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doubleu-anker
27th May 2011, 13:05
This unfortunate tragedy is just one more instance that demonstrates we are all loosing the basics of flying, as a pilot group. If indeed, the basics were there in the first instance.

Modern aircraft, including the A380 are not uncrashable and never ever will be.

Ever heard of K.I.S.S??

Parsnip
27th May 2011, 13:06
Ex 9 PPL syllabus stalling and recovery, level wings, pitch down break the stall apply power climb away.....dont get smart
So proffessional working pilots on this forum must know the answers as to why anyone would be pulling back when the airplane is in a stall condition, if its a reflex reaction brought about by hours flying a computer then I'm NEVER getting on an Airbus again

Poit
27th May 2011, 13:07
Hi there Whatsalizad, thanks for your reply. I suspected someone might take issue with my comments, and I have no problem with your reply. I've never flown a commercial airliner, but did fly in the military, and as you mentioned, Power + Attitude = Performance was king of my world.

Yes, the QA A380 incident was alarming / frightening, but they stuck to basics and got it right.

I agree that we don't know what indications the aircrew received, which is why I admitted that my comments might be jumping the gun. Apologies if they annoyed you.

JamesT73J
27th May 2011, 13:10
Ex 9 PPL syllabus stalling and recovery, level wings, pitch down break the stall apply power climb away.....dont get smart
So proffessional working pilots on this forum must know the answers as to why anyone would be pulling back when the airplane is in a stall condition, if its a reflex reaction brought about by hours flying a computer then I'm NEVER getting on an Airbus again

An interesting exception to this might be a dark night, a lot of aural & visual distractions, working through checklist items, and just possibly your instrument(s) telling you that you are speeding up.

sekant
27th May 2011, 13:11
Dear Parsnip, please enlighten me: in what way is today handling a boeing less akin to flying a computer (or not at all) than in an airbus case?????

UNC
27th May 2011, 13:12
27 May 2011 briefing (http://www.bea.aero/en/enquetes/flight.af.447/info27may2011.en.php)

grimmrad
27th May 2011, 13:13
Aviation-interested SLF here with a few question:

So if I understand correctly the AP was disengaged - but do we know why?

Airspeed indicators malfunctioned but apparently only briefly - so why did that not change the law back when they came online again? Because they already stalled?

And is there no warning or indication to the crew that the law has changed?

And why is there in certain laws - if I understand correctly no stall warning - if it is something so essential?

And shouldn't a vertical airspeed have indicated the pilots that they are actually falling out of the sky and prevented them as long as they still had altitude from pulling back?

Thanks much

Capn Bloggs
27th May 2011, 13:19
So if I understand correctly the AP was disengaged - but do we know why?

because the speed sensors went crazy:

From 2 h 10 min 05 , the autopilot then auto-thrust disengaged and the PF said "I have the controls". The airplane began to roll to the right and the PF made a left nose-up input. The stall warning sounded twice in a row. The recorded parameters show a sharp fall from about 275 kt to 60 kt in the speed displayed on the left primary flight display (PFD), then a few moments
later in the speed displayed on the integrated standby instrument system (ISIS).

manphil
27th May 2011, 13:19
hi there,

I be an uneducated SLF type,

Question: the report says that-
at 2:10:51 ..."
The trimmable
horizontal stabilizer (THS) passed from 3 to 13 degrees nose-up in about 1 minute and
remained in the latter position until the end of the flight."


at 2:12:02 ...
"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."

Why did the indication of the THS NOT change in accordance with the pilot input???

Am I way off base here?? Confused???

cheers
Phil

Ashling
27th May 2011, 13:20
Parsnip, the actions you list are in the wrong order.

your first action in a convential aircraft is to move the stick centraly forward while applying full power at the same time, DO NOT TRY TO LEVEL THE WINGS FIRST, as you may induce a spin. Once you have unstalled the wings you can then level them.

Airbus have recently modified their stall recovery procedures to delay the application of power until the nose has been lowered to prevent problems with the pitch up effect of the engines.

IO540
27th May 2011, 13:20
Maybe I am missing something but doesn't a pilot have a big horizon in front of him, on the PFD?

A 35 degree up pitch is kinda hard to miss.

jrsanch
27th May 2011, 13:25
"Firstly, it must be said that conventional instrumentation is not adequate for flight in the vicinity of the stall; pitch attitude can be most misleading, airspeed and altitude and vertical speed are only component parts of the one parameter which is all important - incidence - and in isolation, and indeed in sensible combination, these individual parameters can be either misleading or nearly valueless. The only valuable parameter is incidence. This is what dictates the behaviour of the aeroplane and this is what needs to be presented to the pilot."
From: "Handling the Big Jets", page 124, D.P. Davies, Third Edition, Civil Aviation Authority, December 1971

JamesT73J
27th May 2011, 13:27
Out of curiosity, what happens with the pitch/power dynamic coupling outside of normal law? For instance, if power is advanced to exceed that required for level flight, outside of normal law, will the aircraft pitch up unless commanded otherwise by pilot or the autoflight system?

Secondly, would the stab trim movement be the FCS attempting to trim the aircraft to relieve the elevator load from the commanded nose-up attitude, in other words, everything was behaving as it should?

gatbusdriver
27th May 2011, 13:29
Jet Jockey A4

My understanding from reading the report is that the AP was off for 4min 23secs which was until impact. Not too sure where you get your figures from.

Although I have no manuals infront of me, I thought you could operate in RVSM airspace as long as you have 2 primary altimeters, 1 altitude alerting system, 1 altitude reporting transponder and 1 automatic altitude control system. I don't take that to mean you have to have AP working. As long as FD's are on. I could confirm this later with a check of the MEL.

Poit
27th May 2011, 13:32
Jet Jockey A4:

The autopilot wasn't off for 90 minutes, it disengaged aprox 4 minutes before the crash because of (suspected) pitot tubes freezing up, and resultant confliction of airspeed indications (causing the systems to revert to 'alternate law', or in English, over to the pilots). They weren't hand flying for fun!

You seem to be slightly unfamiliar with this case.

I agree with you on the training front, and when I flew I also had extensive training in stall recovery and UA recovery with a variety of parameters. So your comment 'I just don't get it' has total agreement from me, mate!

decurion
27th May 2011, 13:37
Hi Phil,

If you only briefly give a pitch down input the trim will not change immediately. There is no indication in the BEA Note on how long this down input was given (most likely briefly).

SLFinAZ
27th May 2011, 13:41
I would like a bit of clarification from those with more knowledge of correct procedures in a jet. I have limited single engine time and some limited unusual attitude training in a T-28. The single most fundamental aspect that was repeatedly drilled into my brain was unload the airframe.

If I recall correctly one of the root causes of the 737 crash way back (Pittsburgh?) was the PF's failure to take this fundamental step. I'm becoming more and more concerned at what appears to be a very low level airmanship displayed here....correct me if i'm mistaken...

My feeling is this goes directly back ot the discouragement of hand flying. When the instruments in front of you go south the only instrument left is the one your sitting on:)

manphil
27th May 2011, 13:43
Thanks Decurion.

Noted. Not enough detail in the report.

...and thats where the devil be!!:bored:.

The final report will prove interesting ....as this prelim ...leaves or raises more Q's then answers.

Like many here ...I just can't believe, a capable aircrew would not attempt to recover from what appears to be an obvious stall condition.

Phil

giblets
27th May 2011, 13:48
Could it be similar to China Airlines 006? The pilot fixated at one problem missed other severe issues at hand?

Capn Bloggs
27th May 2011, 13:51
appears to be a very low level airmanship displayed here
"Airmanship" and "Commonsense" are merely the use of things learnt during training, education and practice to keep one safe in the air. One doesn't "pick up" good airmanship or flying commonsense other than by those three aspects (or osmosis over a very long time).

Huck
27th May 2011, 13:54
I haven't studied all the released evidence, so someone correct me if I'm wrong, but it appears that:

1. Level at FL 350, the PF got in an unusual attitude as a result of pitot failures,

2. He climbed to FL 375 - 380 before stabilizing,

3. Once at FL 375, he was flying but above service ceiling,

4. The aircraft therefore slowed to a stall even with TOGA power,

5. A stall was entered,

6. The PF held nose-up controls for quite some time,

7. At some point, the Captain took the left seat and took the controls, at which point the PF relinquished control to him.


Is that the consensus?

decurion
27th May 2011, 14:04
Hi Phil,

I have had several briefings this year on stall events. In most cases the workload was very high and the pilots had difficulties in assessing the whole situation. When the speed becomes unreliable in a modern jet aircraft you can get overwhelmed by all the different warnings. Without more detailed info on the AF event I would not suggest yet that this could be a factor. However, I would not be surprised.

ECAM_Actions
27th May 2011, 14:08
:eek:

'nuff said.

When the speed becomes unreliable in a modern jet aircraft you can get overwhelmed by all the different warnings.Surely the flight crew should stuff the alerts and deal with keeping the air flowing over the wings? If you aren't flying it doesn't matter that you lost the rudder limiter! Getting the aircraft under control should override everything else, IMHO.

I'm rather disturbed that far from applying the pitch/power memory items, he chose to pitch up instead whilst encountering STALL warnings no less!!!

I'm not making judgement on the pilot(s) here, just trying to figure just WTF was going through their minds to do that.

My username is rather ironic right now.

ECAM Actions.

vovachan
27th May 2011, 14:14
How often do pilots get to hand fly at cruise anyway?

Aviator62
27th May 2011, 14:25
Hi, at 38000ft it must be hell to keep the IAS within the limits of the Coffin Corner. Does anyone know how much the IAS can vary before stall occurs given the aircraft parameters stated?

SLFinAZ
27th May 2011, 14:26
Again in an unusual attitude/impending stall condition is not the initial step to unload the airframe? From that position further recovery (nose down/power settings etc) steps occur....at it's simplest airmanship is an understanding of cause and effect. It literally begins to become ingrained the moment you take the controls....by 10 to 20 hrs you have a fundamental understanding. Most solo endorsements come at the 10-15 hour range of initial training.

If fundamental airmanship wasn't relatively easy to absorb we'd have a lot more 152's planted in folks backyards....

AlphaZuluRomeo
27th May 2011, 14:36
@ Huck : Agreed, except your point #7 : I don't see anything that indicates the captain took back his seat.

Robssupra
27th May 2011, 14:38
All this will probably come down to crew composition, very high workload, in adverse weather conditions, having to manually hand fly an aircraft which found it self in alternate law due to spurious information being fed to not only the flight display computers but also the flight control protection and guidance computers, simultaneously.

When something of this magnitude happens you are not only dealing with conflicting airspeed info, you are also presented with multiple spurious ecam warnings and cautions which is sometimes hard to ignore, also depending on the alternate law protection loss which itself can be further divided in two categories, or even direct law which would mean direct side stick to flight control input without any load protection leading to control overload.
Also when it comes to high speed protection, should this crew received wrong airspeed info indicating high speed situation, you have protection where once Mmo + few kts has been exceeded you will get an auto pitch up to try and maintain Mmo + few knots, so should this happen at slow actual airspeed, it will not be too hard to see why the pilot continued to pull back and continue increasing the pitch angle.
Direct law is there to give the pilot more direct control of the aircraft but it still has some protection to offer at the same time the protection on offer is only as good and accurate as the information provided to the computers involved.
Much more info is needed before one can create a picture on what went wrong when it comes to the decisions the pilots made in the last few minutes of the flight.

RIP all lost.

Capn Bloggs
27th May 2011, 14:38
I don't see anything that indicates the captain took back its seat.
2:13:32: control was handed over to someone else.

Edit: Oz ABC News saying "The captain did not retake the controls, with the co-pilots flying the plane until the end, the investigators said during a conference call."

grimmrad
27th May 2011, 14:48
In alternate law - is the amount of warning signals reduced to the bare minimum necessary to keep the tube flying? I.e. you don't need a warning that the lights in the toilets aft aren't working while stalling...?

Hamrah
27th May 2011, 14:49
Food for thought:-

The blocked pitot system resulted in the autothrust applying thrust to stop the " apparent" speed decay. Similarly, the autopilot applied nose up trim for the reducing speed. When it reached the limit, the autopilot gave up, and the handling pilot now had an aircraft with full nose up trim and full power. by the time he reached the apex of the " bunt" (around 38000ft), the aircraft was in a deep stall with a forward speed of around 60kts and a high angle of attack...resulting in the 10,000ft + Rate of descent. In Direct law, which they may now have been in, holding the stick back will maintain the stall.

I really hope the DGAC /Air France/ Pitot Heat manufacturers don't use the get out clause of " Pilot Error" to wriggle out of their contribution to this crash.

Edited to acknowledge Robssupra's post above, which appeared whil I was writing.

Locked door
27th May 2011, 14:57
Hamrah,

Pilot error is just one of several causal factors here. The pitot design, the ice forming, the unreliable airspeed and then finally pilot error.

bubbers44
27th May 2011, 15:01
Huck, step 2 is a bit questionable as well as 7. The nose up pitch by the sidestick probably caused the plane to stall between FL375 and 380, not stabilizing. Wasn't the stall warning activating at that time?

hambleoldboy
27th May 2011, 15:03
Angle of attack can be displayed in a modern EFIS equipped airliner.

It's the difference in vertical degrees between the ADI pitch reference datum and the Flight Path Vector symbol.

Robssupra
27th May 2011, 15:05
Hamrah,
With the little info we have to work with you are on the money with your statement.
Lets wait until we have more to work with and hopefully we will all learn something from this and hopefully no more lives lost, whatever the lesson here might be.

And Hambleoldboy, no one has mentioned the FPV flight path vector yet until you did, all one has to do, and it is recommended that you do, when hand flying an aircraft. Select TRK-FPA and you will get the bird, which will represent the actual flight path of the aircraft. But than again will you get an accurate information from the FPV when you have your pressure sensors iced over?

hambleoldboy
27th May 2011, 15:07
So in my opinion the solution to the situation these two pilots found themselves in was:

- Nail the attitude at 2 degrees nose up

- Fix the throttles at the known cruise EPR

- Switch to FPV and keep the symbol on the horizon...

Simples Messieurs!

AlphaZuluRomeo
27th May 2011, 15:20
@ hambleoldboy : Good point. Would not a dedicated AoA meter be more "readable", though ?

About the FPV : I think they went inop during the last minutes... Memories from ACARS messages...
[edit] having check : FPV disappeared (triggering ACARS message @ 2:11). Most likely because of an IAS below 60kt. But FPV would have re-appeared as soon as the IAS came above 60kt.

hambleoldboy
27th May 2011, 15:29
I would think that the FPV symbols are generated by the IRU's therefore unaffected by unreliable air data inputs...?

In an upset they must surely be an essential indication as they show exactly where the aircraft is going.

Huck
27th May 2011, 15:32
I think they spent a bit of time at FL 375 - 380, thus must have recovered for awhile. The wording is difficult:

The airplane was then at an altitude of about 37,500 ft and the recorded angle of attack was around 4 degrees.

From 2 h 10 min 50, the PNF tried several times to call the Captain back.
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. The recorded angle of attack, of around 6 degrees at the triggering of the stall warning, continued to increase. The trimmable horizontal stabilizer (THS) passed from 3 to 13 degrees nose-up in about 1 minute and remained in the latter position until the end of the flight.

Around fifteen seconds later, the speed displayed on the ISIS increased sharply towards 185 kt; it was then consistent with the other recorded speed. The PF continued to make nose-up inputs. The airplane’s altitude reached its maximum of about 38,000 ft, its pitch attitude and angle of attack being 16 degrees.

ECAM_Actions
27th May 2011, 15:40
hambleoldboy (http://www.pprune.org/members/128793-hambleoldboy) couldn't agree more!

I don't see why the AP pitched UP due to reducing airspeed. Worse still, it seems clear to me that the pilots had several STALL warnings after AP disengagement and prior to it actually dropping like a brick. What is even more perplexing is given that the pilot arrested the 7000 ft rate of climb, why he then proceeded to apply aft stick input and raise the nose?

Were the altimeters functional? It would appear they were; if so, why didn't this tell them they were actually stalling? As for the THS taking over a minute to get to +13 degrees, suggests the pilot held aft stick input throughout. I'm struggling to comprehend just why he would do that.

ECAM Actions.

The Ancient Geek
27th May 2011, 15:48
Something here does not seem to add up.

4 minutes is a very long time. How can 3 highly qualified pilots persist in maintaining a stall for so long without someone figuring out that they have got it wrong.

Having 3 idiots in the office is simply not a very credible explanation, this is not a Colgan situation with a low time pilot at low level with little time to correct a mistake, we have 3 highly trained guys with plenty of time.

My guess (and it is ONLY a guess) is that they must have been getting seriously misleading information and/or some form of incapacitation may be involved.

ilesmark
27th May 2011, 15:52
Hamrah - 'Food for thought:- The blocked pitot system resulted in the autothrust applying thrust to stop the " apparent" speed decay. Similarly, the autopilot applied nose up trim for the reducing speed'

The BEA report states at the top of pg 2 'From 2 h 10 min 05, the autopilot then auto-thrust disengaged and the PF said "I have the controls". The airplane began to roll to the right and the PF made a left nose-up input. The stall warning sounded twice in a row. The recorded parameters show a sharp fall from about 275 kt
to 60 kt in the speed displayed on the left primary flight display (PFD), then a few moments later in the speed displayed on the integrated standby instrument system (ISIS).
Note 1: Only the speeds displayed on the left PFD and the ISIS are recorded on the FDR; the speed displayed on the right side is not recorded.
Note 2: Autopilot and auto-thrust remained disengaged for the rest of the flight.'

The report later on pg 2 goes on to say '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.'

My reading of this is, therefore, that the autopilot and autothrust had already disengaged by the point that the aircraft started climbing and were not responsible for either the application of thrust or nose-up inputs; the crew were.

Does the above alter your hypothesis?

Torquelink
27th May 2011, 15:53
Stalled, with stick held back all the way down - eerily reminiscent of the Colgan Q400 at Buffalo . . .

AlphaZuluRomeo
27th May 2011, 15:54
I would think that the FPV symbols are generated by the IRU's therefore unaffected by unreliable air data inputs...?

Well... Yes... and no. As per BEA's #2 interim report (bold is mine):

ACARS Messages:
02:11:00 - .1/WRN/WN0906010210 228300106FLAG ON CAPT PFD FD
02:11:15 - .1/WRN/WN0906010210 228301106FLAG ON F/O PFD FD

Symptoms:
Disappearance of the FPV (bird) on the PFDs, Captain and First Officer sides, and display of the corresponding flag.

Meaning:
This message indicates that the flight path vector (FPV) function is selected but unavailable. In order to lose completely this function, which is elaborated by the three IRs, in a way that is compatible with the CFR, one of the following three conditions must be met for each ADR:
barometric vertical speed higher, as an absolute value, than 20,000 ft/min,
true air speed higher than 599 kt,
measured calibrated airspeed lower than 60 kt.
Once the operating conditions are satisfied again, the FPVs reappear on the PFD (if TRK/FPA mode is still selected).

