European airlines send up test flights

2010-04-18 18:28

Amsterdam - Several major airlines safely flew test flights without passengers over Europe on Sunday despite official warnings about the dangers of a volcanic ash plume, fuelling a corporate push to end an economically devastating ban on commercial air traffic.

KLM Royal Dutch Airlines said that by midday on Sunday it had flown four planes through what it described as a gap in the layer of microscopic dust over Holland and Germany. The ash began spewing from an Icelandic volcano on Wednesday and has drifted across most of Europe, shutting down airports as far south and east as Bulgaria.

Air France, Lufthansa and Austrian Airlines have also sent up test flights, although most travelled below the altitudes where the ash has been heavily concentrated.

KLM said its planes of various types flew the 185km flight from Düsseldorf in western Germany to Amsterdam's Schiphol Airport at an unspecified normal altitude above 3 000m. They did not encounter the thick though invisible cloud of ash, whose main band has floated from 6 000m to 9 700m, the height of most commercial flight paths.

The announcement prompted some airline officials to wonder whether authorities had overreacted to concerns that the tiny particles of volcanic ash could jam up the engines of passenger jets. 


The possibility that the ash had thinned or dispersed over parts of Europe heightened pressure from airline officials losing hundreds of millions of dollars a day to end a flight stoppage that has thrown global travel into chaos and left millions stranded far from home.

"With the weather we are encountering now - clear blue skies and obviously no dense ash cloud to be seen, in our opinion there is absolutely no reason to worry about resuming flights," said Steven Verhagen, vice-president of the Dutch Airline Pilots Association and a Boeing 737 pilot for KLM.

"We are asking the authorities to really have a good look at the situation, because 100% safety does not exist," Verhagen said. "It's easy to close down air space because then it's perfectly safe. But at some time you have to resume flights."

Meteorologists warned, however, that the situation above Europe remained unstable and constantly changing with the varying winds - and the unpredictability was compounded by the irregular eruptions from the Icelandic volcano spitting more ash into the sky.

KLM had permission from Dutch and European aviation authorities before sending the planes aloft but the Dutch and most other European authorities kept their air space closed to passenger traffic until at least 18:00 GMT on Sunday, saying conditions remained risky.

Kyla Evans, spokesperson for the European air traffic control agency Eurocontrol, said it was up to national aviation authorities to decide whether to open up their airspace. The agency's role was to co-ordinate traffic once it was allowed to resume.

Daniel Hoeltgen, a spokesperson for the European Aviation Safety Agency, said the organisation was in contact with airlines and national regulators with a view to allowing commercial aircraft to begin operating again.

"But there is currently no consensus as to what consists an acceptable level of ash in the atmosphere," Hoeltgen said. "This is what we are concerned about and this is what we want to bring about so that we can start operating aircraft again in Europe."

Air France said its first test flight Sunday, from Charles de Gaulle airport to Toulouse in southern France, "took place under normal conditions".

No anomalies

"No anomalies were reported. Visual inspections showed no anomalies," Air France said in a statement soon after it landed. "Deeper inspections are under way."

It did not say how high the planes had flown.

Germany's Lufthansa flew 10 empty long-haul planes on  Saturday to Frankfurt from Munich at low altitude and under so-called visual flight rules, in which pilots don't have to rely on their instruments, said spokesperson Wolfgang Weber.

"We simply checked every single aircraft very carefully after the landing in Frankfurt to see whether there was any damage that could have been caused by volcanic ash," Weber said. "Not the slightest scratch was found on any of the 10 planes."

German air traffic control said Air Berlin and Condor airlines had carried out similar flights.

A technical inspection of the aircraft after landing "did not reveal any adverse effects", the company said.

Air Berlin Chief Executive Joachim Hunold declared himself "amazed" that the results of the German airlines' flights "did not have any influence whatsoever on the decisions taken by the aviation safety authorities".

The British Meteorological Office said there was no way to be certain that areas clear of ash will remain that way. The cloud "won't be present at all parts of the area at risk at all times, you can see clear area, but it will change, it won't stand still", said meteorologist John Hammond.

The Met Office said the ash reached up to 6 000m, but that the grit also was dropping to low levels in some places and settling on the ground in parts of southern England.

$200m a day

The aviation industry, already reeling from a punishing economic period, is facing at least $200m in losses every day, according to the International Air Transport Association.

National air safety regulators have the right to close down a country's air space in cases of extreme danger. But they can also grant waivers to airlines to conduct test flights or to ferry empty airliners from one airport to another at lower altitudes not affected by the main ash clouds.

The Swiss Federal Office of Civil Aviation began allowing flights Saturday above Swiss air space as long as the aircraft were at least at 11 000m. It also allowed flights at lower altitudes under visual flight rules, aimed at small, private aircraft.

Ash and grit from volcanic eruptions can sabotage a plane in various ways: the abrasive ash can sandblast a jet's windshield, block fuel nozzles, contaminate the oil system and electronics and plug the tubes that sense airspeed.

But the most immediate danger is to the engines. Melted ash can then congeal on the blades and block the normal flow of air, causing engines to lose thrust or shut down.

Scientists say that because the volcano is situated below a glacial ice cap, magma is being cooled quickly, causing explosions and plumes of grit that can be catastrophic to plane engines, depending on prevailing winds.

"Normally, a volcano spews out ash to begin with and then it changes into lava, but here it continues to spew out ash, because of the glacier," said Reynir Bodvarsson, director of Swedish National Seismic Network. "It is very special."

Bodvarsson said the relative weakness of the eruption in Iceland also means the ash remains relatively close to the earth, while a stronger eruption would have catapulted the ash outside of the atmosphere.