What kind of engine failures is this?
If this would happen somewhere in middle of the Atlantic would the plane be in danger of crashing? Or is it a tiny minor problem which 99.99% poses no threat but just to be on the safe side made an emergency landing?
There are many options. Just to list a few.
1. They could've had complete engine failure. If they would've been over the Atlantic they probably could have made it to dry land on one engine.
2. There was a fire in the engine. Airplane engine's are equipped with internal fire extinguishers that can extinguish an engine fire mid flight, still a good reason to make an emergency landing.
And many more options that can call for an emergency landing but you'd probably be just fine if it has happened in the middle of the Atlantic.