Me Myself
27th May 2011, 15:59
The BEA report shocked the entire aviation community and I can sense this thing can do nothing else but snow ball and get huge momentum as very embarrassing questions will be asked.......as they already have above.
The french pilot community is going to have a very hard time swallowing this and no doubt the plot theory will be milling full speed.
Now, the good question is why ? Does it have to do with training ? Or what else ?
What does " experienced pilot " mean today ? Hours and hours of boring cruise at night doesn't really season you.......if you take the whole game for granted.
In this business, one has to remember that despite the sometimes utter boredom, one is still responsible for lives and this alone should keep you on edge.
We are in a job where our brain should never stop asking " what if..... " this keeps you awake for one thing but more important, reduces the gap between normal and wtf is happening when the dung hits the fan. That's the difference beween surprised and not surprised.
That's the difference between life and death.

AF is going to go through some very very testing times and some people will have to open their eyes.....or else.
We haven't seen the unpleasant side of this YET. There will be a civil trial somewhere down the line and some people will demand explainations.

Robssupra
27th May 2011, 16:01
Has anything being mentioned regarding ice buildup on the airframe ie. leading edges, THS. and so on? The conditions they must have been in, was W/A.Ice selected at any stage? It will take seconds to build up enough ice at that altitude to reduce your speed buffer margin to the point of an imminent stall in level flight regardless of attitude and power.

AFTA
27th May 2011, 16:08
" So in my opinion the solution to the situation these two pilots found themselves in was:

- Nail the attitude at 2 degrees nose up

- Fix the throttles at the known cruise EPR

- Switch to FPV and keep the symbol on the horizon...

Simples Messieurs! "

The next step in computerized airliner.

A big red panic button in front of the pilots that tells the autopilot to ignore all sensors and pilot inputs exept an independent gyrosystem and achieve the above:hmm:. When certain parameters are stable suggest that the pilot "tries again"

Springer1
27th May 2011, 16:11
"How can 3 highly qualified pilots persist in maintaining a stall for so long without someone figuring out that they have got it wrong."



Probably because they were overwhelmed by the repetitive ecam messages,bells and lights.

I had something as simple as an IDG Low Oil Pressure warnings at rotation on the 320 and it was a major distraction. Every time I cnx the warning it came right back on until I leveled out and the oil covered the sensor. Lights, bells, trying to communicate with each other and ATC was problematic.

I can only imagine how difficult it was to decipher just what was going on in the heat of the battle. I am very reluctant to label this as pilot error at this point.

Springer

flyer146
27th May 2011, 16:12
Do you remember, yeaaaaars ago of an aircraft (I think DC10) got to the coffin corner and entered a deep stall ?

They recovered by pulling heavy g's and landed the airplane which suffered structural damages due to the g's.

Just trying to get back to that event details...

Jetjock330
27th May 2011, 16:13
So in my opinion the solution to the situation these two pilots found themselves in was:

- Nail the attitude at 2 degrees nose up

- Fix the throttles at the known cruise EPR

- Switch to FPV and keep the symbol on the horizon...

Simples Messieurs!

So very true, 3 degrees up, 78% N1 on the RR772, and it will be a safe setting, between M.78 and .82 with the A330. Once this power and attitude is set, the QRH can be evaluated for a more precise setting and the faulty instrument will instantly be identified.:ok:

doubleu-anker
27th May 2011, 16:14
There is one more glue the aircraft was in a stalled condition and that is aerodynamic buffet. That thing must have been shaking itself to bits on the way down. Surely that must have got their attention, as I am quite sure it would have got mine!

Every aircraft I have flown there is a marked aerodynamic buffet at the approach to the stall and there after.

I haven't flown the A330 and never will but I cant imagine it being any different from the many aircraft I have flown.

ECAM_Actions
27th May 2011, 16:28
At over 10,000 ft/min rate of descent, surely they'd have felt it along with the very rapid change of pressure in the cabin?

How many clues did they need that they had stalled?

What are the A330 stall characteristics anyway? Has FBW removed the pilot so far from the basic airframe that he doesn't even have the seat-of-the-pants feeling for the aircraft?

ECAM Actions.

rgbrock1
27th May 2011, 16:37
ECAM Actions wrote:

At over 10,000 ft/min rate of descent, surely they'd have felt it along with the very rapid change of pressure in the cabin

SLF here with no idea on flying an aircraft. What I would like to speculate on, however, is what kind of physiological effects such a rate of descent would have had on the flight deck crew?

We can surmise that the crew was already disoriented by inaccurate instrument readouts, audible alarms and flashing lights. Compounded by 10000ft/min rate of descent is it conceivable that even if the crew been able to reestablish control of the aircraft they could not due to incapacitation or even more disorientation?

Algol
27th May 2011, 16:37
I had something as simple as an IDG Low Oil Pressure warnings at rotation on the 320 and it was a major distraction. Every time I cnx the warning it came right back on until I leveled out and the oil covered the sensor. Lights, bells, trying to communicate with each other and ATC was problematic.

In an A320?
Surely that warning would be suppressed during take-off?
And why not use the Emer Canc button if it wasn't?

ChrisVJ
27th May 2011, 16:39
I am just a PPL so there are quite a few things I don’t understand about flying big jets however I have mentioned before a belief that some of the fundamentals of flying training that I learned back in the early 60’s seem to be passed over or changed for spurious new ideas in the last thirty or so years. I do understand that in a big aircraft some actions, for instance the use of throttle and attitude on approach are different. I have a few questions regarding flying big jets, maybe someone can help.

1) A reduction in speed from 0.82M to 0.80M seems very small for turbulence. I understand stall speed is right up there at that altitude but is the effect of speed reduction proportional to the difference between stall and max speeds? Ie. If the difference is 50 knots and you reduce speed by 20 knots is that the equivalent in a small aircraft at 3,000 ft of reducing speed from 120 knots to 70 knots?
2) Is the Airbus stall warning a light and buzzer which can get confused in all the warnings etc going off or is it a voice saying “Stall . . . . . . “
3) The report does not mention rudder input. Was the rudder used to control the dropping wings or were ailerons used? If rudder was used it would appear to indicate that the pilot(s) understood they were in a stalling condition. (When I was learning it was stressed that one used rudder to control wing drop approaching the stall so that one did not stall the wing by increasing tha AoA with aileron, is it different in big jets?)
4) With steam gauges it is fairly hard to miss the indications that you are going UP while speed is decaying. Is it less clear in a glass cockpit?
5) There are indications that pitot speeds didn’t agree, and the change to alternate law also indicates that, but are there also clear indications that pitot speeds have become reliable again?
6) Just from memory the original reports on the V stabiliser indicated that it was attached till impact. If the aircraft was in alternate law at 250 knots (and the limiter was disengaged) was the air thin enough at 35,000ft not to cause a separation if rudder was applied (ie, the crew recognised approaching stall and used rudder to control roll at some stage.) Could the initial reports have been wrong?
7) Bearing in mind the Buffalo accident, did any of the crew receive training that mandated other actions besides stick forward in an apparent stall situation?
8) Does the Airbus have ‘stick’ shaker and ‘stick’ forward pressure during stall approach. (I do know they are side controls.)
9) I can understand carrying out wrong actions in ‘coffin corner’ especially if suddenly faced with an unusual situation during an otherwise normal flight but surely someone must have recognised the unwinding altimeter and slow speed indications in two or three minutes, that’s an awful long time to be holding stick back in those conditions.

I understand this is a preliminary report to damp down the wild speculation a little, but as already mentioned it raises more questions than answers, for me at least. I have passengered nine times in the last five weeks and the report scares me, a lot.

Melax
27th May 2011, 16:39
I just find it very hard to believe that for the duration of the stall (Recovery attempt ?) the stick was held all the way back ? :ugh:It's very easy to blame the pilots (3 experienced pilots) but could it be something else such as a computer malfunction ? The stick may have been pushed forward but the computer decided to send an elevator up command.....and therefore the DFDR data recorded seems to point to a pilot input rather than a computer command ( I think there has been a few similar incidents). There is much much more to discover...

Lonewolf_50
27th May 2011, 16:45
ECAMS:

I don't see why the AP pitched UP due to reducing airspeed. Worse still, it seems clear to me that the pilots had several STALL warnings after AP disengagement and prior to it actually dropping like a brick. What is even more perplexing is given that the pilot arrested the 7000 ft rate of climb, why he then proceeded to apply aft stick input and raise the nose?

ECAMS, considering the human "stimulus - response - conclusion" chain, did the pilot think he was dealing in a high speed stall? (As I don't know the difference in "feel" that may be an idiotic question. Some weeks ago the difference between the two was described in one of the other threads).

That said, based on how FDR records info (??) will anyone know what the PF was looking at? It is possible (not sure how likely) that his display and the PNF display were not showing the same information ... at some point control of acft changes hands, perhaps display anomalies contributed to that? :confused:

(Used to fail other pilot's gyro during instrument checks during a turn to see what people did. Was very, the variety of reaction, but I never had to take control back ... though had to talk a few folks back to wings level ... )

@ torquelink: significant difference being quite a bit more altitude and time, and experience, available in this scenario. In Colgon case A/S unreliable did not figure into the scenario, IIRC.

ST27
27th May 2011, 16:49
The stick may have been pushed forward but the computer decided to send an elevator up command.....and therefore the DFDR data recorded seems to point to a pilot input rather than a computer command

The DFDR on newer aircraft records the movement of the individual sidesticks and the physical movement of the elevators all separately, so you can readily see if there is any difference between them.

In the report they mention that at one point both pilots were making control inputs. That would have been seen on the DFDR.

irishpilot1990
27th May 2011, 16:51
I just find it very hard to believe that for the duration of the stall (Recovery attempt ?) the stick was held all the way back ? :ugh:It's very easy to blame the pilots (3 experienced pilots) but could it be something else such as a computer malfunction ? The stick may have been pushed forward but the computer decided to send an elevator up command.....and therefore the DFDR data recorded seems to point to a pilot input rather than a computer command ( I think there has been a few similar incidents). There is much much more to discover...

Surely if it was a computer problem giving such inputs the pilots would disconnect and set the standard cruise settings.:confused:
We are going to have to await more information because it makes no sense why 3 pilots nose dived a 330 into the ocean.

10,000 feet/minute dive- you dont need a vertical speed indicator, or any instrument for that matter to feel that and know your only going in one direction -down.

WhatsaLizad?
27th May 2011, 16:54
Hi there Whatsalizad, thanks for your reply. I suspected someone might take issue with my comments, and I have no problem with your reply. I've never flown a commercial airliner, but did fly in the military, and as you mentioned, Power + Attitude = Performance was king of my world.

Yes, the QA A380 incident was alarming / frightening, but they stuck to basics and got it right.

I agree that we don't know what indications the aircrew received, which is why I admitted that my comments might be jumping the gun. Apologies if they annoyed you.

I think your comments were fair enough.:ok:

I agree going to the basics that work rather than trying to solve an automation Rubiks Cube is the way to go. I still can't believe guys who spend time heads down at less than 3000 AFL typing for a simple VFR runway change. My preference in handling any automation confusion is to downgrade to the lowest level of automation, AP and AT off if neccessary and retrace the programming steps. I've found it's easier to ask "what it did" instead of "what's it doing now".

jet grande
27th May 2011, 16:56
Air France is going to have a very hard time explaining this one and I am sure the victim's Lawyers are going to have a field day at the Courts.
If the Air France "Juggernaut" was not one of the "heavyweights" of Europe and if it's safety standards were appraised by the same criteria as the smaller airlines it would definitely be included in the infamous European "Black List".
This airline has the worst safety record in Europe.

Huck
27th May 2011, 16:56
4 minutes is a very long time. How can 3 highly qualified pilots persist in maintaining a stall for so long without someone figuring out that they have got it wrong.


It happened at Roselawn as well (ATR-72).

I'd like to see the data for roll angle. At Roselawn the stall was coupled with wild, violent roll oscillations. The pilots did not recognize a stalled condition.

In Air France's case, with that kind of sink rate their pitch angle was 16 degrees or less, and roll was tossing through 40 degrees each way. They were sitting at 100% thrust. Perhaps they were thinking of structural problems or something else - but they must not have recognized the stall....

The airplane’s pitch attitude did not exceed 15 degrees and the engines’ N1’s were close to 100%. The airplane was subject to roll oscillations that sometimes reached 40 degrees.

Lonewolf_50
27th May 2011, 16:58
Whatsalizad: it would appear that the aircraft was stalled for most (if not all) of the descent, so maybe it wasn't a dive. With the THS (as reported) remaining a 13 deg nose up, how do you dive? :confused:

Huck:

The airplane’s pitch attitude did not exceed 15 degrees and the engines’ N1’s were close to 100%. The airplane was subject to roll oscillations that sometimes reached 40 degrees.

Is this a symptom of a deep stall?

15 deg nose up and falling at 10,000 fpm strikes me as an extremely uncomfortable, and disorienting feeling. Does Unusual Attitude training cover this case?

(Hmm, from what folks have posted in the other threads, Sims probably don't have the data points for it ... )

BarnettErasmus
27th May 2011, 17:00
Could it be possible that the pilots thought they were in a nose-down attitude?

They probably had no external visual reference, and with the deceleration of the plane, even with the slight nose-up attitude, it would have felt like they were in a nose-down attitude. Faced with an altimeter spinning backwards, and thinking that they were in a nose-down attitude, the last thing on their minds would have been to push the nose down any further...

Sorry if this is a silly suggestion, but as a non-pilot I am struggling to understand how three pilots could not figure out that their plane was stalled.

strake
27th May 2011, 17:01
Don't know anything about flying an Airbus or anything above 5700kg for that matter..so happy to be told to to poke off.
However, it's dark, turbulent and something frighteningly strange is happening to a 42 tonne aircraft that is causing a rapid descent. Maybe it just doesn't feel natural to take a deep breath and shove the joystick forwards..

MountainBear
27th May 2011, 17:05
The Ancient Greek writes:

4 minutes is a very long time.I agree with this assessment. I think it nullifies the idea that there was a "startle" factor due to "bells and whistles". A professionally trained pilot is not startled for four minutes. A few seconds, yes; four minutes no.

The critical question that now needs to be answered. For essentially four minutes he rode the stick right into the ocean. Why? Something caused him to do that. Training? Confusion?

Another poster:


but as a non-pilot I am struggling to understand how three pilots could not figure out that their plane was stalled.

If they did not know the plane was stalled, why?

or

If they knew the plane was stalled and handled it wrong, why?

The report as it stands doesn't answer this questions (nor should it).

Lonewolf_50
27th May 2011, 17:06
strake, you may be right ... but if the attitude reference system (attitude display) is still working, your primary scan first goes to attitude gyro/attitude reference/artificial horizon, and you set an attitude.

I would think that's pretty basic "unusual attitude" instrument flight training.

MSAW_CFIT
27th May 2011, 17:13
Two incidents worth reading in light of this report

L1011 Eastern Air Lines Flight 401 in 1972 - CRM

Eastern Air Lines Flight 401 - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Eastern_Air_Lines_Flight_401)

B727 TWA Flight 841 in 1979 - Recovery from rapid uncontrolled rate of descent

TWA 727 (http://fromtheflightdeck.com/Reviews/727/TWA727/)

ECAM_Actions
27th May 2011, 17:20
Regarding the attitude - one would hope at least one of the pilots ignored his senses and trusted the instruments. It seems from the report that (from the lack of reference otherwise) all three ADIs (both PFDs and ISIS) were reading very similar values, so regarding reference to level flight, they shouldn't have had a problem.

Knowing the aircraft to be reasonably upright, but with a screaming altimeter, knowing you are over the ocean with nothing to hit, a pitch-over would seem a far better alternative to not trying stall recovery at all?

As was written above: maybe there was some conflict in data resulting in the pitch-up action?

We need the complete FDR data - too many questions, so few answers.

ECAM Actions.

wiggy
27th May 2011, 17:23
Thing is we now know in hindsight that the altimeters and VSI were ( apparently) working correctly so full stall recovery is a "no brainer" to us, right? But the AF crew had already lost IAS and now the altimeters was winding down at a rate they'd probably ever seen in a simulator reset. OTOH the aircraft is rocking and rolling, buffeting, but in a vaguely sensible attitude and with full power applied...added to which they're being bombarded with compelling electronic warnings demanding immediate attention......

Human beings like you and me, not perfect, short of reliable information, overloaded, at saturation point and in some form of denial?

GC_Graybeard
27th May 2011, 17:27
Probably very similar:

Northwest 705 air crash (http://www.pilotfriend.com/disasters/crash/northwest705.htm)
It appeared that the aircraft did not break up until the crew apparently tried to recover when passing through 10,000ft. The question then was what caused the aircraft to get into such an unusual condition. The answer came in the fact that the aircraft has an inherit tendency to 'weathervane' into gusts. So, when the initial updraft caught the aircraft, it would have an initial tendency to nose down into the gust. This apparently prompted Almquist to give nose-up inputs, which would actually worsen the overall situation. The same effect worked in the downdraft which followed. It is also important to note that, although it appears full up elevator was used in the recovery attempt, full nose-down trim was still wound in from the prior encounter with the updraft.
Regards,

GCGB

atakacs
27th May 2011, 17:31
Did anyone spot an over-speed alert at any time (I could not) ?

If not I really can't understand their insistence to keep the nose up - there is no way they could not feel the stall.

Very perplexing...

ECAM_Actions
27th May 2011, 17:37
Just to add - surely the aircraft isn't capable of maintaining attitude with the trim at +13 degrees if it is *not* stalled?

ECAM Actions.

Fox3WheresMyBanana
27th May 2011, 17:52
Looks like the aircraft was held in the stall, for over 3 minutes; question is, why?
Fitting an AoA gauge seems like a good idea.
I await more info on whether the AH, VSI, altimeter etc were displaying correctly.
Do you airline types get taught/practise limited panel anymore?

I don't think vast numbers of hours help. My IF1 in the RAF was in wave activity in the Vale of York. Max rate climb selected and going down 1 minute, power off glide and going up the next minute - you just need an excellent instructor (mine was ex-CFS A1).

SeenItAll
27th May 2011, 18:02
Official AF reaction to today's news -- the aircraft's instruments failed and the pilots reacted completely professionally.
Air France - Corporate : AF 447 - Air France (http://corporate.airfrance.com/en/press/news/article/item/af-447-reaction-dair-france-a-la-note-dinformation-du-bea/)

AF 447 - Air France’s reaction to the BEA’s information report
Friday 27 May 2011

On the eve of second anniversary of the AF447 tragedy, Air France and its staff are turning their thoughts to the families of the passengers and crew and wish to express their full solidarity.

The perserverance of the authorities, Airbus and Air France has led to the flight recorders and parts of the aircraft being found after a two-year search. The French Accident Investigation Bureau (BEA) is now able to reveal the sequence of events leading to the crash of flight AF447 from Rio to Paris on 1 June 2009.

This description of the facts therefore replaces the assumptions that have been made over the past two years.

