The pilot of a Russian passenger plane said on Monday lightning forced him into making an emergency landing that caused the aircraft to erupt in a ball of fire on the runway of Moscow's busiest airport, killing 41 people.Investigators were attempting to understand the cause of the blaze, which saw the Sukhoi Superjet-100 skid at high speed on the tarmac at Sheremetyevo airport as flames poured from its fuselage on Sunday.Pilot Denis Yevdokimov told Russian media the airliner lost communication and needed to switch to emergency control mode and return to the airport "because of lightning" during the Aeroflot flight, which was headed for the Arctic city of Murmansk.Yevdokimov did not specify if the plane was struck by lightning directly, but storms were passing through the Moscow area when the plane made its emergency landing. "We managed to restore communication through the emergency frequency on our radio connection. But the link was only for a short time and kept cutting out... It was possible to say only a few words," he told the Komsomolskaya Pravda newspaper.Black boxes foundVideo on social media showed the plane crash-landing and people leaping onto an inflatable slide at the front and then running from the blazing jet as columns of black smoke billowed into the sky.Another video shot inside the cabin showed roaring flames outside the window and passengers crying out in panic.Yevdokimov said he believed the plane, which had 78 people on board, burst into flames on landing, most likely because of full fuel tanks.Aside from the dead, nine people were in hospital, three seriously injured, authorities said.Russian President Vladimir Putin offered his condolences and said the investigation into the disaster "should be as thorough as possible". The aircraft's black boxes were found and handed over to investigators, a source in the Russian emergency services told news agencies. Transport Minister Yevgeny Dietrich said there were no plans to ground the Superjet-100 model.Russia's national carrier Aeroflot was once notorious for a poor safety record but in recent years its image has improved and it has not had a fatal accident in more than a decade.The Russian Sukhoi Superjet-100, however, has been dogged by problems since its launch in 2011.In 2017, Russia's aviation authority ordered inspections of all Superjets in the country because of concerns about defects in the model's horizontal stabilisers.