What Caused EgyptAir Flight MS804 To Crash? Theories On What Happened When The Plane Lost Contact Over The Mediterranean

Early Thursday morning an EgyptAir flight from Paris to Cairo went missing over the Mediterranean, just about 175 miles off the Egyptian coast. Before it disappeared from radar, the plane was traveling at 37,000 feet with 66 people on board, including three children. At 2:45 a.m. Cairo time, the plane vanished from radar, and at 4:26 a.m. the Egyptian military received a distress signal. No contact has been made since, and the Associated Press has since reported that the plane crashed. So what caused EgyptAir Flight MS804 to crash? Update: An Egyptian plane has located two orange items believed to be from the missing plane, fueling suspicion that it crashed.

Officials don't know yet. The Egyptian aviation officials that confirmed the plane had crashed — telling the AP that the "possibility that the plane crashed has been confirmed" —based their reasoning on the fact that the plane hasn't landed at any airports in the region. They were speaking on condition of anonymity to the AP.

The official word from the Egyptian civil aviation ministry is that it's too early to say. The debris has not been found, and any number of things could have brought down the plane, from a mechanical failure to a terrorist attack. At this point the French authorities, who will be assisting the Egyptian investigators, haven't ruled out any possible causes, Prime Minister Manuel Valls said on RTL radio Thursday morning.

Again speaking on a condition of anonymity, the Egyptian officials told Reuters that they believe the jet came down in the sea. He said they won't know more about why, for quite a while. "All causes for the disaster are open, whether it is a major technical fault or a terrorist action or any other circumstance. This will be ascertained when we inspect the plane's wreckage and transcribe its black boxes," the source told Reuters.

The flight lost contact at cruising altitude, the safest portion of the flight. In recent years, planes that have crashed in similar circumstances have been brought down by a combination of pilot error and equipment malfunctions. The Air France flight 447 from Rio de Janeiro to Paris that crashed in the Atlantic was an Airbus 330; some of its airspeed sensors malfunctioned and then pilots argued over what was really happening, made the wrong moves, and it plummeted to the ocean below.

On Thursday's EgyptAir flight, though, whatever happened was very sudden. Ehab Mohy el-Deen, the head of Egypt's air navigation authority, noted the crew call in to report an engine failure or some other problem. "They did not radio for help or lose altitude," he said. "They just vanished." He didn't speculate on why this happened. "But," he added, "this is not normal, of course."

Initially it was believed that the plane did not lose altitude before disappearing, but according to Greek defense minister Panos Kammenos, the plane made some sharp turns before plummeting. "[It] turned 90 degrees left and a 360-degree turn to the right" and then dropped 20,000 feet," Kammenos said. Only after did it disappear from radar.

Jean-Paul Troadec, former president of the French air accident investigation bureau, was asked by Europe 1 to speculate on the cause of the crash. He said that due to the lack of contact from the crew, a technical failure is unlikely. Even an engine problem would have given them time to respond. "In this case, the crew did not react, which makes us think of a bomb," he told the television channel. A missile, like in the downing of the Malaysia Airlines flight over Ukraine would also be a possibility, he said.

There are reports from a Greek island, not far from where the plane lost contact, of residents seeing a fireball in the air at about the same time the plane disappeared from radar. Update: This was later confirmed as a hoax by BBC News. A merchant ship also saw it and a Greek defense ministry source said authorities are investigating. It is not confirmed to be the EgyptAir flight.

If it is a bomb, the question would be how it got on the plane. France has beefed up its security at airports since the terror attacks in Paris in November and Brussels in March. The 87,000 employees who have access to the airport's sensitive areas like the tarmac and baggage handling areas were reviewed. Several had their security badges revoked for a number of reasons. Rules limiting gels and liquids were also extended to cover airport personnel. This was the plane's fifth flight of the day. Earlier in the day it had been to airports in Tunisia and Eritrea.

The one and only cause that seems easy to rule out is weather. There were some storms in Europe as the plane took off and then traveled over the Alps, but by the time it reached the end of trip and entered Egyptian airspace, radar was clear. A NASA satellite was overhead and showed clear skies, according to a physics researcher at the University of Oxford.

The plane was an Airbus A320, which is used the world over. More than 6,700 are in operation. This specific plane was about 13 years old, built in 2003. According to a Boeing study, the A320 is one of the safest commercial planes in the sky. That said, a number have crashed in recent years — for about a dozen deadly accidents since the plane first entered service in 1988. The most recent was in March 2015 when a Germanwings flight crashed into the French Alps, an intentional move by the co-pilot who had suicidal tendencies.

What exactly happened will likely remain a mystery until the black boxes are recovered. That will no doubt be the top priority of Egyptian and French investigators.