Originally Posted by
ph-sbe
In technical certifications, we create three standard candidates for the test we're about to write:
- The Clearly Acceptable Candidate: this is a candidate who should pass the exam with minimal to no preparation;
- The Minimally Acceptable Candidate: this is a candidate who should pass the exam with some preparation. Some will pass with high marks, while some will score the cut-score or just above;
- The Not Acceptable Candidate: this is a candidate who lacks the proficiency to pass the exam and should fail;
Any system that you design should be built to the specs of the Minimally Acceptable Candidate: someone who is unfamiliar with the matter (let's say, a pax) does not necessarily need to understand the system. However, those who are trained and licensed to fly should be able to understand the system without much difficulties. If one needs to be an expert on the system itself in order to use it, it is by definition unusable.
Similar to the big internet. Everyone reading this uses the internet, but I doubt more than 1% will even remotely know what a BGP community is. And that's fine, because this system was designed for the "average" user.
When I passed my Private's checkride, I had a reasonable understanding of the 172 I was flying. Engine, electrical systems, flight controls, instruments; the lot. I even understood the workings of the shimmy dampener (it does help if you fly an aircraft with a broken shimmy for a change). Any airman should be able to understand MCAS, or any other flight system for that matter, even on a bad day. If not, then either the system is too complex and risky to introduce, or the airman should not have received their license and rating(s).
Aviation, particularly transport aviation, is a high-performance profession; constant training and knowledge are fundamental for safe operations.
Like nuclear engineering or medicine, procedure is king. However, the operator needs sufficient knowledge to understand "What's it doing? Why is it doing it? Do I need to stop it? How do I stop it? What else does stopping it do?". It's a bit sad to see some sentiment that the crew are just trained to watch the computers (see the old pilot and dog in the cockpit joke) and follow the QRH, otherwise they might be overwhelmed. I really doubt it, in most cases. Aviation got to where it is because of these practices, via some extremely tough lessons.