BBC reporting as follows:
Booker helicopter crash: Three men injured - BBC News
Three men have been taken to hospital - one with "life-threatening" injuries - after a helicopter crashed in Buckinghamshire.
Police and fire crews were called to the Wycombe Air Park in Clay Lane, Booker, just after 09:40 BST.
South Central Ambulance Service said the aircraft, which had three men on board, ended up on its side.
The Air Accidents Investigation Branch is sending a team to the scene of the crash to investigate.
An ambulance service spokesman said one man was taken to John Radcliffe Hospital with life-threatening injuries.
A second man suffered serious leg, chest, abdominal, head and shoulder injuries and a third patient had less serious back injuries.
Three ambulances, two rapid response vehicles and the Thames Valley Air Ambulance were called to the scene.