Twenty-two Eurocopter EC 135 helicopters have been grounded by operator Bond Air Services, over concerns about possible cracks in the rotor blades.

The aircraft were grounded after mechanics carrying out maintenance work at Staverton Airport, Gloucestershire found a crack on a blade and reported it to Eurocopter.

The three Eurocopter EC135s run by Midlands Air Ambulance were grounded by their operator Bond Air Services after discussions between Bond, Eurocopter and the European Safety regulator EASA. It followed cracks being found in the main rotor hub-shaft flange on three aircraft.

A West Midlands Ambulance Service spokesman said: “It is important to note that the cracks have not affected any of the Midlands Air Ambulance aircraft. Safety has to be the number on consideration for both patients and staff.

“A replacement aircraft of a different type is being flown into the Region this evening and will operate from RAF Cosford tomorrow, Wednesday.

“The clinical staff who fly on the three Midlands Air Ambulance aircraft have today been operating from land-based rapid response vehicles; something which occurs in the event of bad weather such as fog.

“We would like to reassure the people of the West Midlands that two air ambulances have been available to West Midlands Ambulance Service throughout today operated by The Air Ambulance Service.

“As of tomorrow the Trust will be able to call on three air ambulances – still one of the best services in the country.”

Last month, the European Aviation Safety Agency (EASA) ordered increased safety inspections on the EC 135 while a possible fault was being investigated.