An employee of Germany's Bundesamt fuer Fluguntersuchung BFU (German Federal Bureau of Aircraft Accident Investigation) holds a voice recorder, an up-to-date model by L-3 Aviation Products that is used in Boeing and Airbus aircraft, at their headquarters in Braunschweig March 20, 2015. The task of the BFU is to investigate into accidents and serious incidents to civil aircraft in Germany, to determine the causes of the occurrences. Flight recorders or ?black boxes?, used in investigations of aviation catastrophes since the mid-20th century, have developed considerably over the years. While older recorders contained spools of magnetic tape, modern devices use crash-survivable digital chips. There have been increasing calls for commercial planes to be fitted with ejectable recorders that separate from the tail during a crash, technology already in use by military aircraft. The ?deployable black boxes? combine voice and data recordings and emit a distress signal to a global search and rescue satellite system. Picture taken March 20, 2015. REUTERS/Wolfgang Rattay TPX IMAGES OF THE DAY