Lyman, my red line coincides with timestamp 02:10:11 - the A/P has been out for 6 seconds, and the PF sidestick trace has been registering significant nose-up inputs from the PF's sidestick since 02:10:05 (i.e. those same 6 seconds).

grity;

Back in AF447 - Thread No.5 Post #229 A33Zab posted a graphic of the SideStick and a brief description.

Here's the same graphic again.

http://i474.photobucket.com/albums/r.../SideStick.jpg

I think this thread is behaving worse than 447.


@2:10:08 "I have the controls". The climb started well before the PF had the stick. And VS SELECT was oscillating independently. Notwithstanding the aircraft captured 5000fpm instantaneously?

Pitch and VS (actual) track together? The graph is eating Wheaties, or was put together by Michael Mann.

how works the mechanik of the rod-spring at the kink of 6.5 mm ??? (1/3 pull)
that is +/- the pitch aerea the PF hold the stick during the climb....


also from A33Zab:

http://i474.photobucket.com/albums/r...99/SSForce.jpg

Lyman;

I've expanded some of the FDR traces and in the case of the Pitch attitude one have added the Elevator and Stabilizer positions (inverted) for easy comparison. Immediately above is the Normal acceleration trace.
http://oi44.tinypic.com/1zr2m2p.jpg
My summation is that the aircraft responded very well to the PF's inputs (as represented by the Elevator and Stabilizer positions) after the A/P hand-off, but just prior to, the turbulence had created a pitching moment that didn't correlate with the vertical speed. Hence the A/P disconnect.

The UAS was a secondary.

EDIT: Patently not true, as the RTLU was locked at 02:10:04.5 in response to the ADRs rejecting the two speeds recorded, or more precisely the Mach value of one of them.

Quote:

---

The two airspeeds recorded were still valid at this time; however, a false value point is present in the recording of the Mach. The low sampling frequency makes it impossible to determine the duration of the disturbance in the measured values; however, it is likely that it corresponds to when monitoring was triggered. (BEA Interim Report No.3)

---

The UAS was the primary reason for A/P disconnect.

EDIT #2: An interactive version of this graphic with vertical/horizontal Cross Hairs and additional time marks and scale is available here. You can also expand your browser page using Ctrl + and return to normal with Ctrl 0.

Yes, I know. Thanks.

Grity, the way this is commonly done is two springs, one for the initial slope and a second that has a certain amount of freeplay to generate the steeper slope.
One of the guys with maintenance experience will have to tell us the specifics of the A330 feel system, but if you will note, there are two spring cartridges in the pitch channel. This may be a redundant design with two identical sets of spring cartridges, or a non-redundant design with one spring cartridge doing the first slope, and the second cartridge (with built in freeplay) doing the second slope. Each cartridge would contain at least two springs (nose up and nose down).

Are you disputing the BEA's findings?

According to the BEA, the turbulence was responsible for the roll, but the A/P disconnect was initiated by UAS - this makes sense as moderate turbulence should not be enough to cause A/P disconnect.

@Lyman - The graph comes from BEA Interim#3 page 111 - I just did a screengrab and moved the relevant traces next to each other (vertical movement only - no horizontal) in the same way I and airtren have done before so that the graphic does not take up more vertical space than it needs to. This is basic pixel-pushing of the kind I've been doing since I was 11 years old. You can print that page and draw the line with a ruler and it will tell you the same thing. I've done it again here with the sidestick trace included just so you'll know I'm not fiddling you:

http://i1088.photobucket.com/albums/...itch-vs-pf.png

The pitch up and climb was initiated by the PF's sidestick input - whether he manipulated the controls before, simultaneously or after he said "I have control", that stick was halfway back for 2 or 3 seconds before the aircraft started climbing.

Doze. Check your RED VERTICAL LINE. You will notice it is at 2:10:10.

