The first key fact, which addresses something I've been wondering about, is that once the 30-day specified duration of the pinger is reached, it's expected to die very quickly. It's a feature of the lithium batteries used. That's in a week's time.
The submarine (or autonomous underwater vehicle - AUV) it turns out is a pretty capable beast. It's untethered, has sonar and camera, and an acoustic link to transmit the sonar and video images to the surface in realtime. Crucially, the most advanced version is rated to 4,500m (15,000ft) depth which is what we're potentially talking about in the crash area. (Earlier ones to 3,000m)
Full details and pictures below.
Air France 447 Search Effort: Phase II Fact Sheet
June 24, 2009
C & C Technologies, Inc. (C & C) has received inquiries regarding our discussions with the French BEA on the second phase of the AF447 search effort.
The following information may help minimize communication errors:
1) Pinger Life: Dukane, the AF447 pinger manufacturer, has confirmed that the pingers may only last a day or so longer than the specified thirty days. Unlike regular flashlight batteries that fade out slowly, the battery technology used in the pingers will hold its voltage for the thirty days, and then quickly collapse along with the transmitted signal.
2) Contact by BEA: The French BEA has contacted C & C by phone and e-mail regarding use of C & C's 4,500 meter (15,000 feet) rated autonomous underwater vehicle (AUV) to perform a sonar search for the flight recorders. C & C has two 250 foot (76 meter) ships near the crash area equipped with state-of-theart AUV systems. However, the AUVs on those vessels are only rated for 3,000 meters (10,000 feet), and the wreck area approaches 4,500 meters. If the pingers are not found by the end of June, French authorities may ask C & C to send its 4,500 meter rated AUV to Brazil to search the mountainous underwater terrain.
3) Comments Regarding BEA's Actions: While the first phase of the search for the flight recorders continues, the BEA is making contingency plans for a second phase. Tapping C & C's world-renowned deepwater AUV search capability indicates the French authorities' commitment to locate the recorders and solve the mystery. Given the complexity of the situation, the BEA is making all the right moves.
4) AUV Description: Like the unmanned drone aircraft used by the military, AUVs are unmanned, untethered, computer controlled underwater vehicles. C & C's 4,500 meter rated vehicle is capable of searching large areas while flying at a constant height off the ocean bottom at four knots for two days at a time before returning to the surface to refuel.
The 6 meter (20 foot) cigar shaped vehicle has an acoustic communications link (wireless underwater telemetry system) that can continuously transmit the sonar images to a surface ship in real time. Any debris detected by the AUV can be seen by observers on the ship in real time. The AUV also has a camera, so ambiguous sonar contacts can be quickly identified.
Because there is no cable between the AUV and the ship, the AUV can travel more than twice the speed of ROVs (remotely operated vehicles), which are tethered. C & C's 4,500 meter rated AUV with mother ship and experienced scientific crew offers the highest possibility of flight recorder location if the current pinger locator effort fails. Pictures and video of the AUV can be found at:! ftp://ftp.cctechnol.com/pub/outgoing/auv.zip
5) C & C's Background: C & C is the worldwide leader in deepwater AUV operations. The company has performed more deepwater AUV searches than any company in the world, having surveyed enough to encircle the globe four times. C & C's AUVs are usually used to perform deepwater oilfield surveys worldwide. C & C has 600 employees and operates worldwide.An interesting white paper on the use of the AUV here.
And here's what it looks like: