered that too us instead of Lufthansa in Germany. Took them almost two weeks to pick it back up. I'm guessing it wasn't urgent. We all made jokes about some FAA investigation delayed because the black box ended up at a biotech firm.
</csb>

[TheBorg]

Turns out the oil slick is unrelated...
http://www.usatoday.com/story/news/world/2014/04/17/malaysia-ocean-bluefin-airline/7808643/

[mikeselectricstuff]

This story is ringing my Snake Oil alarm - detecting elements from Sat imagary....?
Breakthrough or Woo Woo?
Even the name "http://georesonance.com/ screams pseudoscience

https://au.news.yahoo.com/sa/a/23036893/exploration-company-believes-it-may-have-found-mh370/

[tom66]

Modern day dowsers.

[Kjelt]

Maybe, but isn,t it worth to take a look? It would mean the flight did not go south but stayed on west course.

[CaptnYellowShirt]

Remember what TWA 800 looked like after they collected all the bits?




Now compare that to this...




Planes typically have wings before they crash.