BBC News - Boeing: 15 airlines warned over high-altitude ice
Fifteen airlines have been warned about the risk of ice forming on Boeing's new 747-8 and 787 Dreamliner planes.
The issue - affecting some types of engines made by General Electric when planes fly near high-level thunderstorms - prompted Japan Airlines to cancel two international routes.
There have been six incidents since April when aircraft powered by GE engines lost power at high altitude.
The Boeing 747-8 series and the new 787 Dreamliner and the only types of aircraft affected by the high-altitude icing issue.
The new warning was given to airlines including Lufthansa, United Airlines and Japan Airlines.
It says aircraft with the affected engines - GE's GEnx - must not be flown within 50 nautical miles of thunderstorms that may contain ice crystals.
As a result, Japan Airlines (JAL) has decided to withdraw Dreamliners from service on the Tokyo-Delhi and Tokyo-Singapore routes.
"Boeing and JAL share a commitment to the safety of passengers and crews on board our airplanes. We respect JAL's decision to suspend some 787 services on specific routes," a Boeing spokesman said, according to Reuters news agency.
A GE spokesman told the agency the aviation industry was experiencing "a growing number of ice-crystal icing encounters in recent years as the population of large commercial airliners has grown, particularly in tropical regions of the world".
He said GE and Boeing were hoping to eliminate the problem by modifying the engine control system software.