An air ambulance was also called but Mr Roberts was pronounced dead at the scene.
Police said he was treated by paramedics and taken to Royal Blackburn Hospital by air ambulance.
The Welshpool air ambulance is working from 09:00 to 21:00 BST during the trial.
The air ambulance service operates helicopters from Marden in Kent and Dunsfold in Surrey.
She was taken to hospital in Coventry by air ambulance suffering from a head injury.
The Great North Air Ambulance Service later said he had died "despite everyone's best efforts".
The Wales Air Ambulance was also diverted to the scene with paramedics and Porthcawl coastguard.
Mr Barnes also flew for the Derbyshire, Leicestershire and Rutland Air Ambulance Service.
Emergencies will be answered by Royal Navy air sea rescue crews and the Cornwall air ambulance.
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An air ambulance took the woman and the two boys to hospitals in Birmingham.
There are currently 16 different air ambulance services covering Britain, each of which is separate and distinct.
An air ambulance service is teaming up with a specialist emergency team to treat children around England.
The Children's Air Ambulance from Coventry will fly doctors from Leicester's Glenfield Hospital to treat critically-ill patients.
She was taken by air ambulance to hospital in Southampton after the fall in the warm-up arena.
Some other air ambulance services, including the Dorset and Somerset Air Ambulance, say the rebrand has created confusion.
Carwyn Jones recognised the good work done but said that the air ambulance had not sought extra resources.
The Kent Air Ambulance, which aims to transfer patients to hospital within seven minutes, receives no government funding.
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Scotland's Charity Air Ambulance (SCAA) raises funds to cover the cost of both the helicopter and paramedic crew.
Ross Culligan, a paramedic with Wiltshire Air Ambulance, described the scene as "chaotic".
It is hoped the new air ambulance will be operational by the spring.
He was taken by air ambulance to Liverpool's Walton Neurological Hospital for treatment.
The Children's Air Ambulance Service helicopter, based at Coventry Airport, will initially be used to transport specialist paediatric medical staff.
However opponents, including the Dorset and Somerset Air Ambulance service, say the rebrand is causing confusion among people making donations.
On Friday, the air ambulance will go first to the Ulster Hospital at Dundonald and then to Altnagelvin Hospital in Londonderry.
The couple, who lived in Meelin in north Cork, were transferred by air ambulance from Devon back to Ireland in August.
We did have an air ambulance lined up to airlift him out of Iraq, but today's development will help a lot.
An air ambulance charity has been criticised for both the way it raises its funds and the way it spends them.
Cornwall's air ambulance trust has submitted a planning application to Cornwall Council for a new base on the outskirts of Newquay Airport.
Conventional ambulances can take up to half an hour to get patients to hospital but an air ambulance takes just 10 minutes.
The air ambulance attended the incident to check on the driver who was taken to Cumberland Infirmary in Carlisle for a check-up.
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