Good points everybody.
Chris Scott: good post. Our posts crossed at the same time. Glad to have an A320 driver here; my understanding of level change is limited to the predecessor A300 series; I could very well be wrong about everything here. Thanks for the link I'll read it.
Dozy said:
And the old Airbus-Habsheim debate has been done to death. The crew screwed up. M.Asseline was way below alpha-floor protection height and the delay in spool-up time was caused *not* by the FADEC control commanding a gradual thrust increase (otherwise you'd have had multiple fatal failed go-arounds by now), but because the A320 uses high-bypass engines that do take a few seconds to spool up compared to the older low-bypass type.
Dozy;
Corvair automobile owners screwed up and crashed, but it doesn't follow that the design that Ralph Nader finally got killed was faultless. This over-reliance on confusing automation is what caused the above airbus A320 accident, and not the old catch-all refrain "pilot error" imho.
These were experienced airbus [test?] pilots. The only screw up the crew made was not distrusting the automation sooner and switching to full manual early (which is what we are trained to do now.) The problem was that by the time they got done trying to analyze why the automation was not promptly applying climb thrust, it was [nearly] impossible (behind the power curve) to clear those trees even with GA thrust applied. They did override the throttles (about) four seconds prior to impact but [prompt climb] thrust had previously been rejected by FADEC in favor of a gradual level change/slow spool up routine. I've used this "level change" mode a million times on A300's. Nearly always (back then) in "level change" mode [when the machine has a small change in altitude sitting in the alt sel window], a two to four second delay would happen before you saw any appreciable power come up at all. Then you still had to wait another ~five or six seconds before target power showed up. It used to be a lot worse before the software changes came out. Still these are modes that you don't want to be in close to the ground even though airbus didn't used to have any restrictions on it.
747-100's & 200's have had thousands of super low & slow flybys and not one has ever failed to command all the thrust you can handle in six seconds. It has nothing to do with different types of engines or spool up times. Those were also high-bypass ratio engines that required a "flight idle" to get you out of bad go around situations.
M.Asseline should have aborted the pass the second he went under 100ft RA. The FBW protections did actually keep the A320 level when it hit the trees. Not only would a 747-200 not have survived a similar incident (it would never have been able to make that maneouvre in the first place - hence why Airbus were so keen on that demonstration), but without the protections the A320 had it would have probably augered into the trees wing-down and killed everyone.
Naaaa. A 741 or 742 would have never got that slow in the first place because the autopilot was not certified to be engaged below mins except on approach and the AOA is not in charge. A hand flying pilot would feel the required backpressure happening on the yoke and do something about it. The autopilot doesn't possess this airmanship "cowboy" instinct at all (regards to christianj). I don't think the hand-flown A320 sidestick provides a backpressure "feel" does it? In the 747 case, immediate overboost thrust and intentional flight below stick-shaker momentarily to clear trees is possible (like in modern wind shear training.) These "coffin corner" non-book emergency actions (over-boost and momentary extremely high deck angle in ground effect) are not available in the A320 if I understand the limits of FBW combined with FADEC. BTW, we did use them to escape FAA "non-survivable" t/o wind shear down-burst scenarios in the 727, 747, DC10. Sometimes you missed the ground by a whisker and sometimes you weren't so lucky. At least you had that capability if it was needed.
[Down low] Alpha Floor flight is dangerous with the level change mode and should never have even been attempted (we know now of course; and IF that's what actually happened.) There's the possibility that he was in "thrust latch" (A/T mode) at some point: but he stated that nothing happened so he cycled the thrust levers.
The problem with aerospace programers is they think they can anticipate every eventuality and therefore a pilot is just redundant. But what happens when the [Baro] altimeter malfunctions in this case as corrective airbus 320 directives allege it was (according to Wikipedia's et al contributors?) [You fly off the baro altimeter right?, the RA is just a backup.]
Now you don't get prompt power applied on a toga button push and the trees are coming up.
Not to say that a software corruption is what caused BA038. Just making the point that the FADEC between the hand and the spray nozzels is one more weak link that the PIC must use in an emergency GA whether he likes it or not.
Will it work? I know a steel cable will because I just used it hand flying the descent.