By Tim Hepher

PARIS (Reuters – Airbus retaliated against Qatar Airways in an escalating dispute over A350 aircraft on Monday. A British judge ordered $220m in damages for two undeliverable airliners.

Qatar Airways was sued by the planemaker for $600million over erosion of the surfaces of 20 aircraft previously delivered.

Airbus is also seeking to recover credit amounts in excess of millions of US dollars, according to an application. It offers a rare insight into the negotiations that take place within the highly secretive global jet industry.

This counter-offensive comes as the latest in a long-running safety and contractual dispute, which has brought tensions between aviation industry giants to their lowest point.

The two sides once enjoyed global attention when they signed multibillion-dollar air show deals. Now, both are fighting over erosion of the painted surface as well as damage to A350 jets.

Qatar Airways stated that the surface degrading raises questions about the safety of its jets and prompted the regulator to ground each plane as soon as possible.

Airbus stated that planes are safe due to the margins in the anti-lightning systems and charged the safety regulator with initiating this decision.

The airline also stated that it was free to assert that regulator and the airline had “colluded” in the groundings.

Qatar Airways had no immediate comment. Qatar’s aviation authorities did not immediately reply to my request.

Airbus acknowledged that there were quality issues, but the airline accused it of mislabeling them as safety concerns to obtain compensation.

Qatar Airway stated that its regulator was completely independent.

European regulators have stated that the problem does not constitute an issue of airworthiness on the jet. The plane is currently not grounded anywhere else.

Qatar on Monday confirmed that one more of its A350 aircraft had been grounded. This brings the number of idle A350s to 22.

Reuters reports that Qatar tried to infringe a contract with Airbus for A321neo planes.

They also disagreed on the likelihood of reaching a deal.

Airbus spokesperson said Monday’s counterclaim was an “ultimate resort” and that it followed numerous futile attempts to reach mutually beneficial solutions.

Qatar Airways stated earlier that it did not know of any Airbus efforts to make the situation amicable.