HELRAS or the Helicopter Long Range Active Sonar is a

naval helicopter A military helicopter is a helicopter that is either specifically built or converted for use by military forces. A military helicopter's mission is a function of its design or conversion. The most common use of military helicopters is transport ...

undersea sensor, a dipping

sonar Sonar (sound navigation and ranging or sonic navigation and ranging) is a technique that uses sound propagation (usually underwater, as in submarine navigation) to navigation, navigate, measure distances (ranging), communicate with or detect o ...

(a form of

towed array sonar A towed array sonar is a system of hydrophones towed behind a submarine or a surface ship on a cable. Trailing the hydrophones behind the vessel, on a cable that can be kilometers long, keeps the array's sensors away from the ship's own noise sour ...

), deployed by

helicopter A helicopter is a type of rotorcraft in which lift and thrust are supplied by horizontally spinning rotors. This allows the helicopter to take off and land vertically, to hover, and to fly forward, backward and laterally. These attributes ...

s of many

naval air forces Commander, Naval Air Forces ( COMNAVAIRFOR, and CNAF; and dual-hatted as Commander, Naval Air Force, Pacific, and COMNAVAIRPAC) is the aviation Type Commander (TYCOM) for all United States Navy naval aviation units. Type Commanders are in Admini ...

around the world to detect

submarine A submarine (or sub) is a watercraft capable of independent operation underwater. It differs from a submersible, which has more limited underwater capability. The term is also sometimes used historically or colloquially to refer to remotely op ...

s; it is a form of

geophysical MASINT Geophysical MASINT is a branch of Measurement and Signature Intelligence (MASINT) that involves phenomena transmitted through the earth (ground, water, atmosphere) and manmade structures including emitted or reflected sounds, pressure waves, vibra ...

History

HELRAS was first developed in the 1970s by Bendix, FIAR and

British Aerospace British Aerospace plc (BAe) was a British aircraft, munitions and defence-systems manufacturer. Its head office was at Warwick House in the Farnborough Aerospace Centre in Farnborough, Hampshire. Formed in 1977, in 1999 it purchased Marconi ...

. Another rival system was called FLASH (Folding Light Acoustic System for Helicopters). In the 1980s, the system was supplied by Bendix. A competitor of HELRAS is the

Low Frequency Active Sonar Sonar (sound navigation and ranging or sonic navigation and ranging) is a technique that uses sound propagation (usually underwater, as in submarine navigation) to navigate, measure distances (ranging), communicate with or detect objects on or ...

(LFAS).

Capability

It can detect submarines up to 60NM.

Manufacture

Parts for the system are made by

Rolls-Royce North America Rolls-Royce North America, Inc. is a subsidiary of multinational corporation Rolls-Royce plc. The American unit operates under a Special Security Arrangement which allows it to work independently on some of the most sensitive United States def ...

Deployment

The system has been fitted to EH101, S70B, NH90, CH-148, AS532SC, AB412, and AS565 with helicopter of navies such as Italy, Turkey, Greece, Netherlands, Canada, Singapore, Thailand, Chile, Brazil, Indonesia, and Morocco. The system has also been fitted to unmanned surface vessels Seagull and RHIBs for Israel and USN.

References

Anti-submarine warfare Helicopter components Military sonar equipment of the United States {{navy-stub

History

Capability

Manufacture

Deployment

See also

References