Lyman

Organfreak. From the comments PNF makes during run up to STALL, he is basing his chatter on the a/c attitude from displays only, not any suss of PFSS.

Does a concerned PNF want to see a SS display to confirm/mate input with response? Boy Howdy. If it had been available, he'd be on it white/rice, you betcha. Maybe this fella allergic to mayonnaise?

CONF iture

As an instructor initially and long time flying multicrew aircrafts, fully visible yokes have always tell a lot of the story, and so in silence – In relation to the aircraft behavior, timing amplitude duration and speed of displacement of the flight control command tell so much to a PNF.

Airbus thinks otherwise, therefore such direct information has gone, evaporated.
Just get used to it … Put everything on the aircraft behavior, whatever the reasons are, both internal and external.

As Lyman put it, there is tremendous confusion on AF447 about the commands, attitudes, steps that should or not be applied.
Direct visual information from yokes would have relieved big part of the questioning.

That is all of an acknowledgement for someone who just wrote the ongoing Yoke v SS argument is IHHO not relevant to the loss of AF447.

mm43

Touché.

A330s have SS, and I doubt very much that Airbus will be looking at adopting "old" technology. More likely they make the pertinent changes to satisfy BEA recommendations - to be revealed in due course.

RetiredF4

Are those few bits and pieces really enough indicators, that PNF was aware of the situation and would have been able to act in a correct way from the onset (AP ATHR disconect) of the event?

I donīt think so. PNF was out of the loop from beginning and equally surprised like PF by what exactly was happening and was way behind the events. He grasped some bits and pieces further on into the event, but again without grasping the whole picture.

Thatīs also the reason why he did not take over control, why he did not give clear and precise commands, why he could not get the attention of the PF, why he was not able to brief the captain in a clear and professional mannor. Poor captain got nothing out of this crew, when he returned to the flight deck.

Wouldnīt that had been some kind of appropriate information from someone who knew whatīs happening?

PNF recognised early that something went wrong, but he couldnīt get to the point what exactly was going wrong, why it was going wrong and what to do about it to save the situation.

You think otherwise?
Than sit down in that left hand seat, get yourself into the loop of this flight and then write down how you would have handeled the situation from the beginning and compare it to what we know until now (the HF group may shed aditional information in the final report) what PNF really accomplished.........close to nothing.

And then the question stays, why two pilots missed that bad.

A33Zab

rudderrudderrat

Hi DozyWannabe,
The Airbus side stick system lacks the "position of the control surface feed back loop" to the pilot. We have no easy way to sense how much control surface deflection is required to satisfy our side stick input. It is very useful for an experienced crew to know.

Imagine replacing the steering wheel of your car with a side stick.
http://www.auto-ui.org/09/docs/p19-kienle.pdf
On page 21 it shows the results of various side stick control feed back loops. The only negative results are from the "spring centred force reflective" side stick (similar to Airbus s.s.). It's also interesting to note the perceived difference between experienced and non experienced drivers. (your observation in post #396)

Pilots really need to be alerted when their control surface is being deflected by an "unusually" large amount. During asymmetric flying, the deployed roll spoilers on the lower ECAM page attract one’s attention. With the aircraft in trim properly, they remain stowed. Since there is no "position relative side stick" on the Airbus (nor feed back for the side stick demand from the other pilot), we really need something similar to warn us that the elevator (or stab trim) is outside its normal range.

Lyman

This may be the salient determination of several "knocks" on the SS/aware loop.

If one does not know the position of a deflected control surface, and by extension the "actual" position of the SS, well.... "You climb", "I am climbing?"
"Climb, then..." "No, don't climb...." "Well, then, go down...." "He is climbing...:


"Someone should, we are at 4000 feet....." "Tire, Tire, Tire..." (Pull. Pull, PULL)

If PF, at his initial aft stick, then assumes his input is zeroed, he will think, "fine, oops, I need an aft stick..." Each time assuming his input is an isolated one, instead of "additive" (accumulative)..... This is affirmed due the inexplicable travel of the THS full up....

