Boeing Co.’s newest 747 jumbo jetliner faces a risk of dangerous vibrations, known as “flutter,” in limited situations, the Federal Aviation Administration said. Data analysis shows that “divergent flutter,” oscillations of a wing that could cause it to break up, may occur on the 747-8 during a “high g-load maneuver in combination with certain system failures,” the FAA said Wednesday. G-loading refers to the stresses on a plane that can increase during acceleration and turns.