EgyptAir Flight MS804 is feared to have crashed into the Mediterranean Sea after disappearing from radar screens en route between Paris and Cairo overnight.
The Airbus A320 went missing shortly after leaving Greek airspace at 02:45 Cairo time (0:45 GMT) on Thursday.
The plane was carrying 56 passengers, including three children, along with seven crew members, and three security personnel.
Those on board included 15 French passengers, 30 Egyptians, two Iraqis, one Algerian, one Belgian, one Briton, one Canadian, one Chadian, one Kuwaiti, one Portuguese, one Saudi, one Sudanese.
EgyptAir said the plane was at a height of 37,000ft (11,300m) and had just entered Egyptian airspace when it disappeared.
The Greek defence minister said data suggests Flight MS804 swerved 90 degrees right, then 360 degrees left as it rapidly dropped from 37,000 feet.
The Greek civil aviation department issued a timeline of events surrounding the disappearance of the plane:
Greece’s civil aviation department has issued this timeline on MS804 last moments and attempts to reach it:
02:24: EgyptAir flight 804 from Paris to Cairo enters Greek airspace, air traffic controller permissions it for the remainder of its course.
02:48: 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: 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: It is above the exit point (from Greek airspace).
03:39:40: The aircraft signal is lost, approximately 7 nautical miles south/southeast of the KUMBI point, within Cairo FIR. Immediately the assistance of radars of the Hellenic Air Force is requested to detect the target, without result.
03:45: The processes of search and rescue are initiated, simultaneously informing the Flight Information Region of Cairo.
A major search and rescue operation is underway involving the Greek and Egyptian militaries. France has also offered to send boats and planes to aid in the search efforts.
Neither French nor Egyptian officials have commented on what may have happened to the plane.
Airbus confirmed the loss of the aircraft, and said it entered service in November 2003 and had accumulated approximately 48,000 flight hours.