Originally Posted by
RAT 5
Have FBW a/c become too complicated, for their own good?. . .
I admit I am not an AB pilot. I apologise if I've missed something, but there does seem an unresolved debate amongst the AB crews about what is correct in these various scenarios. . . .
All aircraft long ago became too complicated such that pilots could know everything about the aircraft. The L1011 was an exceedingly complex aircraft, very sophisticated for its time, particularly the -500. Whether it is good or not is another question, which I think may be answered in part by the accident rate since true automation was introduced in the mid-eighties, (B767, A320, etc.), which see below.
FBW of course is just another way of moving flight controls, with the additional requirement of feedback and the quality of "gain".
"Protections" are an entirely different matter, made possible by digital flight control. FBW and protections aren't separate but FBW itself (C*) is
not "protection".
In the failure cases where various inputs for protections are no longer valid there has to be a way of maintaining pilot control over the aircraft.
This may seem like stating the obvious and perhaps it is, but sometimes the two can be conflated which can lead to incorrect conclusions. FBW itself, will still stall an aircraft just like any other design. How graceful the reversion is, is a matter of design, and obviously opinion! I can say that in the sim, such reversions are non-events.
The Airbus is a complicated aircraft and so is the B777, more particularly, the B787 which is FBW with protections. All this we know. The "nodes" of the discussion regarding the Airbus revolved around AF447, specifically Alternate Law behaviour, (not around the AirAsia accident however; pulling flight control CBs in-flight is strictly forbidden). The point has been made many times, that thirty-one other crews encountered a UAS event and wrote it up in the logbook. It simply isn't/wasn't an emergency. The ensuing at-length discussion generated by AF447 has however, highlighted the Airbus, in particular those extremely rare circumstances which, like other designs, occur as anticipated, with a rarity approaching 10^-9 or so. The millions of hours of successful, unremarkable flight, though silent, perhaps tells us that concern over autoflight systems (and the 'unresolved debate' matter), may be disproportionate to the reality. Everyone just gets on with flying the airplane they're on, A or B.
In response to your question/observation regarding unresolved debates, part of this is due to not knowing the aircraft well enough or at all, part of it has to do with mythology, prejudice & politics and part has to do with a genuine concern by those who really know their stuff and still have questions regarding some design features, (
two of which have been mentioned in the thread - THS movement continuing during stall & silent stall warning with NCD). These aircraft, (present Boeing and Airbus) are all far too complex for any one person or the pilots themselves, to absorb and retain. Normal flight operations occurs 99%+ of the time for all types.
The
statistical record, maintained by Boeing since 1959, speaks to the question regarding complexity and competency - neither design (A/B) are "way out in front". However, the A319/A320/A321 series' hull-loss-fatal-accident rates is slightly lower that the equivalent-type, B737 rates, (per million departures).