January 5, 2013:
The U.S. Navy has ordered another 48 AN/AQS-22 Airborne Low-Frequency Sonar (ALFS) systems for its anti-submarine helicopters. This model operates at higher and lower frequencies than existing sonars, providing the ability to cover four times as much area. The 272 kg (599 pounds) AN/AQS-22 operates in active (broadcasting) and passive (just listening) mode and can rapidly switch frequencies. This is a dipping sonar, which is lowered into the water from the helicopter using an 806 meter (2,500 foot) cable and winch. Overall, the AN/AQS-22 is a big improvement for navy helicopter anti-submarine capabilities and has been very successful at detecting submarines at sea. The navy will not comment on just how successful, especially against diesel-electric subs when submerged and running silently on batteries. Apparently this system is a big improvement over older models. AN/AQS-22 is a joint venture between American (Raytheon) and European (Thales) manufacturers.
The AN/AQS-22 is normally carried by the U.S. Navy's MH-60R anti-submarine helicopter, which is a navalized version of the army UH-60. The crew spends a lot of time just operating their computers, sonar, and radar in their search for submarines. This work involves staring at a screen most of the time, while manipulating the sensors and computers to detect and locate subs. Once you have a solid location fix, you can launch a torpedo and sink the enemy vessel.
The MH-60R is also equipped with a radar system for detecting subs on the surface or just beneath the surface (with only the periscope or snorkel, which provides air for the diesel engine and gets rid of the exhaust fumes). The sonar system consists of a dipping sonar and sonobuoys that are dropped and communicate wirelessly.