Medical services have been called to RAF Scampton in Lincolnshire after an incident involving a Red Arrows jet and one member of air crew, the Ministry of Defence has said.
Sky's defence correspondent Niall Paterson said the display team's Hawk T1 jet was not airborne when the incident occurred.
Unconfirmed reports state there could have been a problem with an ejector seat.
An MoD spokesman said: "I can confirm there has been an incident at RAF Scampton. The RAF are investigating and will provide more details when they are available."
The incident comes after Red Arrows pilot Flight Lieutenant Jon Egging, 33, from Rutland, was killed in an air show crash near Bournemouth Airport in Dorset in August.
More to follow...