The initial PULL UP by the PF (F/O) is at 2:10:07. The START of the RED STICK TRACE. In the seconds before a/p disconnect, the Nose dropped 4 degrees, and the a/c was climbing at 1000fpm. It is this AoA increase that dropped her speeds (all three) beyond the 30 knot/second threshold, and caused the speeds loss: but after the disconnection. BEA re: ICE is "LIKELY" wrong.

Of Importance is what the a/c has done prior to 2:10:05. BEA wrote at first that the cg was at 37. They changed that later, in a follow on, to 28. If I had bet my life on their written data, I'd be dead.

I had it at 2:10:11, but whatever...

You can't keep bashing away at this, the data is there. The A/P commanded nothing untoward, the pitch-down and roll was induced by turbulence and the climb was as a result of sidestick input.

The *very* start of the PF's sidestick trace is unfortunately obscured by the data points of the PNF's sidestick trace. The "zipper" could be many things - I suspect it's wonky data (it looks too uniform to me to be anything else), but, for the sake of argument it could alternatively be pitch corrections made by the autopilot in MANAGED mode to maintain assigned altitude in turbulence. In any case, the vertical speed and altitude traces show that there is no major deviation from assigned altitude during the time it is happening, and even *if* the autoflight was commanding one of these corrections when it tripped out (which doesn't tie in with the trace - at 2:10:05, it's commanding 0 ft/sec), then a small pitch correction is all that is needed to bring the nose back up. But this is not what the PF does - he pulls back and holds it there for several seconds and commands a climb.

The CG readings given in the interim report #3 (which was the first issued with actual data) are 27.5, 28.7 and 29.1% MAC respectively. Where do you get the other number from? If it's from an earlier report it would have been an estimate because they had no data - hardly their fault.

2:10:11 or "WHATEVER"? Are you kidding? Your line is off by six seconds, and your time index is completely WRONG. Check mm43's graph. Do you dispute that the a/c had dropped 4 degrees in PITCH as she climbed (ACTUAL) at 1000fpm? Look a little closer. Please remember that to climb with nose low requires more vertical than the actual rate of the airframe. This is what duffed the three speeds simultaneously, and by the same value, imho. A computer computation of the discrepancy would result in the descent rate due PITCH to be overlimit. This bounces the A/P. The speeds follow.

mm43's graphs are from a different page than mine, and have had more editing done to them, but for whatever reason, unless i'm reading the graph completely wrong, the pitch attitude only dropped below 0 degrees at 02:10:03 and was on it's way back up at 02:10:05 (AP disconnect - though mm43 has it at approx 02:10:04.7 - perhaps he's privy to better information than me). This has all the hallmarks of a minor turbulence encounter, but the climb proper is started between 02:10:10 and 02:10:11 *as a result of the pitch up ordered by the PF's sidestick*. On this the graphs do not differ.

Dozey;

1.. The RTLU was locked at 02:10:04.5, and
2.. The aural autopilot disconnection warning (cavalry charge) was heard at 2:10:04.6.

We are "splitting hairs", but they're all that's left to split!

@mm43

That's fair enough, but I don't see how that contradicts what the BEA are saying about UAS being the reason for autopilot disconnect as opposed to turbulence. Even if that is disregarded completely it doesn't support the hypothesis that an autopilot that disconnected between 02:10:04.5 and 02:10:05 ordered a climb that did not begin until 02:10:11 (not that said hypothesis is one of yours).

As I said, it looks to me like the autopilot disconnected in the middle of one of it's turbulence encounter compensation inputs when the nose was on the way back up (i.e. not on the way down as Lyman hypothesises), but the real beginnings of the zoom climb are clearly ordered by the PF's sidestick input.

On autopilot disconnect, the aircraft locks thrust at the last setting (as you say) and holds the pitch where it was being commanded at point of disconnect (in the middle of the correction) allowing time for elevators to return to neutral, which is borne out by the graph settling at 2 degrees nose up for a couple of seconds (just short of the 3.5 degree pitch it was holding before) before the nose-up commands from the sidestick begin to take over and progressively increase pitch attitude to 11.5 degrees nose up.

