CAIRO (BLOOMBERG) - Authorities looking for the doomed EgyptAir flight 804 continued their search for data records and more debris as President Abdel-Fattah El-Sisi ordered the deployment of a submarine to help with the operations five days after the Airbus A320 lost contact with radar over the Mediterranean Sea.
A French television channel reported that the pilot spoke to air traffic control in Egypt for several minutes about smoke in the cabin just before the plane, flying from Paris to Cairo, went down with 66 people on board.
France's accident investigator BEA said over the weekend that the plane generated automatic radio messages about smoke in the front portion of the cabin minutes before disappearing.
The electronic signals offer a puzzling twist to what may have happened to the flight, which crashed about 290 km off the Egyptian coast. The aircraft had smoke in the front part of the cabin, BEA said on Saturday. Two error messages, the first at 2.26 am local time, suggested a fire on board, while later alerts indicated some type of failure in the plane's electrical equipment.
Mr El-Sisi, in a televised speech on Sunday, warned against jumping to conclusions about why the aircraft crashed. He said a submarine belonging to the Oil Ministry would help in the search, which now focuses on retrieving the aircraft's voice and data recorders, known as black boxes despite their bright orange color.
"All scenarios are open," he said in his first public comments since the Thursday disaster that has so far not provided any obvious explanation. "It's important that we don't assume that a certain scenario happened."
The UK's Independent newspaper, citing a French television channel M6 that in turn quoted unidentified French aviation officials, reported that the pilot had a "conversation several minutes long" with Cairo control about the smoke that engulfed parts of the aircraft and decided to make an emergency descent to clear the fumes.
The push for caution is critical for Egypt, whose tourism industry suffered a major blow after a Russian passenger jet crashed into the Sinai peninsula in October. Islamic State in Iraq and Syria (ISIS) took credit for that crash, even as Egyptian investigators have resisted ascribing it to terrorism pending the completion of the probe. There have been no claims of responsibility from any militant group in the case of Flight 804.
The few clues that have surfaced so far from the wreckage offer no clear direction. The initial investigation report will be released in a month, Egypt's state-run Al-Ahram newspaper reported, citing probe head Ayman El-Mokadem.
While similar signals have preceded air accidents in the past, the warnings aren't associated with a sudden disappearance from radar as occurred with the Airbus A320 over the Mediterranean. A Malaysian Airlines flight shot down over Ukrainian airspace in July 2014 broke apart so quickly that on board systems didn't have time to send distress messages.
"It's too long for an explosion and too short for a traditional fire," said Mr John Cox, a former A320 pilot who is president of the Washington-based consultancy Safety Operating Systems. "It says we have more questions than we have answers."
Spanning three minutes, the warnings were followed by alerts that fumes were detected by smoke detectors, one in a lavatory and the other in the compartment below the cockpit where the plane's computers and avionics systems are stored, according to the Aviation Herald.
In the case of a mid-flight fire, the pilots would have been expected to radio a distress call and begin attempts to divert, Cox said.
The transmissions, which are automatically sent to ground stations so airlines can monitor whether a plane needs maintenance, will probably provide valuable clues once they're matched up against the plane's crash-proof flight recorders.
Mr El-Mokadem said the cockpit voice and flight-data recorders had not been found, refuting a CBS News report on Saturday that they had been located. It took salvage crews years to locate and recover the devices from the Air France AF447 flight that went down in the Atlantic Ocean in 2009. Malaysian Airlines MH370 still hasn't been found more than two years after it disappeared.
Egypt's army has released both images and video footage of Flight 804 debris that show an intact yellow life jacket lying beside wrecked seat cushioning, tattered clothes and EgyptAir- branded metal plane parts, quashing hopes of finding any survivors.
The condition of those remains and the way debris was found scattered may offer some clues about how the plane went down, with a wide field of small pieces pointing to a mid-air breakup. Large chunks of wreckage might suggest the aircraft hit the water largely intact.
The flight lost contact in the middle of the night in the wider area of the Strabo trench in the so-called Hellenic Arc in the seas south of Greece, where waters are as much as 3,000m deep. The wreckage was discovered about 290km north of the Egyptian city of Alexandria, authorities said.