PPRuNe Forums

PPRuNe Forums (https://www.pprune.org/)
-   Tech Log (https://www.pprune.org/tech-log-15/)
-   -   AF 447 Thread No. 5 (https://www.pprune.org/tech-log/456874-af-447-thread-no-5-a.html)

takata 3rd August 2011 00:43

Red/black issues
 
Hi HundredPercentPlease,

Originally Posted by HundredPercentPlease
What do you get on the speed tape in alternate law at very low speed? A red and black ladder filling your speed tape?


Originally Posted by xcitation
You might have this already 100%.
According to manual see red and black then [stick back] "reflex action".
Quote from airbus manual, my bold for emphasis.

Or more likely 100% wrong...
See BEA reports #1 & #2 (below p.47)
Representation is not exact of the flight parameters but it is how the red/black tapes should look from the beginning of speed issues:

Nominal PFD:

http://takata1940.free.fr/pfd0.jpg

PFD in alternate 2 law (no red/black stuff displayed due to SPD LIM flag on both PFD):

http://takata1940.free.fr/pfd1.jpg

Machinbird 3rd August 2011 01:04

From Thermalsniffer's integrated transcript, Note, and ACARS in post #1323

2 h 11 min 58
PF: J’ai un problème c’est que j’ai plus de vario là
I have a problem it's that I no longer have vertical speed
CAP: D’accord
OK

PF: J’ai plus aucune indication
I no longer have any indication
Apologies if I have missed an explanation earlier, but why would PF think he had lost the vertical speed? That indication essentially relies on static pressure readings which should not have been impaired. I'm wondering if the high AOA is causing more indications to be disabled than we suspected.:confused:

Machinbird 3rd August 2011 01:22

Dozy

(at which point the aircraft approached and entered stall) for 57 seconds, after which point the aircraft was already unrecoverable.
I've been on the road a bit, but is this a personal conclusion, or a BEA statement?
To my mind, the aircraft was only unrecoverable when they ran out of altitude with which to recover. I haven't seen anything authoritative on the subject that says it was absolutely unrecoverable once deeply stalled.

DozyWannabe 3rd August 2011 01:51

Machinbird,

It's a personal conclusion, but I think it's logical.

I've munged some of the FDR traces into a graphic here (apologies for the poor resolution, but I only had the PDF to work with) :

http://i1088.photobucket.com/albums/...dr-munge-2.png

As the stall warning clicks off at around 2:11:47, the THS moves towards its limit of travel and the ground speed falls below 200kts. The THS took approx. 1 minute to move to the limit of nose-up travel from neutral. At this point the PF has been holding full back stick for approx. 5 seconds and will continue to do so for a further 25 seconds or so. To get the nose down and return the THS to neutral is going to take some time, and they're falling at speeds of up to 10,000ft/min.

wallybird7 3rd August 2011 01:57

Who's in charge?
 
It is always crystal clear who's number 1, 2 and 3. Depending on position:
Captain #1, Relief Captain #2, or Co-pilot 1 or 2. All based on seniority.

Where they sit is immaterial.

At least in the U.S.

takata 3rd August 2011 02:08

Hi thermalsniffer,
After a quick reading of the listing, I've got few observations:

Originally Posted by thermalsniffer
2 h 10 min 33
PNF: Selon les trois tu montes donc tu redescends
According to the three you're going up, so you go back down (meaning the three vertical speed indicators... )

Is the vertical speed indicator the only clue? Could be the three AH also, hence better calling them "indicators"


Originally Posted by thermalsniffer
2 h 10 min 49
PNF: (…) il est où euh ?
Uh, where is he?

See previous posts about that. Where is who? The Captain? Why would the PNF not know where he is resting?
French "il" is for both animate/inanimate = he/it ; "euh" is hesistancy, a missing word.
So it means: "where is [...]" -> unfinished (something and clearly not someone).


Originally Posted by thermalsniffer
"ACARS
2:12:10 WRN/WN0906010211 341200106FLAG ON CAPT PFD FPV
2:12:16 WRN/WN0906010211 341201106FLAG ON F/O PFD FPV
Initial event messages in que, delayed transmission.

There is only a very short period of time possible for those ACARS triggering (six seconds).
It is discussed in the report: between 2 h 11 min 48 and 2 h 11 min 54.


Originally Posted by thermalsniffer
2 h 12 min 59
PF: Je suis à fond à… avec du gauchissement
I'm at the limit of the stick... to the left

NO!!
"gauchissement" is a technical aeronautical word which has nothing to do with with the left hand. It's all about [edit: roll] control.
Hence "Gauchissement" => [edit: roll] moment ; it only means that the pilot is applying full stick imput (without direction precised)...

