Yeah um, "don't light up a smoke when you're flying a freaking Airbus" should be a no-brainer. Apparently it's not though:

A passenger jet that crashed killing all onboard was brought down by the pilot having a cigarette in the cockpit, an investigation has found.

The pilot onboard EgyptAir flight MS804 lit a cigarette in the cockpit, causing oxygen leaking from an emergency mask to combust.

A total of 66 passengers and crew died when the Airbus A320 which was travelling from Paris Charles de Gaulle in France to Cairo, Egypt in May 2016 crashed into the Mediterranean Sea south of the Greek island of Crete in mysterious circumstances.

The plane made violent swerves before falling into a "death spiral" over the Med.

If you're ever in the cockpit with a pilot and he lights one up, there's really only one thing to say:

If you're wondering just how they determined how it all went down:

The setting on the oxygen mask had been switched by a maintenance engineer from normal to emergency, the experts said, as reported by the Italian newspaper Corriere Della Sera.

This caused the mask to emit oxygen, creating a highly volatile situation.

A hissing sound made by escaping oxygen was identified by investigators at around 2.25am on the morning of May 19, just minutes before the passenger jet crashed into the sea.

Thankfully, smoking on EgyptAir flights has now been banned. But how was it not already banned in 2016???

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