An EgyptAir flight traveling from Paris to Cairo went missing in the early hours of May 19 about 16 kilometers (10 miles) into Egyptian airspace, according to information released by the airline. The Airbus A320 was reportedly flying just under 37,000 feet at the time it disappeared from radar. A company official said the pilots did not make a distress call or indicate any trouble ahead of the plane's disappearance. 

 

Mechanical failure at cruising altitude is unlikely — such an event typically occurs at takeoff or landing, when stress on the aircraft is at its highest. Catastrophic failure of the airframe cannot be ruled out. A surface-to-air missile strike is also possible, though militants in Egypt and surrounding areas are not believed to have access to missiles capable of hitting an aircraft at that altitude.

 

Detonation of an improvised explosive device is a more obvious possibility. Unlike the bombing of Metrojet Flight 9268 from the Sinai city of Sharm el-Sheikh in October 2015, however, EgyptAir Flight 804 originated in Paris. Security measures at Charles de Gaulle Airport are stringent compared with those of many other airports, and security has been raised since the recent attacks in Paris and Brussels. But even a relatively small and unsophisticated IED in either the passenger cabin or the cargo hold could significantly damage a plane at cruising altitude and lead to flight complications.

 

Inside assistance contributed to the success of the Metrojet 9268 bombing, and if the cause of this flight's disappearance was an attack rather than an accident, some degree of insider involvement is likely. A cargo handler (as in the Metrojet case), a crew member, or even a pilot (as in the 1999 EgyptAir Flight 990 crash or the March 2015 Germanwings Flight 9525 crash) could have been involved.

 

The Egyptian government's civil aviation authority has reportedly sent search and rescue teams to determine more. Once the plane is located, its condition will be key to determining what caused its disappearance. An electrical failure, for instance, would likely enable pilots to glide the plane toward the ground and prevent a catastrophic disintegration, meaning the debris field would be small. An intentional crash would also leave a small debris field. An IED or projectile, on the other hand, would cause a catastrophic breakup of the aircraft — especially considering the plane's high altitude — and the debris field would be much wider.