Just my personal opinion, but if we really want to get to the core of the nose up control input, I think we have to look at PF's control problem.
Something along the lines of what he did versus what he should have done. If Grity's chart of control motions is accurate (and not overly interpolated/smoothed) then PF used an inappropriate control strategy.

Having never flown an Airbus, I'd like to hear from those that have, regarding control strategies used in Normal Law, and Direct Law.

For example, from the videos recently posted, it appears that the majority of Normal Law control inputs are pulses away from neutral, but sometimes in two axes simultaneously.

Is direct law also done with pulses, or is it a continuous input? (I have to assume that Alt2 Law experience with mixed control modes is very unusual/scarce.)

As I mentioned in an earlier posting, Grity's chart shows a lot of diagonal control inputs along the NE-SW axis. I really think PF was having difficulty separating his lateral inputs from his pitch inputs, probably due to an improper stick grasp.

I'm posting grity's image again below for convenient reference.
http://i.imgur.com/X3HIW.png

Hi Machinbird,
In ALT Law, it has to be flown like any conventional aircraft in roll. The control input has to be held against any roll tendency until the load is trimmed out. Since there is no aileron trim, you have to use rudder in order to be stick free. It would appear that PF was attempting to fly the aircraft using large pulses when he was in roll direct.

Most of my ALT LAW practice in the sim was at low level.

Machinbird, after taking a second look at grity's graph, and assuming that the data contained therein is correct; I make this conclusion - Something is lying to us.

The graph shows an initial move out of center, followed by three complete left/right reversals including two up/down movements in 11 seconds. That amount of movement in that time frame is IMO almost impossible based upon my time spent handling the A320 SS. In other words, the Bus SS is not a cheap video gamer's joystick. The spring loading and damping would make that amount of movement quite difficult.

Secondly, that amount of movement would be on a scale never before ordered by the PF prior in his career. If I have followed the timeline correctly, the aircraft was relatively stable when the a/p and a/t dropped off line. This graph indicates that the PF began this series of SS movements within two seconds of a/p a/t disconnect. The aircraft does not appear to have been in an upset at that time, so what caused the PF to almost immediately begin a series of spastic SS movements? These movements are not compatible with normal hand flown inputs.

We are left with resolving a series of over exaggerated control inputs with a relatively stable aircraft. Either the data is corrupt, or the PF made completely inappropriate control inputs, almost impossible control inputs. ...........OR, the PF was just hanging on. Or, the aircraft was upset more than I realized from reading the data.

Regarding control strategies, I find that small deflections, held for longer time spans work better than short higher magnitude deflections.

FWIW, the 320 requires very minor control inputs when flown a/p, a/t, f/d's off.

Roll law and stick forces
 

Salute!

I believe the stick inputs being awry due to spring failure or degradation is a red herring. The pilot commanded and the system responded best it could with screwed up speed and disregard for AoA limits.

The chart of the breakout forces was a surprise to me and I had missed that if posted before. The breakout force is lots lower than the Viper. Ours was 1 lb for roll and 1.75 for pitch. Secondly, the gradient for max command is lots steeper. For example, ours was about 7 pounds to command 2 gees. Then the curve got steep and a 9 gee command was about 31 or 32 pounds.

Secondly, my understanding from looking at the roll laws is the roll command works the same in "alternate" as in "normal". The only difference I see is the max roll angle allowed in "normal", not the command, but actual body-referenced roll angle. So what I see is what I was used to - let go of the stick and the roll command is zero deg/sec. Am I missing something?

