Air ambulance and police helicopters are returning to service across the UK, after the model of helicopter which crashed into a pub killing ten people was suspended when a fault with the fuel gauge was detected on a flight.
Operator Bond grounded its fleet of 22 EC135 helicopters as a precaution while the issue, discovered on an air ambulance in the north west of England yesterday, was examined.
The Association of Air Ambulances (AAA), which represents the majority of the air ambulance network, said 16 of its 36 helicopters in the UK were affected by the grounding.
Police Scotland said restrictions had been lifted and their helicopter had been cleared to fly.
A spokeswoman said: "As of 3.18pm today, Thursday 12 December 2013, the restrictions placed by Bond on the Police Scotland helicopter have been lifted. The Police Scotland Air Support Unit is now fully operational."
Wales Ambulance Service said two of its three helicopters had been cleared to fly with checks continuing on a third aircraft. East Anglia air ambulances have also returned to service.
The grounding came as it was announced that a tenth person had died in hospital after a police helicopter crashed into the Clutha bar in Glasgow.
Joe Cusker, 59, died at Glasgow Royal Infirmary almost two weeks after the tragedy.
An initial report from the Air Accidents Investigation Branch (AAIB) issued this week said there was ''no evidence of major mechanical disruption of either engine'' of the Police Scotland helicopter as it returned from an operation in Dalkeith, Midlothian, on the night of the crash.
The helicopter that crashed into the Clutha bar in Glasgow on November 29 was a Bond-operated Eurocopter EC135 Type 2 aircraft.
A statement from Bond Air Services said: "As a precautionary measure, following an issue with the fuel indication system on one of our aircraft yesterday we temporarily suspended service operations whilst we undertook further technical investigations of our fleet of EC135s.
"These investigations are expected to be completed by the end of the day. Those aircraft that are confirmed as having no fault will return to service. We will continue to work with the manufacturer Eurocopter on any aircraft which are found with this fault, with the aim of resuming normal service as soon as it is safe to do so.
"This is in line with our commitment to the highest standards of safety in all our operations.
Areas affected included Dorset, Somerset, Thames Valley, the Isle of Wight, the Midlands, Scotland and Wales.
Eurocopter, the manufacturer of the grounded aircraft, said the decision taken by Bond did not apply to the rest of the EC135 fleet.
Other air ambulances remained in operation to cover the affected areas during the grounding, AAA said.
Director Clive Dickin said: "Aircraft of all types occasionally are grounded for bad weather or routine maintenance. In these circumstances, other air ambulances and ambulance service providers work closely to ensure no patients are affected.
"Obviously, when an extremely rare incident like this happens, stresses can be placed on the services however these contingencies are planned for."
A Eurocopter spokesman said: "Eurocopter was informed by Bond that they decided to temporarily suspend flights with their EC135 fleet yesterday late evening. Based on an observation made on an aircraft engaged in medical services the decision was taken on their behalf for precautionary reasons.
"Eurocopter does not recommend any further action for the other EC135 aircraft in service around the world. The European Aviation Safety Agency has never issued an airworthiness directive to ground the EC135 fleet ever since its entry into service in 1996."
A helicopter from East Anglian Air Ambulance and one from Hampshire and Isle of Wight Air Ambulance had been temporarily suspended but have now been cleared.