The missing EgyptAir Airbus that crashed into the Mediterranean Sea two weeks ago was forced to turn around and make an emergency landing at least three times in the 24 hours before it disappeared, according to reports.
French media claim the aircraft made six rotations between Asmara, in Eritrea, Cairo, Tunis and Paris, before it suddenly disappeared from radar screens on May 19.
According to France 3, in its different rotations between 18-19 May, ACARS -Aircraft Communications Addressing and Reporting System - messages sent to the ground signalled anomalies on board shortly after takeoff from three airports.
Airlive said the exact nature of the calls was unknown, but each alert led to "a technical audit on the ground". Despite this, the plane was repeatedly allowed to take off again and continue on its journey.
The claims were put to former aviation security official Jean-Paul Troadec, who Euronews quoted as saying: “These new findings are an important element for the investigators.
"We cannot presume to know know exactly what happened on board but it’s not entirely normal to turn around several times after a technical incident without finding anything.”
The missing Airbus 320 was flying from Paris to Cairo when it disappeared over the Mediterranean with 66 people on board, triggering a flurry of speculation as to the cause, including suggestions it was brought down by terrorists.
The emergency landing claims come after French authorities on Wednesday confirmed that one of its search ships, Laplace, picked up signals from deep under the Mediterranean Sea from one of EgyptAir's black boxes.
"The French vessel 'Laplace'... has received through its search equipment signals from the seabed of the wreckage search area assumed to be from one of the data recorders," a statement Wednesday by the Egyptian Aircraft Investigation Committee said.
Although investigators did not identify the location in the Mediterranean Sea of the signal, they added a second ship, with deep sea divers aboard to retrieve the flight recorders, will arrive at the site later this week.
COMBING THE SEAS
Ships and planes from Egypt, Greece, France, the United States and other nations have been combing the Mediterranean north of the Egyptian port of Alexandria for the jet's voice and flight data recorders, as well as more bodies and parts of the aircraft.
The French naval ship Laplace, a research vessel that specialises in underwater searches, has picked up the signal of a detector attached to one of the recorders of flight MS804, according to the Alseamar company, which operates the onboard equipment.
A second ship, the SV John Lethbridge, which is affiliated with the Deep Ocean Search firm, will join the search later this week. The 75-meter-long survey vessel is equipped with sonar and a remotely operated underwater vehicle that can search up to 6,000 meters deep.
Egypt's President Abdel-Fattah el-Sissi said an Oil Ministry submarine will head to the crash site to search for the black boxes, but Ayman al-Moqadem, the head of the investigation team, said the submarine is not equipped to detect flight recorder signals.
RECOVERING THE BLACK BOXES
Search teams will now work to find and recover the black boxes, which are mounted in the tail sections of planes and designed to survive crashes intact.
The black boxes should lead searchers to the crash site, which the investigation team believes to be within a 3-mile area. Then they'll have to develop a plan for recovering the boxes.
"The main question now is how deep the black boxes are and what is the equipment capable of pulling them up," said Tawfiq al-Assi, former head of EgyptAir. "It will be a huge challenge if the black boxes are resting at a depth of more than 3,000 (meters)."
Once the black boxes are retrieved, the search will continue for the rest of the wreckage.
WHAT THE RECORDERS CAN TELL US
The black boxes may help investigators determine what happened to the Airbus plane, which crashed hours after taking off from Paris on May 19 bound for Cairo.
Egypt's civil aviation minister Sherif Fathi has said he believes terrorism is a more likely explanation than equipment failure or some other catastrophic event. But no hard evidence has emerged on the cause, and no militant group has claimed to have downed the jet. Earlier, leaked flight data indicated a sensor detected smoke in a lavatory and a fault in two of the plane's cockpit windows in the final moments of the flight.
The voice recorder should contain a record of the last 30 minutes in the cockpit, and is equipped to detect even loud breathing. The data recorder would contain technical information on the engines, wings and cabin pressure. Investigators hope the black boxes will offer clues as to why there was no distress call.
"The information will direct the investigation in a certain direction," said Hany Galal, a retired pilot and plane crash investigator.