DHL 611 - Überlingen Mid-Air Collision

On the night of July 1, 2002, two aircraft collided mid-air over Überlingen, Germany, at flight level 360 (approximately 35,000 feet). Bashkirian Airlines Flight 2937, a Tupolev Tu-154M passenger aircraft carrying 60 passengers (mostly children) and 9 crew members from Moscow to Barcelona, collided with DHL Flight 611, a Boeing 757-200F cargo aircraft with 2 crew members flying from Bergamo, Italy to Brussels, Belgium. The collision occurred due to conflicting air traffic control instructions and a failure in the ground-based collision avoidance system. The single air traffic controller on duty gave contradictory instructions to the Russian aircraft while the TCAS (Traffic Alert and Collision Avoidance System) advised a climb. The crew followed the controller's descent instruction instead of the TCAS advisory, leading to the fatal collision. All 71 people aboard both aircraft were killed, making it the deadliest aviation disaster in German history. The accident led to significant changes in air traffic control procedures and protocols worldwide.