Can somebody correlate the ACARS messages with the recently released CVR/FDR information? It would be interesting to see some of the mysteriousness cleared up as to what triggered the ACARS messages and their meaning in light of this new information.

Thanks

hi takata

We don't know that the roll to the right happened because of the stall or just before it. The report mentions the roll, the pitch up and then the stall warning in that order. Perhaps the PF merely thought the a/c was rolling and and pitching down, having forgotten that the engine thrust was set at a lower level when AT disconnected.

There is no evidence to even slightly suggest that they were in a CB. In fact, based on the statements in the report (the call to the cabin, the 12° left turn, the decel to M0.8) they knew very well what was going on with the weather and were steering around the worst bit. IMO they were obviously not in a CB, but in cloud in bad icing conditions.

Vertical stab isn't the THS, ;) but thank you for the load factor. :)

I cannot access the BEA report - will wait until later and try again.

Meanwhile I have a question for anyone with actual technical knowledge of the A330:

If stablizer trim is full nose up (why is not important at this point) and TOGA is applied - does the elevator have the ability to overcome the consequences if full nose down input is made and held (without changing stabilizer trim)?

Well, I'm no clearer now that I was! There are too many inexplicable events to make sense of this, including pilot input and THS angle. It is unfortunate we do not have the RHS IAS readings, and I'm not clear from that report which seat PF was in, nor which IAS readings he was reacting to. A 'zoom' from FL 350 to 375 with 7000fpm is pretty dramatic. It also appears that they were close to being unstalled at the 375 point.

The only observation I can make is that I have seen a full and maintained nose-up demand from a pilot in a different aircraft before, in reaction to a large (and unexpected) rate of descent while stalled.

Way to go yet.

Stall training
 

takata wrote :

Agreed.

PENKO wrote :

Agreed, too.

One hypothesis is along the lines of "stall training" such as airline pilots usually get during recurrent simulator training. Since the aircraft is reputedly "protected" against stall, training for upset recovery, stall identification and recovery has been, at best, extremely poor. The only manoeuver which is considered is "approach to stall, minimum altitude loss". And as takata pointed out, in Normal Law, perhaps modified through landing configuration (such as was attempted in Perpignan).

In this specific sequence of "approach to stall, minimum altitude loss", the reaction is to power out of pre-stall condition using TOGA thrust, maintaining some kind of "average" pitch attitude. This is of course completely self-defeating in a high-altitude post-stalled condition. But this condition must be identified first...

Both major manufacturers produced together a video document about upset recovery a few years back. But that was likely the only "training" the accident flight pilots ever got about it. And of course, I am with those who will claim that a pilot should know how to get out of a stall (like someone mentioned from a beginner's PPL experience, very valid point).

Unfortunately, what we have here is the glaring example of why pilots should remain pilots for real, and not become system operators, or cockpit managers, or what have you. The design of any aircraft, especially one as revolutionary in its time as that which appeared in the late eighties, will have an influence on what the role, function, skillset, attitude of those on the flight deck will become. I maintain that these changes were intentional, but of course not from individual engineers or programmers, this is ludicrous. It is a political decision.

One does not live through the career of an airline pilot in isolation, working their skill at home with personal dedication. Any airline pilot is essentially the product of a whole system, regulator, airline and manufacturer included. The only personal thing that can be added to this is personal light aircraft training (as can or cannot be afforded depending on work and wages conditions...), homework with the FCOM and other documents, personal discipline regarding sleep, food, physical activity, and personal ethics.

But even if I was ready to pay for it in person (I cannot), I doubt I could get even a 12hrs simulator training syllabus to get me vaguely up to par about all the upset and stall conditions I would have perhaps to face one day in a large heavy jet airliner. But in all likelyhood, I will never face these conditions. How expensive would that statistically useless training make me ?

Finally, as the pilot's responsibility with the life or death of his charges justifies inquiring in detail into all his actions even post-mortem (and this occasionally includes very personal details), similarly, the authority claimed by the aircraft (design policy-makers, technical designers, head of project and so on) over life and death "protection" justifies that it be subjected to a similarly detailed scrutiny. There is enough evidence already to justify such scrutiny.

Question.

Most of the new BEA info regarding instrument read-outs explicitly relates to the left-hand seat displays (with the right hand-seat displays not available in the FDR). But which seat was the PF - at the time of the initial upset - sitting in?

There was speculation in one of these various threads that he would almost certainly have been in the right-hand seat. That he handed over control in the final moments (presumably to the Commander, who had returned to the cockpit) seems to support that.

Could the initial PF have been seeing different values on his displays than on those recorded in the FDR?

[Obviously, everyone could hear the stall alarms wherever sitting / standing.]

How about moving stick, throttles and trim wheel?
 

