The cosmonaut Yuri Gagarin – the 1st man to have travelled into outer space on his Vostok 1 spacecraft on April 12, 1961 – died on March 27 1968. However, the precise cause of the jet crash remains uncertain.
Colonel Gagarin and his instructor Vladimir Seryogin (as Gagarin, director of the Star City, had to obtain his fighter pilot rating again), flew a MiG-15 Midget that day, and they should not have kept the fuel tanks under their jet. As the spin turned into a deadly crash, it has been suggested since 1986 that the afterburner turbulence of a Sukhoi Su-11 Fishpot-C interceptor aircraft could have caused the MiG-15 to go out of control.
The MiG-15 had first been designed to intercept USAF nuclear-capable B-29s.
Some governmental documents were declassified in 2003. They revealed that in addition to the official investigations, the KGB tried to advance a new line of inquiry. Since then, it has been deemed that the accident could not be due to any conspiracy theory. Though little is certain about this mistery, you can click on the frame below to read further information: