I bet there were a few " merde's" being thrown around !

shogan1977

Nice, I agree. I know nothing about the Airbus, is there any indicator readily available to the pilots to show what angle the stabiliser is at ? Is there any way of trimming the stabiliser really "manually" ?

Shogan1977

I prefer to see facts rather than claims in a self serving article (lawyereese speak)

The above is nicely laid out to assess blame before the report is finished.

Such words as culpability have no meaning without examining all facts

Also I really don't understand how one can assign a regulatory word of "catastrophic" to a single system manufactuer such as "Thales". The presumption should have been a simple failure condition (if operated outside its certified enevelop) to be accomodated by the installer (Airbus)

Good point, the old 707 had two dirty great 'coffee grinder' wheels on the sides of the central consol, so that the pilots could really 'manually' trim the stabiliser should it decide to do something one didn't want. Sometimes one had to relieve the airload on the stabiliser by pushing the nose in the opposite direction to that desired, then when the pressure was reduced cranking the handle like mad in the desired direction. In this context the pilots may have had to pull the nose up even further momentarily of course to operate this truly manual method.

There was also a pointer which moved along a scale, so that one could see what angle the stabiliser was at.

Course it's all computerised now, therefore far superior, so nothing can go wrong, go wrong, go wrong.

Hi,

Same for Airbus

Answer was already posted somewhere in this forum (with pics)
The answers are YES for the two questions.

To ExSp33db1rd

Same system on A320.
Of course normally the AUTO-TRIM does it automatically, but you can do it manually with the wheel IF NEEDED.
The angle is also indicated

There are two PITCH TRIM wheels on the mid pedestal. They have scales to set the CG for take-off. Inflight the CG scale is not valid but the indicator shows the position of the THS (trimmable horizontal stabilizer).
The THS is only controllable manually when on ground or when inflight in direct law. In direct law one uses the wheel to trim the pitch manually - therefore USE MAN PITCH TRIM is displayed on the PFD.

Oooops: two've been faster...

So if the THS is 13 deg up and the sidestick held fully forward, will the a/c recover from the stall?

Hi,

Add to your question the AOA angle .. the air speed and the altitude of the AC ... as it can be important to know the outcome ......

Does this mean they would NOT have been able to trim the pitch in Alternate Law?

Assume sufficient height for recovery - the question I am asking is that with the THS at 13 deg up and the side stick held fully forward and the engines at idle thrust (which they were) is the stall recoverable? What difference would positioning the THS fully forward make?

Hi,

This mean that they were able to use manually the trim wheels
The manual trim is available under all laws

Hi,

Undoubtly a big difference but keep in mind the AOA and air speed factors.....

jcjeant: "The manual trim is available under all laws"

DouglasFlyer: "...only in direct law..."

Who should I believe? :confused:

Hi,

In its conclusions the BEA makes no allusion to the pitot tubes to justify the inconsistent speeds

What would happen if a high speed upwind (possible bad weather in area) of + - 100 Km / h met the static probes ...
That will he not cause a significant decrease in the indicated airspeed .. and this does he not bring up the plane very quickly?

As with ExSp33dblrd reply for a B707, manual cranking of a TP trim wheel can be arduously slow, on some craft there is an electric trim motor (B727 example) which does this work much quicker, how about on the A330?

Hi,

Check this !
http://www.smartcockpit.com/data/pdf...t_Controls.pdf

Also:
http://img402.imageshack.us/img402/8669/thsinfo.jpg

It adds nothing to the discussion but some highly tendentious speculations...

As far as we can gather from the report, at least initially not the THS forced the plane nose up, but the stick input did.

2h10m51:
Stall warning
(...)
PF maintained nose-up inputs
(...)
The trimmable horizontal stabilizer (THS) passed from 3 to 13 degrees nose-up in about 1 minute
(...)
The PF continued to make nose-up inputs
(...)

2 h 11 min 40:
The PF made an input on the sidestick to the left and nose-up stops, which lasted about 30 seconds

2 h 12 min 02:
Around fifteen seconds later, the PF made pitch-down inputs. In the following moments, the angle of attack decreased

This is the first mention of any nose down input after the stall warning, 1m26 later. It is not known how long this input lasted (and BTW it is also not known whether PF ceased the ND input due to the reactivated stall warning, as many here claim).

We don't know that. The report states merely:
simultaneous inputs by both pilots on the sidesticks were recorded

Report says: and the PF said "go ahead you have the controls".
Admittedly probably not dramatic enough for a "serious" publication.

Which would necessitate a continuous downward acceleration. We know downward velocity at 2h11m40 to be -10000 fpm, final velocity at 2h14m28 to be -10912 fpm. :(
They appear to have reached terminal velocity pretty early on.

