MOSCOW (Reuters) - Two Moscow airport workers admitted responsibility on Thursday for the death of Christophe de Margerie, the CEO of Total and a staunch defender of Russia's energy policies, whose plane collided with a snow plow as it was trying to take off.

The snow plow driver, Vladimir Martynenko, and duty engineer Vladimir Ledenev - two of five suspects in the case - both pleaded guilty to causing Margerie's death in October 2014.

That will make it difficult for the court to rule that anything other than a breach of airport safety systems led to Margerie's death.

His family has not publicly commented on the case.

The French energy group's chief executive, who died along with three air crew, oversaw multi-billion-dollar Total investments in Russia and was killed just as the conflict in Ukraine raise tensions with the West to levels not seen since the Cold War, triggering economic sanctions against Moscow.

Martynenko admitted in court that he had driven his snow plow onto the runway, colliding with Margerie's jet. Ledenev, who was in charge of the team of airport workers on the night of the crash, pleaded guilty to failing to prevent the accident.

The three others charged in the case, all air traffic controllers, pleaded innocent.

All five suspects were released from jail last year after about 11 months inside.

(Reporting by Gennady Novik; Writing by Maria Tsvetkova; Editing by Louise Ireland)