DozyWannabe 3rd August 2011 02:11

@takata - IIRC the translations themselves come from Lemurian - I believe thermalsniffer merely added the requisite parts from the BEA press release in June.

takata 3rd August 2011 02:18

Hi Dozy,

Originally Posted by Dozy
@takata - IIRC the translations themselves come from Lemurian - I believe thermalsniffer merely added the requisite parts from the BEA press release in June.

What I can tell you, and I'll bet my life on that, is that this "gauchissement" error doesn't come from Lemurian!!
So, no proof reading here and I didn't myself read everything listed.

DozyWannabe 3rd August 2011 02:27

@takata


Originally Posted by spagiola (Post 6604857)
2 h 12 min 59
PF: Je suis à fond à… avec du gauchissement
I'm at the limit ... to the left


Originally Posted by Lemurian (Post 6605209)
2 h 12 min 59
PF: Je suis à fond à… avec du gauchissement
I'm at the limit of the stick... to the left

(the icons next to the poster's name will link to the original post)

I also know Lemurian, and I don't think he'd make that kind of mistake. I think what the translation means is "I'm at the limit of the stick - adding left rudder".

deSitter 3rd August 2011 03:03

3holelover hit it exactly
 

At the risk of making myself appear more foolish than I already have, I feel compelled to offer an observation;

Some time back, in one of these threads, someone posted a link to some utubes of some Airbus simulator training in progress. At the time, probably because I've had very little experience in the pointy end during flight, I was struck by the "automaton" nature of the behaviours I saw. I thought it truly looked as though pilots had become mere accessories to the computers, with little room for thought and/or any sense of actually "piloting" their machines.

It looked to me, as I watched the gents twiddling knobs and going through checklists and pecking away at keys, that these sorts of pilots had been programmed to deal with their jobs as a computer tech might with his network administration tasks.

It struck me that these were not at all like the pilots of old who could fly any big old bird with several broken bits and malfunctioning whatnots, because they knew the basics of keeping their machine in it's element.

"Two kinds of pilot" I thought. "Old" and "New". "Old" could fly almost anything with wings, but not a newer, glass and computer machine. "New" could fly the computer generation "smart" birds, but probably not an old DC3.

I'm still mulling over those distinctions, but it has occurred to me more recently that this particular airplane needed both kinds of pilot, and the two "New" types that were in the seats just had none of the abilities of that "Old" type. I simply cannot fathom any of the type "Old" failing to recognize a stall. ... at any point during a 35000ft descent.
This is exactly right, confirming what I suspected all along, and it is appalling in a way no other crash has ever been - a perfectly recoverable situation, an airplane without any problems flying, 80% thrust and 3 deg nose up, and wait for the sun.. they crashed this airplane because they were not even pilots, they were confused computer administrators, something I have seen in real time, without the human cargo to disperse among the fishes.

I will never, in my life, set foot on another 'Bus. I can't trust it to be actually piloted.

bearfoil 3rd August 2011 03:26

It was not the Bus. Not in any sinister way it wasn't. Nor was it the Pilots.
The more discussion that arrives, the less pat is the answer. I am unable to let the Right turn alone. "I am at the limit of the STICK, LEFT!" "I'LL put in Rudder." Yaw was a problem, each time to the right. It won, so the Pilots were unable to mitigate the Yaw right. All the ROLL input is not PI.

This thread is out of control, nearly as far as the a/c it addresses. The Pilots are crap! The Bus is a Coffin!

Each time there is new data, gestating theories latch it like dogs on meat.
The territory of wild questions and dumb theories used to be mine.

You're scaring me. :p

deSitter 3rd August 2011 03:35

Yes, it was the Bus, because Bussism assumes that the pilot is a mere operator, and not someone in his natural element at angels 35.

bearfoil 3rd August 2011 03:42

Bussism, yes. But we knew that. If an a/c needs a driver, so be it. It is what it is, and the a/c is not dishonest. No one is. The danger lies in not understanding what is. If I get a speeding ticket, I can't kick my car.

deSitter 3rd August 2011 03:49

I saw on some show about aviation disasters, a German pilot talking about the sidestick, and how there was absolutely no feedback from the airplane and its controls; that inhuman attention to the minutiae of data that is constantly streaming from the instruments was persistently required, and that the distracting voice of some perhaps very attractive stew was enough to momentarily lose situational awareness, whereas having the yoke in one's hand, with its pull and push, was sufficient to restore engagement of the bigger head. That told me everything I needed to know about Bussism.

xcitation 3rd August 2011 03:56

Is it just my perception or is it that both FO's talk in vague terms. Lots of ambiguous references to up/down and to indicators. At one point is there confusion in what they are conversing about? I am not a native french speaker however at best the terminology sounds imprecise. Perhaps AF pilots have a verbal short hand? Did the pilots suddenly down shift from precise technical language only at the onset of problems?
Clearly there was adreniline with workload off the scale. However there appears to be much confusion in communications between pilots which is not normally present in incidents. Is this an area that needs adressing in training/line culture?

takata 3rd August 2011 04:01


Originally Posted by Dozy
I also know Lemurian, and I don't think he'd make that kind of mistake. I think what the translation means is "I'm at the limit of the stick - adding left rudder".

