Wales air ambulance and police helicopter grounded for checks
Wales' three air ambulances, and the South Wales and Gwent police helicopter, were grounded for checks - but most are now back in operation.
The air ambulance is an EC 135 T2 aircraft, the same type as the one which crashed into a Glasgow pub last month.
Operator Bond Aviation ordered the suspension for maintenance checks.
It comes after a fault was discovered on an EC 135 operated by Bond in England.
That fault was found in a North West air ambulance aircraft, which flies from bases at Royal Preston Hospital and University Hospital of South Manchester, Wythenshawe.
All Bond's UK air ambulances and police helicopters are affected.
The three Wales air ambulances were grounded on Thursday but two later returned to service, as did the police helicopter serving the South Wales and Gwent force areas.
A Wales Air Ambulance spokesman said: "Our helicopter operator has concluded checks on two of our three aircraft, which have returned to service.
"Checks are continuing on a third aircraft."
In a statement South Wales Police said: "Bond Air Services, the operator of the helicopter which serves South Wales and Gwent Police forces, has grounded its fleet of EC 135 helicopters.
"While this situation continues air cover for the region is being provided by other sources."'Precautionary measure'
The Wales air ambulances fly out of Caernarfon, Swansea and Welshpool.
The aircraft's manufacturer, Eurocopter, said it was not telling other operators of the EC 135 to ground their helicopters.
Bond Air Services said in a statement: "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 EC 135s.
"These investigations are expected to be completed by 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."
A police helicopter which crashed in Glasgow came down on the busy Clutha bar on 29 November.
Three crew members and seven people in the pub were killed.