Boeing issued a warning to airlines operating Boeing 747-8 and 787 Dreamliner aircraft equipped with General Electric GEnx engines. Those aircraft have a risk of engine icing problems, and airlines are advised to avoid flying in specific weather circumstances.
This move was prompted by several icing incidents this year. Five Boeing 747-8s and one 787 suffered a temporary loss of thrust while flying at high altitude in icing conditions. In the notice sent to airlines, Boeing prohibits the aircraft from flying at high attitude within 50 nautical miles of thunderstorms that may contain ice crystals.
General Electric and Boeing are working on software modifications to the engine control system, which they hope will eliminate the problems.
One of the incidents was probably an event on July 31, 2013 when an AirBridgeCargo 747-8 diverted following the in-flight shut down of two engines over Russia due to the ingestion of ice clumps and engine surges.