Please do not worry about them too much. Most engine failures that occur can be dealt with in an entirely routine manner by the flight deck. It is only engine fires, loss of multiple engines and "uncontained" engine failures that are significant. It will be a small element of the risks associated with travelling on NW.

If you get a failure on a twin, it may well have to descend to a lower level (as it will slow down and therefore stall at high cruise level altitude) and divert (flying at say 26,000 feet is less efficient and therefore burns more fuel). This is designed into every flight plan across the Atlantic or Pacific.

The only major causes of multiple engine failures in recent years have been bird ingestion, fuel leaks and maintenance technician errors. The technician errors have now been identified and new working practices introduced to reduce the possibility.

Fuel leaks are rare, although Air Transat had one a few years ago. Of course, Air Canada ran out of fuel as well in a 767. Is there something about those Canadians...

If I were you, I would worry more about accidents at airports and in the ATC system. However, if you are going to worry about the risk of flying on one of the big US carriers on a mainline jet, you may as well just go and have a nervous breakdown with the rest of life's risks.

I am not saying that you should not be aware. You should know how to open the overwing exits, the brace position etc. If you think that there is something wrong, do not be afraid to speak up and ask the crew. There are a few experts around on FT to ask too

Happy landings

Spottie