The air ambulance was called to Uckfield on Sunday afternoon after a teenage girl fell from a horse.
She was airlifted to hospital in Eastbourne in eight minutes.
The 16-year-old was reported to have suffered a broken wrist and possible spinal and limb injuries.
* The Air Ambulance service in Kent, Surrey and Sussex costs around £5 million annually to stay airborne. Receiving no funding from the National Lottery the charity relies almost entirely upon the generosity of the public to support the two helicopters, based at Marden and Dunsfold.
Read more about the air ambulance here