Passengers held in their seats!
 

Quote...

The passengers, who had just a short time before been pressed into the backs of their seats, were now being held into their seats only by their seatbelts. "At this moment, I would have feared for my life even if I was sitting in the passenger cabin," said one A330 pilot after reading the BEA report. That the plane was in freefall would have been clear to all on board. The nose of the plane pointed skyward at an angle of 16 degrees. "That's more than immediately following takeoff," the pilot said.

Unquote.

Having flown many times and thinking about my built-in senses of horizontal and gravitational, I tend to agree. To me the unanswered question is then - why didn't the pilots realise they were pointed up towards the sky and they were falling like a leaf? They could see the altitude bleading away extremely rapidly. Could they not read the attitude also? At least they knew they were pulling up!

REALLY, did they think they were diving! Continuous efforts to pull up over more than 2mins had resulted in no reduction in loss of altitude, so why didn't they realise they were "going down backwards" - well, almost. It seems ridiculous in hindsight that pulling up over that length of time and not reducing the descent MUST only mean you are not diving, you are stalled. Easy to say now, but those guys are supposed to be professionals, yes?

A major contributing factor must be the 13 deg THS trim. I know, if you pull up continuously you will get the THS auto trim as well but for the autotrim to then later give up and LEAVE the aircraft in this trim, ESPECIALLY if pilots are trained NOT to touch the trim, is "less than desirable" IMO (mildly). Surely a recommendation needs to come from this unfortunate part of the control setting, either re-trim back to neutral when giving up or make the pilots check the trim wheel = SOP/training. Not the first time (Perpignan), lets make it the last.

Hi,

And we don't know if the vertical stabilizer angle changed during those pitch down inputs ...
We only know it changed when it was pitch up inputs.

Thanks Zorin75 - Your clarification is well taken and duly noted.

jcjeant is right!
Sorry for the wrong expression: should have read "only controlled" instead of "only controllable".
Manually moving the pitch trim wheel overrides the auto trim.

Quote from Air France:

"The crew, made up of three skilled pilots, demonstrated a totally professional attitude and were committed to carrying out their task to the very end and Air France wishes to pay tribute to them."

I'm not ready to put all the blame on the pilots. However, a statement like this at this time makes me think they have hired "Bagdad Bob" as their press officer. Is this just French arrogance or do they know something we don't?

On a Dutch news site here ( Inmiddels 77 lichamen uit ) the following claim is made (translated into English):
Reading this kind of surprised me, as I didn't have the impression that they wanted to fly over the storm, but it would explain why they suddenly went into this steep climb.

Apologies: I posted essentially the same message as this a bit later (below) - not having noticed that there would be a delay pending moderation.

Whatever the investigation will reveal, there can't be any doubt whatsoever that these men did everything they could to save the plane. Now the task should be to find out why that wasn't enough. Not to put blame but to learn.

Hi,

When I read the Air France statement .. I ask myself (already posted)
Why Air France will make such statement ? .. as maybe the final report will go in a contrary way .....
Maybe they know more on the CVR-FDR that what we know ?

had they done NOTHING or atleast followed the Unreliable Airspeed Abnormal Checklist and turn to the GPS page for speed and Alt..

No they weren't hero's. If (and I say) the BEA report is correct they were idiots.
Like the A340 crew in YYZ

"there can't be any doubt whatsoever that these men did everything they could to save the plane."

So you mean sitting with the stick pulled fully back for 3,5 minutes while you are descending with 10000 fpm demonstrates a "totally professional attitude"?

What I'm saying is, if AF know more than we do, they might have a point. But, from what we know so far... absolutely not.

Just as I won't put all the blame on the pilots before I have the final report you should be careful to completely clear them of responsibility. Can we agree on that?

Stall warning system a contributory factor?
 

To me as a lawyer with an interest in aviation safety, the preliminary report implies that the design of the stall warning system may have been a major contributory factor in this accident.

The PF was confronted with conflicting signals as well as degraded instruments. Nevertheless, at quite an early stage, his inputs commanded nose-down pitch. He appears successfully to have initiated a recovery. What he needed to do, was to develop this response further.

However, the stall warning system did not recognise this. It did not encourage the PF to develop his solution further. On the contrary, it sounded a stall warning. This is essentially because it could not reward the improving trend which the PF had initiated: it could only recognise the threshold above which the stall warning should be available (<60knots = stall warning unavailable; >60knots = stall warning available).

