Investigators said crew error was the cause of a Feb. 13 Ukraine South Airlines Antonov AN-24 crash at Donetsk airport, which killed five.

First reports said the aircraft overshot the runway, while later reports said the accident happened when the pilots were trying to land in fog. The aircraft was on a domestic flight from Odessa.

Ukraine Vice Prime Minister Alexander Vilkul was quoted by Interfax as saying the cause of the crash was a “loss of speed by the aircraft during landing approach due to an error of the unprepared crew, which had no clearance to make the flight in those weather condition.” He added nine unregistered passengers were onboard, which is against Ukraine Air Code.

The investigation team did not find fault with the air traffic control management performance and said the crew received correct information about weather conditions.

Authorities are holding a pre-trial inquiry, which may result in bringing charges against those responsible for the accident, according to Interfax.

Following the crash, Ukraine’s aviation authorities grounded operations of the local charter. There were 52 people onboard, including eight crew and 44 passengers who were soccer fans traveling to a championship league match.