Igor Levitin said experts would have to check about 300 technical parameters from the flight data recorder to establish the cause of the tragedy, and that Armenian technicians would have to be involved because the plane's pilots spoke Armenian during the tragedy.
The recovery operation at the scene of the disaster was officially declared over on May 24.
Tatiana Anodina, head of the Interstate Aviation Committee, said earlier that experts might face problems deciphering data from the cockpit flight recorder, because of damage to the recording medium.
The airliner, operated by Armenia's Armavia, crashed while flying from the Armenian capital, Yerevan, in stormy weather 6 kilometers (3.7 miles) from Russia's Adler airport, which services the popular resort of Sochi. All 113 people on board died.
