Nuclear Sub joins Air France search

A French nuclear submarine has arrived in the Atlantic to help to search for the missing data recorders of Air France flight 447.



BBC reports say the submarine, called the Emeraude, should cover an area of 26 square kilometres per day.



The ongoing search has required more machinery as the black box data recorders will emit signals for only 30 days.



French military spokesman Captain Christophe Prazuck says as time goes by the search will become increasingly difficult.



He says it will be difficult to find the black boxes.