Qatar Airways is seeking $618 million in damages from plane maker Airbus in a row over surface corrosion of its A350 aircraft, a court document showed on Thursday.

The company is also demanding an additional compensation of $4 million for each day it stopped operating its 21 aircraft of this type, by order of the Qatari regulators, due to this defect, which includes corrosion and holes in the lightning protection surface.

Qatar Airways - which is the largest customer of the European plane - made this claim last December, saying that Airbus had failed to provide a comprehensive analysis that explains the root causes and provides conclusive answers to its questions regarding the validity of about 40% of its fleet of A350s. .

Airbus said it had recognized the cause and would "deny" the company's allegations in a circuit of the High Court in London.

"Airbus confirms that there is no airworthiness issue," an Airbus spokesperson said, adding that this was a confirmed view of European regulators.

There was no immediate comment from Qatar Airways.

The two companies have been feuding for months over damages, including paint flaws and corrosion in a subsurface layer of lightning protection.

The dispute widened last November when a Reuters investigation revealed that at least five other airlines had discovered defects in the aircraft's surface, prompting Airbus to form an internal working group and explore a new lightning-proof design for future A350 aircraft.

Qatar is the only country so far that has grounded some aircraft.