air corridor over East Germany on the last stretch of its journey to Berlin. The aircraft impacted the ground near Dallgow, East Germany, almost immediately after the crew had acknowledged further instructions received from Berlin Control, just from Tegel Airport. All three crew members lost their lives in this accident. Visibility was poor, and it was snowing at the time of the accident. Following the accident, the Soviet military authorities in East Germany returned only half of the aircraft's wreckage to their US counterparts in West Berlin. This excluded vital parts, such as the flight data recorder, the cockpit voice recorder as well as the plane's flight control systems, its navigation and communication equipment. The subsequent National Transportation Safety Board investigation report concluded that the aircraft's descent below its altitude clearance limit was the accident's probable cause. However, the NTSB was unable to establish the factors that had caused the crew to descend below its cleared minimum altitude. Notes and citations Notes Citations Further reading Bonjour Deutschland – Luftverkehr unter Nachbarn: 1926–2006 Air travelers were pawns in 1970-71 Four-Power negotiations. Air traffic control in Europe Aviation in Berlin Air Corridor Airline routes Geopolitical corridors