Originally Posted by
jaysona
No, this is definitely not an exercise in semantics by any stretch.
I meant to say that your sentence was an exercise in semantics, not the process itself.
Not that I truly believe the process itself to be terribly meaningful. Still mostly guesswork.
(I have been marginally involved in tree things in the past. Safety assessment, but not in aerospace. I would rather stay out of that sort of things.
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I still would say it's a bit of an exercise in wishful thinking. The excuse being that it's more or less the best one can do...
There is no guesswork of any sort involved. I think most people here would probably go insane before being able to figure out just how to quantify the risk levels. There were many days where I was certain taking a bullet to head would have been less painful than going through the ARP safety assessment exercises.
The image below is probably the simplest of the safety assessments that are conducted.
Surely assigning odds is pure wishful thinking though. Until you have good experimental data. Until you have enough actual failures that is.
You'd think so, but not really, good quality prognostic data is not all that common. The recent development of IVHM (Integrated Vehicle Heath Management) for new platforms is changing that and single component failure rate prediction will get better as the years progress.
To me, what makes aviation safe, and what makes assessing safety in aviation relatively straightforward (say compared with the nuclear industry) is that there are so many flights and so many events that you end up with a fairly reliable database. that comes from fact, not trying to guess scenarios and (more or less arbitrarily) assign odds.