As the Bus drivers are now finding out, there are "hidden" aspects of the control laws. Same as we had in the Viper. For example, no stick pressure in roll and zero roll rate command. Not so fast! Turns out that there are flight dynamics which are not completely corrected for. Look at the pic on my profile bio. With that LEF up I had to apply almost full left stick to stay wings level ( it was a control surface limit, and the engineers told me that I only had about a pound or two of authority or would have had to bail). The zero roll rate "law" didn't work. We also saw this when dropping a heavy store from one wing. We had to apply aileron pressure to stay wings level on the pullout and we had thot the jet would maintain zero roll rate. Same deal with allowable control surface deflection.

Only thing that puzzles me is the pilot having to apply roll in the first place. Could be a spoiler or aileron wasn't moving correctly, and a determined manual input was required to override the deflection limits. Same as I had to do with the LEF failure. And remember, control surface movement rates and such use dynamic pressure for "gains". What does the system do when dynamic pressure is deemed unreliable by the system?

later,

Repeating my dumb question
 

@TTex600:
I'm going to repeat my possibly stupid questions that I asked the other day:
1. What about a broken longitudinal transducer?
2. Were all four transducers found?
3. Have they been verified as working properly at the time of the accident?

If there were to be such an (outrageous) finding, that one was broken, this might explain the unexplainable.:8

Simply put, The Pitch was below cruise for nine seconds from 2:10:00.

It reached its lowest value (4.5 degrees ND) just as the a/p tripped out.

As it increased, the aircraft was still in descent.

At 2:10:07 PF input back stick, after the a/c had started to climb.

The airframe was out of phase v/v ascent/Pitch for nine seconds.

The PF inherited an airframe in phugoid oscillation.

How many times had PF been handed an a/c out of autopilot? As many as he had landings logged, most likely. His stick work is a copy of the two vids grity has posted, perfectly acceptable, when approaching to land.

His elevators were following the airframe at first, from his display.

The autopilot could not keep up with the turbulence, and tripped out. Out of this trip came airflow that sensed airmass inconsistent with the airspeed prior to its disturbance, and so the airspeeds were lost.

In two seconds, the handling pilot was given an impossible task. True to form, just as the Airbus got into hot water, it changed the "rules", and took a powder. So now, the Pilot has a very long list of things to learn, or die. Not the least of which is to acclimate to a Stick that has morphed into a goblin in ROLL, and a PUSSYCAT in PITCH. Has he trained for this?

I think NO. As someone has said here, put a single engine pilot in a twin, and pull an engine at liftoff. What are his chances? Not good.

At 2:10:00, the a/c started a phugoid. Was it speeds? No, I think airmass related. Had it been speeds, I think the engines would have been throttled, and they remained at cruise level. And if not speeds, then ICE is not a player.

For good or ill, in my opinion, this flight was out of control when the Pilot's input doubled PITCH, at 2:10:11. One can insist it is complex, and it may be, but had PF had a current Attitude display, and listened to PNF......

The other explanation is adrenalin. The "startle response" is quickly gaining currency as the biggest potential killer in line flying. With Colgan 3407 you have two tired pilots, one of whom is shocked into pulling up into a stall when the stall horn sounds. West Caribbean 708 had a Captain who was convinced he had a double flameout and concentrated on that, pulling up all the way into the ground. Birgenair 701 had a captain who focused on the initial overspeed warning to the exclusion of all else and pulled the aircraft into a stall.

Then you have success stories - US Airways 1548, BA038, Aloha 243 and United 232 as a few examples where in all cases the crew kept calm, overrode their internal panic switches and found a way to resolve things.

Whether you're flying, driving, doing your job or whatever - after doing it for some time things become routine - if something happens to break that routine then you have to keep your head about you and logically focus your way out of an event, but you've got millions of years of evolution behind the human brain which triggers a "fight or flight" response. Sometimes it works to the good and people have found almost superhuman resolve in themselves to get the job done, but sometimes it does not - people freeze or try random combinations of things they half-remembered in training or heard on the line with tragic results. It's all part of being human and training must address that.