It appears that the flight deck crew was monitoring the changing weather conditions and thus altered the flight path, that the initial problem was the failure of the speed probes which led to the disconnection of the autopilot and the loss of the associated piloting protection systems, and that the aircraft stalled at high altitude. It also appears that the flight captain quickly interrupted his rest period to regain the cockpit. 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.

All the data collected must now be analyzed. It will only be at the end of this complex task, which requires patience and precision, that the BEA will be able to establish the causes that led to the disaster.

We can already see that the authorities, the manufacturer and the airline have taken measures to avoid the repetition of such an accident.

Air France hopes that everyone has the patience to wait for the interim report that the BEA will publish in a few weeks, no doubt along with additional recommendations. The safety of the global air transport industry will be even stronger.

bearfoil
27th May 2011, 18:07
"...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..."

....Air France, Corporate release

bear

GC_Graybeard
27th May 2011, 18:08
Dear ppruners,

from early reports after the incident,
I remember indications of disintegration
of parts (tail) - from the location pattern
of the debris found.

If, in the middle of a heavy thunderstorm
with massive alternating +/- G forces
(updraft/downdraft, compare Northwest 705)
working on the airframe, what would you think
what the PF would notice if some tail parts
are gone?

(I'm only an "armchair pilot", sorry if the
question doesn't make sense.)

Thanks & regards

GCGB

green granite
27th May 2011, 18:10
If not I really can't understand their insistence to keep the nose up - there is no way they could not feel the stall.

It's called a mind-set, a good example of that is the pilots of a Boeing freighter who's pitoheads froze and the air speed started to increase so they pulled the nose up, the speed continued to increase so they pulled it up some more and some more again, by this time common sense should have been screaming at them that you cant just keep pulling the nose up and continue to speed up, eventually they pulled once to often and stalled with fatal results.

Hamrah
27th May 2011, 18:40
GC Graybeard

The Tail detachment was probably a function of the aircraft striking the ocean in a nose high attitude at a high rate of vertical speed ( 10,000fpm)

Ashling
27th May 2011, 19:07
Chris VJ

No you do not use rudder to control roll in an airliner. The rudder pedals are, in effect, footrests apart from crosswind landings and engine failure. In fact, if you are in a stall the use of rudder will be a singularly bad idea as it may lead to a spin. A planned spin entry involves approaching the stall and inputting full aft stick and full rudder. The consequences of the incorrect use of rudder to correct roll were demonstrated when an airbus and its fin seperated over New York.

Of course if you fly air comat or aerobatics then rudder at slow speed to augment roll can be very usefull.

Roseland
27th May 2011, 19:24
If you're level but descending at over 10,000ft/min (c 110kts) is a vane on the side of the fuselage going to give a meaningful AoA anyway?

ECAM_Actions
27th May 2011, 19:37
If the VSI is buried in the floor and the altimeter is spinning faster than a fair ground ride, then I think measuring AoA is pointless!

Still, it seems they missed it.

ECAM Actions.

Ashling
27th May 2011, 19:55
The stall warning is based on AoA so even with unreliable airspeed it will activate correctly. So the stall warning was telling them their AoA was too high. That indication was correct even if their airspeed indications weren't. Its also why you always honour a stall warning with unreliable airspeed.

ChrisVJ
27th May 2011, 19:57
The question of whether the pilots could 'feel' the descent of 10,000ft/min is of interest.

In theory one should certainly feel the initialising of the descent but if theory holds good then once you are established in a descent at a steady rate, whether 1,000 or 10,000 ft/min your 'bum' would feel only1G, you could be in descent, level or ascending flight. This effect might be heavily compounded by the wing rocking and buffeting. Pure speculation, of course, but it might be conceivable that after indications of instrument failure you might ride the aircraft all the way to the sea while still thinking you were at 30,000 ft. Dark, no visibility, no horizon, can't trust the Altimeter, AH or ASI?

Just thinking out loud.

jcjeant
27th May 2011, 20:03
Hi,

With provision that all the communications between pilots are not yet reported
From reading the BEA communication I notice that never the pilots communicate about a procedure to follow (a check list) in case of such event (unreliable airspeed)
At the time of the event Air France has a procedure for such event (and this procedure was revised sometime after the AF447 event)
I also notice that the captain come in the flight deck .. but nothing more about what he tell (he tell nothing ??? )

ChristiaanJ
27th May 2011, 20:09
If you're level but descending at over 10,000ft/min (c 110kts) is a vane on the side of the fuselage going to give a meaningful AoA anyway?Why not?
I agree nobody would ever have done the flight testing etc. to calibrate the vane to two decimals accuracy at that AoA, but the vane output would still be meaningful, even if not terribly accurate.

CJ

Mr Optimistic
27th May 2011, 20:16
I agree, without all the communication between the crew, and a statement that all the communications are given, what has been given may be someone's idea of a reasonable PR release: not intended to be misleading but not anticipating this depth of analysis.

ChristiaanJ
27th May 2011, 20:19
...no horizon, can't trust the Altimeter, AH or ASI?So far there are no indications that the altimeter (hence VSI) failed (they get their data from the static ports, not the pitots).
Neither are there any mentions of the attitude reference system, hence AH (or standby AH), having failed.
"No horizon ?" Normal situation during instrument flight, at night or in cloud. That's why the "artificial horizon" was invented.....
Let's not confuse the story unnecessarily.

CJ

wheelie my boeing
27th May 2011, 20:22
The fact of the matter is that there IS NO PROCEDURE for unreliable airspeed in the cruise. I fly the 319/320/321, so I am not referring to the 330 but given that they are very similar the guessing the procedures are similar. Airbus have a procedure with how to deal with it, and if you google it you will find it. Fact is, above 10,000 ft the procedure is 5 degrees pitch with CLB power. In heavy turbulence when the aircraft is pitching allover the place then you can forget about holding 5 degrees pitch!
Not to mention the fact that 5 degrees pitch with CLB power is certainly not the best thing to do with unreliable airspeed in the cruise. Most Airbus guys now have their own pitch/power settings memorised for this - only because of AF447, and before the accident the majority of guys would have said "well, I guess its 5 degrees with CLB power as technically that is what the QRH says". All of this is not forgetting that there still is NO procedure from Airbus, the procedure in the QRH is suited to unreliable airspeed much lower down.

For those who says "why didn't the Captain take control"? Well, given the aircraft may have been out of control by that point it must have been difficult in getting to the cockpit alone, let alone getting someone who is handling the situation (badly or not) out of their seat and you strapping in. He probably decided that the two people in the seats had the best idea of what was happening as they had seen all the evidence and he had entered later on.

Speevy
27th May 2011, 20:47
The fact of the matter is that there IS NO PROCEDURE for unreliable airspeed in the cruise.

Sorry but I think you got it wrong here...

The procedure on the 320 family says:

If the safe conduct of the flight is impacted :
-A/P and F/D off
-A/THR off
-Pitch thrust:
.Below Thrust Reduction altitude 15° Toga
.Above Thrust Reduction altitude 10° CLB.
.Above 10.000ft 5° CLB.
-Flaps Maintain.
-Speedbrake retract
-L/G up.
.When at or above MSA or circuit altitude level off for troubleshoot.

Therefore if it happens during cruise, and safe conduct of the flight is impacted you have to go for 5° and CLB, then level off, and go for the pitch power data from the checklist.

If instead the safe conduct of the flight is not impacted (which was definitely not the case for the AF) the memory items can be skipped and the pitch power data used to maintain the level.

I am not accusing the AF pilots involved of not having used the proper procedure (too little details have been released at this moment especially on the intensity of the turbulence ), I am just saying that the procedure for unreliable speed is clearly there..

Speevy

TheShadow
27th May 2011, 20:49
"The stall warning sounded twice in a row. The recorded parameters show a sharp fall from about 275 kt to 60 kt in the speed displayed on the left primary flight display (PFD), then a few moments later in the speed displayed on the integrated standby instrument system (ISIS)."
This is what I'd expected and earlier predicted here in this thread as being the "onset" (an eventual total pitot clog - see explanation at post 335 (http://www.pprune.org/rumours-news/447730-af447-wreckage-found-17.html#post6462091) (page 17) on this thread ). The DFDR was of course recording exactly what the pilots were seeing but meanwhile the aircraft's autothrust had actually been increasing power to maintain that programmed speed (and as a result of the gradual ice-crystal pitot blockage, actually exceeding that programmed speed by a considerable margin, whilst headed towards Mach Crit). But what triggered the autopilot disconnect? Was it a Mach Crit encounter or was it that the autopilot couldn't hold the increasing elevator force gradient of a system-driven mis-set THS (hoz stabilizer)? Or was it the sudden total clog of the pitots (see hail formation "exponential" analogy at my previous post).

"At 2 h 10 min 51s, the stall warning was triggered again. The thrust levers were positioned in the TO/GA detent and the PF maintained nose-up inputs. The recorded angle of attack, of around 6 degrees at the triggering of the stall warning, continued to increase. The trimmable horizontal stabilizer (THS) passed from 3 to 13 degrees nose-up in about 1 minute and remained in the latter position until the end of the flight." Over time, as they cruised in the ice crystals of Cirrus cloud (a known "pitot heat capacity" anomaly for that mark of pitot tube), the gradually clogging pitot system resulted in the autothrust incrementally applying power to stop the "apparent" speed decay. Similarly, the auto-trim maintained the nose-up trim for that programmed speed - and the autopilot offset the elevator (via "fwd stick") to hold height - as the aircraft was actually flying faster than shown. When it reached its design pitch-holding limit (i.e. the max nose-down force gradient it could hold), the autopilot gave up, and the handling pilot now had an instant unalerted surprise handful of an aircraft in Direct Law with nearly full nose-up trim and near to full power. So did the DFDR faithfully record this or did the BEA just construe (and misrepresent) it as the pilot's aft sidestick input? i.e. in the absence of any better/more logical explanation?

When it comes to high speed protection, should this crew have received wrong airspeed info indicating a high speed situation, you have protection where, once Mmo + few kts has been exceeded, you will get an auto pitch-up to try and maintain Mmo + few knots, so should this happen at slow actual airspeed, it will not be too hard to see why the pilot may have continued to pull back and continue increasing the acft's pitch angle. But my theory was that they were actually at an initially higher speed than indicated. Here (most importantly) we have to consider that after their involuntary zoom climb (due trim), the static pressure changes would thereafter have had a considerable additive (and further confusing) effect upon the blocked pitot systems and the displayed airspeed/mach. i.e. ( "The speed displayed on the left side increased sharply to 215 kt (Mach 0.68). The airplane was then at an altitude of about 37,500 ft and the recorded angle of attack was around 4 degrees.")

"the angle of attack exceeded 40 degrees" later saith the report. You have to close your eyes to this, because it's not anything those AF447 pilots would have known (i.e. no AoA display for them).

"By the time it reached the apex of the ensuing pitch-up and subsequent " bunt" (around 38,000ft), the aircraft was ACTUALLY entering into a deep stall with a forward speed of around 60kts and a high angle of attack...ultimately resulting in the 10,000ft +/minute Rate of descent at high AoA. But they'd initially responded correctly to the stall warning with TOGA power? - however that response was soon to change. Why? In Direct law, which they should now have been in, holding the stick back will maintain that stall. But why would the pilot do that back-stick thing? Perhaps they were attempting to attain level flight - and unaware that they were in Direct Law? But was there another reason and why did they then idle the TOGA thrust? Who knows for sure? But here's a clue. In the subsequent descent with static pressure increasing and the pitots still blocked?, even though the airplane was actually stalled (complete with stick-shaker) the indicated airspeed would be increasing alarmingly - courtesy of increasing static pressure. That's my guess - and it's anyways a physical fact, Been there and done that trick with frozen trapped water in the static lines (i.e. the opposite effect of trapped dynamic pitot pressure). There's also a report on the Irish Accident Board's site about a 747 on a test flight with uncapped static lines due maint error. It's an elucidating gaelic tale that shows just how confusing the pitot-static scenario can be. See below for how much a 1000feet of altitude change is worth in terms of additional "displayed knots". Ask any instrument technician. That's what I did. He'll demo it for you on his test-bench.

As somebody said: "All this will probably come down to crew composition, very high workload, in adverse weather conditions, having to manually hand-fly an aircraft which suddenly found itself in alternate law at high altitude due to spurious information being fed to not only the flight display computers, but also the flight control protection and guidance computers, simultaneously." Suddenly? Don't underestimate the power of surprise. Spurious info? Maybe, but when it's what you are taught to believe (your instruments), that's what you react and respond to. You see a high and increasing airspeed and you apply backstick to attempt to control it - and you idle the throttles..... but instead you are (unbeknownst to you) embedding yourself in a deep-stall condition. Will the stall warning cease once embedded in deep-stall at 40 degs AoA?. That's my guess. That they were non-plussed by developments is obvious from the limited dialogue. Even the captain was struck dumb by what he saw. No solution was obvious in the time available - as the airspeed was seen to be much more than just "adequate" (i.e. even high - and even higher as the static pressure increased inexorably upon descent) i.e. so how could they be stalled? Unthinkable - so it wasn't even considered. It was perhaps a meteorological phenomena?). They just ran fresh out of ideas. Freeze-framed twilight zone? Been there and done that too.

Someone also said (and theShadow said earlier in his 20 May post - and last year): "You are not only dealing with conflicting airspeed info, you are also presented with multiple spurious ECAM warnings and cautions which it is sometimes hard to ignore, also depending on the alternate law protection loss which itself can be further divided in two categories, or even direct law which would mean direct side-stick to flight control input without any load protection - leading to control overload." Isn't automation wonderful?

A pitot-static system's pneumatic airspeed data (the usable output product) relies wholly upon very accurate dynamic pressure and static (i.e. ambient atmospheric) pressure inputs - and the latter changes rapidly during a descent at 10,000fpm. No digitized sourcing of that info, it's all air pressure analogue. Falsify either one (via blockage or leak) and zoom or descend and the story will be ever more confusing. Birgenair and Air Peru 757's found that to be the case. For example, with a snap-frozen static pressure (at FZLVL) the airspeed indication will wind back from 250 knots to zero over as little as 3400 feet of climb at 250kts IAS. I think that the BEA is still trying to wrap their minds around that obscure fact here (Gallic and not Gaelic closed minds). They are also (possibly) assuming that the zoom was a result of pilot input and not an aerodynamic pitch-up..... i.e. as a result of (possibly) hitting Mach Crit with an A/P disconnect and a very nose-down trimmed horizontal stabilizer (@3 degs nose-up but increasing to 13 degs nose-up due to pilot's aft sidestick inputs after top of zoom climb). But do I actually think they hit Mach Crit? No, more likely it was the excessive elevator force gradient that kicked out the autopilot and kick-started the fatal zoom sequence..

Someone also said: "Direct law is there to give the pilot more direct control of the aircraft but it still has some protection to offer - BUT at the same time the protection on offer is only as good and accurate as the information provided to the computers involved. Much more info is needed before one can create a valid picture of what went wrong when it comes to the decisions the pilots made in the last few minutes of the flight." However the change in static pressure resulting from the zoom into ever more rarified air and the instinctive attempt to maintain level flight and use backstick to reduce the ever higher displayed airspeed indicated during the ensuing descent (subsequent to the zoom climb) are key factors dictating an inevitable entry into the unrecognized deep-stall condition. Additive to this was the dearth of info that they had to work with and little prior exposure to degraded flight control laws. And all this in night and in cloud.....

Confirmatory (for me anyway):
Did the pilot zoom climb the acft or was it caused by the automated mis-trimming in pitch? Perhaps this next statement in the report is a clue: ]"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."[/COLOR] Perhaps the left and right roll inputs were his insufficient attempts to get the nose to drop (airline pilots rarely use more than 30 degs angle of bank due to the pax sensitivities - and in an Airbus? Perish both the thought and possibility....). When you've got a stuck elevator, or an aircraft pitching up of its own volition due to a runaway elevator pitch-trim, that's the way to go (i.e. roll the beast onto its wingtip to get the nose to drop - and drop flap). Pity they didn't think of that during the Jan 2003 Beech 1900 stuck elevator take-off accident at Charlotte NC.(52 degs nose-up at 1200feet agl).

So having read all the above, please feel free to shoot it all down. But ultimately, whether it's right or it's wrong, you have to ask yourself: "Is the training to combat automation anomalies and its inherent malfunction complexities adequate?" As someone else said: "In alternate law - is the amount of warning signals inhibited to the bare minimum necessary to keep the tube flying? i.e. you don't need a warning that the lights in the aft toilets aren't working - while busy with a stalling conundrum...?" Note how quickly the situation described above can become completely and incomprehensibly unglued. The debate yet to come is going to be ponderous and inherently evasive. The AF447 crew were caught out by a little known pneumatics phenomenon and reacting understandably to what they saw. They died clueless as to their actual predicament but I cannot bring myself to blame them. As they said: "We have no valid indications". They were right. Man can easily be defeated by automation. It's a burgeoning and futuristic problem. I can't shame them for being cheated of life by a system that's too conscious of cost and inconsiderate of consequence. The engineers and designers? Well they live in Never Never Land. If only the twain should meet....

On another subject, my post SR-111 invention in 1998 of satellite-uplinked recorder data is back in the limelight and I hope, with a vengeance. Wish it wasn't. But if you want to familiarize, just Google Iridian/Roadshow. Like all similar solutions to the long-winded AF447 saga, it's not as if somebody somewhere wasn't prescient. If we could just stop those holes in the Swiss cheese from aligning...... or more easily and quickly determine why they did.
____________________________________________________________ ___
Edited to add an afterthought:
a. I've heard two different qualified opinions as to whether the acft would have ended up in Alternate Law or ultimately transitioned to Direct Law. ???

b. "Just 20s after the captain returned to the cockpit, said the BEA, the thrust levers were set to the 'idle' position, with the engines delivering 55% of N1." i.e. Did the captain, upon entering the flight-deck, see the high (but fraudulent) IAS on descent and order the throttles to idle, understandably assuming a LOC existed and everything/anything BUT a stalled condition. You tend to take in and believe what you see on a first scan..... when the matter is urgent.

White Knight
27th May 2011, 20:53
Air France is a third world airline with 3 hull losses since 2000....


I fly 332/343/345 and if the ride looks bumpy ahead I pull out the QRH and get the required N1 settings. Simple!!!!!! Even better - fly away from the big red bits!!! And - as the skipper - I'll be on the flightdeck for the awkward parts, such as flying through the ITCZ or monsoonal weather!!!!

Never give the aeroplane to the co-jos when it's going to be rough! As skipper you are responsible for the safe operation of the aeroplane. You cannot do this from the bunk!!!!!!!!!!!!!!!!!!!!!

White Knight
27th May 2011, 20:59
A long but interesting input TheShadow!

However what ever happened to Pitch and power???

wheelie my boeing
27th May 2011, 21:09
Speevy, that was my point. 5 degrees and CLB power is certainly not the thing to do at 39,000 in a 320 for example, yet it is the airbus procedure. The procedure was not developed for a cruise scenario... Hence it recommends 5 degrees with CLB power. Totally wrong thing to do, and if you don't believe me go and try it in the sim and see how long you stay above VLS when at max cruising level.

