The head of the Egyptian investigation into the crash of a Russian airliner said Saturday that the cause has not yet been determined but noted that data recorders showed the plane was climbing at the time it broke up and that a "noise" of an undetermined source was heard before the black box suddenly went dark.
USA Today: Sudden ‘noise’ heard on black box as Russian plane broke up in flight

An Orthodox priest looks on as Russian Ministry for Emergency Situations employees prepare to unload the bodies of victims of the Russian passenger jetliner crash from the ministry's plane at Pulkovo airport in St. Petersburg on November 6, 2015. Russian airline Kogalymavia's flight 9268 crashed en route from Sharm el-Sheikh to Saint Petersburg on Oct. 31, killing all 224 people on board, the vast majority of them Russian tourists.