New Delhi: Amid continued forays by Chinese submarines into the Indian Ocean, the Indian Navy will soon get a new set of American-made sonobuoys, a deal cleared during Defence Minister Rajnath Singh’s four-day visit to the US last week.
The US announced that the State Department approved the sale of sonobuoys–a critical expendable system for anti-submarine warfare–for an estimated cost of $52.8 million to the Indian Navy which will be deployable from MH-60R helicopters.
While India already operates the American sonobuoys from the P-8I maritime surveillance and anti-submarine warfare aircraft, the fresh deal is for the MH-60 Romeo helicopters, also procured from the US.
The sonobuoys are a mix of active and passive capabilities, and are expendable, meaning they are meant for use only once.
Use of sonobuoys would make these aircraft more potent in carrying out anti-submarine warfare as they raise the probability of detection of enemy submarines.
There are three types of sonobuoys the Indian Navy is procuring: AN/SSQ-53G high-altitude anti-submarine warfare (HAASW) sonobuoys, the AN/SSQ-62F HAASW and the AN/SSQ-36.
What are sonobuoys
Sonobuoys are expendable, electro-mechanical acoustic sensors that relay underwater sounds emitted from ships and submarines.
They remain active for about 24 hours and help in detection, classification and prosecution of adversarial ships and submarines. A naval helicopter or fixed-wing aircraft generally drops sonobuoys in a pattern.
They are dropped in canisters and are deployed automatically upon impact with water.
An inflatable system with a radio transmitter remains on the surface for communication with the ship or aircraft tracking it while sensors descend below the surface to predetermined depth.
It then relays acoustic information back to those monitoring them. A group of sonobuoys deployed in a pattern can find out the exact location of the submarine which then can be tracked by other systems.
Some sonobuoys are designed to be deployed in passive mode and some in active mode. Active sonobuoys emit sound energy and receive the echo, based on which it transmits information back to the aircraft. Passive sonobuoys, on the other hand, only listen for sounds coming from ships or submarines. They then transmit the sound back to the aircraft.
(Edited by Tikli Basu)