SoaringTheSkies
27th May 2011, 21:17
I read the report.
I read most of this discussion.

I don't understand.

There were cases where the pilots confused overspeed buffeting with a stall (or the other way round) which led to stick shakers and pushers. Is there no pusher on the AB? (maybe because the protections in normal law should always prevent a stall?) Hard to believe.

I was expecting to see an increasing IAS as they climbed (static decreasing while pitot remains constant as it is iced shut). The report does not mention that, so there was no indication of overspeed.

Stall recovery is the most basic thing that everybody who flies an airplane gets taught. I can't believe that they had three pilots that were unable to recognize the situation and do anything about it.

Very strage.

wheelie my boeing
27th May 2011, 21:28
Soaringtheskies, go have a go in an Airbus sim (no stick pusher on Airbus), set it to nighttime with moderate/severe turbulence and then unreliable airspeed along with multiple ECAM messages - all at the same time. Given that you know what's coming you should be able to deal with it, however if you don't know it's coming then given those circumstances it certainly wouldn't be an easy job to deal with. People who say "fly the plane" are correct, but flying the plane won't necessarily be a concern if you don't realise there is an issue with it in the first place.

Edited to add: You can stall an Airbus, there have been several cases of people/mother nature doing it. Biggest problem with Airbus is it has lots of lovely protections (I.e. normal law) however whenever anything major goes wrong you lose them! Not a great thing to have happen and in many peoples opinions it is a serious design floor.

Phil Space
27th May 2011, 21:31
White Knight
Air France is a third world airline with 3 hull losses since 2000....
I fly 332/343/345 and if the ride looks bumpy ahead I pull out the QRH and get the required N1 settings. Simple!!!!!! Even better - fly away from the big red bits!!! And - as the skipper - I'll be on the flightdeck for the awkward parts, such as flying through the ITCZ or monsoonal weather!!!!
Never give the aeroplane to the co-jos when it's going to be rough! As skipper you are responsible for the safe operation of the aeroplane. You cannot do this from the bunk!!!!!!!!!!!!!!!!!!!!!

I am reassured there are still decent hard working responsible pilots like you White Knight. I was lucky enough to be trained by your kind 30 plus years ago and have flown all sorts of small aircraft and helicopters across the world and still live to tell the tale. I know when to turn back.

There are pilots and there are systems managers and we all know what happens when Windows crashes.

In the case of this accident the captain chose to fly a direct route through bad weather and retire for the night.

A bit like the Titanic:ok:

Gary Brown
27th May 2011, 21:32
Ashling:

The stall warning is based on AoA so even with unreliable airspeed it will activate correctly. So the stall warning was telling them their AoA was too high. That indication was correct even if their airspeed indications weren't. Its also why you always honour a stall warning with unreliable airspeed. But the Air Caraibes internal "Unreliable Airspeed" incident report (in somewhat similar circumstances to AF 447, though with significant differences, not least the end result) said [in French, mostly]:

"The PF was absolutely convinced that the two STALL alarms were inappropriate. He used his own judgement to discount the [checklist] phrase RESPECT STALL WARNING AND DISREGARD "RISK OF UNDUE STALL WARNING" STATUS MESSAGE IF DISPLAYED ON ECAM.

superdash
27th May 2011, 21:40
Shame White Knight wasn't on AF447 this thread wouldn't exist :ugh:

jcjeant
27th May 2011, 21:43
Hi,

All on the deck .. battle station (not between ppruner posters but between AF and Airbus) :eek:

Le Figaro - France : AF447 : les avis d'Air France, de ses pilotes et d'Airbus (http://www.lefigaro.fr/actualite-france/2011/05/27/01016-20110527ARTFIG00696-af447-les-avis-d-air-france-de-ses-pilotes-et-d-airbus.php)

I let for you the translation work if needed.

goldfish85
27th May 2011, 21:48
These weren't the first airline crews to go all the way to the ground with the stick back. I just gave two briefings on Loss-of-Control Accidents and it seems to be a common theme.

I've also been researching cascading failures and multiple apparently random annunciations. We may have a bigger problem than it appears at first glance.



Goldfish

jcjeant
27th May 2011, 21:53
Hi,

TheShadow

Interesting .. but I read

and the handling pilot now had an instant unalerted surprise handful of an aircraft in Direct Law with nearly full nose-up trim and near to full power

The aircraft (announced by one of the pilot) go in alternate law and it's big difference when compare with direct law.

Speevy
27th May 2011, 21:57
Hence it recommends 5 degrees with CLB power. Totally wrong thing to do

Sorry but I disagree, 5° CLB is the pitch and power data to get you away from troubles (if the safe conduct of the flight is impacted), then you set the pitch and power from the table off the cecklist...

If you are at 39000 and loose the airspeed indication all of sudden but still level, no change of airframe noise and altitude then you go for the table without setting 5° and CLB, therefore I cannot agree with you when you say that there is no airbus checklist for unreliable speed at cruise level, there is, and to me it's quite clear.

Fox3WheresMyBanana
27th May 2011, 22:03
Thank you, TheShadow, very informative. I guess I come from a generation when "having to manually hand-fly an aircraft" was the preferred option.
If there's to be any real progress, I guess we need to examine what training led to the 'human factors' error they made. From my humble flight safety background, it usually turns out to be human factors rather than pilot error.
Next time I fly the pond, I'm tempted to fly it myself in a puddlejumper(again).
p.s. there will only ever be one 'procedure' for everything; it's called "airmanship".

thcrozier
27th May 2011, 22:26
Sorry if this has already been brought up, but why would THS go from 3 to 13 degrees during the interval 2:10:51 (red ball 5) and the next entry 50 seconds later, and stay there for the next 4 minutes until the data stops?

The way I read it is that the AP had disconnected by this time, so was some other system automatially increasing THS in the 2:10:51 interval?

Manic Moran
27th May 2011, 22:27
But here's a clue. In the subsequent descent with static pressure increasing and the pitots still blocked?, even though the airplane was actually stalled (complete with stick-shaker) the indicated airspeed would be increasing alarmingly - courtesy of increasing static pressure. That's my guess - and it's anyways a physical fact, Been there and done that trick with frozen trapped water in the static lines (i.e. the opposite effect of trapped dynamic pitot pressure). There's also a report on the Irish Accident Board's site about a 747 on a test flight with uncapped static lines due maint error. It's an elucidating gaelic tale that shows just how confusing the pitot-static scenario can be. See below for how much a 1000feet of altitude change is worth in terms of additional "displayed knots". Ask any instrument technician. That's what I did. He'll demo it for you on his test-bench.

Well, as an example of how confusing it is, I happen to have my Jeppesen basic IFR book here, and it seems to say the opposite:

The second situation occurs when both the ram air inlet and drain hole become clogged, trapping the air pressure in the line. In level flight, the airspeed indicator typically remains at its present indication, but no longer indicates changes in airpseed. If the static port remains open, the indicator will react as an altimeter, showing an increase in airspeed when climbing, and a decrease in airspeed when descending. This is the opposite the normal way an airspeed indicator behaves, and can result in inappropriate control inputs because you will observe runaway airspeed as you climb, and extremely low airspeeds in a descent. This type of failure can be very hazardous because it is not at all obvious when it occurs

As an aside, what's wong with a good, old-fashioned idea of having a small red or yellow ribbon on a small stick which is bolted just outside cockpit window? Shine your flashlight out at it and it will give you a very fast indication of what direction the air is going past the airplane.

Ask21
27th May 2011, 22:34
So it seems this plane was into a deep stall with nose up 16 degrees. Angle of attack 40 degrees. Vertical speed 110 knots. Horisontal speed low(60knots) Seems to me that the only option to get the plane out of this condition would be to get the nose of the plane into the direction of movment. Even full trottle would not be able to make a horisontal speed high enough to give a flyable angle of attack. So the only option would be to get the nose down in a steep dive.

I suggest using the rudders hard to one side to completely stall one wing get the plane to flip over in a spin would acctually help to get the nose down fast and then get the correct angle of attack back. An other option to get the plane to flip over would perhaps to give a high trust on only one of the engines - to create the nessesary rotation to loose all lift in one wing and get the nose.

I suggest even taking trottle to idle would not harm at all (once the spin is there - at suficcient altitude of course) - It might simplify recovery not have to deal with those nose-lifting forces and to rapid increasing speed diving with the nose to the ground. Simply get the nose of the plane into the direction of movementwould exchange height for flying speed rapidly and solve the problem. .

Also - I would like to know if comercical pilots ever practise stall recovery in a real plane in real air. I have practiced stall/spinn from 3000 feet in a sail-plane several times - and suggest practice of this method in a sailplane could be valuable even to comercical pilots.

The initial stall-spinn does not involve high G-forces. The G-forces will be felt when at high flying speed with the nose to the ground will slowly lift the nose back to horisontal (and then add some trottle to keep a normaliced flight) In my sailplane typically 2-3 G.

I'm not talking about "what to do when you get the stall-shaker alarm" but - what to do when your allredy deep into a stall - but horisontal wings - and nose up.

I also realize that there may be some flaws to my argument here- Im not an expert in this area.

xcitation
27th May 2011, 22:37
If the pilots did believed "all indicators are down" then they could have used a bottle of water to get a rough idea of horizon. It would give an instant sanity check on the pitch and bank.
If you think you are -45 deg but you look at the water level shows +45 then you are likely to change from pull stick try to push stick. When you do so and the water level instantly responds gradually returning to level. The pilot then has a feel for the spacial orientation of the a/c in the absence of a visual horizon out of the window.
The jostling of the airframe would move the water around however I believe it would be enough to approximate in the absence of any other indicators.
It really sounds like they had no instrumentation or at least did not trust the stall warnings. Otherwise they would follow the stalled checklist.
GPS gives the ground speed and direction. Again not ideal but better than nothing. Clearly the pilots were way out of the normal trained situation and flight envelope.

A few comments refer to "seat of the pants" flying. This has itself caused incidents when pilots don't look at the instruments and instead rely on gut feel. The mind plays nasty tricks when you experience acceleration without visual reference points.

wheelie my boeing
27th May 2011, 22:40
Speevy,

If you get unreliable airspeed in the cruise suddenly with smooth flying conditions and everything normal then 5 degrees climb power may not kill you straight away. However, in a realistic scenario, with moderate turbulence, by the time you realise the aircraft has unreliable airspeed it's going to be possibly over 20 seconds from when it occurred. As a result your airspeed may already be far too high/low. By then pitching UP to 5 degrees (it will be a pitch up as you don't have 5 degrees pitch in the cruise normally) you are potentially worsening the situation. A slight overspeed is better than a low speed. Yet again, there is no procedure from Airbus for this situation. Your point of 5 degrees CLB was not designed for this scenario, let alone the fact that if your at your ceiling this is potentially disastrous.

JJFFC
27th May 2011, 22:51
Contrary to what is mainly reported, it seems that the pilot recognized a stall but changed his mind because the stall warning stops when in a stall :

"From 2 h 10 min 05, the autopilot then auto-thrust disengaged and the PF said "I have the controls". The airplane began to roll to the right and the PF made a left nose-up input. The stall warning sounded twice in a row. "

=> One can understand : the PF is the cause of the stall.

"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 "

=> The pilot recognized a stall.

"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."

=> The PF is responsible for a new stall

"the Captain re-entered the cockpit. During the following seconds, all of the recorded speeds became invalid and the stall warning stopped. "

=> when the captain re-entered, no information was available to him

"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."

=> the stall warning sounded when he pitch-down then his reaction is to come back to the last situation when the stall warning didn't sounded i.e. with the nose up.

It is just a human reaction and the captain had no clue to help him.

QUESTION : since the stall warning stops when you are in a stall ( speed < 60 kt) but sounds when you are recovering, what has to be changed ?

captplaystation
27th May 2011, 22:57
Hamrah post #530 , wiggy post # 569, think your two posts are a good summary of the unfortunate situation the crew were handed by their aircraft.

I am, quite unashamedly, anti Airbus FBW.

22 years on a 737 perhaps labels me somewhat Jurassic, but the same scenario (more or less) on my prof check 48hrs ago (my instructor was psychic? ) was difficult but eminently doable.
Not entirely sure if the wonders of Airbus (uncrashable! ! as I cringe yet again remembering Bernard "cablecar "Z emphasising on the Beebs coverage of Farnborough airshow all those years ago) actually help or diminish the human ability to alleviate sh1t happening, my personal opinion is very much the latter.

Edited to say The Shadow post #590, I think you deserve "post of the thread award" & I wish I had the influence/contacts to secure you a secondment to the BEA for a few months.
I sincerely hope they have, and are allowed to utilise, as much imagination/lateral thinking/insight, as you have shown.
Illuminating post :ok:

2nd edit jcjeant post #598, interesting link. If indeed BUSS was a good thing, yet again, like AF skimping costs by not installing GPWS and the resulting A320 crash in Strasbourg, the bean counters should be ahead of the pilots, when we attribute blame.

Oh BTW, only very slightly off topic, have all you (fellow ) Boeing drivers read the recent bulletin re ice crystals ? ?

Checkboard
27th May 2011, 23:18
Bottle of Water = Attitude Indicator
Bottle of Water = slip/skid ball. Water doesn't know where the horizon is any better than you do. :rolleyes:

xcitation
27th May 2011, 23:20
Perhaps a big red button in the flight deck that instantly uplinks a live data feed from the flight computers to boffin headquaters at airbus would help. The boffins can analyse and have a chief test pilot tell you in real time what the heck is going on and the optimal recovery procedure. Meanwhile you can concentrate on flying. Low cost as you only get billed when you activate the uplink

thermostat
27th May 2011, 23:32
My question is why did the crew fly through the storm in the first place. Other aircraft diverted up to 90 nm to go around the storm but not this crew. WHY ??
Was the radar working ? Did they leave Rio with inop radar? Did they simply ignore the radar?
It seems quite stupid to me to fly a passenger jet at hight altitude close to the coffin corner through a CB. What were they thinking? Had they diverted, they would be alive today.

Checkboard
27th May 2011, 23:35
There is absolutely NO evidence the crew flew through or near a storm.

fireflybob
27th May 2011, 23:48
The first step in solving a problem is the acquisition of the correct information.

From the reports so far it seems obvious that this crew were faced with a considerable amount of conflicting information and distractions.

It is all too easy to look at an accident and think how an earth did that crew allow themselves to get into that situation? They were doing the best they could with the resources that were available to them at the time.

Captain Fishy
27th May 2011, 23:52
I think TheShadow has interpreted the available facts and portrayed an extremely plausible sequence of events. That scenario is horribly plausible. That it was erudite and technically accurate certainly add validity. As a current 330-200 pilot I can envisage just such a sequence and can now perhaps understand the confusion and fear that must have reigned. Bravo!

thcrozier
27th May 2011, 23:53
In the subsequent descent with static pressure increasing and the pitots still blocked?, even though the airplane was actually stalled (complete with stick-shaker) the indicated airspeed would be increasing alarmingly - courtesy of increasing static pressure. --TheShadow Post 590
Wouldn't it be the opposite, trapped pitot pressure against decreasing static pressure showing IAS increasing as they climbed, and decreasing as they descended?

bubbers44
28th May 2011, 00:09
The captain left the cabin 10 minutes before the encounter so must have looked at the radar 100 miles ahead and been happy with it. Sounds like the turbulence wasn't a factor according to the report but the handling of the erronious airspeeds and autopilot and autothrottle disconnect were. I have never flown an airplane that you pull back on the controls with stall warnings but my Airbus friends say you can and the computer won't let you stall. I guess that depends on whether it is in normal, alternate or manual law. I think that is why I refused to fly the Airbus. My 4 airliners and 70 other types said if you stall lower the nose and add power. Not one said pull back. That was our spin entry when I was teaching aerobatics.

All the airlines I flew at had charts for unreliable airspeed showing power and attitude for your weight and altitude which would have taken care of this situation. We also had very qualified pilots in both seats so all had basic hand flying skills which were tested before being hired.

Now a lot of airliners are offering 18,000 per yr for a 250 hr pilot because the airplanes are automatic and don't require pilot skills, according to the manufacturer. See where we are going? I know these guys had some experience when the captain left but how much actual hands on time?

We were paid for our experience.

Ask21
28th May 2011, 00:37
That ribbon outside cocpit window would do the job better than any digital instrument to indicate direction of air compared to the plane.

Also:

What would be the difference, if any -aerodynamically - between a "deep stall" and a "flat spin". Correct me if I'm wrong; but wings and stabilizers are completely stalled. You have little if any elevator authority. Increasing throttle will push the nose up increasing the AoA further. No ailron authority. I guess the difference is in the rotation.

So: How to get out of it?

Milt
28th May 2011, 00:58
Xcitation

Bottle of Water!!!

Isn't it embarrassing when you realize how rediculous was your suggestion? Trouble is someone might just believe it.

bubbers44
28th May 2011, 01:04
Milt, it makes as much sense as anything else on this thread.

thcrozier
28th May 2011, 01:31
Ask21:

A flat spin is a spin where the AOA is almost 90 degrees, so you are headed virtually straight down but with very little pitch.

Recovery is as follows:

Have all of the pax crowd into the front. Then have them all return to their seats as you level off with airspeed, if they can do it under the G's. :8

A deep stall can occur in some in some designs, generally T-tailed aircraft, and unlike a flat spin, the aircraft is steeply nose down. In this condition the wings block airflow over the tail, so you have no pitch or yaw control.

They say the chances of recovering from a deep stall are greater than from a flat spin, but I've never flown an aircraft with deep stall characteristics, so I don't know the recovery procedure for that one. I imagine it varies by aircraft.

jcjeant
28th May 2011, 01:35
Hi,

Bottle of Water!!!Indeed .. high viscosity oil will made better .. but hey .. in emergency you take what at hand .....

You have all of the pax crowd into the front. Then have them all return to their seats as you recover, if they can do it under the G's. I was in the crowd time ago .. in a Super Puma ...
10 people rushed forward on the pilot order .... some seconds after take off (bad loading cargo at the rear (was a ****load visible rear the net !)
Moving cargo during flight and no more prob !
That was in Libya ........

BarbiesBoyfriend
28th May 2011, 01:45
White Knight.

Thanks for stating the bleeding obvious truth.

Keep saying it.

These 'button pushing' pilots are easily overwhelmed and if I do not watch it , I will soon join them in their fantasy button-pressing '**** all to fall back on' world.

The de-skilling of flying is NOT well intentioned!

The de-skilling of Flying is intended solely to cut costs, thus allowing airlines to make more money.

The PPL should advise pilots about basic stuff but many pilots, who have thousands of hours (doing sudoku & eating) can barely remember how to pilot an aircraft.

Time for a big-Time wake up call I think.

