Urgent.. Causes of a plane crash with 66 passengers on board at sea

A new investigation has shown that the cause of a plane crash in the Mediterranean in May 2016 was the pilot lighting a cigarette in the cockpit.

The pilot on board EgyptAir Flight MS804 lit a cigarette in the cockpit, causing oxygen to leak from the emergency mask, according to the investigation published by the New York Post.

66 passengers and crew died when an Airbus A320 flying from Charles de Gaulle Airport in France to Cairo, Egypt in May 2016 crashed in the Mediterranean Sea south of the Greek island of Crete, under mysterious circumstances.

Among the dead were a Briton, 12 French tourists, 30 Egyptians, two Iraqis and a Canadian.

After a major search mission involving the US Navy, the plane's black box was found in deep waters near Greece.

The Egyptian authorities claimed at the time that the plane had gone down in a terrorist attack, although no group has claimed responsibility.

An official investigation concluded that smoke from the pilot's cigarette accidentally leaked oxygen from the emergency mask.