By Agence France-Presse A new glitch causing in-flight shutdowns of the Pratt & Whitney engines that power the Airbus A320neo has prompted some airlines to postpone delivery of the aircraft, the aviation giant said Saturday. "We are in discussions with the airlines and responding on a case-by-case basis," an Airbus spokesperson told AFP. "Some have decided to put off their delivery and others have not." The Airbus A320neo (New Engine Option) takes off during its first flight event in Colomiers near Toulouse, southwestern France, September 25, 2014. (REUTERS/Regis Duvignau / MANILA BULLETIN) The European aircraft manufacturer and Pratt & Whitney said late Friday that a new problem had emerged with the Geared Turbo Fan (GTF) engine whose cause was still under investigation. Last year, other problems with the GTF engine also caused delays in deliveries of the twin-engine A320neo, a more fuel-efficient version of the Airbus company's best-selling airliner. On Friday, Europe's air safety authority EASA issued an "emergency airworthiness directive" saying that "several occurrences of inflight shutdown and rejected takeoff have been reported" with the single-aisle aircraft. It warned that potentially both engines could shut down simultaneously. An industry source said 11 A320neos have been grounded to replace the engines. A total of 113 planes in the A320neo family, used by 18 airlines, are currently in service that are equipped with the engines. Airbus also uses LEAP engines co-produced by General Electric and Safran on the planes.