Perhaps not. Think of the cost!

jcjeant
28th May 2011, 01:49
Hi,

2nd edit jcjeant post #598, interesting link. If indeed BUSS was a good thing, yet again, like AF skimping costs by not installing GPWS and the resulting A320 crash in Strasbourg, the bean counters should be ahead of the pilots, when we attribute blame.
Yes .. bean counters ...
To notice that the "BUSS" from AF statement not work well over level 250
Well ... the AF447 had about two minutes before reaching sea water when passing level 250
Methink it was maybe enough time to apply useful corrections .. if AC had a BUSS
Results may varies ....

Mr Optimistic
28th May 2011, 01:59
As a mere SLF this is all very interesting but I don't understand why, if faced with an altimeter winding down, the instinct isnt to put the nose of the a/c into the windstream. If control authority isn't there well unwind the THS ( as per Schipol, not) and if that doesn't work put it to idle, and if that doesn't work deploy the gear. Did these guys not know they were fighting for their lives ?

Yipoyan
28th May 2011, 02:01
On the A330 FBW, with the IAS indicating excessively low speed, the pilot's correct action of pushing the nose down and pushing the thrust to max may, in my opinion, cause the auto trim to trim "backwards" causing a pitch up. In a normally indicating IAS, the pitch trim should trim forwards, but because of the false low speed indication, the forward application of the side stick will be interpreted by the FBW as a pitch forward and therefore countered with the pitch trim going backwards.

If I am not mistaken, a similar situation developed in a non-FBW A300 doing a botched-up go-around in Nagoya, Japan, many years ago. In that incident, the auto pilot interpreted the pitch forward command of the pilot through the control column as a situation that required the auto trim to trim backwards, causing the aircraft to stall, and eventually crash.

In FBW, with the auto pilot off, the pitch trim still acts on its own, as if the auto pilot is on (in a conventional aircraft). You must remember that there is no trim switch on the control column wheel on the A330 for the pilots to trim forwards or backwards as Normal and Alternate Laws do all the trimming for you. In fact, most FBW pilots will not notice the position of the pitch trim at any given moment, so it would not surprise me if the pilots on the ill fated AF447 had not noticed the extreme pitch up position the auto trim had placed the aircraft in... and so they would naturally react to the stall situation by pushing the side stick forward more, further aggravating the situation.

As I see it, with hindsight, the correct action to recover from the stall in this case would be to release the side stick, and manually roll the pitch trim forwards until it is out of the extreme pitch up position the aircraft was in.

BarbiesBoyfriend
28th May 2011, 02:13
What Pish some folk post!

To fly an aircraft in IMC, one merely has to fly a certain attitude and a certain power.

Given that (probably) these guys had good attitude info, that only left them to sort out the power and fly.

The fact that they could not do 'straight and level' tells badly both about the computerised Airbus and the pilots easy reliance on its systems.

In rotten wx, autos often go for a wee lie down. Who then shall fly the aircraft?

Surely, the pilots?

In other words: Yet another 'loss of control' accident.

We need to get away from the automated flight regime that we are in today.

The writing is on the wall for all who care to read it and 228 people and their relatives know it.

Pilots must be able to fly.

And to a better standard than the autopilot!

To be brutally honest, a great many of my co-pilot colleagues could NOT manage their flying day without the autopilot. They would be sorely taxed.

These same co-pilots are now being promoted, having accrued about 2000 hrs.

To be even more brutally honest, I'll soon join them in their inadaquacy unless I make more of an effort to fly. (I have 10,000 hrs on regional ops)

It wil cost a lot of money to retrain these 'button pushers' to fly again, but they did it before (briefly) on their IR!

How much did recovering AF447 cost?

just an edit to say, there but for the Grace of God.......:sad:

cairnshouse
28th May 2011, 02:25
I am definitely SLF.

The Captain re-entered the flightdeck in the middle of the developing situation. He had to gain situational awareness. He either gained it from the other pilots, in which case there would be a recording of what they thought was happening to the aircraft, or he gained it from his own senses i.e. whatever the instruments were then saying and what he could hear and feel.

It is fairly easy to assume the other pilots misinterpreting the information available to them and having formed an incorrect interpretation, continuing to apply the erroneous interpretion, disregarding evidence that conflicted with it. Unless the newcomer gained his understanding of the position by receiving an incorrect briefing, it is more difficult to accept that the Captain joined his fellow pilots' erroneous view of the situation without there being some pretty compelling, but ultimately wrong, data as to what the aircraft was doing.

Mr Optimistic
28th May 2011, 02:25
The bare facts will show that they had 4 minutes plus to save the plane. Surely that should have been enough.

BarbiesBoyfriend
28th May 2011, 02:42
Mr Optomistic

That would be loads of time if you knew how to pilot an aircraft.

To be fair, when did anyone last do stall/ spin training on an A330?

"You can't stall it!"

:rolleyes:

Mr Optimistic
28th May 2011, 02:50
You clearly know that I don't know. But how can you ride that thing down from 35k feet like that?

Yipoyan
28th May 2011, 03:07
When the aircraft reacts opposite to what you were trained to do, and did.

Artificial Horizon
28th May 2011, 03:26
As someone who has witnessed an A330 stall in the simulator I can assure you it is a 'pig' of an aircraft to recover if you get it fully developed. Also don't forget that you will only have the benefit of the BUSS if you have the presence of mind to switch off all the ADR's below FL250 in the middle of a very confusing situation and then it is as useless as a chocolate teapot if the aircraft is still in a stall. Sounds similar to the AIRNZ airbus in France, the aircraft should have been totally recoverable if the initial situation had been handled properly.

Photonic
28th May 2011, 04:10
SLF question here: Given the weather conditions at the time, is it possible they thought that they were caught in a violent sinking air column in the storm (ignoring the stall warning and paying more attention to erratic airspeed and the altimeter), and tried to power and climb their way out of it?

Of course something like that should be evident from the CVR, so I don't know what to think otherwise.

thcrozier
28th May 2011, 04:12
As I see it, with hindsight, the correct action to recover from the stall in this case would be to release the side stick, and manually roll the pitch trim forwards until it is out of the extreme pitch up position the aircraft was in. What if they had chosen Direct instead of Alternate Law?

wafelbolletjes
28th May 2011, 04:59
We've had so many theories since the crash about what may have happened... from lightening to new composite materials on the plane delaminating in flight to a storm so bad that it broke the airplane apart.

In fact, it crashed just because the pilots couldn't fly the plane in a way that anyone with a PPL would know how to do (when stall warning occurs nose down full throttle!).

So basically the mystery of AF447 crash is that... the pilots crashed an aircraft that was in perfect working order. Yes, it was in perfect working order, failed pitot tubes doesn't mean the plane was not in PERFECT working order.

The pilots incompetentness are to blame for the death of all those poor helpless passengers.

Garrison
28th May 2011, 05:04
I'm a light airplane guy and don't know much about this, so forgive me if this is nonsense, but it strikes me that the A330 displayed remarkably good post-stall behavior -- no departure, no spin. It seems to have plowed along in a steep glide at 250 ktas or so (100 knots vertical speed, 20-25 degree flight path) and continued to respond to roll commands. But the advice to fly attitude confuses me. If you put the airplane symbol on the horizon, the airplane itself would still be stalled; it would be necessary to point it 20 degrees or so below the horizon to unstall it. It appears as if the sheer complexity of the systems masked the simplicity of what was really going on.

Yipoyan
28th May 2011, 05:45
thcrozier, you cannot select Direct Law just like that on the A330. Alternate Laws 1 & 2, and Direct Law are reversion modes... which means that they come in only after a higher law cannot be maintained (usually because of flight control computer(s) failures).

Theoretically in Normal Law, the FBW A330 cannot stall, but as we all know now, did so on AF447. Whether the aircraft reverted to Alternate Law or not I do not know, but even if it did (to help recover from the stall), pushing the side stick forward could very well have caused the pitch trim to go backwards because of the false low speed sensed (outside of the flight envelope), thus causing aggravation to the stall situation.

thcrozier
28th May 2011, 06:19
Just so I understand correctly, then there is no way to take direct control of the aircraft unless the computer itself decides to let you, or perhaps more correctly stated, decides you should. Sounds like Skynet in "The Terminator".

MountainBear
28th May 2011, 06:19
it is more difficult to accept that the Captain joined his fellow pilots' erroneous view of the situation without there being some pretty compelling, but ultimately wrong, data as to what the aircraft was doing.

I don't agree. Hindsight is 20/20. The issue facing the captain when he came to the flight deck was simply who was in the best position to fly the plane. That's a judgement call, and a bit of a coin flip. To me, it says that he trusted in the professionalism of his fellow pilots. In hindsight, that judgement may have been wrong. But I won't second guess that decision.

It's like his decision to take his rest break when he did. In hindsight, maybe it wasn't the safest course of action. But he had no more of a crystal ball than anyone else on that flight.

I think there is a temptation to expect the captain to ride on his white steed from the bunk onto the flight deck, manfully throw the stupid PF out the door, and heroically wrestle the plane to safety. That would make for a thrilling movie plot but it doesn't reflect the way CRM actually works.

Yipoyan
28th May 2011, 06:32
thcrozier, it is not quite like that. Normal Law in a FBW Airbus is a very well thought out system, and allows the pilot to directly control the aircraft very well, maneuvering it almost like a fighter... but provided it is within the flight envelope. Attempts to go outside of the flight envelope (like over speed, under speed, over bank, over pitch) will not only be resisted, but will be corrected. So, if you are in an over speed situation, and you push the side stick forward, the aircraft will not only not pitch down further, but will actually pitch up to slow the aircraft down. The logic is simple... the flight computer would rather disobey you than let the aircraft become unflyable because its wings had broken off!

Reversion occurs only when there are faults found in the flight control computers, knocking them out (usually automatically through a voting system); and depending on the severity, reverting to either Alternate Laws 1 or 2, or to Direct Law. The best of non FBW aircraft is only equal to an Airbus in Alternate Law, with Direct Law being exactly the same as manual flying.

SoaringTheSkies
28th May 2011, 06:55
do we have a good explanation for the elevator trim setting?
would it have been obvious to the pilots (prominent / highlighted display?)

I'm still very confused about this.

From reading what is available, I believe that "Pilot error" will very likely be declared the accident cause. I'm not sure I'll necessarily agree, albeit "perfect pilot" would probably have saved the day.

Correct me if I'm wrong, but it seems to me that with greater automation comes an ever larger pile of sh*t that the automation systems place on the pilots hands if they decide to give up trying to be smarter than a human.

Automation systems basically handle pre-defined situations very well. Whatever scenario the engineers, flight test crews and probably even accident reports came up with goes into the system and becomes then part of what the system can handle. So far so good, but at the fringe of this, the resulting situations become increasingly complex to understand and manage.

There are a few things that need to be questioned:

Why is the stall warning silenced at indicated airspeeds below 60knots? Surely because whoever designed the system decided that, at an airspeed below 60knots, something is so terribly wrong that you would have noticed, possibly the airspeed being unreliable. However, as we all know, a stall has absolutely nothing to do with speed but is a function of AoA only. Why gate the warning with anything if you have consensus of the AoA sensors?

Is there no stall protection outside of normal (alternate 1/2?) law on an AB? Stick pushers have been around for many many decades, they are simple technology and rather effective. They need one input (AoA) and do one thing (make you pitch down). I know the AB have a much fancier system when the protections are effective, but do they really leave you entirely on your own when you drop out to alternate or direct?

[edit] and one more thing:

MountainBear

I think there is a temptation to expect the captain to ride on his white steed from the bunk onto the flight deck, manfully throw the stupid PF out the door, and heroically wrestle the plane to safety. That would make for a thrilling movie plot but it doesn't reflect the way CRM actually works.
:D

the public expectation is trained by Hollywood movies, so this seems to be EXACTLY what they would have expected to happen. After all, some German media STILL report that the PILOT was not on the flight deck!!!
Utter BS! And as we see, when the CPT came back to the flight deck, he was just as confused as his two FOs. That's why I got rather annoyed about those fellows who claimed that they'd be in their left seat in every critical phase of the flight. It's a judgement call and this crew decided that the phase ahead was not going to be critical. Little they knew, but that's a general fact about what we call "future".

Graybeard
28th May 2011, 06:59
The A330 Autopilot can't handle varying erroneous airspeed from 3 sources, so it disconnects and hands the task to the pilot. That shows a lack of forethought.

Juneau, the capitol, is reached from the rest of Alaska only by sea or by air, so a lot of gold has been spent perfecting low IFR approaches. The GPS approach and go around are hairy enough on a good day, but if the mountains block the signal on go around, the A/P reverts to IRU guidance to give a precious 30 seconds flywheel effect. That is true for the 737 A/P as well as the HUD.

Why is there no flywheel in the A330 A/P to provide reversion and stability, and continue flying when sensors fail?

Capn Bloggs
28th May 2011, 07:08
The best of non FBW aircraft is only equal to an Airbus in Alternate Law, with Direct Law being exactly the same as manual flying.
... with a stick shaker and pusher (which probably would have saved 447's day). :hmm:

wafelbolletjes
28th May 2011, 07:10
I have over 3000 hours as PIC on the md11 (at fsairlines) and i can say with confidence i have more flying ability than the pilots who yanked back at the sidestick all the way down to the ocean.

gatbusdriver
28th May 2011, 07:12
The people I feel truly sorry for in this tragic situation are the poor moderators. When you read some of the rubbish that is posted here it makes you wonder what they actually remove.

At this tragic time spare a thought for your mods.

My favourite to date......"Nigel get the standby horizon out"
"......errrrr......sorry sir I've drunk mine"
"....bugger....finished mine too. Don't worry I'll get my torch out and look at red and yellow ribbon fluttering outside the window"

Bienville
28th May 2011, 07:14
Says Graybeard: The A330 Autopilot can't handle varying erroneous airspeed from 3 sources, so it disconnects and hands the task to the pilot. That shows a lack of forethought.Tell me... if the computer knows it is getting "varying erroneous airspeed from 3 sources" and does not know which one to believe, what should the computer do... keep flying the plane itself basing its judgments on known bad data or hand the job to a human?

Did ya even think that comment through before you made it?

jcjeant
28th May 2011, 07:32
Hi,

Tell me... if the computer knows it is getting "varying erroneous airspeed from 3 sources" and does not know which one to believe, what should the computer do... keep flying the plane itself basing it's judgments on known bad data or hand the job to a human?

Did ya even think that comment through before you made it? Methink .. if I understand the idea of the poster....
The autopilot can't rely on bad datas of course ... but it's possible to have another law for the autopilot in this case:
Immediately .. when bad data detected .. autopilot keep speed and altitude attitude (freeze settings) and warn the pilot for check what is wrong .....
The plane continue to fly with same settings as before all go bad ....
It's almost what AF ask in their procedure ......
Actually .. seem's that the autopilot is used as a alarm (by disconnecting) for warn something is wrong ......

captplaystation
28th May 2011, 07:38
Yipoyan post#626, to that accident you can add 2 VERY near misses with the A310 involving Tarom at Orly & Interflug somewhere in the former E Germany ?

If you look them up in Aviation Safety Net you will be gobsmacked that they got away with it.

I too am gobsmacked, that in this day and age Airbus have managed to design another generation of machine that doesn't do what you could reasonably& logically expect.
Just as illogical as the trim system on the earlier generation, I cannot fathom any logic in a system that will trim back if YOU are pushing forward to unstall the aircraft.

As THY & Thomson proved in 737's, a dispute between the stab & the elevator will always be won by the big guy in an underwing engine configured jet transport.
I am also gobsmacked, given the history of previous pitot problems & indeed the need to design & fit uprated ones, why the crew were not taught & made comfortable with this scenario during their recurrent (if not initial ) training.
Surely this should have loomed LARGE in the recurrent sim syllabus as soon as the possibility was identified some time before.
Anyone familiar with Airbus ops in AF care to tell us if they were made sufficiently aware, & or trained , to cope with this scenario ?

bubbers44
28th May 2011, 07:38
For anybody else that couldn't download the report yesterday.

