Black Hawk down near Sydney

A Black Hawk helicopter has made a forced landing northwest of Sydney after sending out a distress call.

The RAAF helicopter, likely from a base in nearby Richmond, landed in a field at Wisemans Ferry, on the Hawkesbury River, just after 7pm yesterday.

The alert it broadcast to all aircraft in the area was one step below a mayday – which signals an immediate danger to life – and instead indicated some matter of aircraft urgency, Fairfax Media reports.

A Defence Department spokeswoman described the incident as a "precautionary landing".

"A warning light came on, and as soon as that light came on, they had to land," she was quoted as saying.

No further details were available.

In 2006, an Australian Black Hawk helicopter crashed onto HMAS Kanimbla in Fiji, killing two Australian servicemen.