A correct interpretation of the stall warning would possibly have been difficult in any situation. Particularly in the difficult conditions which must have prevailed at the time, the PF may well have inferred that there was a causal connection between the stall warning and his most recent command: ie, nose-down. Naturally, he would have wished to reverse the cause. So he would command nose-up instead.

What is worse, the PF would now have learned by experience that commanding nose-down pitch would "cause" a stall warning. He would have been reluctant to try it again.

Therefore, my tentative view is that the stall warning at this stage in the attempted recovery gave precisely the wrong message to the PF. It may well have been an important step in the "critical path" of the accident.

I think we should not rush to blame the pilots: the term "pilot error" sometimes disguises the degree to which "human error" has been induced by automatic systems.

Late but hopefully useful
 

This thread is galloping forwards so fast that I'm replying to something three pages ago, but it was only a few hours ago, and it needs answered because it is another daft blind alley.

Someone said:
I think you will find that is completely normal, and even a microsecond of thought will tell you why. Think "parked on the taxiway". There's a strong chance the wing is fully stalled, but we'll supress the stall warning until we've got some speed up, thank-you.

First of all paying tribute to those men is not a matter of arrogance but of decency.
No, what I'm saying is at that point, to them pulling on that stick appeared to be the best way to save the plane.
Considering what we know now (which is, as has been said numerous times, still very little), that was likely not the case and probably the final report will prove us, sitting in our comfy chairs, right and those men who died that night wrong.
But what then? It's so easy to shrug it off, label them as idiots and go back to business, while learning from their mistakes will be work and will cost money. But I think we owe it to them.

Patty: agree totally.

as another earlier post pointed out. At 350, flight controls neutral and correct trust setting should get you out at lower alt with faulty IAS. not rated on 330 but sure as hell works for most other tubes with wings that I flown in the past.

Ever heard of a squat switch?

Great Post Zorin_75.
You're absolutely right.

First mention of a nose down input is here:

2 h 10 min 16:
(...)The airplane’s pitch attitude increased progressively beyond 10 degrees and the plane started
to climb. The PF made nose-down control inputs and alternately left and right roll inputs. The
vertical speed, which had reached 7,000 ft/min, dropped to 700 ft/min and the roll varied
between 12 degrees right and 10 degrees left. The speed displayed on the left side increased
sharply to 215 kt (Mach 0.68) (...)

At 2 h 10 min 51, the stall warning was triggered again. The thrust levers were positioned
in the TO/GA detent and the PF maintained nose-up inputs.(...)
Around fifteen seconds later, the speed displayed on the ISIS increased sharply towards 185 kt;it was then consistent with the other recorded speed.


So IAS was well above 60 kt at this point. The stall warning simply meant they were going into a stall.
The only time a reappearing stall warning due to nose down / increasing IAS is mentioned is much later:

At 2 h 12 min 02, (...) Around fifteen seconds later, the PF made pitch-down inputs. In
the following moments, the angle of attack decreased, the speeds became valid again and the
stall warning sounded again.

But the report doesn't say anything at all about the PF's reaction to that warning.

That is probably true on a basic pshychological level...but shouldn't a pilot have a bit more of a grasp on the physics of flying? Why would lowering the nose in this case cause a stall warning? And even without the stall warning sub-60kts, the altimeter was still winding down in spectacular fashion with engines at full and the nose up for a good amount of time. I know about heat of the moment and all that but its amazing the amount of time that passed without the full stall becoming apparent to them.

@ costamaia

I meant later when they still had a high rate of descent..

...although I admit it doesn't mention what they did with the throttles after that.

BEA report unclear
 

I am French, so I have the happiness to read the BEA report in the text.

It is very confused and incomplete. Don't trust it too much and don't exhaust yourself trying to make a coherent theory from it.

For example, there is not enough informations to understand why the A330 climbed and stalled at 38 000 ft :

> the pilot gives «ordres à cabrer» (pitch-up orders)

> then the PF gives «ordres à piquer» (pitch-down orders)

and then «le PF mantient ses ordres à cabrer» (the PF keeps giving pitch-up ordres)

Obviously, there is something missing here : when did the PF resume his pitch-up orders after having tried the pitch-down orders ? And why ?

The whole report is like this : ill-phrased, hardly understandable and lacunar.

Be careful when you use this report : I thing some very important informations are missing (or withheld ?).

Does that work if you start in the stalled condition with high rate of descent and 40 degree AOA? Will it accelerate out of the stall at cruise throttle?

Optional, or Mandatory
 

Shogan1977, from Der Spiegel: Money is in play here, I'm sure. Typically, if the component maker or airframe builder make a Service Bulletin mandatory, they pay for it. If the SB is optional, the airline pays. I've known airlines who refuse to pay for SB that are to correct defects, regardless.