> A reminder that aviation regulations are written in blood.

It's enormously expensive for an airframe manufacturer to deal with the fallout of a crash.

There aren't any engineers in an airframe manufacturer willing to sign off on a faulty design. Some good engineers are so worried about that they get shifted to working on conceptual projects.

I took a loooong time for Boeing to convince the FAA that a twin engine jet was safer than a 4 engine for ocean crossings.

> took a loooong time for Boeing to convince the FAA that a twin engine jet was safer than a 4 engine for ocean crossings

I don't believe they convinced the FAA twin is safer, just that it meets the necessary safety margins. Airlines want them to meet that regulation for fuel efficiency, but I'd want a source that they're actually safe-er, instead of simply safe enough

Boeing proved it safer. The reason is the increased complexity of more engines increased the risk of a major problem.

My source is I was told this by the engineers who where involved.

Not necessarily safer but safe enough. A modern 4 engine jet should still be safer than the 2 engine equivalent