A man is fighting for his life and two others are injured after a helicopter crashed onto its side at an airfield.
Ground crew watched in horror as the aircraft plummeted to the ground at Wycombe Air Park in Marlow, Buckinghamshire, injuring the pilot and two passengers.
Emergency services were alerted shortly after 9.30am.
An off-duty paramedic waiting for his own flying lesson at the airfield saw the crash and helped the injured as he waited for emergency services to arrive.
Three adults were inside the helicopter and were either pulled from the wreckage by airfield crews or managed to free themselves, emergency services said.
One man was rushed to the major trauma hospital at John Radcliffe Hospital with life-threatening injuries.
A second man suffered serious leg, chest, abdominal, head and shoulder injuries and was also taken to the same unit.
The third man sustained less serious back injuries and was taken to Wexham Park Hospital, in Slough.
One trainee pilot was in the air having a lesson when he saw events unfold beneath him. He praised his instructor who helped the shocked learner safely put down his aircraft.