A report that it was the pilot's 15-year-old son who plunged the Airbus A310 jet into a nosedive was denied by an Aeroflot official, but the Moscow press said several unauthorised personnel were in the cockpit at the time and neither the pilot nor the co-pilot was in his seat.
About 30 Aeroflot employees and their relatives, including eight off-duty pilots, were aboard the flight from Moscow to Hong Kong. The reports said some of them had gone forward into the cockpit and a steward was in the co-pilot's seat when the crash happened.
An Aeroflot official said: 'This affair is a catastrophe for Aeroflot and will be held against us for a long time.'
The Airbus crashed near the Mongolian border on 22 March and all on board were killed. The flight recorders are being examined by the French accident inquiry bureau, whose officials have refused comment.
On Friday an unidentified Russian air accident specialist told French television: 'There was someone in the pilot's seat who was not part of the plane's crew and was probably the son of one of the company's pilots. He was probably being given instructions on flying the plane when he made a false manoeuvre.'
Valery Eksuzyan, head of Russian International Airlines, a branch of Aeroflot, said the crew was not to blame: 'The plane started to act in ways which were not programmed into the autopilot,' he told Interfax news agency.