Twenty passengers on missing flight 370 worked for Freescale Semiconductors

[mikeselectricstuff]

There is a 37.5KHz carrier and a 1Hz repetition rate.

https://www.youtube.com/watch?feature=player_detailpage&v=mQehX0rVYuY#t=225

[pickle9000]

@Mike

The best doorstop ever!!

[pickle9000]

So 300 nautical miles between the two pings. That's extremely far for a device that has an operating range of under 10 miles. So assuming one is bad I guess they will drag a listening device between the two points. I would be inclined to think that the origin of the ping would be closer to the Chinese ship. They probably have less sophisticated equipment (less range) and made 2 contacts one being 90 seconds. I'm not sure about the Australian contact. I'd really like to see what the signals looks like.   

[pickle9000]

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?

[pickle9000]

Looks like a solid signal

From the handout

The Australian navy's Ocean Shield, picked up two separate signals within a remote patch of the Indian Ocean far off the west Australian coast.

The first signal lasted two hours and 20 minutes before it was lost. The ship then turned around and picked up a signal again - this time recording two distinct "pinger returns" that lasted 13 minutes.

"Significantly, this would be consistent with transmissions from both the flight data recorder and the cockpit voice recorder,"

The position of the noise needs to be further refined, and then an underwater autonomous vehicle can be sent in to investigate.

[peter-h]

That Chinese "discovery" from the inflatable boat is rigged. The gear they have is not good enough by a factor of 10 to pick up the signal. No idea why they did such a stupid stunt.

It will be amazing if they find the aircraft in one piece. I am betting on it - by far the simplest explanation, though very unsavoury.

[stitch]

   It's difficult to believe that luck or skill accounts for how the Chinese managed to drop their detector right on top of the wreckage (if that is what has happened).  Maybe the Chinese knew exactly where to look.
    Maybe one night their radar picked up an unidentified aircraft heading into the middle of the Indian Ocean in the middle of the night.  Maybe a sight like that caught their attention but they didn't make the connection between the aircraft they were watching and Malaysia 370 - and why would they?  When the news about Malaysia 370 broke, it was reportedly headed north toward  Beijing.  Maybe the Chinese  continued to watch the unidentified aircraft until it went down.  Only after new data pointed the search to the south did they put "two and two together" and realize that what they had been watching days before was 370.  Maybe by then it was too late for the Chinese to say anything about what they had seen because people would blame them for not making the connection sooner.

[pickle9000]

Rather than is being unusual the simple answer is normally the best. Either they caught a weird signal bounce or found surface wreckage. In either case it makes no difference as long as it leads to the site. The same holds for any and all theories, they are often incorrect but may allow you to develop or eliminate another. 

[EEVblog]

The Chinese detection is unlikely to be BS or false, as it's just way too coincidental that the Aussie ship found a solid signal with 300nm of there. That's on top of the luck of having been in the right place to begin with.

[Kjelt]

The signal seems to have stopped according to the latest reports 
Last week I read that the batterypack was going to be replaced this summer as standard maintenance so it was at its end of commercial life.

[EEVblog]

The signal seems to have stopped according to the latest reports 

Cue the conspiracy theorists even more. Signal conveniently stops just as they are getting close to recovery, but been there long enough to make everyone confident that's where the plane ended up.
Seems bad luck that both would have died at the same time. Could just be thermal layers etc playing silly buggers again, probably a good chance one or both are still active.

[pickle9000]

I'd have to say the searchers have done awesome so far, not to mention crazy lucky. I bet you could ask any one of them and they'd say "I"ll take what we have".

[pickle9000]

Looks like they reacquired the signals. Canadian news CBC.

http://www.cbc.ca/news/world/malaysia-airlines-mh370-underwater-pings-relocated-1.2603564

[TheBorg]

 
Really hoping they will zero in on this.
Still, it's pretty crazy that they've gotten this far. I mean, the amount of data they had to extrapolate, and trawling hundreds of thousands of square miles is no easy task, combined with the sheer improbabilities of finding a jet in the middle of a gigantic ocean...  To even find the tracking signal is pretty crazy.