Can the captain in the jump seat, even SEE that PF was giving pitch up input, not pitch down? After all, they are impulses, not stick positions?

spagiola comments:

Agree that the report is very light on some details but that does bring up a question in my (obviously not heavy pilot) mind:

Given the lack of feedback/coupling between the 2 sets of controls what other immediate clues are available to the PNF on the action the PF is taking?

Note: This is a sincere question not an attempt to stir the A/B pot.

Hi glenbrook,
First, I fully agree that we don't know (nothing is said about it) and I may be totally wrong about that!
I just tried to answer the sharp turn to the right as seen on the BEA map:
- Red dots as legended:
(1) 0135:15 (last contact with ATC)
(2) 0159:32 (meteo briefing with Captain, light/moderate turbulences expected
....................Captain leaves flight deck)
(3) 0208:07 (12 deg offset manoeuver start, light turbulences, Mach 0.80)
(4) 0210:05 (icing: autopilot off, autothrust off, ALT law, stall alarm -twice-, right wing bank;
.............PF: pitch up, left roll ordered, speed decr. 275-> 60 kt)
(5) 0210:51 (stall alarm again. PF: TOGA, max pitch up and left during 30 sec., THS +10, ...
(6) 0211:40 (Captain is back in the cockpit...

http://takata1940.free.fr/LastFlight.jpg

AoA vs Pitch
 

Question from ignorant SLF, the BEA report quotes different values for AoA and pitch at the same point in time.
Are these not the same datum?
Or is pitch calculated from the laser ring gyro and AoA via an aerodyamic sensor?

What we won't know is where the PF's eyes were. (Interesting question on if PF and PNF were seeing the same things on their instruments) Where his eyes were would inform what his hands were doing while he tried to regain control of the aircraft.

In a CB or not?
 

But there was convective WX around and we don't know what the tilt setting was - they could have been dangerously overscanning the storms, leading to a false impression that the flight path choosen (10 left) was clear:

http://http://www.weathergraphics.com/tim/af447/

Manual pitch trim
 

takata, have you ever flown an Airbus ? Have you ever trained for type rating on either 320, 330, 340 or 380 ? I will tell you a ghastly secret : using manual pitch trim is one of the very first things one has to unlearn in order to be accepted as a candidate for type rating. After which, during all operational flight hours, and during every simulator training and check, it is verboten to touch that wheel.

CPT : A330/340 experience -> 1700hrs (plus all hours on A320 not mentioned)
F/O 1 : A320/330/340 experience -> 6500hrs
F/O 2 : A320/330/340 experience -> 2900hrs

It would seem obvious that touching that verboten wheel would have perhaps been useful. But the pilots here had never touched it, even in benign conditions, for a total of more than 10000 hours...:{

Sad and deadly combination of factors
 

Having read the BEA document, to the SLF I am, and with all due respect to people who lost their lives, this sad accident seems to result from :

1. loss of airspeed indication resulting from ice-clogged pitots

2. inappropriate reaction of crew that did not immediately apply the recommended unreliable airspeed procedure which prescribes 5° pitch and CLB thrust setting (see HyperVeloce post in part #1 of this thread) until the situation has been sorted out

Yet another combination of technical failure and human error. Apart from R&D work about how to prevent UAS condition, this seems to call for a better training of pilots in unusual situations.

Professional opinions welcome of course.

Pitch is the aircraft attitude vs. the horizon, while Angle-of-attack is wing airfoil vs. airflow direction (an air vector is needed but may be calculated by Inertial Reference). When you have a pitch of 0 deg and an AoA of 90+ deg, you are in "ligne de vol", but you are falling down vertically. BEA says that [edited: pitch was 16.2 deg at impact and AoA was not valid].

You are only a troll, Svarin. If Airbus didn't want someone to ever use the trim wheel, the very simple way was not to put one in the cockpit at the first place. They would even have made the electrical imputs to have a precedence over the pilot mechanical control which was, of course, made the other way.
Get a life.

takata, the pitch angle was 16.2 degrees on impact, there was no valid AOA data at that point.

Right, I stand corrected. wrongly remembered "incidence" instead of "assiette".

For interested layman:

Angle of Attack Indicator

If I hold the pitch of my airfoil constant in a fixed wing aircraft (I'll do that by controlling the nose pitch attitude, either via visual reference to the horizon, or on the attitude indicator based on a gyro of some sort)

and then I vary my airspeed,

my AoA will change: increase as I go slower, decrease as I go faster.

Depending upon model of aircraft, when the fuselage is roughly level compared to the ground, you may have a few degrees of pitch up, relative to level to the ground on the airfoil. (There is also on some aircraft "twist" from wing root to wing tip, which would induce the wing root to stall before the wing tip at high angles of attack ... )

Could the physical sensation of a rapid descent combined with doubt about the veracity of the flight information and the lack of outside visual references simply trick the brain into misreading the situation they were in?

