Qatar Airways has announced it is suing plane manufacturer Airbus after a months-long row over flaws in the 'skin' of jets.
The carrier has started proceedings in a British court against the firm over its A350 passenger jets, a move which is set to bring the two sides closer to a rare legal showdown over aviation safety.
It is the culmination of a long-running dispute between the two companies over damage to the outer layer of A350 jets including blistered paint and corrosion to a sub-layer of lightning protection.
The airline said the defects have led its domestic regulator to force the grounding of 21 of its aircraft. These represent 40 per cent of its current fleet of A350s, for which it was the launch customer with the biggest order.
Other airlines still operate the jet, saying its airworthiness is not affected by what they consider cosmetic issues.
Airbus insists the carbon-composite passenger jets are safe to fly despite some “surface degradation,” while Qatar Airways says it is too early to say whether safety has been compromised.
The battle came to a head last week when Airbus, in what experts called an unprecedented move, accused the Gulf airline of misrepresenting the problem as a safety issue and threatened to call for an independent legal assessment.
On Monday, Qatar Airways hit back, saying it had taken its complaint against Airbus to the High Court in London.
“We have sadly failed in all our attempts to reach a constructive solution with Airbus in relation to the accelerated surface degradation condition adversely impacting the Airbus A350 aircraft,” the airline said in a statement. “Qatar Airways has therefore been left with no alternative but to seek a rapid resolution of this dispute via the courts.”
Later on Monday, Airbus confirmed it had received a formal legal claim and said it would “vigorously defend its position” in court.
A spokesman earlier said it had found the cause of the problem and was working with customers and Europe's safety regulator, which has said it has not identified a safety issue.
Qatar Airways denies that the issues are properly understood and said on Monday that it wanted Airbus to mount a “thorough investigation".
Witnesses claim the surface flaws have left some of the jets with a pockmarked appearance.
Such a public legal row between a major international airline and a leading plane manufacturer is unprecedented, several industry executives have said.
The dispute looks set to cost Airbus a major Qatar order for a new A350 freighter version.
Until recently, Airbus had maintained the problem was focused only on paint on Qatar's A350s, based in the Gulf.
But in November, Reuters reported that it had seen documents revealing at least five other airlines in varying climates had complained about paint or other surface problems since 2016.
In light of the complaints, Airbus is drawing up plans to change its anti-lightning system.
It says it has offered Qatar Airways interim solutions including repainting but its offers were ignored.
The airline has said it cannot be sure whether the proposed repairs would be effective without deeper analysis.