Accident to the Airbus A330-203
flight AF 447 on 1st June 2009
Update on Investigation
Bienvenue sur le site du Bureau d'Enqutes et d'Analyses (http://www.bea.aero)
27 May 2011
SPECIAL FOREWORD TO ENGLISH NOTE
This note has been translated and published by the BEA to make its reading easier for Englishspeaking
people. As accurate as the translation may be, the original text in French should be
considered as the work of reference.
History of Flight
On Sunday 31 May 2009, the Airbus A330-203 registered F-GZCP operated by Air France was
programmed to perform scheduled flight AF447 between Rio de Janeiro Galeão and Paris
Charles de Gaulle. Twelve crew members (3 flight crew, 9 cabin crew) and 216 passengers
were on board. Departure was planned for 22 h 00(1).
At around 22 h 10, the crew was cleared to start the engines and to leave the parking space.
Take-off took place at 22 h 29. The Captain was PNF, one of the co-pilots was PF.
The take-off weight was 232.8 t (for a MTOW of 233t), including 70.4 t of fuel.
At 1 h 35 min 15 , the crew informed the ATLANTICO controller that they had passed the
INTOL point then announced the following estimated times: SALPU at 1 h 48 then ORARO at
2 h 00. They also transmitted the SELCAL code and a test was undertaken successfully.
At 1 h 35 min 46, the controller asked the crew to maintain FL350 and to give their estimated
time at TASIL.
At 1 h 55, the Captain woke the second co-pilot and said "[…] he’s going to take my place".
Between 1 h 59 min 32 and 2 h 01 min 46 , the Captain attended the briefing between the
two co-pilots, during which the PF said, in particular "the little bit of turbulence that you just saw
[…] we should find the same ahead […] we’re in the cloud layer unfortunately we can’t climb much
for the moment because the temperature is falling more slowly than forecast" and that "the logon
with Dakar failed". The Captain left the cockpit.
The airplane approached the ORARO point. It was flying at flight level 350 and at Mach 0.82
and the pitch attitude was about 2.5 degrees. The weight and balance of the airplane were
around 205 tonnes and 29% respectively. Autopilot 2 and auto-thrust were engaged.
At 2 h 06 min 04, the PF called the cabin crew, telling them that "in two minutes we should enter
an area where it’ll move about a bit more than at the moment, you should watch out" and he
added "I’ll call you back as soon as we’re out of it".
(1)All times
are UTC.
At 2 h 08 min 07 , the PNF said "you can maybe go a little to the left […]". The airplane began a
slight turn to the left, the change in relation to the initial route being about 12 degrees. The level
of turbulence increased slightly and the crew decided to reduce the speed to about Mach 0.8.
From 2 h 10 min 05 , the autopilot then auto-thrust disengaged and the PF said "I have the
controls". The airplane began to roll to the right and the PF made a left nose-up input. The stall
warning sounded twice in a row. The recorded parameters show a sharp fall from about 275 kt
to 60 kt in the speed displayed on the left primary flight display (PFD), then a few moments
later in the speed displayed on the integrated standby instrument system (ISIS).
Note 1: Only the speeds displayed on the left PFD and the ISIS are recorded on the FDR; the speed
displayed on the right side is not recorded.
Note 2: Autopilot and auto-thrust remained disengaged for the rest of the flight.
At 2 h 10 min 16, the PNF said "so, we’ve lost the speeds" then "alternate law […]".
Note 1: The angle of attack is the angle between the airflow and longitudinal axis of the airplane.
This information is not presented to pilots.
Note 2 : In alternate or direct law, the angle-of-attack protections are no longer available but a
stall warning is triggered when the greatest of the valid angle-of-attack values exceeds a certain
threshold.
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). The airplane was then at an altitude of about 37,500 ft and the
recorded angle of attack was around 4 degrees.
From 2 h 10 min 50, the PNF tried several times to call the Captain back.
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. The recorded angle of attack, of
around 6 degrees at the triggering of the stall warning, continued to increase. The trimmable
horizontal stabilizer (THS) passed from 3 to 13 degrees nose-up in about 1 minute and
remained in the latter position until the end of the flight.
Around fifteen seconds later, the speed displayed on the ISIS increased sharply towards 185 kt;
it was then consistent with the other recorded speed. The PF continued to make nose-up
inputs. The airplane’s altitude reached its maximum of about 38,000 ft, its pitch attitude and
angle of attack being 16 degrees.
Note: The inconsistency between the speeds displayed on the left side and on the ISIS lasted a little less
than one minute.
At around 2 h 11 min 40 , the Captain re-entered the cockpit. During the following seconds,
all of the recorded speeds became invalid and the stall warning stopped.
Note: When the measured speeds are below 60 kt, the measured angle of attack values are considered
invalid and are not taken into account by the systems. When they are below 30 kt, the speed values
themselves are considered invalid.
The altitude was then about 35,000 ft, the angle of attack exceeded 40 degrees and the vertical
speed was about -10,000 ft/min. The airplane’s pitch attitude did not exceed 15 degrees
and the engines’ N1’s were close to 100%. The airplane was subject to roll oscillations that
sometimes reached 40 degrees. The PF made an input on the sidestick to the left and nose-up
stops, which lasted about 30 seconds.
At 2 h 12 min 02, the PF said "I don’t have any more indications", and the PNF said "we have
no valid indications". At that moment, the thrust levers were in the IDLE detent and the
engines’ N1’s were at 55%. 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.
At 2 h 13 min 32, the PF said "we’re going to arrive at level one hundred". About fifteen seconds
later, simultaneous inputs by both pilots on the sidesticks were recorded and the PF said "go
ahead you have the controls".
The angle of attack, when it was valid, always remained above 35 degrees.
The recordings stopped at 2 h 14 min 28. The last recorded values were a vertical speed of
-10,912 ft/min, a ground speed of 107 kt, pitch attitude of 16.2 degrees nose-up, roll angle of
5.3 degrees left and a magnetic heading of 270 degrees.
New findings
At this stage of the investigation, as an addition to the BEA interim reports of 2 July and 17
December 2009, the following new facts have been established:
ˆˆ The composition of the crew was in accordance with the operator’s procedures.
ˆˆ At the time of the event, the weight and balance of the airplane were within the operational
limits.
ˆˆ At the time of the event, the two co-pilots were seated in the cockpit and the Captain was
resting. The latter returned to the cockpit about 1 min 30 after the disengagement of the
autopilot.
ˆˆ There was an inconsistency between the speeds displayed on the left side and the integrated
standby instrument system (ISIS). This lasted for less than one minute.
ˆˆ After the autopilot disengagement:
„„the airplane climbed to 38,000 ft,
„„the stall warning was triggered and the airplane stalled,
„„the inputs made by the PF were mainly nose-up,
„„the descent lasted 3 min 30, during which the airplane remained stalled. The angle of
attack increased and remained above 35 degrees,
„„the engines were operating and always responded to crew commands.
ˆˆ The last recorded values were a pitch attitude of 16.2 degrees nose-up, a roll angle of
5.3 degrees left and a vertical speed of -10,912 ft/min.

xcitation
28th May 2011, 07:45
Try the water bottle next time you are up to see.
clearly any acceleration will impart a distortion from the g vector. however at constant velocity the water surface will remain parallel with the surface of the earth.
obviously the water bottle is not a substitute for the avionics. but it does make a quick and dirty sanity check for which way up you are.
do you have any better suggestions?
thats why 3 orthogonal gyros are used to overcome any acceleration from movement.
if you want a more advanced solution you could have multiple gps receivers at extremities of the plane to compare timing pulses on the gps signal to figure out attitude to a v high precision.

jcjeant
28th May 2011, 07:54
Hi,

Water bottle ... (2min05)
YouTube - &#x202a;Stopped engine aerobatics&#x202c;&rlm;

opherben
28th May 2011, 07:55
a. Based on BEA factual report, that wasn't the case with AF447.
b. In such case, a few system design options to consider for autothrottle logic:
1. Use FMGC last known flight phase (climb, cruise, descent) as autothrottle reference to maintain optimal AOA, or
2. Set engine thrust used before the onset of airspeed indication error, or
3. Set CONT thrust.

The accident, onset by airspeed erratic readings (which lasted for one minute) and autoflight disconnect, the problem was lack of stall recovery by the pilot, for which he had 3:30 minutes and a mostly functional aircraft. A pilot descending 10,000 FPM with 107 KT indicated, should not expect a pitot system to generate correct dynamic pressure readings. He should get the aircraft under proper control firsdt, and only then carry out non-normal checklists.


As military flight academy commander, to me this case clearly shows the lack of proper selection (for personality and psycho-motoric skills) and training of pilots (complete flight envelope mastering in aerobatic trainers including deep stalls and spins, for better understanding of flight mechanics and human impact. Not necessarily to be used, but rather avoided. In case they are encountered, a pilot at any level should recognize and counteract out-of-controlled flight. It could also help him understand as captain, why full repeated pedal deflections in A300 might shear the vertical tail, what entering an aircraft wake feels like and how to avoid it. All is basic flying stuff). AF447 is just one of many such cases, including B737-800 in automatic ILS approach, throttles in idle, stalling before touchdown in Schipol, or a captain woken-up around FAF to watch his A320 demolish. Everything I wrote in this paragraph is 100% applicable to transports, even if many never thought about it.

Bienville
28th May 2011, 07:58
jcjeant say: Methink .. if I understand the idea of the poster....
The autopilot can't rely on bad datas of course ... but it's possible to have another law for the autopilot in this case:
Immediately .. when bad data detected .. autopilot keep speed and altitude attitude (freeze settings) and warn the pilot for check what is wrong .....OK so... rather than hand the plane back to the pilot, you want the computer to keep flying the plane but to not even try to respond to inputs, just freeze itself at the last setting.

I'm REAL glad you don't design autopilots for a living.

As I asked the last guy... Did you even think that comment through before you made it?

Capn Bloggs
28th May 2011, 08:01
however at constant velocity the water surface will remain parallel with the surface of the earth.
No it won't. In a steady-state turn, for example, it'll be parallel with the wings, just like the iphone "AH"... Are you seriously suggesting that these guys, in the dark of night with all hell breaking loose, should have pulled a waterbottle out of their bag and held it up to see whihc way was up?

do you have any better suggestions?

Yes, an aeroplane that presents attitude, angle of attack and has controls that do what the pilot wants and tells him what he needs to know eg if AoA indicates a stall, keep the stall warning going, not stop when the speed drops off the clock.

jcjeant
28th May 2011, 08:04
Hi,

OK so... rather than hand the plane back to the pilot, you want the computer to keep flying the plane but to not even try to respond to inputs, just freeze itself at the last setting.

I'm REAL glad you don't design autopilots for a living.

As I asked the last guy... Did you even think that comment through before you made it? The pilot can disengage the autopilot when he want ... at least he is warned of something wrong instead a brutal disconnection.

kwat
28th May 2011, 08:07
When I read the Accident Update (27th May) two things jump out at me.

At around 2 h 11 min 40, the Captain re-entered the cockpit. During the following seconds, all of the recorded speeds became invalid and the stall warning stopped.

At 2 h 12 min 02, the PF said "I don’t have any more indications", and the PNF said "we have no valid indications". At that moment, the thrust levers were in the IDLE detent and the engines’ N1’s were at 55%. 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.

So the system is such that entering extremely high angle of attack invalidates the speeds, which in turn silences the stall warnings. Conversely, reducing the angle of attack causes the stall warning to reactivate. The crew are in a situation where they are getting the exact wrong feedback. Couple this with possible mind-sets about turbulence, overspeed and structural damage – just my thoughts.

captainflame
28th May 2011, 08:15
The BUSS is only displayed once ALL ADRs are switched off iaw QRH.

Milt
28th May 2011, 08:23
jcjeant

Bottle of water

That should do it for Xcitation. NOW he will be embarrassed - perhaps?

Checkboard
28th May 2011, 08:26
I too am gobsmacked, that in this day and age Airbus have managed to design another generation of machine that doesn't do what you could reasonably& logically expect.
That's not how the system works. Yipoyan is confusing an autopilot trimming against a pilot induced control input with the normal FBW response. If the crew here had pushed on the stick with sufficient authority, at any speed, the trim would move nose down to match that response.

cwatters
28th May 2011, 08:47
At 2 h 12 min 02, the PF said "I don’t have any more indications", and the PNF said "we have no valid indications"....snip... In
the following moments, the angle of attack decreased, the speeds became valid again and the stall warning sounded again."

So PF doesn't think anything is working and lowering the nose appeared to trigger a stall warning. How many people in that situation would continue to trust the stall warning system was working?

Bienville
28th May 2011, 08:52
>So PF doesn't think anything is working and lowering the nose appeared to trigger a stall warning. How many people in that situation would continue to trust the stall warning system was working?

The question was asked in a private forum I am on and every pilot there (about 2-3 dozen) said they would have pushed the nose down. At 38,000 feet it is an absolute no-brainer.

Tourist
28th May 2011, 08:58
I find the crash details very worrying in terms of pilot skills, however, I find the chatter on here absolutely terrifying! My god please tell me that most of you don't fly commercially?

nitpicker330
28th May 2011, 09:05
Power PLUS attitude = Performance

On my A330-300, set 2.5 nose up and 78% N1 for S + L flight at most weights.

You should also know what sound levels to expect in the cockpit from the Airspeed in cruise.

If you think that you might indeed be too slow then set CLB detent and lower the nose to 0, wait till the noise level returns to near normal then set it back to 2.5 and 78%.

All the while checking the GPS groudspeed from the FM to use as a gross error check whilst flying the Aircraft as smoothly as possible until I exit the area and hopefully all returns to normal.

Anytime I approach an area of suspect wx I cannot avoid I try to do 4 things:
1/ sit the cabin crew down, 2/ check the current GS and listen to the noise
levels, 3/ note the current attitude and N1 to achieve current speed and finally 4/ brief the FO on all of the above just incase all hell breaks loose.:{

I've done this for the last 10 years or so. Why did I consciously do this? Because our Airline has had it's share of Iced up Pitot static systems causing overspeed and stall warnings On the 744, 777 and A330 types where the crew did what I suggest above ( ie: fly the damn plane on Attitude and N1 ) to a successful outcome.


At the end of the day

Power + Attitude = Performance.

bubbers44
28th May 2011, 09:08
jcjeant, thanks for the Bob Hoover video. I see him and Chuck Yeager every year at the Reno Air Races. He would come out to Riverside to a small airport to see Art Scholl a lot in the 60's. I was instructing aerobatics back then for Art. What a gentleman and great pilot. He is 89 now so we are lucky to still have him. I saw his last Shrike show about 10 years ago at Reno.

Also takes care of the water container being parallel to the earth idea.

Zorin_75
28th May 2011, 09:11
At 2 h 10 min 51 , the stall warning was triggered again. The thrust levers were positioned in the TO/GA detent
So it would appear PF registered the stall warning, believed it and chose to apply TOGA. So far, so good...
and the PF maintained nose-up inputs. To me this is really the WTF? moment...
The recorded angle of attack, of around 6 degrees at the triggering of the stall warning, continued to increase. The trimmable horizontal stabilizer (THS) passed from 3 to 13 degrees nose-up in about 1 minute and remained in the latter position until the end of the flight. Around fifteen seconds later, the speed displayed on the ISIS increased sharply towards 185 kt; it was then consistent with the other recorded speed. The PF continued to make nose-up inputs.
So clearly he wasn't fighting the computer, but to the contrary, the computer was merely reacting to the sidestick commands as expected.
So the puzzling part is why did he keep pulling up? Is it possible he was relying on the stall protection to sort things out? Not realizing he was in alternate law?

Can one of the bus drivers perhaps chime in with the procedure for unreliable IAS? Whatever it is, I'm pretty sure it wasn't followed here?

Rananim
28th May 2011, 09:18
All this crm and where has it got us?The Captain is pilot in command and it is his/her ship from pushback to on chocks.No-one else's.All this politically-correct chat about planned rest being done according to Ops or which pilot has a baby at home or did you get undisturbed rest etc.I know what 411 would say and I am here to say it for him.The Captain looks at the planned route and forecast weather and ensures that he/she is in the LHS when weather/terrain(cabin depressure) or whatever risk he thinks might be encountered along the route is present.TIRED OR NOT.He/she decides this nobody else!And any Captain who lets this decision be made for him/her is a fool,an emasculated fool.

The flight should have diverted around the weather to begin with!!A good Captain would never have flirted with ITCZ weather like this.25-50nm lateral separation minimum with or w/o clearance.

The failure to carry out the stall recovery is a mystery and as others have said the only excuse can be distraction from multiple warnings,lack of training and year-in year-out automation reliance.

I look at the safety statistics and two airlines stick out;SWA and Qantas.They are beacons in this rapidly deteriorating profession.Airmanship is all that you need to stay alive up there,nothing else matters.

Could someone please explain clearly when "stall" warning is inhibited in these wonderful Airbus aircraft again?Dependent on law or speed?An aircraft that is stalling should never have the stall warning inhibited.

nitpicker330
28th May 2011, 09:20
From the A330 QRH

Unreliable Airspeed check ADR Procedure above FL 250:-

1/ A/P F/D off
2/ A/THR off
3/ PITCH/THRUST 5 deg/CLB
4/ Speedbrakes. Check retracted
5/ Level off for troubleshooting. Ie set about 2.5 nose up and 78% N1 or if you have time check the sev turb attitude and N1 from the QRH.

lomapaseo
28th May 2011, 09:26
Many comments using words like "shocked", "stunned", "surprised"

Still to be explained in the investigation is "why", because we must not be so simple as to blame the pilots on so early a release of selected data.

Some questions come to mind

Could the data be duplicated without a pilot input ?

if not, is there a possible combination of inputs (instruments or otherwise) that may fool the pilot's natural response to a stick shaker?

bubbers44
28th May 2011, 09:30
Now that procedure makes a lot more sense than let's pull the nose up until this thing stalls and see what happens.

jcjeant
28th May 2011, 09:40
Hi,

An aircraft that is stalling should never have the stall warning inhibited.

This is irrefutable and that really is the black dot in the automation system.
It can mean the difference between death and life.

IcePack
28th May 2011, 10:07
Mmm! no valid indications. Wonder what that means did they loose their attitude displays? (yes I know that is virtually impossible)

JJFFC
28th May 2011, 10:08
1/ Why this stall warning did stop ?
2/ Reading the confusion here : Is there anylonger a real pilot in the air ?
3/ Could the PF have decided to suicide ?

Zorin_75
28th May 2011, 10:09
Thanks, nitpicker.

I still can't (rather don't want to) believe that a professional crew would run an otherwise perfectly fine aircraft into the ground after a temporary failure of one instrument. Guess we'll have to wait for further updates from BEA to get a clearer picture.

FAStoat
28th May 2011, 10:17
In the Mid 90s I had a very small chance to fly the Last Big Banger,a Pilots Handling Airliner ,the DC10.A much respected colleague and Ex RAF Truckie,who had flown them at Laker and Arrow,so enthused about this marvellous Pilot's Aeroplane,I applied to Caledonian while they still had them.After the Interview, I had to fly a Sim Test in an Airbus 320 Sim,which I passed after being given pointers and a brief "go" first.I was told by the Instructor that that was probably the best showing I would ever make apart from maybe the first Base/IR sim check after joining!! as I was current on a Jet that you could hand fly ,so had plenty of such practice !When told I would not be eligible because of my age to do a DC10 course,as they were to be phased out shortly for the Airbus 330,and that I would have to fly a 320(I think they only had 2),and then go onto a 330,I backed off and explained my brain could not handle the size of a 330 with only 2 engines and only computers controlling it with Alternate and Direct law as protection.I needed a big Red lever that said "I have Control".I seem to remember in the QRH emergency section "After this no further problems deemed feasible",and then blank spaces!! Could be wrong,but that features in the memory banks.I am glad I have retired.

JJFFC
28th May 2011, 10:19
We have to wait for the next BEA report.

If the BEA has published such a report where the PF looks like a dumb, it probably means that the BEA has more infos about the PF fault.

I don't believe that the BEA, with all the international authorities having participated to the work, wouldn't have pointed out a real technical problem.

The Pitot tubes were incoherent for less than one minute.

Since there are still planes in the sky, it is impossible to loose a plane for this only little problem.

Stu B
28th May 2011, 10:32
Anyone who has looked at an unrestrained vane-type AoA sensor on a parked aircraft on a windy day will have seen the vane wandering all over the place. On take-off, as speed increases, eventually the forward component of airspeed is enough to straighten out the vane, so by 60 kts it IS reading (something related to) incidence. At some speed below 60 kts its reading means nothing. We don't want spurious stall warnings during the t/o run (or even on roll-out) so the system ignores the AoA below 60kt. All very logical until we hit this scenario. Perhaps the "ignore AoA under 60kt" rule should only apply when WoW switch is on?

It seems agreed that the flight controls were sustaining a nose-up attitude and no one has (yet !) suggested that this was not related to a back-stick command. So either (a) the crew were fixated on the "overspeed" scenario and maintained their "pull-up" input, ignoring the (intermittent) stall warnings (and pitch attitude?), believing they were trying to recover from a dive, OR under pressure they "overlooked" that the degraded control mode/ sensor input problems no longer gave a safety protection that full back stick will not be allowed to stall the aircraft?

cairnshouse
28th May 2011, 11:00
I don't agree. Hindsight is 20/20. The issue facing the captain when he came to the flight deck was simply who was in the best position to fly the plane. That's a judgement call, and a bit of a coin flip. To me, it says that he trusted in the professionalism of his fellow pilots. In hindsight, that judgement may have been wrong. But I won't second guess that decision.

It's like his decision to take his rest break when he did. In hindsight, maybe it wasn't the safest course of action. But he had no more of a crystal ball than anyone else on that flight.

I think there is a temptation to expect the captain to ride on his white steed from the bunk onto the flight deck, manfully throw the stupid PF out the door, and heroically wrestle the plane to safety. That would make for a thrilling movie plot but it doesn't reflect the way CRM actually works.



