Glass build-up from Iceland's volcanic eruption has been found in an engine of a Nato F-16 fighter plane, a US official said today, underlining the dangers to aircraft of flying through the ash cloud.
The official did not say which nation's aircraft had been affected, where it happened or when, but it is the second air force to report problems from the ash cloud. Finland, a non-Nato member, reported similar problems on Friday.
The volcanic ash consists of tiny particles of rock and glass as fine as talcum powder, which under extreme heat can fuse onto the blades of an engine, causing imbalances or damaging delicate rotating machine parts.
"Allied F-16s were flying and they did find glass build-up," the US official said, adding that the glass had been found in the engine of one plane that had flown in European airspace.
"So this is a very, very serious matter that in the not too distant future will start having real impact on military capabilities" if the volcanic cloud doesn't disappear, he said.
The official said the ash cloud had already led to the scaling down of some US military exercises. While planes are flying, he said it was dangerous.
"I think the airspace is closed for a reason," the official added, referring to flight bans that have affected much of Europe for the past five days.
As well as fusing into glass, volcanic ash is abrasive and can strip off aerodynamic surfaces. It can also damage aircraft electronics and windshields.
Finland's defence forces said on Friday they had conducted flying tests with F-18 Hornets in Lapland, and even during a short test time it was possible for the ash to cause "significant" damage to the plane's engines.
They said they studied an engine from one of the planes with a fibre-optic camera and saw the extreme heat had caused the ash to melt, raising the risk of blockages and possible overheating.
They said that this, in turn, could lead to moving parts cracking and, at worst, breaking off and destroying the engine.
Dutch airline KLM, which has flown several test flights, said most European airspace was safe despite the plume of ash, and sent two commercial freight flights to Asia on Sunday.
The US official said he expected the impact of the ash cloud to be taken up as part of Nato's agenda and said it underscored the importance of agreements reached with Russia and Kazakhstan for the transit of military supplies and troops to Nato's main operation in Afghanistan.
"It opens up the possibility of the polar route for lethal equipment and troops to be shipped into Afghanistan which is exceedingly important given the force buildup we have ongoing there," the official said
"With the closure of airspace in Europe it becomes even more important that we can do that, so in that extent the Russian assistance on Afghanistan is absolutely critical," he added.
Officials said the ash cloud had raised doubts about whether a meeting of the 28 Nato foreign ministers scheduled on Thursday and Friday in Estonia and due to be attended by US secretary of state Hillary Clinton could take place.
"She is in the US and has to get here, and it's too late to take a boat," the US official said.
Nato officials said the flight ban had forced Nato secretary general Anders Fogh Rasmussen to travel by road back to Brussels from Copenhagen at the weekend, a journey that takes more than 10 hours.
Reuters