There's a new development in the baffling disappearance of Malaysia Airlines Flight 370 four days after it took off from Kuala Lampur on its way to Beijing. Malaysian authorities now say that — after it stopped communicating with ground controllers — it made an unscheduled turn to the west. Patrick Smith is a pilot and author of Cockpit Confidential: Everything You Need to Know About Air Travel. (Questions, Answers, and Reflections). He hosts the website AskThePilot.com.