Investigation participant of A321 flight confirmed information about explosion

YEREVAN, NOVEMBER 6, ARMENPRESS. The black boxes of the plane recorded the sound of the explosion. “Armenpress” reports about this, citing CNN.

The clues emerging so far about the final moments of Metrojet Flight 9268 don't paint a clear picture of what happened to the doomed passenger jet.

Was a midair heat flash that a U.S. satellite detected over the Sinai Peninsula when the flight went down a sign of an explosion aboard the plane? And if that was the case, why haven't investigators found signs of an explosive impact on the crash victims' bodies, as Russian state media reports? Could the plane's wreckage show that a past repair went awry?

There are a wide range of theories on what made the passenger jet plunge to the ground, killing all 224 people on board, but Russian officials say it's too soon to speculate on the cause.

Aviation experts agree, and officials have downplayed an apparent claim by Islamic militants that they brought down the Airbus A321-200, saying technical failure is the most likely reason for the crash.

Here's a look at the evidence investigators are looking at:

Radar

Flight 9268 was on its way from the Egyptian resort of Sharm el-Sheikh to St. Petersburg early Saturday when it dropped off radar about 23 minutes into the flight, Egyptian officials say.

Air traffic controllers apparently didn't receive any distress calls.

The website Flightradar24, which tracks aircraft around the world, said it had received data from the Russian plane suggesting sharp changes in altitude and a dramatic decrease in ground speed before the signal was lost.

Egyptian officials have said they are finishing fieldwork first, and then will go on to investigate the data in the black boxes. Experts started retrieving data from the recorders on Monday, Egypt's Civil Aviation Ministry said.

Russia's privately owned Interfax news agency quoted an unnamed source in Cairo as saying the plane's cockpit voice recorder had captured uncharacteristic sounds the moment before the flight disappeared.

It cited the source as saying that an "unexpected' and "nonstandard (emergency)" occurred "instantly," which was why the pilots failed to send an emergency or alarm signal.

A top Russian aviation official has said the plane broke apart in midair. Sounds in the black-box recording could help investigators determine what caused that to happen, said Peter Goelz, a CNN aviation analyst and former managing director of the U.S. National Transportation Safety Board.