MOSCOW - Russian investigators on Tuesday accused senior airport officials of criminal negligence over a plane crash at a Moscow airport that killed the CEO of French oil giant Total, Christophe de Margerie, whose private jet hit a snowplough on takeoff.

Several executives would be suspended, the investigators said, adding that the driver of the snow-clearing machine was drunk on the job - a claim disputed by his lawyer.

At Total, one of the world’s biggest oil companies, staff at its Paris headquarters observed a minute’s silence for their 63-year-old boss who had been known by the affectionate nickname “Big Moustache” for sporting one.

“The group is set up to ensure the proper continuity of its governance and its activities, to deal with this tragic event,” Total’s secretary general Jean-Jacques Guilbaud said, as top executives were due to hold an emergency meeting.

While respected by the industry for expanding Total’s activities around the world, De Margerie was also often mired in controversy as he led the group when it was embroiled in judicial woes, including the UN “oil-for-food” scandal.

Just hours before the crash, De Margerie had met Russian Prime Minister Dmitry Medvedev at his country residence outside Moscow to discuss foreign investment in Russia, the Vedomosti business daily reported, despite Western sanctions over Moscow’s role in the Ukraine conflict.

Even as relations between the West and Russia deteriorated to the worst since the Cold War, the French oil boss had been critical of the sanctions, calling them “a dead-end” and urging “constructive dialogue” instead.

In his last public remarks in Moscow, De Margerie urged Russia to “do the necessary to fix the situation” with the West. But he also said Total’s strategy “remains absolutely unchanged. We are engaged with Russia”.

Russian President Vladimir Putin described De Margerie as “a true friend of our country, whom we will remember with the greatest warmth”.

In France, President Francois Hollande said he learnt of De Margerie’s death with “shock and sadness”, while Prime Minister Manuel Valls said France had lost “a great captain of industry and a patriot”.

Total said De Margerie died around 2000 GMT after the crash at Vnukovo Airport, along with three crew members.

Vnukovo airport said the Falcon Dassault business aviation jet crashed as it prepared to take off for Paris and that rescue services had put out a blaze.

Visibility was 350 metres (yards) at the time, it said, as Moscow saw its first snowfall of the winter on Monday.

The Interstate Aviation Committee, which investigates all Russian air accidents, said “it has been established that the driver of the snowplough was in a drunken state”. It added that a preliminary theory was that “an error by air traffic controllers and the actions of the snowplough driver” were to blame.

The possible role of “bad weather and errors by pilots will also be checked,” it said, as France dispatched three experts to join in the investigation. The committee also blamed senior airport officials for causing the accident through “criminal negligence” as they failed to ensure proper staff coordination. Moscow transport investigators said they had opened a criminal probe into breaches of aviation safety rules causing multiple deaths through negligence, which carries a maximum jail term of seven years.

The snowplough driver has been detained, but his lawyer suggested that his client was being made a scapegoat. “My client has chronic heart disease, he doesn’t drink at all. His relatives and doctors can confirm this,” lawyer Alexander Karabanov told Interfax news agency.

 “We don’t want the responsibility for the accident to be shifted to just another ordinary man,” he added.

De Margerie had been chief executive of Total, Europe’s third largest oil company after Shell and BP, since 2007 and spent his entire 40-year career there.

A descendant of a family of diplomats and business leaders, he was the grandson of Pierre Taittinger, founder of the eponymous champagne and the luxury goods dynasty.

Married with three children and highly regarded within the oil industry, he was known for his good humour.

Employees at Total’s headquarters remembered a man who never neglected to say “bonjour” when he popped down to smoke a cigar. “He had a very human side, very close to his employees,” said Sylvie, who works in the company’s human resources division.

De Margerie had taken over the helm of Total at a challenging time for the group. Shortly after his nomination, he was handcuffed and taken into police custody for more than 24 hours over corruption claims in deals with Iran. He also had to defend Total against allegations of corruption during the UN “oil-for-food” programme in Iraq.