[edit: sorry] Dozy!
Gauchir is a verb meaning "twisting", there is no notion of direction, you can "gauchir" to the right or to the left! Gauchissement is the noun of the action of twisting, in aeronautical, it is [edit: roll moment] ... in whatever direction!

When he says, "avec du gauchissement", he just says that he is using [edit: roll] imputs, where do you read that he applies "left" [edit: roll]?

Please, find the meaning of that:
"Le gauchissement est l'action de gauchir c'est-à-dire tordre, vriller."

xcitation 3rd August 2011 04:02


Bussism, yes. But we knew that. If an a/c needs a driver, so be it. It is what it is, and the a/c is not dishonest. No one is. The danger lies in not understanding what is. If I get a speeding ticket, I can't kick my car.
Even if the speedometer broke and you were driving in the dark without lights?

DozyWannabe 3rd August 2011 04:10

@takata, calm down... I gave you a link to spagiola's post, and to Lemurian's follow-up. Lemurian added the words "of the stick" but did not alter "to the left". Don't shoot the messenger!

takata 3rd August 2011 04:20


Originally Posted by Dozy
@takata, calm down... I gave you a link to spagiola's post, and to Lemurian's follow-up. Lemurian added the words "of the stick" but did not alter "to the left". Don't shoot the messenger!

I did read those posts too, including Lemurian's, two days ago, and did not catch the mistake until last repost of the list. The reason is that we all know that he certainly applied left [edit: imputs]... but it is not what he precisely said.

JD-EE 3rd August 2011 04:28

DozyWannabee, commenting to BOAC you mention Birgenair. I think Takata rather noticed something I didn't chiefly because I have to guess what the graph titles are. What happened at 02:11:45? It looks like the nose dove down sharply if that is what "assiette (D- A cabrer)[DA]" means on the title for the dark green trace near the middle on page 114 of the French version of the recent report.

If that really is "nose plate" or the pitch angle of the nose of the aircraft that explains the sharp nose up stick input at that point. Before that moment stick inputs appear to have been rather mild.

It appears the plane, based on its aerodynamics not automatic anything, did exactly the right thing, get the nose down to pick up airspeed for stall recovery. Unfortunately I suspect transport pilots have a rather visceral fear of a 12 degree nose down pitch. Hence we see the nose up inputs. And of course the PF would see the aircraft's attitude making no sense given his nose up inputs.

It makes just a whole lot of good sense. And points up the utterly unprepared/untrained state of the pilots (plural intentional) on AF447.

I think takata should stand up and take a bow on this observation.

spagiola 3rd August 2011 04:41

When I did my quick translation, I had quite frankly no idea what "gauchissement" meant; I don't recall having ever in my life heard this term.

Having now checked a dictionary, I see that one of the definitions given is "Manœuvre des ailerons placés au bord de fuite d'une aile d'avion"; that is "maneuvering the ailerons". Which does not make things much clearer.

takata 3rd August 2011 04:59


Originally Posted by spagiola
Having now checked a dictionary, I see that one of the definitions given is "Manœuvre des ailerons placés au bord de fuite d'une aile d'avion"; that is "maneuvering the ailerons". Which does not make things much clearer.

Yes, I'm always doing the lapsus yaw/roulis, while roulis is of course roll!
hence, this doesn't bring any single precision about PF imputs. Aircraft is rolling and PF don't say in what direction his imputs are applied... he his just countering the roll.

dcasali 3rd August 2011 05:04

Why the first stall warning?
 
I'm puzzled by the initial stall warning which occurred only 5 seconds after the AP disconnect. It seems spurious, and the pilots clearly notice it and then seem to attribute it to the 'loss of speeds'. Which perhaps created a mindset in which the significant stall warnings at the apogee (?) 40 seconds later were seemingly disregarded. Did the PF make SS inputs sufficient to cause the initial warning? Or what?