Remember that the this was the PF's first day back on the job - he had just ended his holiday in Brazil and his wife was down the back - if there's a situation more conducive to be startled and try absolutely *anything* to keep that aircraft at the assigned cruise level, I can't think of it.

@Lyman - a phugoid cycle is something that happens over longer periods of time than the turbulence encounters the aircraft was experiencing. Remember JAL123 and UA232 - with dead flight surfaces the cycles happened over the course of about a minute and a half, so it was about 45 seconds of slow climbing followed by about 45 seconds of slow descent. The turbulence encounters and autoflight corrections we're talking about here were on the order of a few seconds at most. The pitch attitude was increasing at A/P disconnect as a result of one of those corrections, and stopped short of 4 degrees nose up because of the A/P disconnect. The elevators don't remain in the position they were in when A/P disconnects, they are set to match the last requested flight path angle, which was about 2-3 degrees nose up.

@Dozey;

You are right regarding the A/P disconnect. The RTLU locked because the ADRs disagreed, and I have made an edit to post #526.

I am not going to get into the argument regarding the cause of the climb, other than to reiterate that the elevator and THS responded to the PF's SS stirring and the aircraft pitched into the climb almost immediately at 02:10:09.

So, a robust updraft. Very warm, sufficient to corrupt Mach value? Unless the increase in VS is due baro, then it is airmass. The point is, the a/c was out of phase, and the pilot was given an a/c that was climbing with the NOSE showing low. His Pull was additive to an input made by AutoPilot("STALLSTALL"), and the confusion began. Yes, he should have been "ready", and managed a better get than he did.

The problems encountered were not complicated, but the timing was.

Those two videos show but one pilots control technique. I bet you a cup of coffee that they could have both kept their hand off of the SS and the end result would have been the same. In other words, the Bus doesn't require that kind of SS input in/on final. The pilot was working too much. Those little corrections he made were not likely necessary because the Bus will stay where you left it, and/or return to where you left it without any input. Once you learn too let it correct itself in roll on approach, you find yourself making very few roll inputs.

It depends on your definition of "climb" - it looks like the tail-end of a small pitch correction due to turbulence that would have ended maybe a second later than it did due to A/P disconnect - the aircraft's pitch attitude was increasing, but all the evidence suggests it was not about to climb significantly, it was simply trying to regain the assigned flight level and pitch attitude.

The pitch attitude was lower than it should have been at A/P disconnect, but it was a matter of 2 degrees - it briefly settled at 2 degrees nose-up after A/P disconnect. That kind of difference is barely noticeable on a modern PFD, let alone steam gauges - it was two points in the blue. It certainly does not require half back stick to correct, which is what the PF did.

He may have mentally been correcting for the bump they felt at disconnect, even though the autopilot was ahead of him - seeing the ADI pointing into the brown for a second might have been a shock. This is where Human Factors comes in. For those who aren't pilots but can drive, would you say you take more care when driving with your loved ones in the car than you do on your own? I know I do. See someone driving erratically or dangerously when you're on your own and it's tempting to just go past him. Do it with family in the car and I'm inclined to leave him to his own devices and back off because it's more than just me at stake. Professional airline pilots live with the knowledge that there are hundreds of people behind them who are depending on their skill - that's part of the job and why I respect them so much. If you're flying a jet that nevertheless has family on board? All of a sudden instincts start to cloud rationality and there's an emotional pull there too (which is why the Aeroflot crash with the children in the cockpit is to my mind the saddest aviation story I've ever heard).

No - the autopilot disconnected at 02:10:04.6 as mm43 has it. PF inputs begin at approximately 02:10:07 (by your own statement) and the first STALLSTALL does not sound until 02:10:10. There is no "additive input" to the autopilot from the sidesticks.

It happened in a matter of seconds, no doubt - but the control inputs the PF made were completely disproportionate to what was required from the outset.

At long last I believe we are closing in on what may be a lay solution. As such, it is of little value, save for some sort of truce. It also may be as close to a resolution as anyone gets, including BEA.