It can. 3-D disorientation is a common phenomnon in instrument flying.

Part of the purpose of instrument training is to get you to focus on your instruments, regardless of spatial disorientation, and to develop scan patterns that allow your brain to sort out what the aircraft is doing. It's a skill that is useful to practice in case you need it. If you have some instruments that are of doubtful accuracy, most scan training teaches you to cross check other instruments to see what the aircraft is doing. (I called this "partial panel scan" in another thread but that may not be the current term of art).

Now, if you are stalled, the flight controls don't respond as they normally do, getting unstalled on instrument scan (the first time you do it) is a bit tougher than simply flying maneuvers on instruments. If you are stalled and rotating, the degree of difficulty goes up an order of magnitude or so. (First time I ever did a training spin "under the bag" in instrument training was an eye opener. It took a few tries to get the hang of what I needed to do, and to actually do it. Some years ago in a single engine trainer).

Good catch!... I didn't see it while typing/posting that.
:ugh:

The difference between "the bird" (the flight vector symbol) and the pitch reference on the PFD gives you the angle of attack - if you are aware of it.

No - for any aircraft with this configuration, the stabilizer is more effective than the elevator, and easily overpowers it, especially with the added pitch up moment from high thrust.

Stall warning comes from the angle of attack sensors, not the airspeed indicators - so a stall warning with an indicated high speed is possible.

That's right - in the pic below (this one from a Boeing, but airbus use the same systems) you see two pitot tubes which detect airspeed, and between them the angle of attack vane, which detects the direction of the airflow (and thus the angle of attack).


The inertial reference system also supplies vertical speed information, along with ground speed - so the vertical speed is independent of any air sensing failure.

What is also interesting is that the pilots discussed the wx ahead. They told the cabin crew that here would be an increase in turbulence. How did they know that? Were they planning to fly through some of the returns? Flying through echo's at level 350 is a bit iffy, not something I would do voluntarily and not something I can imagine the captain leaving to the two FO's.

So here is the retrospective catch-22. The wx could not have been that bad, otherwhise the captain would linger a bit longer in the flightdeck. However the wx was bad enough for the FO's to warn the cabin crew. Was it that bad that there was no space to properly avoid the echo's? In that case, why was the captain away? The PNF suggested tentatively a turn, but only a turn of 12 degrees was made. What were they avoiding?

I have never flown across the ITCZ, so maybe others can comment, but again I feel as if we are missing a lot of information.

Verdict not in, but a question or two
 

Hey, TK??? Or others, for that matter.

- Don't have the full manual, only some flight control law pages. So...

Is the THS manual trim wheel connected to the THS via a mechanical means versus simply another electric command to the servoactuators/jackscrew motor/whatever?

- Is the THS position displayed in the cockpit?

- Any mention of "runwaway trim" procedures?

AoA vs Pitch
 

Got it, thanks ( and tanaka too )

high incidence
 

Hi there,
The BEA note states that
- most of the pilot actions were pich up commands
- @ 02:10:51: incidence around 6° (when the stall alarms sounded), TOGA, pich up commands. 15 sec later, incidence around 16°, FL380, pich up commands again
- @ 02:11:40: end of stall alarms, FL350, -10 000 fpm, pich angle 15°, N1=100%, large (40°) roll excursions, pilot commands: roll compensation & pich up (during 30 s)
- @ 02:12:02: FP says "no longer any reliable indications", N1=55 %, 15 s later: pich down commands, incidence is decreasing, IAS reliable again, stall alarms
- @ 02:13:32: FP says "we are going to get under the FL100"

the incidence has always exceeded 35°, and seen from the pilots, the altitude was decreasing rapidly (a bit more than -10 000 fpm) with an inertial piching attitude reaching 15°: how can we explain that most of the pilot commands were to pich up the plane except around 02:12:17 (15 s after 02:12:02) ? Did the crew apply the AF SOP in the early phase (around 02:10:51) by setting TOGA thrust and a pich up at high altitude ? It is only 1 min 11 sec after that THR is on IDLE, the N1 is on 55 %, and that pich down commands are applied.

the stall is not recovered and the terminal vertical velocity is around -10 000 fpm.

why a crew would respond to the early stall alarms by a nose up ? spatial disorientation ? confusion/stress due to multiple conflicting indicators ? or tricky/misliding/lengthy procedures ?

You know what? That makes absolute sense.

Yes, cable connection to the hydraulic servo motor (in the A320 at least) with a placard position gage next to the wheel. If you have hydraulic power, you have trim.

