Simultaneous radio transmissions during a crucial point in communications preceded a serious incursion at Leipzig, which forced a Boeing 777 freighter to abort take-off to avoid a light aircraft.
German accident investigation authority BFU says a Cessna 172 had been holding at taxiway H5 some 1,900m from the threshold of runway 08R, on which the 777F was preparing to depart to Bergamo.
The Cessna pilot called the tower, declaring that he was "ready for departure" and the controller responded, identifying the Cessna's callsign and adding: "Leipzig tower, hello."
Around 90s after this exchange, the 777F was cleared for take-off on runway 08R, and its crew read back the clearance.
But BFU says this coincided with a transmission from the Cessna. The controller heard the 777F crew's readback and then the words "eight right" from the Cessna pilot.
Both aircraft then began to move, the 777F beginning its take-off run while the Cessna moved into departure position on the runway. The 777F had been travelling at around 80kt when its crew saw the Cessna moving, and had reached 109kt before the take-off was aborted.
BFU says the 777F came to a halt 789m (2,590ft) from the Cessna, according to radar data. Weather conditions and visibility at the time were good.
The Cessna pilot claimed to have heard a take-off clearance for his aircraft over the radio, and had assumed that he was being allowed to depart ahead of the freighter to avoid wake-turbulence problems.
While BFU does not identify the carrier involved, Leipzig flight records show that the timing of the 21 April 2013 incident matches that of a AeroLogic 777F service to Bergamo. BFU has not issued conclusions or recommendations in its inquiry into the event.