2 h 10 min 05
Cavalry charge (Alarme de déconnexion du pilote automatique)
Cavalry charge (Autopilot disconnect alarm)

2 h 10 min 06
PF: J’ai les commandes
I have control

2 h 10 min 09
PF: Ignition start
Ignition start

02 h 10 min 10.4 :
VS : « Stall, stall » (sans cricket)
VS: "Stall, stall" (without cricket)

2 h 10 min 11
PNF: Qu’est ce que c’est que ça ?
What's that ?

2 h 10 min 13
VS : « Stall, S »
VS: "Stall, S"

2 h 10 min 14
PF: On n’a pas une bonne… On n’a pas une bonne annonce de…
We don't have a good... we don't have a good indication of ...

JD-EE 3rd August 2011 05:14

airtren, if the captain had removed a potentially critical bit of documentation from the cockpit to study it in the back that's rather reprehensible on his part. The fact that there is no spare that can be taken back and studied is verging on criminal.

If this is the case it may have amounted to a "single point of failure" in a multiple redundant aircraft existing in the cockpit.

takata 3rd August 2011 05:30


Originally Posted by JD_EE
airtren, if the captain had removed a potentially critical bit of documentation from the cockpit to study it in the back that's rather reprehensible on his part. The fact that there is no spare that can be taken back and studied is verging on criminal.

After thinking about it, this seems quite improbable that an experienced captain would really do that.

airtren 3rd August 2011 06:13

Bogus Stall Warnings inhibiting correct ND actions, and recovery
 
DozyWanabee,

Your post makes a very strong statement.


Originally Posted by DozyWannabe (Post 6615411)
Rubbish - poorly researched article.

And it steers up the questions:

Did you do your research? Did you read the 3rd BEA Interim Report, paragraph 6 from the top of page 78, and paragraph 1 from the top of page 79, and did you understand them?

Did you read the many posts on this Forum, regarding the Stall Warning bogus behavior? Did you understand them, if you read them ?

It's clear, from the BEA Report, and it's clear from many posts on this Forum, that all the Stall Warnings that occurred [B]During the entire "Fall, and attempt to recover from Stall", after 2:12:45, when the plane was on its way down, from 35000 ft (FL350), with the two pilots and Captain in the cockpit, were giving the wrong information!!!

From 35000ft and bellow, all the Stall Warnings have started as a result of Nose Down actions, and have ended as a result of Nose UP action, and thus each of them has mislead the pilots into believing that their corrective actions of ND were wrong, while NU actions were right, creating the deadly confusion that lasted to the end, and inhibiting the very corrective actions that were necessary, and encouraging the very wrong actions that were inducing them further back into the stall !!!.

8 of these bogus Stall Warnings were between 35000ft and 6000ft, which is recoverable height.

4 of these bogus Stall Warning were between 35000ft, and 30000ft, which what would one want more, in terms of recovery?

Based on the correct analysis of the BEA Report, I am completely surprised to not see an explicit recommendation in the Recommendation Section. The planned Human Interface research of the next phase, will probably address that.

So, therefore, the La Tribune Article, and Le Figaro Article are making a lot of sense.


Originally Posted by DozyWannabe
The stall warning sounded continuously from the apogee of the climb (at which point the aircraft approached and entered stall) for 57 seconds, after which point the aircraft was already unrecoverable.

Unrecoverable at 35000ft? What's the base of your claim?

An Airbus 310, approaching Orly, Paris, in 1994 has recovered at 800ft, from a stall at 4100 ft (yes 30900 ft lower!!!), and from a pitch of 60 degrees, and only 30knots airspeed. Report & CVR transcript, CVR voice, video clips are available on the net.


Originally Posted by DozyWannabe
It would appear that one thing that has not changed since 1988 is the predeliction on the part of certain parties to attempt to use the press to muddy the waters when the finger appears to be pointed in their direction.

In this case, it is exactly the opposite, the press is helping the truth.
Air France has a good share.
But the "a/c category" has a number of its own, besides the pitot tubes:

a. the Stall Warning,
b. the unannounced trimming of the THS (Machinebird post #57, etc...)
c. the lack of AOA indication (BEA report),
d. the lack of sharing stick position information between PF and PNF (recent posts),

and possibly others.


Originally Posted by DozyWannabe (Post 6615646)
Machinbird,

It's a personal conclusion, but I think it's logical.

I've munged some of the FDR traces into a graphic here

Your graphs show clearly the 8 Stall Warnings, that between 35000 ft and 6000 ft, which is the recoverable window, have created confusion in the pilots and Captain minds.

Four (4) of these Wrong Stall Warnings were between 35000 ft and 30000ft - plenty of height to recover.

