Qatar Airways has refused to take delivery of four Airbus SE A350-900 jets and is set to scrap its orders for the planes, according to people with knowledge of the matter.

The Gulf carrier declined to take the wide-bodies amid issues with quality control and cabin specifications, said the people, who asked not to be named because the decision hasn’t been made public. The cancellation may be reflected in Airbus’s monthly order data later Thursday, the people said.

France-based Airbus wasn’t immediately available for comment. Qatar Airways is the biggest buyer of the A350, with 80 orders before any cancellations, as well as the launch customer, having taken its first plane in December 2014.

Any delivery issues stem from Airbus, not Qatar Air, Akbar Al Baker, the carrier’s chief executive officer, said in response to questions in Dublin on Thursday, adding that he wants planes handed over faster. The A350 contract includes a clause allowing the cancellation of deliveries where delays go past a certain point, freeing up planes for allocation to other buyers, one person said.

The airline, ranked No. 1 worldwide by ratings service Skytrax, has a history of declining aircraft that fail to meet its exacting standards, with Al Baker having previously turned down deliveries of A380, A320neo and earlier A350 planes. At the same time, the carrier is grappling with a dip in demand for Mideast travel together with curbs on flights due to airspace bans imposed by Arab neighbors over Qatar’s links to Iran.

Cancelled orders won’t immediately impact growth plans, with Qatar Air having agreed in March to lease four A350s from Latam Airlines Group, in which it owns a 10 percent stake, for four to six months. The South American company doesn’t immediately need the jets because of a dip in demand in the region.

Qatar Air has 19 A350-900s in its fleet, including the Latam planes, together with orders for 28 more of the baseline variant plus 37 larger A350-1000s, of which deliveries are due to commence before the end of the year.

The Gulf airline is separately operating nine of its narrow-body A320 jets for the British Airways arm of IAG, in which it has a 20 percent stake, during a strike by cabin crew at the UK operator’s London Heathrow hub.