ZURICH (Reuters) - A Russian who lost his wife and two children in Germany's worst aviation disaster went on trial in Switzerland on Tuesday for killing the air traffic controller he held responsible. Vitaly Kaloyev, 48, lost his family when a DHL cargo plane and a Russian passenger jet collided in Swiss-controlled airspace over southern Germany on July 1, 2002. He is charged with the premeditated killing of Peter Nielsen, the only air traffic controller on duty at the time. Under Swiss law this charge ranks between murder and manslaughter and carries a maximum sentence of 20 years. "I went...