The largest customer for Europe’s premier long-haul jet claims Airbus failed to provide a full root-cause analysis needed to satisfy unresolved questions over the airworthiness of the affected jets including the lightning protection system.

The jets feature a layer of copper mesh under the paint to prevent lightning – which strikes planes on average once a year – damaging the carbon-composite fuselage, which is lighter but less conductive than traditional metal.

Airbus said it understood the cause and would “deny in total” the airline’s complaint. It has accused the airline, once one of its most highly courted customers, of trying to mischaracterize the problems as a safety concern.

“Airbus restates there is no airworthiness issue,” a spokesperson said, adding this had been confirmed by European regulators.

Qatar Airways has long had a reputation as a demanding buyer, sporadically rejecting deliveries for quality reasons.

The dispute between Qatar Airways and Airbus widened in November when an investigation revealed at least five other airlines had discovered surface flaws, prompting Airbus to set up an internal task force and to explore a new anti-lightning design for future A350 planes.

Qatar is so far the only country to ground some of the jets.

Vzhľadom na pretrvávajúci problém s flotilou A350 začala spoločnosť Qatar Airways vyraďovať svoje zakonzervované super-jumbo lietadlá A380 z dôchodku, pretože sa pripravuje na majstrovstvá sveta vo futbale.