2:10:04.7. A/P quits. Here, the Nose is 4.5 degrees lower than what it should be. With MASTER CAUTION and CAVALRY CHARGE, the PF is brought up short, from whatever his status was, re: SA. A quick glance at PFD, if not already looking, shows NOSE LOW, and VS in descent, perhaps 500fpm. 2:10:07, and he inputs back stick with a ROLL LEFT.

The a/c has started to climb at a/p quit, and there is not a reason to doubt his input causes sufficient NOSE UP to trigger STALLSTALL. His next inputs are NOSE DOWN, so he 'gets it'. The rest depends on what he sees on his screen, feels, (The g is <1 until after his input), and decides. (Hears?).

If there is mitigating data, sufficient to establish his inputs were based on data not seen here, I propose there is a 50/50 we will never see it. That is the way of the world; life is harsh, and seldom "fair".

At long last the discussion is where it should have been from the outset.

With NOSE DOWN, I would submit that it takes a healthy Updraft to cause such an ascent as we see just prior to a/p loss. Was it sufficient to cause the accident? Was there ICE? or only variable TEMPS and a bumpy airmass?

It's been a real slice.

No Lyman, the nose was on the way *back up* when the A/P disconnects. The PF may have *seen* the brief turbulence induced nose-low attitude and might have been trying to correct for it but there was no major updraft. The aircraft climbed because the PF's response was incorrect - in a perfect world he would have waited a few seconds to get a feel for what the aircraft was doing before trying to join in.

Hypothetically speaking - put yourself in the PF's position. You have not been trained in manual handling at altitude, most of the 2,000-odd hours on your flight log have been completely uneventful (and not to mention automated), you've been on holiday with your wife and you're now returning home with her in the passenger cabin. The Captain has nominated you as the relief pilot despite being the junior flight crew member on board - you're on top of the world. Suddenly you get an autopilot disconnect alarm followed by an alarming bump in which the ADI showed the nose dipping below the horizon for a second or two. What do you do?

We'd all like to think that we'd be calm and rational and behave as if this was any other flight - but all of a sudden one of your best days has turned into your worst nightmare.

Gums, What you wrote is correct for Alt1 Law but not for Alt2 Law. Alt2 Law is roll direct, i.e. aileron deflection proportional to stick deflection.

Organfreak, There is a reason each transducer on the stick has its own control mechanism, it is redundancy. That redundancy undoubtedly carries through in the software design of the "Bus" so that it can recognize a bad transducer, but don't ask me details because I don't know. At this point, all I know is that it would be extremely out of character not to cover that potential problem.

[quote Dozy]but the control inputs the PF made were completely disproportionate to what was required from the outset. [/quote]
Dozy, I agree with this summation

TTex, he was essentially reversing his roll input every two seconds. Maximum control input pretty well corresponds to maximum wing down. Just hanging on is probably as good a description as any. Over time the intensity of his inputs begins to decrease as he began to get the "touch".

PF was definitely driving a lateral oscillation by means of his excessive control inputs. This period where he is struggling with roll is when the aircraft became committed to a nose up attitude.

So why didn't PNF at least coach him back on altitude? All I can conclude is that both of their scans were in the toilet. "GO Down" , YGTBSM. :yuk:

Thanks Rudderrat. I just wanted to be sure. No lateral pulses then in Alt2.

Machinbird wrote:
Thanks for addressing my question/speculation. I had assumed, apparently wrongly, that there was one TD for each direction of stick travel. Your contention that they are redundant rings true. Damn, and here I thought I'd come up with The Answer. :O

Artificial feel spring rod as in A330 SS
 

2 identical rods are installed in each SS.


http://i474.photobucket.com/albums/r...999/ArtRod.jpg

A33Zab, Thank you for posting the drawing of the spring rod (or cartridge).
It appears to be an elegant design in that the same springs work in compression during both extension and compression of the cartridge. Additionally, it appears that one of the springs is of a non-linear design and does not follow Hooke's Law. :ok:

Lyman, not really possible in an Airbus in Normal or either of the A330 Alternate Laws. The flight control system, by managing g, sets a stable flight path on the average.

