Malaysia Airlines loses contact with plane en route to Beijing with 239 aboard

[BrianB]

http://www.washingtonpost.com/busine...71f_story.html

In an age when people assume that any bit of information is just a click away, the thought that a jetliner could simply disappear over the ocean for more than two days is staggering. But Malaysia Airlines Flight MH370 is hardly the first reminder of how big the seas are, and of how agonizing it can be to try to find something lost in them.

Originally Posted by WildaBeast

Like Air France 447... I can't remember of the top of my head how long it took before any wreckage was found from that crash, but it seems like that took days, too.

From this article:

It took two years to find the main wreckage of an Air France jet that plunged into the Atlantic Ocean in 2009.

From the BBC article Richard posted:

The presence of two passengers with stolen passports is a breach of security, but could relate to illegal migration.

Illegal immigration was the very first thing that came to my mind, particularly with the fact they were en route to Europe.

Brian

[kia]

The first small pieces of wreckage from AF447 were spotted within a couple of days. The vertical stabilizer was picked up 5 days after. the first bodies were also found around that time along with items like seats. It took 2 years for the black box to be found.

[snopes]

The modern pace of communications, where GPS features in our cars and smartphones tell us our location at any given moment, has set unreal expectations. “This is not the first time we have had to wait a few days to find the wreckage.”

The article didn't really explain why this is so. Don't airliners have some kind of transponder that would allow them to be tracked wherever they end up? Or at least up to the point of whatever disaster might have destroyed the transponder?

[GenYus234]

Generally, the systems are designed to tell the aircraft where it is in regard to the world rather than tell the world where the aircraft is. And when the world needs to know where the aircraft is, it usually uses its own systems like radar rather than depend on the aircraft to report its position.

Aircraft do have transponders, but they report back a unique identification number and other information when pinged by a radar signal, they don't usually broadcast coordinates continuously.

[DrRocket]

The 777 is a very big aircraft. I don't care from what altitude, or speed it might have crashed from. There would have been SOME kind of debris/luggage/seat cushions/bodies/bouyant airfoil pieces floating around, I would think.

Just makes this total disappearance all the more odd.

Perhaps in the heat of the moment, while below radar, the pilots attempted to change course, resulting in the search parties looking in entirely the wrong area. That's the only possibility I can think of for now.

[Little Pink Pill]

Originally Posted by snopes

Don't airliners have some kind of transponder that would allow them to be tracked wherever they end up?

Flightrader, the company whose system was tracking the flight, explains how it works on their website. It sounds like how well they can track depends on the location of the flight. According to the news report I read, the ADS-B transponder is "the black box."

Flightradar24 has a network of more than 3,000 ADS-B receivers around the world that receives plane and flight information from aircraft with ADS-B transponders and sends this information to our servers. Due to the high frequency used (1090 MHz) the coverage from each receiver is limited to about 250-400 km (150-250 miles) in all directions depending on location. The farther away from the receiver an aircraft is flying, the higher it must fly to be covered by the receiver. The distance limit makes it very hard to get ADS-B coverage over oceans.

They have released some specific information about MH370.

https://www.facebook.com/photo.php?f...type=1&theater

[erwins]

I heard the former chair of the NTSB on the radio today explain that for the Air France flight, they had over 4 minutes of data from the plane after it was clear something had gone wrong on the plane. In this case, they have neither that data nor any point where they became aware that there was a problem while it was still on radar. Instead, they just have its last known position and then whenever it was noticed to be gone from the radar. That's a huge difference. They have to extrapolate its course and then search the whole area where it might have gone down.

He mentioned too something about that they probably extrapolated the most likely area where it could have gone down and then started searching where it was easiest to search.

[Alchemy]

Originally Posted by GenYus234

Aircraft do have transponders, but they report back a unique identification number and other information when pinged by a radar signal, they don't usually broadcast coordinates continuously.

You're referring to (for airliners) Mode S of the transponder, which broadcasts ID, altitude, and some other information only when interrogated by an ATC terrestrial station, which comprises secondary surveillance radar (SSR). And for quite a while this was true; aircraft only identified themselves when pinged by ATC.

Eventually people realized it would be a great safety tool if an aircraft could "ping" all the transponders of all the aircraft in the vicinity; the "pinging" aircraft could use its radionavigation equipment to identify the position of those aircraft and issue alerts when a risk of collision was imminent. Thus was born TCAS.

And, reasonably, once TCAS became common it made sense for aircraft to just broadcast their GPS-determined position, continuously, and this and numerous other position-reporting concepts were rolled into ADS-B.

All this is still about situational awareness and safety, so ADS-B data is nominally reported by radio, rather than satellite uplink. Which is what you want anway; any traffic in your vicinity that you need to know about will be in VHF range. So tracking the flight requires a station actively listening and recording.

