Qatar Airways has been instructed by its regulator to ground 13 Airbus A350 planes due a faster than expected deterioration of the fuselage surface below the paint on the jets.
The state-owned Gulf airline said on Thursday it had been told to ground the planes until "the root cause can be established and a satisfactory solution made available to permanently correct the underlying condition."
Qatar Airways has been locked in a months-long public dispute with Airbus, insisting it would not take any deliveries of the carbon-composite widebody jet until the problem was resolved.
"With this latest development, we sincerely expect that Airbus treats this matter with the proper attention that it requires," Qatar Airways Chief Executive Akbar Al Baker said in a statement announcing the regulator's grounding of the jets.
"Qatar Airways expects Airbus to have established the root cause and permanently corrected the underlying condition to the satisfaction of Qatar Airways and our regulator before we take delivery of any further A350 aircraft."
An Airbus spokesperson told Reuters the planemaker was always in talks with its customers but those discussions were confidential, declining to comment further.
Qatar Airways said in June it had grounded some of its A350 jets until the issue could be understood and fixed, without disclosing how many aircraft had been pulled from service.
It said on Thursday it had brought A330 aircraft back into service to make up for the lost capacity and was also "looking at other solutions."
Qatar Airways is the largest customer for the A350 and has taken delivery of 53 out of 76 on order.
The airline has periodically criticised Airbus and its U.S. rival Boeing for delays or quality lapses.
It says its exacting standards reflect its premium brand, although aerospace executives have accused it of seizing on such details in the past to delay taking deliveries or gain leverage in other negotiations, a suggestion Qatar has denied.
Many airlines have adjusted deliveries due to the pandemic-related travel downturn. Qatar Airways said in June 2020 it would not take Boeing or Airbus jets in 2020 or 2021 and later that year said it had reached a deal on schedules with Airbus.