▁synchron izing ▁information ▁from ▁the ▁flight ▁record ers , ▁A TC ▁data ▁and ▁meteor ological ▁information . ▁ ▁On ▁ 2 1 ▁March ▁investig ators ▁in ▁Rost ov - on - Don ▁finished ▁collect ing ▁de br is ▁from ▁the ▁crash ▁site ▁and ▁started ▁re construct ing ▁the ▁fus el age ▁layout ▁in ▁a ▁hang ar . ▁Another ▁group ▁of ▁investig ators , ▁based ▁in ▁Moscow , ▁together ▁with ▁Em ir ati ▁investig ators , ▁air line ▁represent atives ▁and ▁exper ts ▁from ▁Cy pr us ▁and ▁Spain , ▁started ▁to ▁collect ▁and ▁analy se ▁materials ▁on ▁the ▁aircraft ' s ▁air worth iness , ▁Fl ight ▁ 9 8 1 ' s ▁prepar ation ▁before ▁departure , ▁and ▁the ▁training ▁of ▁its ▁flight ▁crew . ▁ ▁On ▁ 2 3 ▁March , ▁Russian ▁and ▁foreign ▁investig ators ▁began ▁to ▁test ▁the ▁Rost ov ▁Airport ' s ▁radio ▁communication ▁equipment , ▁examine ▁A TC ▁communic ations ▁with ▁other ▁flight ▁cre ws ▁before ▁the ▁crash ▁and ▁evaluate ▁the ▁actions ▁of ▁the ▁A TC ▁and ▁the ▁air port ' s ▁meteor ological ▁services . ▁Using ▁data ▁retrieved ▁from ▁the ▁flight ▁record ers , ▁as ▁well ▁as ▁information ▁from ▁the ▁aircraft ▁maintenance ▁log ▁and ▁flight ▁documentation , ▁the ▁investig ators ▁began ▁to ▁analy se ▁the ▁operation ▁of ▁all ▁Fl ight ▁ 9 8 1 ' s ▁aircraft ▁systems , ▁including ▁the ▁flight ▁control ▁system ▁and ▁engines , ▁and ▁also ▁analyze ▁the ▁actions ▁and ▁state ▁of ▁the ▁flight ▁crew ▁during ▁the ▁entire ▁flight . ▁ ▁On ▁