This is not about the Captain taking control. It is inconceivable that the Captain did not seek to form a view of what was going on. The question then becomes why, given that he was not present for whatever cues led the other pilots originally to misinterpret the situation, he nevertheless joined in that misinterpretation.

Usually when a non-participant acquiesces in, whilst not sharing, an erroneous view, the non-participant is junior to the actor(s). That is not the case here. Assuming the Captain wasn't erroneously briefed by one of his colleagues, then the natural conclusion is that the Captain independently came to the same conclusion as the other pilots or, at the very least considered that no alternative explanation was sufficiently likely so as to distract other pilots by raising it.

It seems to me the likeliest explanation is that the aircraft was still giving some powerful cues consistent with the erroneous interpretation. They must have been powerful cues because three men did not interpret a stall warning as meaning that the aircraft was about to enter a stall.

Zorin_75
28th May 2011, 11:21
So either (a) the crew were fixated on the "overspeed" scenario and maintained their "pull-up" input, ignoring the (intermittent) stall warnings (and pitch attitude?),
Would you set TOGA if you believed to be in an overspeed scenario?


believing they were trying to recover from a dive,
Assuming they still had correct pitch information (and there's no indication whatsoever that they hadn't) it's hard to understand how they might have come to that conclusion.

This leaves

OR under pressure they "overlooked" that the degraded control mode/ sensor input problems no longer gave a safety protection that full back stick will not be allowed to stall the aircraft
which doesn't sound that good either :uhoh:

Exnomad
28th May 2011, 11:27
As one whose very limited pilot hours were a long time ago, might I ask if any simulator time is spent on flying difficult manoeuvres on basic flying instruments, Gyro driven horizon, attitude indicator etc (presumably basic turn and bank is no longer there.
The ability to realise what was happening seems to have been a factor.

nitpicker330
28th May 2011, 11:41
Yes, this is not a new occurrence for Airbus or Boeing.

I've done the unreliable airspeed training in the sim from 10,000' down to landing. There are a few things you need to think about ( obviously !! ) but it's manageable without any Airspeed indicators. Granted it was in a Sim, reasonably good wx and with no risk of dying ( my heart rate was relatively normal in the sim !!) but we did have a lot of bells and whistles going off for a while which proved a headache for the PM. My job wasn't overly difficult, fly the power and attitudes for the config etc.....

Every Pilot in my Airline did this as part of their 6 monthly recurrent training package.

SMOC
28th May 2011, 11:44
Stu B, The 747 uses the nose wheel squat switch, the stick shaker goes off when the A/C is jacked if the CBs aren't correctly pulled prior to jacking.

RansS9
28th May 2011, 11:53
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. The recorded angle of attack, of around 6 degrees at the triggering of the stall warning, continued to increase. The trimmable horizontal stabilizer (THS) passed from 3 to 13 degrees nose-up in about 1 minute and remained in the latter position until the end of the flight."


Is it normal for the stall warning to be triggered at 6 degrees ? To the uneducated this appears quite low. Wouldn't the stall AOA in clean config be around 13-15 degrees?

If the aircraft was still in Alternate Law as indicated by PNF is there anyway the automatics could trigger an uncommanded (by the pilots) THS nose-up change of 10 degrees?

Can anything be read into the rate of increase in nose up ? To the uneducated it appears relatively slow / deliberate ?

Trim Stab
28th May 2011, 12:01
It seems to me the likeliest explanation is that the aircraft was still giving some powerful cues consistent with the erroneous interpretation. They must have been powerful cues because three men did not interpret a stall warning as meaning that the aircraft was about to enter a stall.

Agreed 100%.

I suspect the scenario will become clearer once we know what pitch information the pilots were seeing.

Also, note that the speed information displayed to RH pilot is not recorded. The PF was in the RHS. The PF may therefore have been reacting to speed information different to that recorded.

Count Niemantznarr
28th May 2011, 12:02
I think it is interesting to revisit the situation the Captain William Hagan on the BA 744 (LGW-NBO) in December 2000, who came onto the flight deck to find an intruder attacking his F/O and the very dangerous stall that the aircraft was in. Another four or five seconds he said, and the aircraft would have been on its back! Again it was at night with no horizon and credit must be given again to that F/O who saved the aircraft without overstressing it. I would say that was a worse predicament for the BA 747-436 than the AF A-330.

Incidentally I flew that 744 to PHX soon after the event with our new CEO, Rod Eddington, on board. My F/O was shocked to find there was still blood spattered on some of the instruments! Eddington told me that he had 'phoned the President of Boeing to congratulate them on building such a strong airplane.

Gentlemen, it is all down to airmanship. Reading the reports in the Press of Air France congratulating the heroic efforts and professionalism of the flight crew on AF 447, makes me think if you are going to tell a lie, you might as well tell a whopper.

In a similar situation on a 747-236, my instinct was not to raise the nose and put the aircraft even closer to coffin corner. The AF pilot(s) allowed the situation to deteriorate where the aircraft had almost no forward speed or momentum. How do you recover from that?

The fact that Air Caraibe pilots demonstrated the appropriate airmanship in two similar scenarios, shows that basic flying skills are lacking at AF. How can you otherwise explain landing an A-340 half way down the runway in a thunderstorm at YYZ and expecting to stop, the heavy landing at CCS, the taxying incident at JFK and even the loss of the Concorde may have been a different result, if BA procedures had been followed as well as maintenance. Maintenance of course, regarding the pitot tubes (changed by Air Caraibe following their upsets) is again a factor in an AF crash.

Air France needs to go through a flight safety audit similar to Korean Airlines, who since that have not suffered a hull loss.

737-NG
28th May 2011, 12:05
C.N. you sure got that right!

Caygill
28th May 2011, 12:09
Power PLUS attitude = Performance

On my A330-300, set 2.5 nose up and 78% N1 for S + L flight at most weights.

You should also know what sound levels to expect in the cockpit from the Airspeed in cruise.

If you think that you might indeed be too slow then set CLB detent and lower the nose to 0, wait till the noise level returns to near normal then set it back to 2.5 and 78%.

All the while checking the GPS groudspeed from the FM to use as a gross error check whilst flying the Aircraft as smoothly as possible until I exit the area and hopefully all returns to normal.

Anytime I approach an area of suspect wx I cannot avoid I try to do 4 things:
1/ sit the cabin crew down, 2/ check the current GS and listen to the noise
levels, 3/ note the current attitude and N1 to achieve current speed and finally 4/ brief the FO on all of the above just incase all hell breaks loose.http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/boohoo.gif

I've done this for the last 10 years or so. Why did I consciously do this? Because our Airline has had it's share of Iced up Pitot static systems causing overspeed and stall warnings On the 744, 777 and A330 types where the crew did what I suggest above ( ie: fly the damn plane on Attitude and N1 ) to a successful outcome.


That sounds like the missing procedure, and hopefully one that will be thought hereafter!

nitpicker330
28th May 2011, 12:10
As I said above this scenario is not new unfortunately. There are now quite a few documented cases around the world with Boeing and Airbus operators. Enough incidents that Boeing and Airbus have for some time now included checklists in their QRH's and also recommended all crew be exposed to it in the Sim during their recurrent training cycles.

Thread drift.........This maybe more proof that employing low time inexperienced crews is just plain dumb, Airline managers trying to save money please take note.:=

There is no substitute for experience, full stop end of story:ok:

nojwod
28th May 2011, 12:11
As expected reading the last few pages, the usual crowd of perfect pilots comes on to disparage those pilots who were imperfect, the only difference between the perfect pilots and the rest are that the perfect pilots strut around here like a bunch of cockerels, the imperfect pilots are out there facing the real world scenarios...

Anyway that aside, to me what was said and the actions of the PF, with no real dissent from either of the other two imperfect pilots who were there, indicate that something either in the instrumentation or the plane's response to inputs was diametrically opposed to what the crew expected to see or experience. Unless you perfect pilots believe that all three highly trained pilots on the flight deck on that dark night were so grossly incompetent that they could not follow basic airmanship as a matter of course, then there must be some factor(s) that the data recorders have not been able to provide and which may never be known.

As for the dogmatic statements by some perfect pilots above that the crew shouldn't have flown into the storm or flew a perfectly serviceable aircraft into the sea, your comments are beneath contempt, not only for their insensitivity but also for their gross simplification of a situation that you in reality know absolutely nothing about.

fboizard
28th May 2011, 12:12
Could someone explain to me why there was no distress call in 3 minutes ?

Schnowzer
28th May 2011, 12:13
An interesting read, forget technology and stall recovery techniques, I believe beyond the system failure the cause to this accident runs deeper. Whenever we go into a degraded mode the assumption made is that the pilots have the skill recency to deal with the problem. My view is that modern EFIS systems have led to pilots forgeting to scan their instruments. Their focus is on the MCP/FCU and the FMAs not the attitude or performance instruments. Even on the approach rather than looking at the speed many pilots just trust the autothrust to maintain it.

Retaining basic instrument skills is easy even with a low tech PC flight simulator but few people do it unless they are going for an interview. Until this issue is addressed, events such as this will continue albeit infrequently.

Power + Attitude does equal performance but first you have to look at the instruments.:(

FatalFlaw
28th May 2011, 12:19
The key question here is - 'did the pilots have enough information to realise they were stalled, pitched up, throttles closed, and recover'?

I am surprised that in all this discussion (including that of the thoughtful Shadow) putting forward idea that the pilots didn't know what the AoA is, nobody has mentioned the backup AI (about 6 inches to the right of the captains MFD)? Was it really not noticed by 3 experienced pilots that the there was a huge difference between PFD and backup AI, which would have indicated a big pitch up, and yes (as mentioned by another poster) - no noise in the flight deck? Isn't this why the backup instruments are there? Or am I missing something (only a humble PPL/IR)?

Obviously there's a fundamental difference between AoA and attitude (ie the vertical speed of the air) but I am trying to think of a conceivable Wx scenario that would deliver up to 40 degrees pitch up on the AI with closed throttles for an extended period, and not indicate a stall.

nitpicker330 - yes! Power+Attitude=Performance. They had power - they had a backup AI. They also had, I presume, an 'alternate air' feed (like my Mooney!) which would have got the altimeters working again, at least the backup ... There was a lack of training and/or airmanship here, probably a huge dollop of denial (surely EVERYTHING can't have gone wrong!), though it looks as if Airbus need to seriously look at some kind of mechanism to warn the pilots if the computer lacks confidence in it's view of the world (due to inconsistent inputs) and advise the pilots to check the backup instruments.

We have all been trained and examined in the effects of icing in the instrumentation. It seems amazing that 3 experienced pilots wouldn't have guessed something was up, especially IR onwards.

All in all, I am concerned that it can't be as portayed as those 3 guys should have figured out what was happening.

Centaurus
28th May 2011, 12:21
Retaining basic instrument skills is easy even with a low tech PC flight simulator but few people do it unless they are going for an interview. Until this issue is addressed, events such as this will continue albeit infrequently.


Never a truer word...

VeniVidiVici
28th May 2011, 12:28
Whenever flying as multiple/augmented crew, my company schedules 2 captains & 1 F/O (this was gotten forcefully accepted by our pilots' association and the captains). So at all times you have 1 capt on the flight deck and somestimes 2 capts whilst the F/O is on a break. In the relaxed cockpit crew scheduling regime at AF and possibly other reputable carriers as well they put 2 F/Os in a 3 member set. Considering enroute WX forecasts and/or actual WX returns the Capt on AF 447 should have retained his seat and reclined it for rest. I can't understand how any responsible capt would prefer his allotted rest over safety of operation especially if that rest meant being away from the flight deck. Sheer negligence I'd say. AF and other companies that allow crew rest periods need to urgently review their scheduling policy and advise their crew to exercise sound judgement and discretion for rest periods considering segments of bad enroute WX. I always thought that one takes adequate rest prior to assuming duty and layover time is best spent and meant to arrive fresh for duty. I hope and am sure that the final report will adequately address the question of this capt, his rest break, and absence from the cockpit.

nitpicker330
28th May 2011, 12:28
Yes but it's not only the Pilots that need to do this.
The onus should also be on the operators to 1/ recruit the appropriately experienced crews and 2/ ensure they retain their Piloting skills through targeted appropriate training packages throughout their career insisting they maintain basic instrument skills and know how to fly raw data ( this is not encouraged at all, indeed it is frowned apron now days )

wafelbolletjes
28th May 2011, 12:30
I have a question:

the news media has described the 3 minute drop into the ocean as having been 'horrifying' for the passengers. However, if indeed the pilots didn't even realize that the plane was stalled and was descending so quickly, could it be that the passengers were completely unaware of anything being wrong during their final minutes?

You can only feel a fall during the initial acceleration. And surely if the pilots could feel that 10 000fpm decent then they would know they must be stalling and stop the nose up attitude inputs.

jcjeant
28th May 2011, 12:36
Hi,

Could someone explain to me why there was no distress call in 3 minutes ?

I think they were so busy that if you would ask them their names they would not have been able to respond

nitpicker330
28th May 2011, 12:37
Fatal flaw...... It's my understanding the ALL the Attitude indicators where fully functioning all of the time throughout. It was only Airspeed that gave incorrect indications via iced up Pitot tubes screwing the 3 ADM's.

FatalFlaw
28th May 2011, 12:47
nitpicker330 - I guess you must be right otherwise the flight data recorder wouldn't have recorded it ... so they spent 3 minutes pitched up with the throttles closed and the altimeter plunging waiting for the speed to come back down ... what did they think was happening? :uhoh:

nitpicker330
28th May 2011, 12:58
In all the documented incidents so far there has never been an issue with the Inertial Attitude displayed on the primary flight displays or on the separate standby. A simple cross check of all 3 would confirm the same.
Airspeed issues and associated overspeed or underspeed ( or indeed both ) warnings were what happened requiring the crew to look "through" their displays and revert to "basic flying skills"

Oh, and no modern western built transport has an AOA indicator fitted.

Who knows what this crew were thinking, who knows how fatigued they were on the night? Who knows how much Turbulence they were dealing with?

All things being equal they "should" have been able to deal with the situation, obviously all things weren't equal.:(

forget
28th May 2011, 13:18
nojwod ....... indicate that something either in the instrumentation or the plane's response to inputs was diametrically opposed to what the crew expected to see or experience.

Is there any explanation/reason for the two momentary roll inputs by the PF?
Could these indicate a deliberate check by the PF as in, 'Am I really connected to the control surfaces?'

andrew_wallis
28th May 2011, 13:18
my comments as a PPL/IMC holder:

If I know that Power plus attitude=performance, so did all 3 pilots there that night. They had power (the engines were working normally) they had attitude info (attitude indicator, not derived from pitots) so obtaining a performance seems the logical way to go. The time the descent took rules out the startle factor, and as is well known, once the descent stabilises at 1g, the seat of the pants feel is useless at best and misleading at worst, yet they still should have had the AI. Again, even as a PPL I know to trust my instruments and ignore the seat of pants sensations. So, why didn't they??
I can see a couple of possibilities- 1. they didn't trust the AI as they were aware of the pitot problems and decided to go with the seat of pants sensations or 2. the stall they found themselves in was irrecoverable due to some design problem or issue inherent in the jets design. No comment whatsoever on AB vs boeing, but don't swept wing jets has a nasty characteristic of entering a flat stall which is hard/very hard to break?
Given the possibility of option 2, and if I were AF or AB I would be looking to promote option (1) since option (2) has the unpalatable effect of admitting that some stalls are invariably fatal, not something which passengers want to hear. So much cleaner to blame it on human error, psychologically, its easier on passengers to believe that the pilots made a mistake, rather than face the possibility that a particular set of circumstances will result in an invariably fatal outcome. What do the stable extroverts amongst us think?

Spooky 2
28th May 2011, 13:22
Nitpicker330, (post 700) sorry but I have to call you on that statement. Many Boeing 777's and 737NG's have AOA indicators displayed in the upper right corner of the PFD. Delta Air Lines and American Airlines started this trend back around 2001. It is a Boeing option, you just have to tick the box when you order the airplane and they will deliver the AOA. I believe it's standard on the 787.

nitpicker330
28th May 2011, 13:32
Fair enough I stand corrected :ok:

The info is in the system so it obviously isn't too hard to program onto the display. Maybe it will become a mandatory update for all soon?

JJFFC
28th May 2011, 13:42
"From 2 h 10 min 05, the autopilot then auto-thrust disengaged and the PF said "I have the controls". The airplane began to roll to the right and the PF made a left nose-up input. The stall "

At this time, it seems that there were no Pitot problem ?

Why did the autopilot then auto-thrust disengaged ?

Zorin_75
28th May 2011, 13:55
At this time, it seems that there were no Pitot problem ?

Why did the autopilot then auto-thrust disengaged ?
Yes, there was. That's exactly why it disengaged.

Yo767
28th May 2011, 13:55
A couple years ago, I had to fly between two mounstrous squall lines (30nm appart) on a B767300ER. I was descending thru FL250 in dusty air (no water content) for an approach into Lahore, Pakistan, when the stick shaker was triggered continuously for about 1 minute with severe turbulence. I was on FLCH, thrust idle and the airplane was climbing at 500fpm for the whole minute. The AI was showing about -5 to 0 degree. Until today, I assume I encountered the mother of all updraft and for that reason, a high angle of attack information was sensed and triggered the stall warning system.

I was then transferred to the Airbus fleet and prayed everyday I wouldn't encountered the same scenario aboard the A320 I was flying because I had no clue how it would behave in such a situation. I am sure it would be way more confusing than how it happened in the 76 due to the relative complexity of the flight envelope protection system.

This is not an Airbus bashing post but a personal experience that may help understand what happened in AF447.

If it ain't Boeing I'll be going but not by choice...

md80forum
28th May 2011, 13:59
Is any OAT information available? I am recalling the Pulkovo 612 accident, that beside a daredevil decision by the Captain to overclimb CB also was hit by a monstrous updraft sending the plane into a 16,000 fpm zoom to FL420, where it stalled.

"Pulkovo 612 departed Anapa (AAQ) for St. Petersburg (LED). The Tupolev climbed to the cruise altitude of 35,100 feet (10.700 m). Because of storm cells ahead, the pilot decided to change course laterally by 20 km and attempted to climb over the storm cells. However, the thunderstorm front was unusually high, extending up to 15 km (49,000 feet). The Tu-154 entered an area of severe turbulence, pushing up the airplane from 11.961 m to 12.794 m within just 10 seconds. The angle of attack increased to 46 degrees and the airspeed dropped to zero."

Very little is being said in this thread about highly unusual and unexpected WX phenomena that may have caused the rapid freezing of the pitots and the initial upset. Could sudden changes in OAT those minutes into the flight give a hint?

Pardon me for entering ID badge area with my RTF and ICAO 5 English rating.

engine-eer
28th May 2011, 14:06
I too am gobsmacked, that in this day and age Airbus have managed to design another generation of machine that doesn't do what you could reasonably& logically expect.
That's not how the system works. Yipoyan is confusing an autopilot trimming against a pilot induced control input with the normal FBW response. If the crew here had pushed on the stick with sufficient authority, at any speed, the trim would move nose down to match that response.
This is not correct. When the system is in alternate law the auto trim function is disabled. Pushing the stick forward only results in limited elevator motion. Trim must be addressed by the pilot in this mode, so simply pushing the nose down isn’t going to retrim, the pilot has to do it manually.