A phugoid oscillation is a relatively slow oscillation at ~constant AOA, where potential and kinetic energy trade back and forth, but that isn't the way the 'Bus flight control system works.

A330 phugoid
 

Back in june i posted the A330 phugoid that results when the system in normal law enters high AoA protection and maintains AoA equal to alpha-prot (as in the TC-JDN airprox incident).

I like this forum very much for such a design-picture, thank you A33Zab

but machinbird I am shure, there is a smal mistake in the drawing both springs will work in hook´s law, but the bigger(purple) spring IMO is a few mm shorter than shown, there is more space on the yellow side..... so first you press the weaker green spring and later you have to ad the hooks force of green and purple

so we have a redundant system with two catridges, well gums it can be a herring but if one of the green spring was broken then I am shure this is not easy to detect on the taxiway, the SS feels full ok for left/right/up+down and only the force for 1/3 pull is half of normal........ remember we search for the smalest possible defekt who can explains the action of the PF shown on the FDR!

the basis of my chart was the datas shown in interimreport3 s.29 (F/O pitch and roll command position) I used 2 valus/sec put both together for 2D and smoothed a splinline over it.... so it is little interpolated but not much,

it looks not as he has made pulses ore something like this in this time.....

much more interesting for the control strategy is if you overlay the sidstickway with the left/right asceleration, which was also left-right-left-right-left in this 10 sec with values +/- 0.1 g

Non-Linear springs
 

Grity, it is quite possible that you are correct and there is actually some spring freeplay that is not shown in the drawing. It is also possible to make a non-linear compression spring by wrapping the spring in such a way that the adjacent loops make contact in only a portion of the spring and thus effectively shorten the active portion of the spring. The guys who make springs can do it very consistently, even with 50 year old equipment.

HN39,
Thank you for the reminder on how you cannot forget completely about the phugoid on an Airbus in Normal Law.

In the AF447 case, the phugoid did not apply since as soon as the AP dropped, it was not in Normal Law. And before the AP dropped it was not in high AOA protection.

Agreed entirely. My intent was no more than to provide an illustration to your post #553.

Another mystery?
 

Does anyone know what the parameter 'TLU Position (DA)' shown on page 112 of IR no.3 (English) stands for? Since with 1300 recorded parameters it is inevitable that the report must necessarily involve a selection of the relevant parameters, showing this parameter means that somebody thought this one might be relevant.

On page 89 we read at 02:10:18: "The ‘TLU 1 availability’ and ‘TLU 2 availability’ parameters become NOT AVAILABLE" and the traces of these parameters are shown on page 107. Since this time roughly corresponds to the end of the initial 10 second speed monitoring process, I thought that TLU could stand for RTLU (Rudder Travel Limiter Unit). But what then is TLU position?

From page 40 -
* the loss of the normal law between 2:05:10 and 2:10:06. The position of the rudder limiter, set by the rudder travel limiter unit (RTLU) is locked at 2:10:04.5 and this function is recorded between 2:10:17.5 and 2:10:18.5.
NOTE: The report uses "stuck" instead of "locked".

From page 89 -
* 2 h 10 min 18 - The ‘TLU 1 availability’ and ‘TLU 2 availability’ parameters become NOT AVAILABLE.

From page 112 -
* TLU 1 and TLU 2 parameters repeated, and at 2:10:08 the Side Slip from IRS becomes ACTIVE.

I suspect this is related to the Yaw Damper.

I've previously commented that the Rudder Pedal demands (up to RTLU limit) had the Yaw Damper output algebraically added.

The french text is quite clear:
What about the changes of 'TLU position' before 02:10:04.5?