a three engine ferry is perfectly safe and legal on a B747 and ferry is the word, no passengers allowed. As a rule of thum, the fan on the ead engine has to be either tied up or the blades removed and the three good engines borescoped before each and every departure. Even the good old DC10/MD11 can depart on 2 engines, a ferry of course and no Chinese accounting allowed. As Dodgy says, 2 Cross pens, a Leatherman and plenty of B******t