Do I need to explain more, why that is?


Originally Posted by DozyWannabe
As the stall warning clicks off at around 2:11:47, the THS moves towards its limit of travel and the ground speed falls below 200kts. The THS took approx. 1 minute to move to the limit of nose-up travel from neutral. At this point the PF has been holding full back stick for approx. 5 seconds and will continue to do so for a further 25 seconds or so. To get the nose down and return the THS to neutral is going to take some time, and they're falling at speeds of up to 10,000ft/min.

The A310 that I've mentioned had at stall, the THS full NU, and Elevators full ND. Pilots understood early, and worked very hard, ND, to recover. Plane landed, within 30 minutes or so, at Orly, with no injury, or damage

All AF 447 needed, was to turn ND,and keep it that way - pitch was a lot less than the 60 degrees of the A310 - and continue to fall Nose Down with the 10000 ft/min speed, which would have accelerated soon to the appropriate speed to recover.

Please note that there is at least one post on this thread, that shows that Stall Recovery is possible also from a theoretical perspective.

airtren 3rd August 2011 06:24

JD_EE,

At first, I thought you were teasing me, but after checking up and down, I do appreciate your wise question! :)


Originally Posted by JD-EE (Post 6615849)
airtren, if the captain had removed a potentially critical bit of documentation from the cockpit to study it in the back that's rather reprehensible on his part. The fact that there is no spare that can be taken back and studied is verging on criminal.

If this is the case it may have amounted to a "single point of failure" in a multiple redundant aircraft existing in the cockpit.


airtren 3rd August 2011 06:41


Originally Posted by takata (Post 6615837)
Yes, I'm always doing the lapsus yaw/roulis, while roulis is of course roll!
hence, this doesn't bring any single precision about PF imputs. Aircraft is rolling and PF don't say in what direction his imputs are applied... he his just countering the roll.

The rudder/palonier is mentioned by the Captain, and the FDR has registered some Rudder moves, at around that time, with the Captain mentioning "easy with the Rudder/Doucement avec le palonier la" after about 30-40 secs later.

airtren 3rd August 2011 07:38

Takata,

That's funny. Based on your posts I’ve read on this Forum, I can say this post brings a welcome change: you're acknowledging your occasional rudeness for the first time... :D:)

Originally Posted by takata (Post 6615464)
Not wanting to sound rude, but guys, please, stop making up stuff.



But if I take your post seriously then, regarding my post, which I can speak about, I think either it was not written clear enough for your reading, or you didn’t read it carefully.

The post has one paragraph with accurate references to the BEA report, with the rest being some thoughts, exploration of various tracks, with NO claim of being BEA information, and an acknowledgement of being speculative,.

That’s not “making stuff up”. It’s called discussing, and expressing some thoughts, and the exploring of various logical tracks, which is what a large part of the posts on this Forum is about.

That being said, let's looks at your (claimed) facts. I marked in RED, the text, for which I would be curious to see your supporting information.

1. Please point to the BEA report text mentioning that "at impact both Left and Right cockpit seats were occupied".
2. Please point to the BEA report text mentioning that all the belts and harness were attached?

Correct or accurate information is: partially belted, that is, only one out of two belts were attached, and the harness was NOT attached. See translation of BEA text bellow.

2. Who ever told you anything about pilot's bodies state and details, besides tabloids.

What tabloids are you referring to? Are you equating the entire press, radio, and TV with tabloids?

Do you include in the tabloid category all the official press information regarding Phase 5, either from the Ministry of Transportation & Ecology, or other organizations involved. Do you include interviews of officials, like Nathalie Kosciusko-Morizet, and Thierry Mariani, etc….?

PS. A word for word translation of the BEA Report text I have referred:
1.13 Renseignemants medicaux et pathologiques

L'examen des corps remontes lors de la phase 5 confirme les observations consignees dans le rapport d'etape nr 2.


1.13 Medical and Pathologique Information

The examination of the human remains recovered during Phase #5 /conforms with/confirms/ the observations mentioned in the Phase #2 Report.


1.12.4.2.1.3 Les sieges du cockpit

Sur le siege situe en place gauche, les centuires ventrals etaient attachees, le centure de 'l'entrejambe et les harnais d'epaules ne l'etaient pas.


Sur le siege situe en palce droite aucune ceninture n'etait attachee.


1.12.4.2.1.3 The cockpit seats

On the left side seat, the ventral belt was attached, the between the legs and the shoulder harnass were not.


On the right side seat none of the belts were attached.




