UK Edition
Did pilot's mobile phone play a role in EgyptAir 804 crash?
French investigators are probing whether an EgyptAir jet may have crashed into the Mediterranean last May after lithium batteries on a pilot's mobile phone and tablet overheated and sparked a fire.
There is a "troubling parallel" between where the fire broke out in the cockpit zone on board Flight 804 and the spot where the co-pilot of the Airbus A320 had placed his phone and tablet on the glare-shield above the instrument panel, said Le Parisien newspaper citing an air transport gendarmerie investigation.
However, one air expert questioned the theory, saying that the most "plausible" cause of the tragedy remained that of fire in the avionics bay beneath the cockpit, sparked either by a short circuit or explosion. Industry experts also questioned whether it was plausible for a pilot to have taken off with his phone on the dashboard.
France is conducting judicial and civil inquiries into the disaster, which killed all 66 people on the plane en route to Cairo on an overnight flight from Paris.
The black boxes suggest that the plane broke up in mid-air following a fire in the cockpit or vicinity - perhaps beneath in the avionics bay.
The Egyptians have stated that terrorism may have been to blame after reporting that explosives had been found on the remains of passengers. French investigators, however, have homed in on data pointing to an accidental fire in the area of the flight-deck and next-door lavatory.
Initial alerts indicated a string of malfunctions with the windows on the right-hand flight deck window next to the co-pilot, with the message "3044 anti-ice right window". Smoke alerts ensued in the adjoining lavatory and hold, along with an order from the captain to the co-pilot to put out a fire.
CCTV cameras at Charles de Gaulle airport clearly show the personal belongings lying on the glare-shield, said Le Parisien.
“The images very clearly indicate that the Egyptian co-pilot put his telephone, tablet and bottles of perfume bought before boarding on the glare-shield,” the paper said. There were no security issues with the devices when the co-pilot passed through the normal airport security controls, it went on.
“The investigators hence note a troubling parallel between the placing of these items that are fed by lithium batteries and the triggering of alarms during the flight,” it added.
The stability of lithium batteries has been the subject of controversy. Some are banned from aircraft and certain models in mobile devices have been known to overheat and catch fire. In December 2010, a fire broke out in an Air France flight from Atlanta to Paris when a lithium battery jammed under a seat. ignited. A small fire also broke out on a device being charged in May 2013 on another Air France jet, flying from Paris to Sao Paulo, Brazil.
However, David Learmount, operations and safety editor at Flight International magazine and a former pilot, said he thought the idea that mobile devices were the cause was a "red herring".
"Firstly, pilots don't leave objects on the dashboard because they know the they will end up in their lap when they take off or on the floor and they'll get airborne in turbulence and could jam the controls."
"Also, a phone bursting into flames just below the windscreen is a fairly spectacular thing to take place on a flight, and they would have told somebody on the ground. Nobody has mentioned this.
"But the key point is while there were warnings about the window heating systems, there were also smoke alarms in the toilet and avionics bay under the floor. How would the fire have got under there? It doesn't make sense."
"My guess is the little computer in the avionics bay was damaged by fire; and issued spurious warnings, which were in fact the box screaming for help." This could have been started by a short circuit or explosion, he said.
The reported findings came as Egypt is to return the remains of 15 French passengers from the flight next week.
In media briefings not open to the wider public, French investigators voiced scepticism over Egyptian claims that explosives might have been placed on board the aircraft in Paris.
Officially the French air accident agency, the BEA, said it considers it "not possible at this stage to draw any conclusions on the origin of the accident". Egyptian authorities, it said, had failed to provide sufficiently “detailed information on the conditions in which the samples and measures were taken that led to the detection of explosive traces".
There was no response from French investigators on Friday.
Apple, the manufacturers of the iPhone and iPad devices used by the pilot, on Friday said it had not been contacted by "any authority investigating this tragic event", which indicated these did "not believe our products are in any way involved".
"We have not seen the report but we understand there is no evidence to link this event to Apple products. If investigators have questions for us, we would of course assist in any way we can," it said.
"We rigorously test our products to ensure they meet or exceed international safety standards."