Lonewolf, #960, again no disagreement.
... what has changed more ... The total aviation system?
We have the same 'reliable' aircraft, same 'unreliable' human, and an evolving operational environment. The intensity and complexity of modern operations defy simple understanding, accidents are rare, and few have a single cause or solution, yet public and professional expectation is for increased safety with more fights and lower cost.
In many ways we are operating too close to the edge of safety boundaries(*), there are more unforeseen interactions, and there are new societal effects on the human operator.
Perhaps if we considered all aircraft as potentially unreliable, humans as an asset, capable of rescuing situations, then we might learn more from normal operations than attempting to train and constrain them with more SOPs.
Buzz, #962, just because a 20 yr old design was approved does not mean that the assumptions made then hold true today. Operators and individuals are very good at adapting to 'small problems', and formalise their workarounds with more training.
The danger is that with more and more adaptions and training demands on memory, the more likely that the human will encounter resource limiting situations, combinations of 'challenging factors' (surprise, unexpected, low experience, or infrequently trained), then the risk of crossing a safety boundary increases.
'Small problems' are the essence of safety reports, yet few of this type are made because humans would rather adapt than report an 'error' (the opportunity of finding out why vs avoiding embarrassment); when we identify a mistake we infer that we will not suffer the the same one again, we can cope, etc. But error-inducing-situations are rarely the same, even though the small problem is, and with increasing operational pressures the human is unable to detect these new situations (context), and the situation escalates to a safety incident.
The safety task is to identify these small problems, relate them to the complexity of modern operations by reviewing previous assumptions and considering new contexts.
And for the assessors (operators and regulators) to be aware of the human weakness that because they knew of the problem, they managed, so it won' be a problem for anyone else, thus do nothing.
(*) page 20
http://ihi.hamad.qa/en/images/Keynote_Haraden.pdf