The early long-range-jets were operated by five cock-pit crew members: Captain, Copilot, Flight Engineer, Navigator and Radio-Operator. Nowadays even the big jets are flown by only two pilots. This development could only be achieved by introducing new technologies to the airline industry and automating aircraft systems. Due to the scientific progress made in the last decades today's aircraft are most reliable - a fact which is clearly reflected by accident statistics. Technical failures became more and more unlikely and the lack of manpower on the flight deck was more than compensated. However, starting in the late 80s a number of accidents occurred to highly automated aircraft, which alarmed accident investigators worldwide. In most of the cases automation was a factor or at least one link in the accident chain of events. The Federal Aviation Administration (FAA) launched a study on "The Interfaces Between Flight Crews and Modem Flight Deck Systems" and came up with numerous findings. In the following article I like to discuss the topic 'Man-Machine-Interface in modern Transport Systems' from an Aviation Safety Perspective. (C) 2001 Editions scientifiques et medicales Elsevier SAS.