Originally Posted by
safetypee
Another thought, is that the manufacturer was similarly ‘unable’ to describe, or have awareness of the overall system; e.g. flight control /aerodynamics use AoA input (dual) to overcome a stability issue, but with a viewpoint of a redundant (triple) system - AFCS / trim. Such a situation can arise from ‘egg-box’ like organisations or extremely large, complex, and interacting subsystems; in these cases then there should always be some one in design, airworthiness, or certification who can ask ‘the question’, but what is the question, who asked, when. Similarly for the FAA.
These comments just triggered a "time warp" for me!
Many years ago at Boeing Seattle on B734 we had to do a test point which required input of false flight condition information to the autothrottle. I don't remember the detail but it required a comprehensive preflight briefing on the system.
A meeting room with 12 Boeing engineers - from the TOGA button specialist to the fuel control output specialist and 2 hours to give us brief rundown on how it all worked. The only specialist who had a reasonable overall understanding were the Boeing TP's. The others had a very detailed understanding of their part in the "egg box". There was no one "go to" person who understood the entire system to the level of detail we required.
Sorry about the subject drift.