Fire fighters from Boroughbridge, Knaresborough, Harrogate and Ripon were sent to the scene shortly before 1.30pm.
Police and paramedics are also attending.
North Yorkshire fire service said it was unable to confirm whether there are any casualties.
It added that fire fighters were “using hose reels to dampen down the scene”.
North Yorkshire Police said the aircraft came down in a crop field and the area has been cordoned off.
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The Air Accident Investigation Bureau (AAIB) says it is sending a team to Boroughbridge to look into the downing of the helicopter.