Qatar Airways is speaking to Boeing  to secure substitute aircraft after further problems were discovered with the Airbus A320neo, the airline’s chief executive said on Monday.

The Gulf airline could walk away from between four and six aircraft orders that have yet to be delivered after problems affected the A320s hydraulics and software, Akbar al-Baker told reporters at a media roundtable in Dubai.

Baker criticized U.S engine maker Pratt & Whitney last month, saying the engines it supplied for the A320neo were inadequately tested for the high temperatures experienced in the Gulf region.

“They have indicated they will have all those fixes by the end of the year,” Baker said of Airbus on Monday.

“We have talked to Airbus, they know very well that we’re a very unhappy, very unhappy customer.”

Baker said it could turn to the Boeing 737NG as a replacement, noting the U.S. aircraft maker was “trying to oblige and give us the aircraft that we require”.

Source Reuters, picture Rob Vogelaar