Depends which side of the pond you are!
IIRC a BA747 flew LHX-MAN after an engine failed just after take off, there was a spat between the FAA and BA, FAA insisted that the aircraft should have landed whilst BA quoted CAA regulations which allowed the flight.
Is the type safe on 3 engines, yes, although your options are less.
Last edited by Momoe; 5th Aug 2015 at 13:45.
Reason: wrong originating airport