As others have implied apart from obvious performance problems (i.e. heavyweight low level failure) a double engine failure on one side will theoretically still allow enough redundancy to fly safely. However the secondary damage involved will probably decide the survivability of the incident. Having done the 2 eng lost scenario in the sim I found the procedure fairly straight forward. However I am led to believe that the simulators do not realistically reflect even a clean separation. The sim , I am told, reflects a total loss of thrust on one side but does not account for the big loss of weight on the same side. Allegedly!