The two jets were flying over the Arabian Sea on January 7th when the incident took place, the German Federal Bureau of Aircraft Accidents Investigation (BFU) revealed on Tuesday.
The Airbus A380 and the Challenger 604 flew past each other at the regulation altitude difference of 300 metres. But 48 seconds later, when the planes were already separated by a distance of 27 kilometres, the small jet hit the turbulence caused by the Airbus.
The 20-tonne machine spun several times on its axis and dropped 2,500 metres before the pilot was able to wrestle back control and land the plane in Oman.
Four passengers and a stewardess, all of whom were not wearing safety belts, were injured. The plane was also seriously damaged in the incident.
“We need to now clear up what measures could prevent something similar happening in the future,” said BFU spokesman Germout Freitag.