Originally Posted by
zzuf
Quote Airbus response to NTSB
"On the last 10 sec in the air of Flight 1549 , DFDR data show that pitch attitude is increasing and CAS decreasing. "
---- Hey, Airbus, thats called a "flare". LOL Are they saying he flared too early? I don't think he did flare early, as his descent rate was so high, he needed to start mushing it in close to maxCL (max lift) before entering ground effect.
Originally Posted by
zzuf
Quote Airbus response to NTSB: "Then, the phugoid damping terms are non null and are acting in the sense to decrease the finally commanded AoA vs. the stick command, in order to prevent the Aircraft from increasing the phugoid features."
---- This a red herring argument by Airbus. It is incredibly important to say that impact is imminent, and no phugoid ever has time to develop. Airbus loyalists, apologists, and lawyers love that statement. Truthy folks don't.
Originally Posted by
zzuf
Would appear that Airbus have no enthusiasm for the "turn off" phugoid damping just prior to the flare scenario.
The NTSB did at first, then backed away under the slightest pressure from the BEA and Airbus. Snowflakes populate the NTSB.
You can go on and on about how Sully was too slow up higher than 100' or so, yet no aircraft automatic feedback should ever exacerbate the situation by nosing down in critical flare, seconds before impact. We don't punish pilots & passengers that way. Instead, we do what we can. Obvious to most.
This water ditching just uncovered similar issues that occurred at Habsheim & Bilbao, & maybe other landing accidents of A320's.
Originally Posted by
zzuf
QuagmireAirlines, I would be interested in how you would intend to wash out the phugoid damping term,....
That's easy, just ramp it out gradually from 200' to 50'. Routine. It won't excite anything, since its going away, and remember, speed protection has a valid presence above flare altitudes.
Originally Posted by
zzuf
You don't seem to have addressed if, at the speed available, there is any advantage in terms of manoeuvre in even attempting to increase alpha.
Yes, in flare, where Sully attempted to get more pitch, it would have increased lift, flaring harder, then it hits the water. Don't worry about "long term" speed effects since you hit the water quickly.
Originally Posted by
zzuf
Your stylized CL/Alpha curve may show the relationship of various alpha limits, but in no way does it represent the A320 CL/Alpha curve, nor does show just how much usable CL was left available.
Those are Airbus's "stylized" CL/Alpha curves. And its reality. It shows there's MORE CL available, which is what counts.
All this is probably a lower-quality version of the arguments at the NTSB just before they caved to political pressure to back away from their original correct position. On this forum, we do need the Airbus/BEA apologists to present better arguments, if possible. Too weak.
