[bolger] Re: Safety Factors

donald hodges wrote:
original article: 2963

> The commercial aircraft design profession is probably the most

conservative

> enterprise of any real size out there. The approach is almost totally
> empirical, and glacially slow to innovate.
>
> Way off topic I know,

And I thought commercial nuclear power was the most conservative,
glacialy slow to innovate. We do work with probability risk
assessment, multiple failures, have backups for the backups, etc.
Clicked right in on the thread on chained failures.

Way off topic I know ....

Phil Lea

The commercial aircraft design profession is probably the most conservative
enterprise of any real size out there. The approach is almost totally
empirical, and glacially slow to innovate. If the military did not absorb
the failures inherent in innovation, we probably would never have such
things as fly-by-wire, gps navigation, composite structures, etc. The
penalty for fatal errors in commercial aviation is so disproportionate that
no company could bear the risk. Can you imagine an aircraft controlled by a
Microsoft algorithm?

Way off topic I know, but our previous lives have a way of creeping into
these pastimes...

>
> There is another approach possible: if you REALLY do your homework so
> you know the exact stresses anticipated, and you have excellent quality
> control,
> you can shave down the safety factor quite a bit. I remember a lecture
> from one of my professors asserting that jetliner pressure hulls have a
> safety factor as low as 1.5.
>
> Of course, if you modify the environment a little when using such a
> small factor you can get a Boeing 737 convertible, as occured in Hawaii
> some years ago.
>