`` We need time to reach the recorders , '' said Paul-Louis Arslanian , head of France 's accident investigation bureau . NEW : Oil slick experts argue against an in - flight accident , Brazilian official says . NEW : Determining where plane broke up will be difficult , U.S. aviation expert says . Air France flight disappeared over Atlantic Ocean after taking off from Brazil . Memorial for the victims of Flight AF 447 takes place in Paris at Notre Dame .
NEW : Oil slick experts argue against an in - flight accident , Brazilian official says . NEW : Determining where plane broke up will be difficult , U.S. aviation expert says . Air France flight disappeared over Atlantic Ocean after taking off from Brazil . Memorial for the victims of Flight AF 447 takes place in Paris at Notre Dame .