Two workers at Moscow’s Vnukovo airport have told a Russian court they bear responsibility for the death of former Total chairman and CEO Christophe de Margerie in an October 2014 ground accident at the airport. De Margerie’s corporate jet was struck by a snowplow in the late evening hours of Oct. 20 as it prepared to take off for Paris, The 63-year-old French executive had been talking to Russian prime minister Dmitri Medvedev about future investment in the country. The jet’s three crew members also died.

Total was and still is one of the biggest foreign investors in Russia. The oil and petrochemicals producer had just announced a doubling of investment in the country before the invasion of Ukraine led to European sanctions. Initial reports from Russia said the snowplow driver, Vladimir Martynenko, was inebriated at the time of the accident. His lawyer later said his client suffered from a heart condition.

In court, Martynenko admitted he had driven his vehicle onto the runway. Duty engineer Vladimir Ledenev, who supervised the airport team of workers on the night of the crash, pleaded guilty to failing to prevent the accident. Three air traffic controllers pleaded not guilty. All five reportedly spent 11 months in jail.

Observers commenting to news agencies said the admissions of guilt will make it difficult for the court to reach any verdict thing other than that a breach of airport safety standards led to the accident. Immediately following the crash, Total appointed two interim replacements for de Margerie . Thierry Desmarest served as chairman of the petrochemicals giant until his retirement at the end of 2015, and Patrick Pouyanné served as interim CEO beore adding the chairman’s job following Desmaret’s departure.