Top Russian airport officials quit on Thursday as more employees were detained over the Moscow plane crash that killed the CEO of French oil giant Total.
The driver of the snowplough that collided with Total boss Christophe de Margerie's plane as it was taking off from Moscow's Vnukovo airport late Monday was also ordered to be held for two months behind bars for further questioning.
The new staff detained in the probe include a trainee air traffic controller who directed the doomed plane, her immediate supervisor and their boss and the head of the department responsible for clearing the runways.
"The investigation suggests that these people did not respect the norms of flight security and ground operations, which led to the tragedy," said the powerful Investigative Committee in charge of the probe.
Vnukovo airport also said its general director and his deputy had resigned "due to the tragic event" after the management was accused of "criminal negligence" by investigators.
However they have not been detained.
Funeral on Tuesday
De Margerie, 63, was killed along with three crew members when the private jet hit the snowplough as it was taking off shortly before midnight and burst into flames.
He will be buried on Tuesday in a private funeral in Normandy in northern France, a day later than first announced by local officials.
"The burial has been postponed until Tuesday," a local source said, citing information from a funeral home in Granville. No reason was given for the delay.
A Moscow court ruled that the 60-year-old snowplough driver, who was detained immediately after the crash, be kept in custody for two months after investigators said he was drunk at the wheel.
The court said Vladimir Martynenko had a blood alcohol content of 0.6 grams of ethanol per litre of blood, compared to the legal limit of zero for driving in Russia.
Interfax news agency reported that he had admitted drinking coffee with a liqueur.
Martynenko, still wearing his work uniform, did not speak at Thursday's hearing.
But his lawyer Alexander Karabanov said afterwards that Martynenko "does not admit guilt, he admits his involvement".
Russian investigators, who have been joined by French experts, released details of the final few seconds before the crash after a preliminary probe of air traffic control data and the doomed jet's black boxes.
Experts from Russia's Interstate Aviation Committee, MAK, said that the runway had been clear when the Total plane was given clearance to take off.
"After the plane started moving the crew noticed an object identified by them as 'a car crossing the road'," official Alexey Morozov told journalists.
"The observation of this object did not cause concern for the crew and the take-off was continued as normal," he said.
Fourteen seconds later the plane collided with the snowplough as it took off at a speed of some 250 kilometres (155 miles) per hour, the expert said.
Martynenko had previously told investigators in footage of his questioning shown on television that he "lost my bearings" and failed to notice he was on the runway.
In Paris on Wednesday, Total named new bosses to replace De Margerie at the head of a group which posted 190 billion euros ($240 billion) in revenues last year and employs 100,000 people.
The board brought back Thierry Desmarest -- who was both chairman and chief executive at Total from 1995 to 2007 -- as chairman of the group.
Philippe Pouyanne, who currently heads the refining and chemicals division, was named chief executive.
De Margerie had been chief executive of Total since 2007 and spent his entire 40-year career at the group.
A descendant of a family of diplomats and business leaders, De Margerie was the grandson of Pierre Taittinger, founder of the eponymous champagne and luxury goods dynasty.
Married with three children and highly regarded within the oil industry, he was known for his jolly nature.
Not one to shy from controversy, De Margerie was an outspoken critic of Western sanctions against Russia over the Ukraine crisis.
Even as relations between the West and Russia deteriorated to the worst since the Cold War, he had criticised the sanctions as a "dead-end".
Vedomosti business daily said in an editorial Thursday that De Margerie was "one of the most active investors of the Russian oil and gas sector" and that his death -- caused by "elementary" management failures -- was emblematic of Russia's increasingly dire investment climate.