Here’s what we know about the deadly crash of a Russian airliner in Egypt that killed all 224 people on board Saturday. (Monica Akhtar/The Washington Post)

A public quarrel erupted Monday over the cause of the weekend plane crash in Egypt that killed 224 people, and it pitted the airline that operated the Airbus jet against the Russian government.

Metrojet, a small Russian airline scrambling to protect its reputation after the devastating crash, found itself at odds with government officials who wanted to contain speculation about what led to the deadliest civil aviation disaster in Russia’s history.

When a senior Metrojet official declared Monday that the company had ruled out pilot error or a technical malfunction as the reason for the crash, the government responded with a swift rebuke.

“That statement is premature and is based on no real facts,” Alexander Neradko, the head of Russia’s Federal Air Transport Agency, said in a television interview from Egypt.

'Mechanical impact' felled Russian plane

Investigators have not said whether a technical malfunction, pilot error or an act of terrorism caused the Airbus A321-200 to disintegrate over Egypt’s troubled Sinai Peninsula on Saturday, scattering debris over seven square miles of desert. Investigators have retrieved the plane’s black boxes but have not reviewed them yet, Neradko said in the interview.

“Yes, we know that components of the plane have been thrown over a wide area. That says that the breakup took place in the air, at a high altitude,” he said. “But it is very premature to talk about the reasons. I would like to call on the aviation community to abstain from premature statements.”

While an Egyptian affiliate of the Islamic State seized the opportunity to claim responsibility for the plane crash Saturday, Russian officials remained skeptical.

The claim led some international carriers to reroute flights away from the Sinai, though defense experts have raised strong doubts about whether the Islamic State could have missile systems capable of hitting an airliner at 31,000 feet.

In Washington, James R. Clapper Jr., the director of national intelligence, said that there was no “direct evidence of terrorist involvement yet” but that it cannot be disregarded. “It’s unlikely, but I wouldn’t rule it out,” Clapper told reporters.

Prevailing wisdom holds that once an airplane reaches cruising altitude, it’s clear sailing, but there have been at least half a dozen times when a commercial jetliner has fallen to pieces without help from a bomb or a missile.

: Russia mourns after airliner crashes in Egypt: None of the 224 people on board a Russian aircraft survived after it went down en route from an Egyptian resort area to St. Petersburg. ( / )

What happened to the Metrojet flight is a riddle whose answer is fraught with consequences, either implicating Russia’s troubled airline industry or suggesting that Russia was targeted by terrorists, possibly because of the country’s intervention in Syria’s civil war.

“On the one hand, saying that it was ISIS might be convenient from the point of view that it’s not actually lax maintenance and safety standards” that caused the crash, said Alex Kazbegi, a transport analyst at Renaissance Capital, using an acronym for the Islamic State.

“But on the other hand, saying it was ISIS could be saying it was actually a response to Russia being in Syria, which may also be considered politically unacceptable.”

Russian President Vladi­mir Putin called the accident “a great tragedy” Monday.

“Everything must be done to create an objective picture of what happened so that we know what happened and react accordingly,” Putin told Transport Minister Maxim Sokolov during a televised briefing on the investigation.

As the investigation continues, there are unmistakable signs that Metrojet is in the crosshairs.

Investigators this weekend opened a probe for criminal negligence in the crash and searched Metrojet’s offices. Russia’s Federal Labor Agency announced Monday that the airline had not paid its employees in the past two months, indicating financial problems in the company. And a state-owned television channel broadcast an interview with the pilot’s wife, who said her husband had complained about poor maintenance on the plane.

Metrojet’s embattled leadership mounted a public defense Monday at a news conference in Moscow.

Alexander Smirnov, the deputy general director of the airline, said no combination of factors, including bad fuel or engine failure, could have led the plane to break up in midair. Metrojet officials also said that the plane was regularly reviewed for signs of structural weakening and argued that although the company had withheld wages recently, that did not affect safety standards.

“The only explanation could be a mechanical impact on the aircraft,” Smirnov said. He declined to elaborate as to what such an impact could have been.

Though Smirnov discounted the possibility that the Metrojet plane could have fatally malfunctioned, it would not be unprecedented.

Planes climb to a cruising altitude of six to seven miles above the Earth’s surface because there, the air is far thinner, and against that lessened resistance they can fly faster and use less fuel.

When they reach that altitude, however, they must maximize the air pressure in the cockpit and cabin — and that puts stress on any component that has weakened over time.

“Typically, if there was that type of defect, you would expect it to manifest just as it reached the peak” altitude, said Steve Wallace, a former crash investigator for the Federal Aviation Administration.

In 1988, a hole opened in the fuselage of an Aloha Airlines plane in Hawaii, sucking out a flight attendant. Metal fatigue was blamed in 2002 when China Airlines Flight 611 disintegrated after takeoff from a Taiwan airport, killing all 225 people on board.

“That airplane had an improper repair after a tail strike,” Wallace said, “and I think this Russian airplane that was in the accident had had a tail strike.”

The Aviation Safety Network reported that the Metrojet plane suffered a “tail strike” in 2001, a type of incident in which an airplane’s tail hits the runway. The damage took three months to repair, but the jet was certified as airworthy this year by regulators in Ireland, where it was registered.

The Metrojet crash comes as Russian airlines are facing an economic crunch that has forced Transaero, the country’s second-largest airline, to file for bankruptcy. Russia’s aviation authorities grounded Transaero flights recently over concerns that the airline could not maintain safety standards.

But historically, Kazbegi noted, Russia’s regional and charter airlines have suffered the majority of the country’s air disasters. And with the recent devaluation of the ruble and the country’s economic crisis, they are struggling to make ends meet.

Travel to Egypt has declined by about 20 percent this year, said Maya Lomidze, executive director of Russia’s Association of Tour Operators. For charter airlines such as Metrojet, that has meant canceling or rescheduling flights, among other measures.

“Everyone has been saving in one way or another,” she said.

Meanwhile, thousands of Russian tourists in Egypt still have to find their way home.

“Some people are panicked; of course there is fear; many people are still in shock,” Lomidze said. “People are afraid to fly. But one way or another, they have to get home.”

Halsey reported from Washington. Erin Cunningham and Heba Habib in Cairo, Daniela Deane in London, and Brian Murphy and Ellen Nakashima in Washington contributed to this report.

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