[pickle9000]

Apparently they are spending over 2 million USD daily (all countries combined). 

I can imagine the pinger manufacturer is looking for some old stock batteries (that match the ones on the plane), rechecking current draws just to make sure the numbers are as good as they can be. I'd love to see a behind the scenes documentary on this.

[EEVblog]

Looks like they reacquired the signals.

Sweet.
Odds are they would have I'd thought.
As much a I like unsolved mysteries, the truth can be stranger than fiction. Hope they find and can recover it.

[Kjelt]

Apparently they are spending over 2 million USD daily (all countries combined).   

Well maybe when they find the plane it lies above the Flor do Mar and they break even 

The fortune on board was said to be enormous, making the Flor do Mar the most sought after lost shipwreck in history. The ship is said to have carried the treasure of the Melaka kingdom, located in modern day Malaysia, which reportedly included more than sixty tons of gold.

[mikeselectricstuff]

Apparently they are spending over 2 million USD daily (all countries combined). 

I can imagine the pinger manufacturer is looking for some old stock batteries (that match the ones on the plane), rechecking current draws just to make sure the numbers are as good as they can be. I'd love to see a behind the scenes documentary on this.

Hard to model as it will be dependent on temperature amongst other things. I would assume there is a FAA or whatever spec on required minimum lifetime, and one would hope that any manufacturer would add significant margin to that.

[EEVblog]

Hard to model as it will be dependent on temperature amongst other things. I would assume there is a FAA or whatever spec on required minimum lifetime, and one would hope that any manufacturer would add significant margin to that.

For our underwater stuff (sonarbuoys, ocean bottom recorders, + others, military and civilian) we had to characterise the battery life over various storage/transport temperature cycles, and then again with operations temperatures ranges. And non of this accelerated testing stuff, if it was a months battery life, we'd run groups of them for a month under the real loads.
Then on top of that you'd have vibration as well, and there are standards for for aircraft, trucks etc. Not to mention different suppliers, and batch differences.
So it's very complex business if you take it serious, remember that batteries like this get hot and cold cycles and vibrated during transport as well as operation. .e.g parts of the the back deck of a seismic boat in the hot sun could get to 60C+, and then the ocean can be below freezing due to the salt water. And all that before they get used.

[Psi]

I'd love to see a behind the scenes documentary on this.

you can be sure it will end up on air crash investigation eventually

[mikeselectricstuff]

And non of this accelerated testing stuff, if it was a months battery life, we'd run groups of them for a month under the real loads.

The problem with something like this is that shelf life is also a very important issue, which is somewhat  less practical to do non-accelerated testing for.

[pickle9000]

- When it comes to the batteries, both the manufacturer of the cells and the pinger would have an interest. Both in estimating the expected life and death of the cells. It's a rare opportunity to do these kind of estimates. I would bet both have requests in to obtain the cells (perhaps jointly) to get the data.
- "Air Crash Investigation" (Mayday in Canada) probably has people on location already, made in Canada series.
- The spec after the Air France crash was 30 days pinger operation at specified range and 2 years battery life. No requirement for operation past that but it noted that the old pingers would often run on for 3-7 days at reduced output levels. This may have been an early spec.
 

[mikeselectricstuff]

Random semi-related question - when there's a high-profile crash, do they change the flight number for future schedules?
( I was actually  on the previous week's AF447 )

[pickle9000]

Yes they do.

http://en.wikipedia.org/wiki/Flight_number

[rollatorwieltje]

How accurately can they actually locate the wreck based on those pings? Would they actually know it when they pass straight over it?
A quick look at the map shows that it's at least 3km deep at the search location, same as the Titanic wreck. That ship was only found because it left a large debris field with huge parts that could be seen by a camera. Sonar didn't really work for them. They also had a reasonably accurate (compared to this plane) position, the position sent by the radio operator was "only" 30km out. The search area for this plane is orders of magnitude bigger, the plane itself is much smaller and likely didn't leave lots of large debris. Maybe it will be found in 80 years, just like the Titanic