Two helicopters have collided and crashed while fighting a fire west of Athens, the Greek broadcaster ERT reported on Sunday.The pilots of one of the helicopters have made contact with fire brigade headquarters by radio, but the fate of the crew of the second helicopter remains unclear.Each helicopter was carrying a two-person crew, the Greek fire department said.A large-scale search and rescue operation has been launched in the area near the village of Psatha.Nearly 500 firefighters and 23...