Originally Posted by takata (Post 6615464)
Can't you make the difference between pilots bodies and seats?
Facts:
Both pilot seats were recovered and analysed. (structural analysis).
it was found that at impact:
- both were occupied;
- one was belted (PNF, LHS) -> at impact!
- one was not belted (PF, RHS) -> at impact!
This is the only clue they have. They can't deduce anything about when the pilot umbelted before impact, or if he ever was belted during the flight.

Who ever told you anything about pilot's bodies state and details, beside tabloids? We don't even know officially, beside captain's body, if they were actually recovered.


vbp.net 3rd August 2011 07:41

Hello airtren,

I did post a link but it took some time for moderator review and, since the translation I gave in a separate post contained no link, this one was available at once.

Sorry for the confusion. Next time I'll embed both in the same post !

The link is available at #1343

mm43 3rd August 2011 07:48

The graphic below shows the the Roll Angle, Rudder Angle and Magnetic Heading throughout the LOC incident. The vertical redline at 02:12:59 indicates the situation recently discussed where the PF indicated he would use rudder to correct the right roll/bank.

http://oi54.tinypic.com/14bqdky.jpg

As can be seen from examining all the traces, the aircraft had a marked tendency to roll to the right and this could be stabilized with the use of about 3° to 5° of left rudder. The PF only worked this out in the last minute.

Why was there a propensity for this righthand roll? I have previously posted that I believe that it was due to the nature of the descent, i.e high AoA, high vertical speed possibly causing an associated corriollis effect. A lower air pressure on the righthand side of the vertical stabilizer may have been aiding the roll to the right. The THS/elevator position assisted in coordinating the eventual turn when the roll angle became excessive.

If the aircraft hadn't become relatively stabilized in the 15° NU attitude with the THS and the elevator positioned as we know, the chances of entering a spiral dive would have been high.

NOTE: Magnetic variation at 3°N 30°W was 18°W, giving a heading at impact of 270°M - 18°W = 252°T.

EDIT :: The aircraft was noted as yawing to the right (tail to the left) in Interim Report No.1, and it is possible that the vortex being created during the descent was causing this yaw. That being the case, the right wing was flying slower than the left, and hence the tendency for the righthand roll.

vbp.net 3rd August 2011 08:36

airtren, I'm 100% with you on that one.

First, sorry: I answered your question about the link to the newspaper but, it again contained a link so it is again waiting for the moderator's review. You will get it some time soon, but in the mean time you found it yourself on internet. Could be called "learning from mistakes..."

We know that nowadays pilots are less likely able to handle a stall at high speed/altitude. They were obviously confused about what was happening (taking the noise of high flow of air against the frame with tremendous speed and the like). And in the mean time, whenever they do the right thing, the stall warning which was silent while they were falling down like a stone came back in as a sort of "don't you do that"! Isn't that adding more confusion to people trained to trust what the system says ?

In short, it seems we should expect pilots who normally fly a machine that thinks for them to the extend that it won't allow them to do stupid things, all of a sudden, to understand that they should override a system indication (stall !), understand why it is wrong and do the exact opposite. All that in a little less than 4 minutes.

I don't pretend this is the cause of the disaster but still I don't agree that it should not be addressed in the future if we want this mistake not to happen again.

Besides, not all newspapers and journalists are complet idiots, I think.

vbp.net 3rd August 2011 08:44

@ dozzy

quote :

2 h 12 min 59
PF: Je suis à fond à… avec du gauchissement

To me, "avec du gauchissement" in the context means he is acting so hard on the SS that he is bending it. Of course, he is not. But it is to indicate that he could not do more.

thermalsniffer 3rd August 2011 09:36

CVR Translation
 
Sorry to all, I should have been a little more clear on where the information came from.

I was just trying to piece together the late NAV ADR DISAGREE and the PRIM AND SEC1 FAULTS (which I could not get out of my head and still bother me for some reason) with the CVR transcript and the Note.

Also, it seemed to me there were some critical statements in the Note that are not in the CVR transcript.

One example is the PNF confirmation that "we have no valid indications" which is not in the CVR, but is in the Note.

curvedsky 3rd August 2011 09:45

A-330 Buffet boundaries at FL380?
 
http://i31.photobucket.com/albums/c3...03at100751.png

Buffet boundaries


Four hours into a Rio-Paris flight, AF447 was cruising normally at FL350. The crew noted from their flight data that they were still too heavy to climb to the next appropriate higher cruise FL.

But moments later AF447 'zoomed' – for whatever reason – up to FL380.

Having unintentionally arrived at FL380 at a heavier than planned weight, what were the new 1g stall (low speed) and Mach buffet (high speed) IAS boundaries for AF447? ..... 20 knots?


