China's Search Vessel Picks up Pulse Signal in South Indian Ocean

China is heavily involvement in this search as most of the passengers [~150 of 230] were Chinese.

These same tow sensors and underwater autonomous vehicles are used for submarine hunting. Guess which country has a large number of nuclear submarines? US does. Its expected China would try search for our subs.

I'm not sure you can generalize that. It was a Chinese agency that "mistakenly" posted those misleading satellite images, while the U.S. was the first to draw a connection between satellite data and the Indian Ocean as a possible crash area.

There have been mistakes, false leads, and promising revelations across the board.

The Chinese also spotted debris on satellite imagery (on an area that had been thoroughly searched) as well as a "sea floor event" (a week after the claimed event) in the South China Sea. I wouldn't jump to the conclusion that this newest finding is an instance of effectiveness just yet.

edit: whoops, 'peeters posted just as I did

Odd to get downvoted for suggesting this is interesting.

1) If China feels it necessary to fabricate sightings in order to mollify its population (also note the way it has tried to manage the bereaved families and focus their anger on Malaysia including providing coordinated t-shirts etc.) then that's interesting.

2) If China, not usually noted as outstanding in air, naval, or orbital surveillance capability is able to outperform Australia (which is both very experienced with ocean searches and is operating on its doorstep) and the US then that's interesting.

3) If China is more willing to reveal its capabilities than the US or Australia that's also interesting. (E.g. I suspect the reason the Australians were so willing to commit to the current search area based on one satellite image is because they actually tracked the flight via Jindalee, but were unwilling to reveal that system's capabilities given there weren't going to be any survivors.)

I assume this search is coordinated and everyone knows the area one ship can cover. That way the same area isn’t examined twice. Wouldn’t it then be simply up to luck as to who finds something?

You can always argue about who sent the most ships and who covered the most ground, but some nation’s ships finding this is not direct evidence for this. I would assume it would be better to determine this directly, not indirectly.

Is the Chinese search part of the Australia-led search effort (i.e. the Chinese vessels are searching areas they are being tasked), or are they doing their own independent search?

How effective have they been? So far China has found absolutely nothing.

If anything, they have been overly enthusiastic to quickly report partial results based on incomplete or bad analysis, which then turned out to be nothing at all.

That's just post hoc fallacy. There are a lot of vessels searching from a lot of different countries. Whoever gets lucky is going to seem more effective, but luck is probably a majority factor in this case, given the size of the search area.

Maybe it's an accelerating frequency, like a chirp? :)

I think they're referring to the fact that it sends the pulse once per second. Could have been worded differently.

Yep, but they did get it right a little further down the article.

But what is the monitor an acoustic wave--isn't it a radio signal?

30 days is not by any means a firm deadline for the blackboxes. They are designed to last a minimum of 30 days and usually do last a lot longer.

I wonder if they could fit them with auxiliary saltwater batteries. So they have N days of power from the main battery, then an additional M days if they land in the sea. Given that it takes a lot longer to find crash sites at sea, that's the main place they need extra energy.

That said, i have absolutely no idea if a saltwater battery actually has a higher energy density than some other kind of battery. Probably not.

If it separated from the plane and floated, it could be sunlight powered.

It's hard to design for outlier data. This is the most unusual search in modern aviation history. It is the outlier. With a couple of exceptions, all crash zones are found within days.

What makes you think that increasing the battery by a couple of months will deal with the next extraordinary case? What you're suggesting isn't even an order of magnitude more, though 30 days is already a couple of orders of magnitude more than what is needed 98% of the time.

Hindsight is 20/20.

There already are such regulations on the way. The European Aviation Safety Agency and the FAA are both likely to start airlines switching over to 90 day batteries within a year or two. The EASA is also looking at increasing the range of the locator ping (by adding an additional lower frequency pinger for planes that do long trans-oceanic flights, I think), and extending the voice recording time from 2 hours to 15 hours - perhaps the FAA is planning something similar.

http://www.flightglobal.com/news/articles/mh370-loss-coincid...

http://www.newscientist.com/article/mg22229634.500-five-ways...

Ok great idea philosopher king, let's make the regulation to demand 90 days ping endurance.

Just one caveat, make sure you open your checkbook for this one, not the rest of us who don't want to pay for yet another trivial feature creep crap every time we buy a flight ticket.

You're just patching a specific bug by adding a special case for it. That's no way to engineer anything. Also, you use the typical fallacy of a fix being just a minor bit of work. If it was low cost and easy to do it'd be done already. Batteries are big and heavy. Increasing the size and weight of the black box is a tricky proposition because it would make it more vulnerable to damage, so you'd need to re-engineer the whole thing to make it stronger. That would make it much heavier and much larger than it's been. And because of such major engineering changes you have to completely redo every aspect of testing. Then you have to begin manufacturing new ones and replacing them in every single plane out there. And every single plane now needs to be extensively retrofitted and updated.

Your assumption is false. There have been a few notable cases of flight-over-water crashes in which the correct zone wasn't found quickly, but in the case of flight 137, ships were over the presumed crash zone within hours of the aircraft turning up missing.

In other cases, particularly where the crash itself was visually observed (US Airways 1549, Ethiopian 961, and others) where a multi-day delay in starting pingers would have been counterproductive.

It's also useful to realize that any change you make on flight recorders applies to all equipment, needs to be replace on existing aircraft, and concerns a system which has to work with very high reliability.

Yes

"The pulse signal with a frequency of 37.5 kHz is the standard beacon frequency for both so-called black boxes -- the cockpit voice recorder and the flight data recorder, CNN quotes Anish Patel, president of pinger manufacturer Dukane Seacom, as saying. "They're identical.""

yes, http://en.wikipedia.org/wiki/Underwater_locator_beacon