U.S. hardware designed to help with that task arrived Wednesday in Perth, the western Australian city that is the base for the search efforts.
The United States sent a Bluefin-21 autonomous underwater vehicle, which can search for submerged objects at depths as low as 14,700 feet (about 4,500 meters), and a TPL-25, a giant listening device that can help pinpoint the location of pings from the flight data recorder. Towed behind a ship, the TPL-25 can detect pings at a maximum depth of 20,000 feet (about 6,100 meters).
-From Above CNN Article
Great!, looks like NTSB is as baffled as I am regarding no worthwhile debris from crash of a fully loaded giant aircraft.
Ian W
You really have no sense of scale - in a post way back at the beginning of the thread the problem was described as looking for a green grain of sugar in Central Park.
The search area has not ballooned it has simply moved around based on drifting models as mentioned by AMSA briefings. The area if anything has become narrower, a fact you can verify by looking at daily search maps published by AMSA on its media site. From the initial area given to them by NTSB, AMSA has essentially factored in only drifting models and satellite sightings. None of these searches have been fruitful. In any case it defies logic that while search area is become narrower, yet there have been zero debris sightings.