LEAD:
Russia has found the first black box from a military plane that crashed into the Black Sea killing all 92 on board on Sunday. The recorder, one of several reported to be on board, contains information that could help investigators identify the cause of the crash, which killed dozens of Red Army Choir singers and dancers en route to Syria to entertain Russian troops in the run-up to the New Year, as well as a member of an NGO and nine journalists. Julia Lyubova reports from Moscow.
IN: Russia's Ministry of Defence..