Scotland’s air ambulances may not be safe to fly unless work is done to a key part of the rotor transmission, according to an aviation inspection body.
The European Aviation Safety Agency has warned that a recent inspection of a Eurocopter EC135 revealed part of the transmission to the main rotor of the helicopter is not up to standard.
The Scottish Air Ambulance Service uses two EC135s, based at Inverness and Glasgow, to fly seriously ill or injured patients to the country’s biggest hospitals every day.
The helicopters are operated by Bond Air Services, which is subcontracted by Gamma Aviation to run the aircraft on behalf of the Scottish Air Ambulance.
The airworthiness directive warns that the problem on the helicopters could affect the oil filter bypass, which is “essential for continued safe flight”.
The agency says the problem, which also affects Eurocopter’s EC635 models, is caused by the inlet in the oil filter, which “has not been manufactured in accordance with the applicable design specifications”.
The agency recommends operators instal a corrugated washer into the system as a “temporary modification” in the next three months, before reworking the transmission’s oil filter within 4,000 flight hours or during the helicopter’s next overhaul.
The directive will come into force on October 28.
A spokesman for the Scottish Air Ambulance Service said the service was “confident” its operators ensured its aircraft were compliant with safety directives.
A Bond spokeswoman said they were aware of the directive and work would be done to the set timescale.
A spokeswoman for the Scottish Government, which funds the ambulance service, said: “This is an operational matter for the Scottish Air Ambulance Service.
“They are aware of the issue and their contractors, who operate the helicopters, will ensure these matters are dealt with.
“The safety of both crew and patients is of paramount importance and no helicopter would be allowed to fly if there was any doubt over its airworthiness.”
Eurocopter said last night that it could not comment until it had consulted its safety experts.
The air ambulance service also uses two King Air planes, based in Aberdeen and Glasgow.