"The Airbus side stick system lacks the "position of the control surface feed back loop" to the pilot. We have no easy method to see how much control surface deflection is required to satisfy our side stick input. It is very useful for an experienced crew to know."

Ian W

Dozy
So if a suicidal PF is sitting in the left hand seat in a 'bus it is even easier to be successful - just press override?

I think that the point that has been made several times is that had the captain of 447 re-entered a cockpit equipped with yokes, he would have seen the PF with the yoke pulled into his lap, TOGA power and the altimeter unwinding at a high rate. Without anyone speaking and without any alarms it would have been immediately apparent that the aircraft was sitting in a stall the wrong side of the drag curve.

True it should not have got to that point - but it did; and the PNF and captain seemed totally unaware of the mayonnaise being stirred by the PF so had no reason to press override.

PuraVidaTransport

For all the knowledgeable military guys, a question to help guide my opinion on side-sticks versus yokes. In duel seat trainers for aircraft such as the F-16 or F-18, does the training pilot's stick have a connection with the trainee's stick? In other words, does the training pilot know exactly what the trainee is doing with the stick or is he forced to rely only on the reactions of the plane? Be interesting to know what the military thinks on what information two-pilot airplanes need to convey without a visual reference.

NeoFit

I was searching some old data in my computer... and I have seen ...


La base de donnees WebDAS presente les informations relatives aux enquetes conduites par le BEA a la suite des accidents et incidents d'aviation civile.

Dans cette base de donnees :
Il n'y a pas incident AF mai/juin 2008 - sondes Pitot

Il n'y a pas incident AF juillet 2008 - sondes Pitot

Il n'y a pas les 3 incidents aout 2008 - sondes Pitot

Il n'y a pas les 2incidents ACA de septembre 2008 - sondes Pitot
Il n'y a pas incident AF septembre 2008 - sondes Pitot

Il n'y a pas incident AF octobre 2008 - sondes Pitot


Undoutedly, my computer seems to have lost memory

Lyman

Dozy

The evidence is yelling at you.....No one sussed the PF Stick movements....If they had,,,, etc,.etc,,,,,,

There is another even more troubling possibility....Let's say that the SS performance is "as designed", no problemo.....The Sticks were visible, the actions noted, and.....

There was no response to Recovery solutions? This is the most obvious, had the sticks been merely "one design of two, and I don't have a preference, one way or t'other....",

Something broke, something was wack, and three pilots despite their best efforts, could not recover from STALL, LOC, and jet upset. I need to suggest again that something is missing, inadvertent, or deliberate, from the data.

And the a/c was unrecoverable, as equipped.....

aguadalte

Agree.
And,
What about a software change also, to prevent the aircraft to continue trimming up, below VStall?

roulishollandais

I presume these "unmasking events" have something common with unobservability of effective aircraft ?

Cubs2jets

Good God, you guys are still working this one? I'd have thought you would have finished up the report and sent it on to the accident investigation chaps by now. Time to move on to more recent events.

mm43

@ rudderrudderrat,

A graphic of the Airbus SS arrangement was posted by A33Zab in AF447 Thread No.5.

With the addition of Synchro motors on each axis and interconnected to the opposite SS, the movement of each stick would then follow the other. Dual inputs would result in the appropriate feedback. However, realistic control surface feedback would be more complex, but if the FBW existing control surfaces positional feedback had inertial data added to it, a control transformer could be inserted into the Synchro couplings and a more realistic "feel" would be available to the sidesticks.

That's a simplistic example, and sophistication would improve it.

The disadvantage is as usual - extra complexity and weight.

OK465

What if the captain returned to the flight deck and observed a yoke held full forward?...

And generating, at best, an agonizing 2 degrees per second of nose down pitch rate?

Or a hands off neutral yoke generating absolutely no nose down pitch rate?

bubbers44

better than full up and hopefully full nose down. They didn't do that so a lot of people died. It shouldn't have happened.

OK465

B44:

when you update your experience with true FBW time, not just spoilers, get back to me.

bubbers44

spoilers, fbw?????

OK465

757.........