2002 Überlingen mid-air collision
On 1 July 2002, BAL Bashkirian Airlines Flight 2937, a Tupolev Tu-154 passenger jet, and DHL International Aviation ME Flight 611, a Boeing 757 cargo jet, collided in mid-air over Überlingen, a southern German town on Lake Constance, near the Swiss border. All of the passengers and crew aboard both planes were killed, resulting in a total death toll of 71.The official investigation by the German Federal Bureau of Aircraft Accident Investigation ( -BFU) identified the main cause of the collision to be a number of shortcomings on the part of the Swiss air traffic control (ATC) service in charge of the sector involved, as well as ambiguities in the procedures regarding the use of the traffic collision avoidance system (TCAS) on board.
In 2004, Peter Nielsen, the air traffic controller on duty at the time of the collision, was murdered in an apparent act of revenge by Vitaly Kaloyev, a Russian citizen and architect whose wife and two children had been killed in the accident. Provided by Wikipedia