Lawyers for the five airport employees who are defendants in the case asked the court on Thursday to send the case back to prosecutors, saying the investigation had missed crucial evidence. But the judge rejected those requests.

De Margerie was killed in October 2014 along with three air crew when his jet hit the snow plow as it was taking off from Moscow's Vnukovo airport in the middle of the night.

The trial has been postponed several times and Russia's IAC civil aviation investigative body has yet to release its report about the crash, which critics say exposed the country's patchy air safety record.

(Reporting by Dmitry Solovyov; Editing by Christian Lowe)