About the only way to guarantee flight tracking over regions outside active ATC observation is by periodic reporting of position to some central location via satellite data link, and AFAIK the benefits of this are just not high enough for any authority or company to do this systematically. The satellite datalink protocol ACARS is typically used for clearance and route information with ATC and maintenance information with airliner operations, but these are brief messages made only a few times during the flight.

[erwins]

It was ACARS data that they had for the Air France flight. It was a brief interview--I'm not sure whether they were able to collect that data specifically because they knew there was an emergency on the flight.

[WildaBeast]

IIRC the intended purpose of the Air France ACARS data was just to create a sort of automated maintenance log, a report of stuff that wasn't working right during the last flight for the mechanics to look at when the plane got back to Paris. It just happened to be significant on that flight because it reported a whole lot of stuff in a short period of time, and was the first clue the investigators had to work with as the black boxes were on the bottom of the ocean and weren't found until years later.

[erwins]

Yeah, I just went and read about it. At any rate, he said having a that data was useful for trying to find that plane, and here there's nothing.

[Gibbie]

Originally Posted by DrRocket

The 777 is a very big aircraft. I don't care from what altitude, or speed it might have crashed from. There would have been SOME kind of debris/luggage/seat cushions/bodies/bouyant airfoil pieces floating around, I would think.

Just makes this total disappearance all the more odd.

Perhaps in the heat of the moment, while below radar, the pilots attempted to change course, resulting in the search parties looking in entirely the wrong area. That's the only possibility I can think of for now.

And the Pacific Ocean is a very very large place. I think people underestimate what a needle in a haystack operation this is.

[ganzfeld]

I agree it's a large area to search but, just to be clear, it is not near the Pacific Ocean. It's the Gulf of Thailand or perhaps the South China Sea (which I suppose is technically part of the Pacific but not the part that's very very large).

[DrRocket]

New reports now have authorities shifting focus to the waters on the Western side of Malaysia

[A Turtle Named Mack]

Originally Posted by ganzfeld

I agree it's a large area to search but, just to be clear, it is not near the Pacific Ocean. It's the Gulf of Thailand or perhaps the South China Sea (which I suppose is technically part of the Pacific but not the part that's very very large).

For context that most Americans can understand, the Gulf of Mexico is a little over 600,000 sq. miles (1.6 million sq. kilometers). The Gulf of Thailand is about half that, and the South China Sea is about twice that.

But your point about 'not the whole Pacific' is well-taken, as it is unlikely the plane could have gotten out of the South China Sea area toward the pacific without being picked up by radar from the various countries and military bases ringing the SC Sea.

[Singing in the Drizzle]

What happened to Flight 370? Four scenarios fuel speculation among experts

CNN) -- A Boeing 777, one of the world's most reliable types of airliners, is missing, and no one knows why. Was it a bomb? Mechanical failure? A hijacking gone awry? Pilots and others in the aviation community are deeply disturbed by the mystery surrounding Malaysia Airlines Flight 370.

It disappeared Saturday en route from Kuala Lumpur to Beijing over the Gulf of Thailand, somewhere between Malaysia and Vietnam. It's hard to believe that such huge questions remain three days after the Boeing 777-200ER went missing, carrying 227 passengers and 12 crew members. These questions are so unprecedented that experts have been carefully speculating about possible explanations.

Here are four scenarios they're talking about, and the related facts:

[Richard W]

That article's a bit out of date on the stolen passports - it seems to be confirmed that there's no terrorist link and they were just being used to make it easier for the passengers to get into Germany:

http://www.bbc.co.uk/news/world-asia-26525281

[Ali Infree]

Another theory thrown out last night on the NBC News was a catastrophic decompression and the plane flying on autopilot with unconscious/deceased crew and passenger. Still begs the question of being spotted on radar within its potential 7.5 hours of cruising. A bad Steward Payne scenario.

Ali

[snopes]

Military radar data shows the Malaysia Airlines jet that disappeared last week flew hundreds of miles off course after civilian systems last recorded the plane's location, an official told Malaysian media.

http://www.usatoday.com/story/news/w...ation/6282557/

[Psihala]

If accurate, that would mean the plane flew for about an hour away in the opposite direction of its flight path without communicating to civilian radar or radio communications.

Anecdote is not data and all that, but this isn't entirely unprecedented. Author Martin Caiden wrote of a night flight he was part of to Teterboro, NJ from Florida (I think). All the electronic navigation aids (including the compass, apparently) said they were on course, but the position of the stars indicated they were headed over the ocean.

This isn't likely with a 777, unless the plane's systems were so messed up it didn't have any idea where it was - or they weren't set right. I suppose there's still the possibility of a hijack which might also explain why it could have been going the wrong way.

If nothing else, it could explain why they haven't found any floating debris. It isn't likely that anything the size of a 777 survive a water landing like the Hudson River incident without something coming to the surface eventually.

~Psihala