MOSCOW (AP) — The plane that burst into flames while making an emergency landing at a Moscow airport, killing 41 of the 78 people on board, was without radio communications because of a lightning strike, Russian news media on Monday quoted the pilot as saying.

A flight attendant said there was a sharp flash soon after takeoff Sunday evening from Moscow’s Sheremetyevo Airport as the plane headed to Murmansk.

Some of the 37 survivors were seen on video carrying hand luggage as they plunged down an inflatable slide from the plane’s forward section, raising questions about whether grabbing their baggage might have impeded an evacuation in which every second could separate life from death.

The plane, a Sukhoi SSJ100 operated by the Russian flagship carrier Aeroflot, had taken off from Sheremetyevo but turned back within minutes, asking for an emergency landing. The plane came down hard on the runway and flames and black smoke burst from its underside.

The plane reportedly did not jettison any fuel before the landing, as is common procedure. It was not clear why it did not take the time to do that.

Pilot Denis Evdokimov was quoted as saying by Zvezda TV and the Komsomolskaya Pravda newspaper that “because of lightning, we had a loss of radio communication.”

Flight attendant Tatiana Kasatnika said in a video posted on Yutube that “We took off, got into a cloud, there was strong hail, and at that moment there was a pop and some kind of flash, like electricity.”

Russia’s main investigative body said both of the plane’s flight recorders — data and voice — have been recovered from the charred wreckage. Committee spokeswoman Svetlana Petrenko was also quoted by Russian news agencies on Monday as saying that investigators were looking into three main possibilities behind the cause of the disaster: inexperienced pilots, equipment failure and bad weather.

Storms were passing through the Moscow area as when the plane made its emergency landing.

One survivor praised the plane’s attendants for helping save him and others.

“It was dark and there was gas, very high temperature. They helped people out of there, helped them to descend,” Dmity Khlebnikov said, according to Komsomolskaya Pravda.

Another passenger, Mikhail Savchenko, wrote on Facebook that some passengers grabbed luggage as they fled the plane.

“I do not know what to say about people who ran out with bags. God is their judge,” he wrote.

The SSJ100, also known as the Superjet, was heralded when it went into service in 2011 as a new phase for Russia’s civil aviation industry. It was introduced as a replacement for outdated Soviet-designed aircraft.

But the plane has been troubled by concerns about defects in the horizontal stabilizers. Russia’s aviation authority in 2017 ordered inspection of all Superjets in the country because of the problems. A Mexican airline, Interjet, grounded Superjets in December 2016 and later said it was phasing them out of the fleet.

Transportation Minister Yevegny Dietrich said Monday that it was too early to decide whether to ground the planes in Russia, and Kremlin spokesman Dmitry Peskov said the decision was not within President Vladimir Putin’s power.

One of the dead was flight attendant Maxim Moiseev, Dietrich said. Russian news reports, citing unnamed sources, said the Moiseev was in the back part of the plane, which was engulfed in flames and tried unsuccessfully to deploy an evacuation slide.