Some may put the crew's response down to "startle effect" but I don't think so and I don't buy it, for that is what training is all about - to avoid or reduce the effect of surprise and momentary anxiety and to maintain cockpit discipline in the face of elevated risk to the aircraft.
Right, but as you know, it doesn't always work that way - and startle effect is now very much a recognised phenomenon. I believe we were discussing the Orly Tarom investigation earlier in this thread in which 80% of pilots tested instinctively pulled up when they received a Stall Warning they weren't expecting.
My view (for what it's worth) is that it's a more nuanced scenario than saying the whole crew were subject to startle effect. I believe Bonin certainly was initially, whereas Robert - while he didn't break into the UAS drill - was definitely trying to be more analytical. I'm going to cross-post something I put in a PM a couple of days ago to illustrate what I see:
Originally Posted by me
The way I see it, there have been enough investigations into accidents involving startle response that there doesn't necessarily need to have been a logical reason for an instinctive "pull-up" reaction. What is unusual is that it was effectively held for so long.
Psychologically speaking, it's as objectively fascinating as it is subjectively horrifying - pretty much the absolute worst-case scenario as far as CRM goes.
What I believe beyond doubt is that whatever "spooked" Bonin, it locked him into a panic and "tunnel vision" mindset for the duration. What makes me think that is that he used the SS priority button on no less than three occasions - and not only did he not verbally express that he was doing so, but on two of those occasions did so having previously verbally handed control to Robert.
Robert starts the sequence with a very solid handle on things as far as I can tell, but for some reason his self-confidence seems to evaporate rapidly after he elects to wait for Capt. Dubois to return. From that point on he seems to have been susceptible to an insidious and creeping sense of denial. He wouldn't be the first person this happened to, but I have to say that I've always been of the opinion that he should have trusted in his training and instinct and been more assertive, because of the three crew, he seemed to call it correctly the most.
So it seems to me what we have for the first minute or so is Bonin apparently completely spooked and acting in a totally reactive manner, with Robert trying to be analytical (which is the right thing to do) - however the thought never seems to occur to him that the worsening situation is being caused by Bonin's control inputs and that he should therefore immediately take control rather than try to assist verbally.
For his part, Capt. Dubois bears some responsibility for this breakdown in CRM - but he arrives at the worst possible moment through no fault of his own. I have to suspect that Robert's mounting alarm had him on the verge of taking control anyway just as Dubois arrived - especially with the cue that Bonin's attempt to deploy speedbrakes indicated a significant misinterpretation of the situation.
Dubois' arrival also coincides with the cessation of Stall Warning as the AoA vanes go outside their certified operating envelope. Of course this behaviour is something that the engineers need to look into and improve if possible, but in the roughly five years since the accident, no manufacturer has come forward to claim that this would not have happened with their design, which may possibly be rather telling - though I'm not sure.
From this point onwards, Robert and Bonin's higher brain functions seem to be taken up with trying to explain the situation to their captain, but all the time, Bonin's "hind-brain" is still fixated on "pull up at any cost".
For what little it's worth, I am convinced that instead of electing to call Dubois back, Robert had stuck to his guns and said words to the effect of
"Pierre, you must listen to me. I know what's wrong. I have control. Please put your hands in your lap, read me the ECAM, and keep an eye on the speeds to tell me when they come back."
then we wouldn't be having this conversation.
Originally Posted by
Machinbird
In fact, from the low key recognition by BEA of what the roll oscillation implied, I suspect that they did not appreciate the impact of a PIO on the pilot flying.
In fairness, I don't think this reference was particularly "low-key" - they certainly seem to have considered the effect on the PF (it's worth reading the whole section, but it's a long piece, so I won't quote it all here):
Originally Posted by BEA Final Report Section 2.1.2.3
2.1.2.3 Control of the flight path
When the autopilot disconnected, the roll angle increased in two seconds from 0 to +8.4 degrees without any inputs on the sidesticks. The PF was immediately absorbed by dealing with roll, whose oscillations can be explained by:
- A large initial input on the sidestick under the effect of surprise;
- The continuation of the oscillations, in the time it took to adapt his piloting at high altitude, while subject to an unusual flight law in roll (direct law).
In addition, the deviation in roll may have been caused by the risk of turbulence that had preoccupied the PF in the minutes leading up the autopilot disconnection.
Going back to the discussion of the roll, I was clued in to the existence of Figure 64 in the final report, which is quite illuminating - particularly the 5th (Roll attitude), 7th (Lateral wind) and 8th (Vertical wind) graphs down.
Looking at the bottom two graphs (7 and 8), you can see that the prevailing lateral wind was a crosswind to the right which has a high peak of 35kts and a low peak of 5kts. In general, from 02:10:08 to 02:10:20 the right crosswind is around 30kts. The Vertical wind graph indicates an updraft of around 15-16kts at the point of AP disconnect, which if I'm not mistaken would, in combination with the right crosswind, initiate a tendency to roll right.
Comparing this data with Fig. 26, it appears that Bonin's first left roll input at 02:10:07 coincides with a drop in the prevailing right crosswind to 8kts, which I suspect goes some way to explaining the initial overcontrol. The crosswind subsequently picks up again to 30kts one second later, and remains around there for the following 12 seconds.
What is interesting to me about the 5th graph (Roll Attitude) in Fig. 64 is that there are three plots. One (blue) is the DFDR data, which we've seen in Fig.26. The second (orange) is data from a simulation with both the wind and pilot input reconstructed and, unsurprisingly, this matches the DFDR data closely.
Most interesting to me, though, is the third (pink) plot, which is a simulated reconstruction of the aircraft's response to the winds *without* the pilot input. Now - presuming all the other factors (rudder trim etc.) have been fed into the simulation, this should give an accurate picture of the roll condition had the controls been left alone.
As such, the pink plot indeed indicates a right roll - however, it maxes out at 15 degrees (which is significant, but still less roll than would be considered normal) at 02:10:25. This roll attitude reduces with the reduction in average crosswind and updraft - and by the time the speeds start to come back online at around 02:10:38, the roll has reduced to 7 degrees.
Now - *if* this simulation is accurate, it indicates that there was no immediate risk of a spiral condition that required immediate attention. Obviously there's no way of saying for certain, but to me it indicates that there is at least some degree of accuracy to the "should have left the controls alone" theory.
Sorry for the essay folks! I'm away off with work for the next few days, so if I don't respond it's not because I'm ignoring people.
