Though many mysteries still surround the recent crash of a Russian airliner over the Sinai Peninsula, some explanations of what happened are more likely to be true than others. On Oct. 31, Metrojet Flight 9268 broke into pieces shortly after reaching a cruising altitude of 9,500 meters (31,000 feet), killing all 224 passengers and crew members onboard. Stratfor, along with the rest of the world, is waiting for additional details to emerge from the aircraft's flight data and cockpit voice recorders. Though we cannot fully rule out the possibility of a catastrophic structural failure, such an explanation would be unusual given the circumstances of the crash. Most aircraft accidents that involve a structural failure occur amid the physical stress of takeoff and landing; it is uncommon for aircraft to break apart at cruising altitude.