Meteorological data from Lviv airport shows that it had been experiencing fog and reduced visibility around the time of a fatal Antonov An-12 landing accident.
Several special weather weather reports had been generated in the hour before the accident warning of fog and mist.
Visibility was down to 150m and the runway visual range for Lviv's runway 31 was down to 550m some 15min before the accident.
Ukrainian accident investigation authority NBAAI says the aircraft had been conducting its approach to land, in order to refuel, during a service between Vigo and Istanbul.
It says the An-12 experienced a "hard landing" about 1,500m from the end of runway 31. The aircraft suffered substantial damage and only three of the eight occupants survived.
There was no post-accident fire. The aircraft did not disintegrate, although it sustained severe damage to the engines and propellers on its high-mounted wings as well as a crushed cockpit.
Investigators have not indicated the characteristics of the descent profile, and have not confirmed the type of approach being undertaken. While the aircraft was planning to refuel, there is no immediate evidence that the aircraft was low on fuel at the time of the accident.