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Farnborough 2010: A question of sonobuoys
The US Navy is reviewing its use of sonobuoys, which have for decades been one of the key tools of navy helicopter submarine hunters.
During the Cold War thousands of the devices were dropped into the sea in the cat and mouse game of hunting Soviet submarines.
However the new advanced dipping sonars, such as the AQS-22 Airborne Low Frequency Sonar (ALFS), being used on the new MH-60R Seahawk are proving so effective, that the US Navy are thinking of reducing the number of sonobuoys carried or eliminating the feature altogether.
Captain Dean Peters, the US Navy's programme manager on the MH-60R, told journalists at the Farnborough International Air Show that the ALFS system had demonstrated the ability to detect targets at up to seven times the distance that the current generation of sonars in use is able to.
Currently the MH-60R is able to carry 24 sonobuoys - the devices are ejected from a panel on the port side of the aircraft.
Peters said: 'We are studying the option of carrying less sonobuoys, perhaps six on a trapeze launcher, as this would save weight and space, both very valuable commodities on a helicopter.'
Before the MH-60R, the Seahawk was retained for what was known as the 'inner ring' anti-submarine warfare (ASW) work, sanitising the water around the aircraft carrier or fleet flag ship.
Now with their improved sonar the MH-60R can take over the 'medium ring' while helicopters operating from other surface combatants can flush out submarines in the outer ring, because of the detection ranges possible.
This goes some way to justifying the navy's decision to retire the S-3 Viking carrierborne ASW aircraft as part of its ongoing ‘Hornetisation’ of the fleet.
However, with the introduction of the MH-60R and the MH-60S utility helicopter the numbers of helicopters on the carrier are set to be strengthened.
Currently, an air wing will put to see around six or seven Seahawks for SAR and ASW but new plans will see carriers putting to sea with 10 or 11 MH-60s, with up to six 'Sierras' and five 'Romeos' to meet higher demands for rotary wing assets.
This does not spell the end for the sonobuoy, however, and they will continue to be essential for fixed wing ASW platforms, particularly the P-8 Poseidon when it enters service in the coming years.
In May, Rotorhub.com reported that the Netherlands Navy had been testing the dipping sonar on their new NH-90 NFHs and achieved detection ranges nearly 10 times further than what was capable using their old Lynx.
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