The test flights conducted by Dutch and Austrian airlines have showed no damage caused by the volcanic ash, but the Dutch Airline KLM said the initial result does not mean normal flight can be immediately resumed.

Peter Hartman, CEO of the Royal Dutch Airline KLM, said "this matter will be decided by the Dutch air transport authorities IVW, in consultation with the European authorities."

Hartman's words came after the KLM and the Austrian air traffic control authority announced that no damge was caused by the volcanic ash to passenger planes' engine, as feared earlier by many experts.

The Royal Dutch Airline said nine other test flights will be conducted later on Sunday.

KLM's first test flight was conducted Saturday night between Duesseldorf and Amsterdam. Initial inspection on the Boeing 737-800 showed that no damage was caused to the aircraft. The test flight was performed at lower altitude than usual, and no passengers were on board.

Meanwhile, a spokesman for Austrian air traffic control authority, Austro Control,said on Sunday morning that a passenger aircraft flied through the volcanic ash landed at Vienna airport without any damage.

Markus Pohanka said the inspection from the Austrian Airline and Austro Control on the plane showed that the plane "has no damage to the appearance or the engine."

Since the closure of Austrian airspace, there was a passenger aircraft A321 of Ural Airlines from Moscow to Rome landed at the Vienna International Airport in the morning of March 17.