Diesel aircraft engines and are the light jets pushing out the twins?

Hi Ted,

ETOPS engines are not more reliable physically. The maintenance
requirements are different to eliminate certain past issues,

doesn't that make them more reliable, if certain issues, that might
lead to failure are eliminated? "Physically", all engines are reliable.
If everything works as designed, engines don't fail. Only if faults
occur in parts or systems, failures occur. Maintenance is all about
avoiding faults by regular checks or scheduled replacement.

and
operators have a big incentive not to shut them down and not to fail
to maintain them so they need shutdown.

Now that's certainly a point!

The real issue with ETOPS is that you have the issue of an aircraft
the size of a 777 which may have to complete a long segment on one
engine, descend, and maybe shoot one or more missed approaches. Maybe
onto a slick runway. That's a lot of asymetric thrust and reverse
thrust as well.

same as with a 4-engine plane loosing two. It's still a matter of how
likely this is to occur.

Sooner or later, the bottom line is, we are going to lose nearly
four
hundred people in one whack in a 777. No one, myself included, wants
this, but there has never been a commercially marketed airliner made
in any quantity that hasn't eventually had a catastrophic total loss.
IF that crash was in any way perceivable as a consequence of its
being
a twin rather than four engine crash, heads are going to roll. Boeing
will likely have a judgment on their hands that will make them wish
they'd built piston singles instead, the operator will be in big
trouble and there will be regulatory changes and possibly a new
Administrator.

You might well be right here, but that is an issue of the US legal
system rather than a technical/risk mathematics issue.

regards,
Friedrich

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