.......

takata 3rd August 2011 10:07

Hi vbp.net,

Originally Posted by vbp.net
2 h 12 min 59
PF: Je suis à fond à… avec du gauchissement
To me, "avec du gauchissement" in the context means he is acting so hard on the SS that he is bending it. Of course, he is not. But it is to indicate that he could not do more.

A new interpretation is always welcome to the CVR mess! :O
But, maybe we should all listen to Mr. hulotte who is a former Airbus Industrie SFI which have trained tons of pilots during a full decade:

Originally Posted by hulotte
When a french pilot says GAUCHISSEMENT he speaks about ROLL
That's common sense

Posted here today: http://www.pprune.org/6615823-post2492.html

Here, again, the sentence is incomplete and not very meaningful. Its sense may only be infered from the two bits as there is hopefully only two axis on the sidestick [edit: but there is also the rudder!]:
- "I'm at the limit of ...[the stick] (1) ... adding some roll".(2)
(a1) may only refer to pitch axis (full aft / full forward)
(a2) + roll ... (left or right)

OR [edit: but there is another one! -- Thank you mm43 for the details above]

- "I'm at the limit of... [the rudder](1) ... adding some roll".(2)
(b1) could also refer to rudder (full left / full right)
(b2) + roll ... (left or right)

DozyWannabe 3rd August 2011 12:06


Originally Posted by airtren (Post 6615904)
Did you read the many posts on this Forum, regarding the Stall Warning bogus behavior? Did you understand them, if you read them ?

*All* of them are from people who either do not understand the Airbus FBW concept, have never flown a FBW Airbus and/or have a long-standing axe to grind with Airbus.


It's clear, from the BEA Report, and it's clear from many posts on this Forum, that all the Stall Warnings that occurred During the entire "Fall, and attempt to recover from Stall", after 2:12:45, when the plane was on its way down, from 35000 ft (FL350), with the two pilots and Captain in the cockpit, were giving the wrong information!!!
Not so - as I said on the other thread, there's only 1 positive correlation between nose-down input and the stall warning coming back on:

[EDIT : However it *could* appear that they match up if you flick between pages 110 and 111 in the PDF. This is because the graphics are not scaled identically in the X axis - see my corrected graphic below (note that the blocks of 15 seconds now match up). ]

http://i1088.photobucket.com/albums/.../fdr-munge.png

The first 4 short returns of the Stall Warning (effectively a group of two) occur at approx 2:11:45 when the PF has the stick full-back, possibly as a result of the uncontrolled nose-down attitude that appears to be displayed in the "Assiette" trace.

The next stall warning occurs at 2:12:25, when the PF already has his stick back again after a brief nose-down input which does not trigger the stall warning, immediately followed by one (the only one in what you term the "recoverable" window) which does seem to correlate with a nose-down input, but notice that it comes on again 3 further times when the stick is either neutral or pulled nose-up.

It comes on again at 2:13:55, when the PNF has taken over control and already had the nose down input held for 15 seconds (but note the hesitancy - a positive nose-down gradually becomes relaxed before the stall warning comes back on, and if you correlate that with the CVR, that is about when the Captain says "You're pitching up", and the (former) PF questions whether nose-down is the right input to be making). At this point, both pilots begin to pull, and if their fate wasn't sealed before, it sure is now.



8 of these bogus Stall Warnings were between 35000ft and 6000ft, which is recoverable height.
I respectfully disagree. I also respectfully disagree that the warnings were "bogus" - they were very real! It was the dropouts (caused by the sensor becoming unable to provide readable data) that were the problem.


So, therefore, the La Tribune Article, and Le Figaro Article are making a lot of sense.
Because business tabloids and shock rags are generally well-known for the quality of their aviation coverage. Next time there's a crash in the US, perhaps we should use the Wall Street Journal and National Inquirer as our primary sources?


An Airbus 310, approaching Orly, Paris, in 1994 has recovered at 800ft, from a stall at 4100 ft (yes 30900 ft lower!!!), and from a pitch of 60 degrees, and only 30knots airspeed. Report & CVR transcript, CVR voice, video clips are available on the net.
I read that report a *long* time ago. There are several major differences that you need to take into account.
  • This incident happened in broad daylight, meaning that the crew had a valid external reference, not the case with AF447
  • While the THS did reach full deflection in the early phase of the accident (and again, briefly after the initial recovery), the AoA protection reduced the THS angle to -8.8 degrees, which assisted the recovery - again not the case with AF447
  • The airspeed indications were always valid
  • While not co-ordinating his actions with the Captain (who was PF), the PNF nevertheless did perform several actions to assist recovery (including noticing the THS angle and reducing accordingly)


a. the Stall Warning,
b. the unannounced trimming of the THS (Machinebird post #57, etc...)
c. the lack of AOA indication (BEA report),
d. the lack of sharing stick position information between PF and PNF (recent posts)
Stall warning - I disagree.

