EgyptAir flight MS804 crash: US officials and analysts believe 'catastrophic event' downed plane from Paris to Cairo

They said it was unclear whether an explosion or technical failure could be the cause

Families of passengers who were on board missing EgyptAir flight outside Cairo International airport (KHALED DESOUKI/AFP/Getty Images)

US officials and analysts believe a “catastrophic event” downed EgyptAir flight MS804, although the cause remains uncertain.

An anonymous intelligence source said the plane’s flight path and high speed of its descent suggested it “fell like a rock”.

"All indications are that a catastrophic event took down the aircraft" as it passed over the Mediterranean Sea, they told CBS News, but it was unclear whether a mechanical failure, terror attack or other deliberate act was to blame.

Egyptian officials said suspected wreckage from the Airbus A320 was found alongside passengers’ belongings on Friday morning.

It was being taken to Cairo for analysis and could provide vital clues into the plane’s final moments.

American reconnaissance satellites did not detect evidence of a large explosion on board, officials said, but the infrared data does not rule out the use of a smaller bomb.

As seen with Malaysia Airlines flight MH17, the penetration of a small part of an aircraft’s outer body can cause mid-air break-up and fatal decompression in the cabin.

John Goglia, a former US.National Transportation Safety Board member, said early indications point more to a bomb than to a structural or mechanical failure, citing the lack of a distress call and sudden movements before the plane disappeared from radar.

“Given the fact that (the pilot) made those abrupt turns without broadcasting any maydays would indicate to me that something catastrophic like a device happened,” he added.

The analyst said a mechanical failure “still has to be considered, but at this point I would put that down pretty low”.

A structural failure, like a piece of the plane's aluminium skin ripping away from metal fatigue, was possible but unlikely, he added.

Officials said the US had not ruled out any possible causes for the crash, including mechanical failure, terrorism or a deliberate act by the pilot or crew.

The White House has offered its “deepest condolences” over the disaster, which claimed the lives of all 66 people on board.

“At this time we do not yet know definitively what caused the disappearance of Flight 804,” Press Secretary Josh Earnest said in a statement.

“The United States stands ready to provide our full support and resources to the Governments of Egypt and France as they investigate this incident.”

Investigators will be hoping for the swift recovery of the plane’s flight recorders, or “black boxes”, to access sound recordings from the cockpit and detailed data.

Egyptian authorities said the first possible debris was recovered from the Mediterranean Sea on Friday morning, including part of the wreckage that could provide vital clues.

The Egyptian army said it has found wreckage of the missing Airbus 320 north of Alexandria (AP)

Despite widespread speculation that the plane's disappearance is terror-related, there has been no claim of responsibility and a marked lack of jihadist “chatter” online.

There have been comparisons to the Metrojet crash on 31 October, which killed all 224 people on board. Isis' Egyptian affiliate, Wilayat Sinai, claimed responsibility for the disaster within hours of the plane going down in the Sinai peninsula.

Supporters uploaded footage claiming to show the aircraft falling, while Isis released a propaganda statement celebrating the deaths of “Russian crusaders”. The group later said it had planted a bomb on board.

The scheduled flight left Charles de Gaulle at 11.09pm on Wednesday (10.09 BST) and radar shows it continued on its normal path over Italy and Greece before starting to cross the Mediterranean.

The last signal was picked up by Greek air traffic control at 2.27am (1.27am BST) and the country’s civil aviation ministry said the pilot “did not respond” to contact attempts as the plane headed towards Egyptian airspace.

Egyptian authorities lost contact with the flight at around 2.30am (1.30am BST), 45 minutes before it was due to land at Cairo International Airport

The Greek defence minister has said the plane suddenly started veering to the right and left just before it disappeared from radar.

The crashed EgyptAir plane, an Airbus A320 registration SU-GCC, is seen here taking off from Vienna in August 2015 (AP)

Panos Kammenos told a news conference flight MS804 had been cruising at an altitude of 37,000ft when it started rapidly losing altitude.

It made “sudden swerves” first 90 degrees to the left, and then in a full circle in the opposite direction immediately after it entered Egyptian airspace, he said.

The aircraft dropped by 22,000ft to 15,000ft before contact was lost at around 10,000ft.

Investigators are investigating a report from a captain of a merchant ship who saw a “flame in the sky” at the time, off the island of Karpathos.

Egypt's civil aviation minister said he believes the disaster was more likely to have been caused by a terror attack than technical failure.

“If you analyse the situation properly, the possibility of having a terror attack is higher than the possibility of having a technical (problem),” Sherif Fathy told a news conference.

Alexander Bortnikov, chief of Russia’s top domestic security agency, went further, saying: “In all likelihood it was a terror attack.”

French President Francois Hollande said no hypothesis had been ruled out.

“When we have the truth we need to draw all the conclusions,” he said. “At this stage, we must give priority to solidarity toward the families."