WASHINGTON (AP) — Boeing is alerting airlines about possible engine icing problems on some of its new planes. It is recommending that planes with a specific General Electric engine avoid flying near thunderstorms that might contain ice crystals.

Boeing spokesman Marc Birtel said Saturday that Boeing issued the advisory after ice crystal formation in some instances diminished engine performance. Airlines with planes affected include United, Japan Airlines, Lufthansa and Air India. Models affected are the 747-8 and the 787, which Boeing Co. calls the Dreamliner.