THS - poor training. The mechanics of autotrim *must* be taught as part of the conversion course, and if it has not been then that's a major oversight. Pilots are supposed to know how their aircraft works!

No other airliner of this type has an AoA indicator fitted as standard, you can't blame Airbus for that.

Don't get me started on the "back-driven sidesticks" argument again, I beg you. Suffice to say there are valid design reasons for not doing it and leave it at that.


Your graphs show clearly the 8 Stall Warnings, that between 35000 ft and 6000 ft, which is the recoverable window, have created confusion in the pilots and Captain minds.

Four (4) of these Wrong Stall Warnings were between 35000 ft and 30000ft - plenty of height to recover.
Look again - the PF has the stick full-back during those initial 4 Stall Warning blips.

BOAC 3rd August 2011 12:33

We are now tending to go round in circles.

AoA gauge - red herring - even if fitted and crews trained to use it, by the time anyone on 447 got to look at it it would have been severely 'off scale' at 60 degrees and providing little useful information.

All this about stall recovery is partly irrelevant. In my opinion the a/c could have been recovered. I proposed a 'gut feeling' that 15-20,000 ft would have been the lowest practical unstall height to avoid a crash. This would have meant 1 1/2 - 2 minutes to recognise they were stalled. I also suggested that a pitch change to around 30-40 degrees below the horizon was needed to unstall the wings. As someone pointed out, unless you are an aerobat or military fast-jet trained, that would NOT be in the pilots' syllabi, and would depend on the recognition that they were stalled - which was missing. If nose-high, lots or power, high sink rate and lack of correct aileron response did not suggest a stall then there was little hope.

As for the 'discussion' about the significance of 'heading changes', some folk need to look up 'auto-rotation' and the 'effect of a stall'. These are totally irrelevant too.

Apart from technical issues for AB, AF need to sort out how a relief crew is structured, to ensure their pilots can fly aeroplanes and not just computers and make sure that their pilots (in particular F/Os) are given assertiveness training (and probably a few hundred other things too.

DozyWannabe 3rd August 2011 12:43


Originally Posted by BOAC (Post 6616528)
I proposed a 'gut feeling' that 15-20,000 ft would have been the lowest practical unstall height to avoid a crash.

Agreed.


This would have meant 1 1/2 - 2 minutes to recognise they were stalled. I also suggested that a pitch change to around 30-40 degrees below the horizon was needed to unstall the wings.
Also agreed. If the "Assiette" trace is reliable, the lowest the nose-down pitch ever got was approx -10 degrees (2:11:55, 32,000ft), but due to a combination of the aggressive up-elevator input and the THS position, this was immediately reversed and nose-down was never successfully maintained for more than around 14 seconds.

This does raise the question of what would have happened if the PF had simply let go of the stick at this point and used rudder to control roll as and where necessary?

I'm reminded of the infamous Aeroflot A310 crash where the relief captain's teenage son was at the controls, unwittingly engaged CWS and banked into a stall. All he (and the crew) had to do to resolve the situation until very late in the sequence was to let go of the controls, and the bank angle protections would have righted the aircraft. Unfortunately the crew had not been fully trained in either aspect of the A310's features in that regard.


Originally Posted by deSitter (Post 6615775)
I saw on some show about aviation disasters, a German pilot talking about the sidestick, and how there was absolutely no feedback from the airplane and its controls; that inhuman attention to the minutiae of data that is constantly streaming from the instruments was persistently required ... That told me everything I needed to know about Bussism.

Was it Survival In The Sky (aka Black Box in the UK), and was the pilot's name Heino Caesar, perchance? In which case you'd have got a less-biased answer asking Reagan what he thought of Lenin.

If what he said was true then you'd have seen a whole plethora of FBW Airbus crashes by now, and the type would have a significantly worse safety record than others, instead of the near-parity that is actually the case.

Shadoko 3rd August 2011 13:04

Gauchissement
 
Think correct translation in English of aeronautic use of "gauchissement" is "wing warping". Perhaps the FP was an amateur of old times aeroplanes. Do he means by this word he was using rudder and the plane had some glide ?

Not sure others in the cockpit could understand this word, except if they have spoken of old times aviation before.

See: Dictionnaire Collaboratif Français - Anglais
And: Wing warping - Wikipedia, the free encyclopedia


All times are GMT. The time now is 09:04.


Copyright © 2026 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.