A few thoughts after reading this prelimanary report, and the many questions it raises. I write in a modest way, as it has been some years since I flew those planes, and I have forgotten a lot.
My very sad and friendly thoughts to the pilots of this flight.And everyone aboard, of course.
The THS (trimmable hydraulic stabilizer) auto trims the plane, the PRIM 1 is normally in charge of that job. The report does not say if the PRIMs (there are three) were lost, which is possible after losing speed information, and it does not say (understandably, it will come later) if from normal law, then alternate, the plane ended in direct law, then changed back etc…(possible resettings, speed indications coming back…)
If in direct law, there is not automatic trim, the horizontal stabilizer stays where it is and you have to use manually the trim wheel which a warning on the PFD, among very many other warnings in that case, tells you to do.(I am reminded of the Perpignan accident where the captain fought with the plane but if I remember correctly, never trimmed manually, with a very UP THS, exactly as described here, though for other reasons of course).
The THS is very effective, and even with sidestick applied fully down, if it stays at 13 degrees up, I think lowering the nose will be difficult…
From what I understand, having been familiar with this company, the captain went to take a rest, asked the most experienced of the two copilots (who had the appropriate qualification) to take his seat (left one) and the copilot in the right seat was PF. This is quite normal. If, and I do not believe it for a second, the PF was « lost » and applying full aft sidestick, while on the instruments, all kinds of understandable things happened, with chimes, alarms, synthetic voices etc…the copilot in the left seat , and even the captain coming back and sitting between them, had no way at all of knowing this, and could believe that he was applying the correct inputs, unsuccessfully. In the old days (and I am a very old-timer), putting your hand on the trimwheel was a habit…Nowadays, you don’t even know you have one, except for checking its position at take-off, which is not the same as using it in manual flight. Rolling it manually far forward, and that is always possible, in all modes or laws (correct me if I’m wrong, active bus drivers) and applying cruise thrust might have solved the problem, but that is easy to say from where I sit. I am quite sure of one thing, as you all are, but it bears to be repeated : thos pitot probes were changed by an efficient management, many months before, in another company, after an icing incident. The management of Air France truly thinks, not having done anything, that they did everythin very well, since it was not mandatory. Food for thought. May they sleep in peace.

Hi,

The BEA has kept its promise
He submitted a series of factual facts in chronological order
He announced that this would be incomplete .. it does not disappoint.
Upon reading the end of the release .. Lambda can conclude that:
The aircraft responded to control of the pilots and it was structurally capable
That the pilots did not follow the guidelines of Air France in effect has the time for this kind of event.
As this release is incomplete and is filled with shadows .. full of scenarios can be envisaged.
I am sure members of this forum will describe possible scenarios
Conclusion:
Much work awaits the BEA and the court of Paris

Few remarks come to mind

Apparently those 3 well trained pilots did not manage to recover from a high altitude stall with a fully functional and structurally sound aircraft. They even recovered reliable speed measurements about half way in their descent but still ended up in the water. This is really puzzling and I believe we might still be missing an important piece of the equation.

For the fairly high tech measurements and recording equipments on board it seems that there is in fact not that much information being saved. I would venture to say that with modern FBW planes we should have all inputs covered as well as some "trace / log" of what the software is actually doing.

Although rare pitot icing is not unheard of. As other have mentioned it would be desirable to add some different airspeed measurement devices, as FWB can really become confusing with unreliable airspeed.

... or simply being constantly told during training "You can't stall an Airbus." as an absolute statement, reinforced by full back & side stick climbs at the lowest possible speed in the simulator to demonstrate "How the aircraft won't let you stall."

Gums: take a look here > SmartCockpit - Airbus 330

I believe the flight controls section has what you might need.

My understanding is the trim wheel has mechanical linkage.

Manual pitch trim (2)
 

In the Perpignan accident, manual pitch trim was not used.
In this accident, it would appear it was not used either.

The fact that the manufacturer left this manual pitch trim wheel in the cockpit does not exclude the fact that in real life, in real airlines, on board real airplanes, pilots are actually taught not to use it, and never use it, according to design.

The piloting quality one would get using for the first time in a highly dynamic, critical situation this item of equipment would likely be very poor, anyway.

Hi gums,
Yes. mechanical control, it is all you have in direct law.
Yes.
Yes. indications written on trim wheel are for take-off (not related to flight position). I'll sent you that part later (no time to dig in now).

Does anyone remember why the US Navy set up Top Gun? Maybe it's time airlines start renting Cessnas, Robins, and Pipers.

That, and fixing pitot tubes that ice up.

:confused:.... While it's nice to have some "factual" information, for a change, I'm certainly none the wiser for it. :( .... I hope it's not ages before we get the rest of the story. Conversations in the flight deck could be somewhat illuminating...