The Derbyshire, Leicestershire and Rutland Air Ambulance (DLRAA) has had a record number of call-outs this summer.
The helicopter attended 473 incidents between April and August, an increase of 10% on the number in 2009.
Captain Ian Welsh, air ambulance pilot, said he could not explain the increase but said the team had to respond when called into action.
The air ambulance costs about £1.5m a year to run and relies solely on donations from the public.
"We have no control over this business," said Captain Welsh. "We sit there in a coiled spring position, waiting for something to happen and we may have a very, very busy day followed by a very slack one.
"We just have to react to whatever is going on out there."
More than 700 life-saving missions were undertaken by the DLRAA in 2009.
