Originally Posted by Clandestino
.....Airbus, pitch and power combinations that kept you both out of stall and and overspeed long enough to find pitch/power table in the QRH were memory items; TOGA/15 to acceleration, CLB/10 to FL100, CLB/5 above.
Don't ask me about 330
It's similar.
Originally Posted by PBL
...... there is no such thing as raw data any more
Originally Posted by Clandestino
.....semantics: raw data has specific meaning for transport pilot and it's not literally raw data
I know, but perhaps my point was not well made in one sentence.
There are lots of systems mediating between the physical flying environment and the control surfaces, some of whose data paths go through human eyes and brains sitting in two front seats. It used to be the case that the set of data paths from the environment to the eyes used to be well-understood; usually very reliable with known and simple failure modes. This interface was well understood and relied upon by those eyes in the front seat; the brain was the weakest point in that data path to the controls.
My point: it ain't that way any more. The path from environment to eyes has complex failure modes which the eyes sitting in the front seat cannot fathom in real time. Conversely, some of the systems which used to be relatively unreliable, for example navigation, based on reception of ground-based signals, have become far more reliable, as have systems such as the flight director. The question of what the eyes in the front seat can rely on, and should retain wariness of, has changed radically in the last two decades, with the explosion of avionics mediating everything. The answer is not necessarily that one is best off relying on the interface on which one has traditionally relied, and on which the low end of GA still does.
People flying modified forty-year-old designs are likely thinking appropriately when they think that, when things go pear-shaped, they want to see and use the good old traditional interface, which one calls "raw data". But one should be aware that that is on more modern kit as much an artificial, algorithm-mediated construction as flight director guidance. Witness some recent ADs from EASA.
Concerning QF72, the accident happened because the flight control was being driven by "raw data". Exactly how and why that data was generated has, to my knowledge, not yet been answered, despite dissection of the box through which it passed. Similar things have happened to analogue data-mediated flight control systems, such as the accident to the X31 16 years ago, but in that case the pathways are well understood.
The question is: which filtered data, of what sort and at which stage, are of most use to the eyes in the front seats when there are problems with the veridical operation of all systems? Maybe the most useful data is in fact a data range: the system "thinks" that the actual value of crucial parameters lies in range X-to-Y, with "here" (say, on the FD) the "most recommended" course of action. That is often what a good hazard&risk analysis of data corruption would suggest is the best information to provide to the eyes in the front seat. And you don't get around that Hazan simply by wishing for the same things you have in your weekend Cessna.
PBL