Airbus’ statement came the same day the European Aviation Safety Agency said 20 of the aircraft must be inspected after cracks were found in the wings of Singapore Airlines, Emirates and Air France planes.

“This is not a fatigue cracking problem,” said Tom Williams, a vice-president with Airbus, blaming the cracks on design and manufacturing issues. “The cracks do not compromise the airworthiness of the aircraft.”

Dominique Fouda, a spokesman with the European air safety agency, said eight planes must be fully inspected by Friday and the remaining 12 within six weeks.

“The most urgent inspections concern six planes from Singapore Airlines and two from Emirates,” he said.

Among the 12 others, one plane belongs to Air France and another is a test plane belonging to Airbus.

A source close to the matter had earlier told AFP that 30 A380s were the subject of concern.

“The goal of these inspections is to understand a little better the origin of these problems,” Fouda said. “This directive is aimed at having a better understanding of this phenomenon, which is not complete for the moment.”

He refused to comment on theories that the cracks may be due to a premature launch of the aircraft.

“As long as the investigation is not over, we must not speculate,” he said.

Singapore Airlines said Saturday it had begun inspections of its A380s. By Wednesday, checks had been carried out on four aircraft, and there were “findings” during each inspection.

One aircraft was repaired and was back in service while repairs were being carried out on the others, a spokesman said.

A spokeswoman for Emirates, which operates 20 A380s and has ordered another 70, said one of its aircraft had been inspected and another was in the process of being examined.

An Air France spokesman said the company, which operates six A380s, was in talks with Airbus about scheduling an inspection.

The A380 is the world’s biggest passenger jet and a key product in Airbus’s line-up as it battles its main rival US giant Boeing for the top spot in the world civil airliner industry.

The double-decker plane entered service in 2007 after years of technical delays. There are now 67 in service around the world and while they have never had a fatal accident there have been teething problems.

The plane carries more than 500 passengers or more than 800 if configured entirely in economy class.