Malaysian Air Flight MH370: How Can A Boeing-777 Aircraft Suddenly Lose All Contact?

One of the questions I've been asked repeatedly since word emerged that a Malaysian Airlines 777 had disappeared, is how can a modern airliner flying at 35,000 feet suddenly lose all contact? First, there needs to be an understanding of the type of contact that an airliner in flight typically has. Airline crews communicate with air traffic control both by verbal instructions over radios and through automatic transmissions from various aircraft systems, such as a transponder which relays informat...