What caused EgyptAir flight MS804 to crash?

[Mary Naeem]

What caused EgyptAir flight MS804 to crash?

Aviation officials say the EgyptAir flight from Paris to Cairo with 66 passengers and crew on board has crashed.

It was last detected over the Mediterranean Sea. French prosecutors have opened an official investigation, with President Francois Hollande saying "no hypothesis is ruled out or favoured."
Here are the facts of the incident so far:
Take off from Paris
Flight MS804 left Charles De Gaulle Airport at 11.09pm Paris time (10.09pm BST). The airline initially said said there were 59 passengers on board but later revised the figure to 56 people, including one child and two babies. Three EgyptAir security personnel were on board as well as seven cabin crew members. Greece's civil aviation authority has released a timeline of plane's journey over Greece:
02:24 (00:24 BST) - EgyptAir flight 804 from Paris to Cairo enters Greek airspace, air traffic controller permissions it for the remainder of its course.
02:48 (00:28 BST) - The flight is transferred to the next air traffic control sector and is cleared for exit from Greek airspace. "The pilot was in good spirits and thanked the controller in Greek."
03:27 (1:27 BST) - Athens air traffic control tries to contact the aircraft to convey information on the switch of communications and control from Athens to Cairo air traffic.
In spite of repeated calls, the aircraft does not respond, whereupon the air traffic controller calls the distress frequency, without a response from the aircraft.
03:29 (1:29 BST) - It is above the exit point (from Greek airspace).
03:39:40 (1:39 BST) - The aircraft signal is lost.
Immediately the assistance of radars of the Hellenic Air Force is requested to detect the target, without result.
03:45 (1:45 BST)- The processes of search and rescue are initiated, simultaneously informing the Flight Information Region of Cairo.
The plane was 10 miles into Egyptian airspace when it disappeared at 2:45 a.m. Egypt time (1:45am BST). Greek air traffic controllers were in contact with the pilot as it passed through Greek airspace shortly before, flying at 37,000 feet. It then crossed into Egyptian airspace and made "sudden swerves", the Greek defence minister said. Egyptian officials say the plane sent out a distress signal about 10 minutes before it vanished from radar screens. Military search and rescue operations received the SOS from the plane's emergency devices at 2.26am (1.26am BST). Airbus issued a statement saying it 'regrets to confirm that an A320 operated by EgyptAir was lost at around 02:30 am (Egypt local time) today over the Mediterranean sea'. Egyptian aviation officials say they believe it has crashed into the sea. Contact was lost around 30-40 miles north of Egypt’s coast Search and rescue efforts by the Egyptian air force under way in the area. Weather conditions
Clear skies were reported in the area where the plane went missing. Type of plane
The Airbus A320 was built in 2003. It was on its fifth journey of the day. The captain has 6,275 flying hours, including 2,101 on the A320, EgyptAir said. The copilot has 2,766. The Telegraph News