bear;
On fifteen seconds, sure. Fourty-five takes the examination to the apogee but yes, we can look at a narrower time frame and make sense.
On the UAS, absolutely the notions are inferred, posited, speculated.
There is nothing in the BEA note to confirm/deny such notions. I posited the notion well before the recent BEA note, from knowing the UAS drill and the checklist items.
A year and half ago I timed the loss of speed in an A330 Level D simulator...it took about 4 minutes to lose the 70kts from cruise to Alpha-prot at idle thrust at FL350, 205T, 37%CG, autoflight engaged, normal law.
We know now that the accident began and ended in about the same time it took to lose just 70kts. We know why now.
The aircraft was stalled when it struck the water. When did it stall? Prior to the BEA Note, many here considered the notion of a pitch-up but none of us knew for sure, or if so, why.
A pitch-up could occur for a number of reasons which have been discussed at length. One was executing the memorized items in the UAS drill. Was it possible? Of course it was. That has nothing to do with whether it occurred or whether it is probable.
Shortly after the accident and the loss of airspeed information was becoming known, because it made complete sense and was in complete concurrence with what I knew about flying transport aircraft, I observed in the second thread on this accident that the only thing to do was to leave the aircraft alone, (change nothing, fly manually); it was stable before the loss, and would remain so while the pitch and power were manually controlled by the pilot. A loss of control is not an inevitable outcome of a loss of airspeed information.
On Alternate Law flight,
the ailerons are no more "twitchy" than in Normal C* flight.
Normal law does not "soften" control response.
"Normal" and "Alternate 1/2" laws are about protections, not about the briskness of control response. In roll direct, (Alt 2), the ailerons behave the same way, BUT the aircraft no longer has bank angle protection, and the controls are no longer trying to maintain the last commanded bank angle or pitch angle. The aircraft is a DC8, and that is the way to think about it when laws degrade...one is required to "pilot" the airplane and
think like a pilot, not a video gamer as some author ridiculously wrote.
Originally Posted by bearfoil
Without more explicit data, it is tempting to discuss that which the PF had perhaps no chance of recovering.
No, it is not "tempting", it is a reasonable point to discuss because at the apogee of the trajectory, the aircraft had a pitch of 16deg and an AoA of 6deg, rapidly increasing to 16deg then >40 while the pitch remained NU. The potential for recovery cannot be assessed as high and I have qualified this in my previous post.
The key as we know
bear, is to determine the origin of or the reason for, the pitch up and then to examine the broader factors which contributed to making this a feasible response to the UAS and/or the AFS Disconnection. By no means, is any of this pleasant business, I assure you.