After a Monday announcement by Malaysian authorities said the missing Flight 370 almost certainly crashed in the Indian Ocean, the U.S. Navy deployed its high-tech “tow fish” to search for the Boeing 777’s remains in the ocean’s 23,000-foot depths.
“Basically, this super-sensitive hydrophone gets towed behind a commercial vessel very slowly and listens for black box pings,” U.S. 7th Fleet Operations Officer Commander Chris Budde said in a Wired report.
Towed Pinger Locator 25, or tow fish, is a 70-pound hydrodynamic microphone capable of picking up acoustic signals from a jet’s cockpit data and voice recorders in depths down to 20,000 feet, and is quite possibly the best chance of finding the plane’s “black box” and discovering what went wrong aboard Flight 370.
The Royal Australian Navy Rescue Support ship “Seahorse Standard” will carry two of the Navy’s tow fish through the search area west of Perth, Australia — a remote area of the Indian Ocean close to virtually nothing, and now popularly described as one of the worst places to lose an aircraft.
Seahorse Standard will drag the tow fish through 150 miles square miles of ocean daily at about 3 knots from a 20,000-foot cable, keeping it about 1,000 feet above the sea floor to listen for the location transponder signals from the black box and voice recorder. Tow fish can hear a signal between 3.5 and 50 kHz within a two-mile radius, while most transponders emit at a frequency of 37.5 kHz.
The device was used in the search of other major airline crashes including TWA Flight 800 off the coast of New York in 1996, and Air France Flight 447 in the Atlantic Ocean in 2009.
Though the search effort has condensed considerably down from more than 2 million square miles to 35,400 as a result new satellite data tracking Flight 370’s last location ping, satellite photos of the area showing suspected debris have yet to lead to any tangible evidence.
Add to that the ocean’s currents and the rate at which debris could have spread in the two weeks-plus since the flight went missing on March 8 from Kuala Lumpur to Beijing, and you have what could still be a very long search.
“We’ve used it for just about any aircraft that’s gone down,” U.S. Navy Supervisor of Salvage and Diving Mike Dean told Wired. “There’s an awful lot of ocean to cover.”