There are reports this morning that some of the wreckage has been located. They're speculating that the aircraft did not break up in flight.
They didn't say at what depth wreckage is, other than the robot subs have been diving to over 13,000'. At that depth, the pressure is nearly 400 times atmospheric pressure, or over 5,800 psi. I imagine that the chances are not good that the flight and data records could withstand that kind of pressure for nearly two years.
On the other hand, they are supposed to be rated to 20,000' depth, which is over 600 atm or 8,900 psi, so there might be enough margin. But I doubt if those specifications are for a two year survivability.
Cat Pawtector!
2 hours ago
3 comments:
Electronics intended for immersion is potted -- that is, liquid expoxy is injected into the case and hardens, basically turning it into a solid block of expoxy with connector pins sticking out (and incidentally rendering it unrepairable and when the 5 year battery reaches its rated life the whole thing must be replaced as a unit, but that's a feature, not a flaw, to the folks who make these things -- it keeps the market for new ones going). The connector pins are gold-plated to prevent corrosion. Epoxy doesn't care how long it's at depth. These new jets have digital voice recorders, there's no actual tape recorder and no tape to ruin. If the epoxy "block" didn't crack when it hit the water, it should still be intact whether underwater for 2 hours or 2 decades. The real question is whether they can actually find it, since the battery for the transponder ran out long ago. They're almost literally looking for a rock in an ocean here... the only chance they have of finding it is if the cockpit remained intact enough that it's still in that wreckage, but given the speed at which the jet hit the water, that seems unlikely.
- Badtux the Electronics Engineer Penguin
If it hit in a flat spin, the vertical speed is nothing compared to cruise speed-- maybe 90MPH.
Right, I was thinking more of the cruise speed, not the vertical speed, and was not thinking about a flat spin. Hit water at 300+mph and water is pretty much a solid, it's like smashing into a mountain -- not much of the cockpit is going to be left. Maybe enough that the black boxes survived, like I said they're solid blocks of epoxy inside some rather rugged casing, they're *tough*. But I'll have to see it to believe it.
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