An EgyptAir jet sent a series of signals indicating that smoke had been detected on board before it crashed into the Mediterranean on Thursday, France’s air accident investigation agency said on Saturday.
A spokesman for the BEA agency said the signals did not indicate what caused the smoke or fire on board the plane, which plunged into the sea with 66 people on board as it was heading from Paris to Cairo.
But they offered the first clues as to what unfolded in the moments before the crash.
One aviation source said that a fire on board would likely have generated multiple warning signals, while a sudden explosion may not have generated any though officials stress that no scenario, including explosion, is being ruled out.
Egypt said its navy had found human remains, wreckage and the personal belongings of passengers floating in the Mediterranean about 290 km (180 miles) north of Alexandria.
The army published pictures on Saturday on its official Facebook page of the recovered items, which included blue debris with EgyptAir markings, seat fabric with designs in the airline’s colours, and a yellow lifejacket.
Analysis of the debris and recovery of the black boxes are likely to be key to determining the cause of the crash – the third blow since October to Egypt’s travel industry, still reeling from political unrest following the 2011 uprising that ousted Hosni Mubarak.
A suspected Islamic State bombing brought down a Russian airliner after it took off from Sharm el-Sheikh airport in late October, killing all 224 people on board, and an EgyptAir plane was hijacked in March by a man wearing a fake suicide belt.
The October crash devastated Egyptian tourism, a main source of foreign exchange for a country of 80 million people, and another similar incident would crush hopes of it recovering.