This still doesn’t address why the trim was moved to the 13 degree nose up position.

JJFFC
28th May 2011, 14:09
I have not read in the BEA report that the Pitot had trouble before the first stall alarm ?

nitpicker330
28th May 2011, 14:12
The QRH spells the situation quite clearly:---

Unreliable speed indic/ADR check proc:-

Maybe due to Radome damage, air probe failure or obstruction
Indicated Alt may be effected if static probes effected
Unreliable airspeed cannot be detected by the ADIRU

Since Flight control laws maybe effected maneuver with care
Unreliable speed may be suspected by-
--- Speed discrepancies between ADR 1, 2, 3 and standby
---Fluctuating or unexpected increase/decrease/steady indicated speed or pressure altitude
---ABNORMAL CORRELATION OF THE BASIC FLIGHT PARAMETERS
---Abnormal AP/FD/ATHR behavior
---Stall warnings, or overspeed warning or flap relief warnings that contradicts with at least one of the indicated speeds
-RELY ON THE STALL WARNING THAT COULD BE TRIGGERED IN ALTERNATE OR DIRECT LAW. IT IS NOT EFFECTED BY UNRELIABLE AIRSPEEDS BECAUSE IT IS BASED ON AOA
-DEPENDING ON THE FAILURE, THE OVERSPEED WARNING MAY BE FALSE OR JUSTIFIED. BUFFET ASSOCIATED WITH THE OVERSPEED VFE WARNING IS A SYMPTOM OF A REAL OVERSPEED CONDITION.
---Inconsistencies between radio altitude and pressure altitude
---Reduction in aerodynamic noise with increasing airspeed or increase in aerodynamic noise with decreasing speed

*my capitals to emphasize some sections*

HKPAX
28th May 2011, 14:19
From the Grauniad. Surely there would be multiple pitots. Could there be a software problem in "voting" in event of discrepancies??

A pilot's analysis

You look at this as an A330 pilot and it's a case of there but for the grace of God. The first sign of trouble was the expectation of turbulence voiced by the first officer. He reduced the speed in anticipation to Mach 0.82, which is normal, and warned the crew. Shortly after entering the turbulence and associated ice, the autopilot disengaged and the first officer commented that the flight control computers had disconnected. This happened because the computers were no longer receiving speed information and neither were the pilots.

I cannot speculate why the pilot climbed the aircraft but it could have been due to confusion caused by the turbulence and sudden instrument failure. The controls at very high altitude are very sensitive and there is only a very small speed envelope, often called "coffin corner", where only a few knots of speed up or down can cause a stall.

So you are flying in this little window of a flight envelope which is perfectly normal and, indeed, you do it every day. But if you are suddenly handed control of an aircraft you can breathe on that little stick and the aircraft can go down one degree. In a very short space of time lost speed and stalled, causing it to fall from the sky. Despite what the pilots must have been going through in the cockpit, the pitch attitude remained fairly constant throughout so the passengers would not have sensed something was seriously wrong. They would have felt mild buffeting of the stalled airflow over the wings and the initial sinking feeling. That's all.

I feel a lot of empathy for the pilots. One could imagine suddenly suffering a total loss of airspeed indication in turbulence in the middle of the night and with all the autopilot systems suddenly failing. The indications, both visual and aural, would have been very confusing. The question for me is why did the instruments that are triple redundant, which means that there are three back-ups, all fail together?

Anonymous A330 pilot

JJFFC
28th May 2011, 14:24
Every mother or wife of a pilot should say every day to her son/husband :

"repeat after me one hundred times : when I hear a stall warning I nose down..."

There is absolutely no reason why the PF :

"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. The recorded angle of attack, of around 6 degrees at the triggering of the stall warning, continued to increase. "

This is unbelevable exept if you want to suicide.

jcjeant
28th May 2011, 14:25
Hi,

The dinosaurs must think I'm sure the good old days when you had to put the feet on the dashboard for manoeuver elevators to get out of a dive
In the case of FBW aircraft (Airbus particulary) .. may have the same maneuver with two fingers without any effort.
It certainly does not help to understand what is the force exerted on the moving parts

nitpicker330
28th May 2011, 14:27
HKPAX:-- Please read my post above. Or better still read the actual QRH you have.
All or 2 of the Pitot probes iced up ( basically failed ) and "confused the system" Overspeed/Under speed warnings resulted, Alt Law, AP A/THR dropped out ......etc etc....

It would have all cleared up after they exited the cloud........

Airbus and Boeing have addressed this issue of super cooled water drops and directed that improved pitot probes be fitted.

cairnshouse
28th May 2011, 14:41
Would anyone like to comment on this:-

At 2 h 13 min 32, the PF said "we’re going to arrive at level one hundred". About fifteen seconds
later, simultaneous inputs by both pilots on the sidesticks were recorded and the PF said "go
ahead you have the controls".

The aircraft is telling the pilots (probably correctly) that they are at 10,000ft. The quoted text implies that the pilots believe this. What mechanism (stall/dive/something else) do they believe has got them from FL350 before any problem arose to FD100 (I know they ended up at one point at FL380 but we don't know that they knew that)?

What manoeuvre are the pilots trying to make on the sidesticks and is there any reason why both of them would be making simultaneous inputs other than that they do not trust one or both of the controls to react to the input?

Anaroy
28th May 2011, 14:43
Gentlemen & Ladies of course,
Having watched the story since the beginning, I think it is time a few salient points should be pointed out. I think I am qualified to comment having spend 5000 hours as P1 on 330's although I am now retired. I would therefore be happy to accept any corrections.
As I recall from the original ACARS transcripts, all pitot statics were iced up.
The effect of this disconnects the A/P and A/T without pilot input. The airspeed on both PFD's and STBY ASI would be useless and in total conflict to each other. 2 warnings follow, STALL STALL STALL(verbal) followed by immediately by the OVERSPEED warning (I think it is the "Cavalry Charge" bell).
Any sidestick input at this point would be extremely fraught (remember the autopilot is now off).
So, which one do you believe. It seems like the crew were trying to recover from an overspeed event and ended up stalling (throttles closed, pitched up).

The early analysis of the wx showed the flt to be transiting the ITCZ. I spent more hours transiting the Asian one to know that it is not to be taken lightly.
The question then begs-
was the crew aware of the weather approaching;
was the weather radar operating; was it being operated correctly- was the gain on/off, was the tilt down. The radar only shows water droplets not ice, so if it is level or up, nothing shows up at the temperatures one would be experiencing. As I always said to my trainees-: "you have to look at the bottom(of the CB) to understand what the tops might be like".
Given that I have not seen a full report I wont make further comment accept to say especially in the A320/330/340/380 family if in doubt of the warnings, physically sit on your hands until the conflict in your mind is resolved then maybe touch the sidestick.

Two's in
28th May 2011, 14:43
Whereas it's a great theory for the press and Airbus that 3 experienced aircrew all forgot the basics of how to fly an aircraft simultaneously, it is of course horse manure. This is just another example of Cognitive Dissonance

When two simultaneously held cognitions are inconsistent, this will produce a state of cognitive dissonance. Because the experience of dissonance is unpleasant, the person will strive to reduce it by changing their beliefs. Sewell (2006)

When the aircraft started departing from the indicated pitch and speed, the crew were forced to use their experience do determine what was really happening. When some things didn't fit that model, the model was likely changed to accommodate that. Everybody mistrusts a computer, but air instruments are supposed to remain reliable. When an air data computer is driven from air instruments and then to the AP, the symptoms of failure now become complex and less intuitive.

Pitch and thrust control will generally keep you alive, but at night, in a storm, with a cacophony of alerts and warnings going off and the AP trying to fix a problem that didn't exist, somehow the standby AI and thrust settings were not recognized as being the only control references that could be safely relied upon.

Any one of these crew could have probably executed a flawless stall recovery if they had recognized what was happening, but at the given flight level it appears the aircraft rapidly got away from them. So once again the history of aviation safety has an example of a relatively benign event - in this case the failure of the pitot heaters - conspiring with other circumstances to build a scenario that proved fatal for everyone involved.

The fact that the pitot failure was a known condition simply adds to the sorry tale of tombstone engineering practices conducted by the OEMs.

fgrieu
28th May 2011, 15:00
The BAA report says: "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. The recorded angle of attack, of around 6 degrees at the triggering of the stall warning, continued to increase. The Trimmable Horizontal Stabilizer (THS) went from 3 to 13 degrees nose-up in about 1 minute and remained in the latter position until the end of the flight."

Excuse my ignorance, but what is spposed to have this effect on the THS? Explicit setting by the pilot only, or is it somewhat under the control of FWB logic? Does Alternate Law change that?

Also: was that THS setting enough to make stall recovery near impossible?

matthewsjl
28th May 2011, 15:02
Just a quick question from an interested bugsmasher pilot (no real experience of high altitude flight dynamics) :)

We know that pitch + power = performance.... and lots of talk here about how that could potentially been the answer here. However, if the aircraft has reached a stalled condition at altitude, is some action required to break the stall ie: nose down, power/idle etc. before going to the known power/pitch? If you have unreliable airspeed, how would you know that you're not stalled any longer and could engage the known power/pitch?

Just my own commentary - if Airbus want the aircraft to be fully protected by the computers, they need to make sure that it's very difficult to reach that non-protected state. It certainly seems that having three pitots of the same type and basic design with similar failure modes looks like a single failure mode that can lead to that non-protected FBW state.

Bienville
28th May 2011, 15:17
JJFCC Why did the autopilot then auto-thrust disengaged ?Probably (and it is sorta unclear from the wording of the report) the turbulence caused the AP to drop out.

If the AP can not hold the plane level it gives up and hands the plane to a (presumably more qualified) human. From the brief wording of the report, it sounds like that's why the AP dropped out... Then the PF did some rather odd things.

clearedtocross
28th May 2011, 15:20
From various posts I get the impression that the difference between missing indications and wrong indications is not always fully recognized.

Flying partial panel is easy if some instruments are just shielded off. It's a different story if they show conflicting information (e.g. a toppled horizon). It gets really difficult when not only airspeed shows impossible values, but other airpressure derived readings like altitude and climb/descent rate go to their stops (which they might do if static ports are clogged). Combine this with the sudden transition of a quiet lazy night flight into a nightmare of flashing alarms and horns, tripping autopilot, autothrottle, runaway trim system, law changes and a thick black night in IMC and the old man not available. The crew did not have the option of pressing the "pause" button and sort out quietly which readings make sense and which do not and consider what the hell had hit them. A stream of computer messages just added to the confusion.
It would probably have been much easier to fly this "no pitot" aircraft with a dark panel, using the standby horizon only and the throttles. But alas the displays must have shown a nightmare of utterly confusing and jumping readings, flashing symbols and a cacophony of warnings and alarms. Too much for the poor crew. Manageable maybe for some well trained and fully alert crew but certainly not manageable for most of the pilot bashers contributing to this forum.

Basil
28th May 2011, 15:25
Two's in,
I'd agree with your Cognitive Dissonance theory; that sudden, disorientating WTF!?
The only thing I can add is that I hope everyone has, over the past couple of years, covered recovery from unusual positions and thrust/attitude flying in their sim refreshers.
I feel lucky to have trained in the mil where cost was less of an imperative and we were given a little jet to throw around - useful confidence building for those, like moi, who are not exactly God's gift to aviation.

UNCTUOUS
28th May 2011, 15:30
Engine-eer said: "When the system is in alternate law the auto-trim function is disabled. Pushing the stick forward only results in limited elevator motion. Trim must be addressed by the pilot in this mode, so simply pushing the nose down isn’t going to retrim, the pilot has to do it manually.

This still doesn’t address why the trim was moved to the 13 degree nose up position."
I'm a little uncertain about this horizontal stabilizer position of 13 degs nose-up (from an initial 3 degrees prior to A/P and A/T disconnect). Is it a trim-wheel setting or does it refer to the horizontal stabilizer being 13 degrees up at the leading edge (i.e. a nose-down couple setting). If it's the latter then perhaps the pilot was fighting the post A/P disconnect out-of-trim involuntary pitch-up by manually winding in some nose-down trim..... as he sought to oppose that pitch-up.

However if the Shadow's version of events leading to the zoom climb are correct, when the aircraft topped out circa FL380, it was sporting high power and entered its stall quite ballistically, whilst out of trim. I've a hunch that a stall entered thusly at a very high altitude is itself a very different kettle of fish ...... to the common garden variety level flight approach to a stall (the classic 1kt/sec deceleration). Try throwing (i.e. propelling) a paper airplane off a cliff and then compare its trajectory with one dropped in a level flight attitude. I know that propulsion isn't in that equation but you get the idea, right? What I'm leading up to is that it's not a flight-tested regime for airliners and it may well be embedded and unrecoverable at 40 degs AoA. You might have to try configuration changes or engine asymmetry to become aerodynamic again.

I could liken it to a fall into an inverted attitude from a hammerhead tail-slide stall with fwd stick (one of my favourite low-level aero routines). You needed to throw out the ventral airbrake to get a good rate of re-pitch to the downward vertical for recovery (looks very different with/without that airbrake inject - you can tell from the smoke). Without the airbrake, on a video you can see that invtd stall attitude remaining constant for the descent. That was a theory behind Skippy O'Dwyer's death whilst doing that same stunt.

Some dynamic and ballistic entries to stalls/spins can have surprising results. Anybody who's flown inspin aileron on a JP-5A spin entry will know to what I refer.

The BEA's contribution on 27 May was just a data-dump. It's too early to conclude anything about how those AF447 pilots coped with that sudden pitot-initiated maelstrom. But it is becoming apparent that weather and storms had little to do with the scenario. You can pick up ice crystals during a protracted cruise in smooth CirroStratus. That there was some weather around was not unusual for the ITCZ.

Checkboard
28th May 2011, 15:34
This is not correct. When the system is in alternate law the auto trim function is disabled. Pushing the stick forward only results in limited elevator motion. Trim must be addressed by the pilot in this mode, so simply pushing the nose down isn’t going to retrim, the pilot has to do it manually.
Yes, while in alternate law (and with the AA over 40º, abnormal attitude law) auto-trim is disabled. However my comment was in regard to the scenario Yipoyan referred to with the Chinese A300 Go-Around. In this instance, had a nose down input recovered the stall, and thus normal law returned, the auto-trim would have moved nose down.

Jig Peter
28th May 2011, 15:47
Why mention the Standby AH? From the swathes of pages about this very distressing accident, I don't see any reference to the MAIN Attitude Indicator on the PFD(s) being U/S ...
ATTITUDE, surely, was the clue they missed - but why? The aircraft seems to have been in trim and flying normally, but perhaps with a bit of turbulence ... I won't go on, but this over-insistence on the Airspeed indications makes me feel that contributors to this (and "the other") forum are making a similar error.

As a long-retired military pilot, I once flew what were then known as "medium range twin-jets" for some years in the ITCZ and had the odd encounter at night with an unsuspected cumulo-bumbulo, so I feel a great deal of sympathy for the two pilots at the controls of 447 that night. My point is really that the thread(s) aren't dealing with the main issue. Aeroplanes aren't like cars, with "just" a speedometer on the dashboard, and you "drive" them differently.

yaw_damper
28th May 2011, 15:50
I will begin with the A310-325 approaching CDG years ago.
Capturing G/P from above the plane overspeeded the flaps placard, obviously, THE SMART COMPUTER decided it is a go-around so throttles up, and nose-up trim!
The dummy in the L/H site pressed the yoke, and pressed the yoke and...
---> THE SMART COMPUTER trimmed further nose up, and trimmed...
So the little thing goes strait up like the smoke, one engine flamed out, the other was near enough and... at speed ZERO...
Yes, you got it, tail-way back to the Mother Earth...
It's said somebody gave a rudder input, like in an ''acrobatic pendulum'', the plane turned sideways the engines regained power by themselves...
The ground looked terrifically close and the front guys... Were, maybe wetting their underwear.
All that from 4000ft. to... God Almighty and back to 1800ft. when, in control, the bird lingered to the RWY.


I know nothing about A330, was only in the rear, from MRS-ORY many times in the '94, '95. Impressed by the wing mechanization, I know guys who said to me that A330 has 5 ways for each computer, for each thing aboard and it's the best of her class!
But the side-stick, and the computer all-knowingly...
Well I hardly understand how close they are to a play-station... and there are some presumed innocent living people in the rear, aren't they!?!

YES!!! the ''AVIGATE-NAVIGATE-COMMUNICATE'' ignored-rule is likely what took them out of sky ''God Bless Them All'',
But they had only 200 seconds from sky-high to death and so many announcements, faults, and an adverse responding computer in rough turbulent weather!!!
And they were JUST HUMANS trying in pitch black night, in rocking clouds to deal with all that havoc???
Just remember, if you know, the Qantas A380 incident!?!
Five mega pilots, hyper-instructors, ultra-experienced guys dealt 2h30min... 150min with announcements, check-lists, and defective gauges, systems and WHAT???!!!???
Finally decided to leave it all aside, go to land and to see on ground what's next...
They smartly decided to wait 90min on RWY, with the engine running, PAX ON-BOARD... a.s.o.!?!
AN THEY HAD ONLY ONE ENGINE EXPLODED!!! I don't say it was easy, NO! Just trying to compare the two situations?!?
In AF447 they were only two F/O, with probably the P/F NOT IN HIS LICENSED PLACE...!!!???!!!

JJFFC
28th May 2011, 15:55
The BEA gave few informations in this may 27 report but one message :

„ the airplane climbed to 38,000 ft,
„ the stall warning was triggered and the airplane stalled,
„ the inputs made by the PF were mainly nose-up,
„ the descent lasted 3 min 30, during which the airplane remained stalled. The angle of attack increased and remained above 35 degrees,
„ the engines were operating and always responded to crew commands.

Everyone understand that the PF didn't cope with a stall warning.

This is the only thing that said the BEA. Everything else is speculation.

Touch'n'oops
28th May 2011, 16:05
I myself have hit sever icing at FL 320 and it comes apparent as the noise in the flight deck rockets and the windshield, even at night, whitens very quickly. Thankfully for myself it lasted all of 20 seconds.

-Time and time again I can't understand why crews execute the wrong stall recovery technic as seen again in this case. Stall recovery has never been taught different from day one. Pitch down, roll wings level then power!

:confused: Why fight to maintain level if the aircraft is going down? (Referring to nose up inputs, but maybe the pilot was trying to avoid a believed overspeed. Once a pitot is blocked and an aircraft climbs, speed will increase. This might explain why he initially pitched up thinking he was caught in a sever up draft.)
:confused: Why apply TOGA thrust to recover from stall when you have altitude? The thrust coupling would have been a great hindrance to attempts to drop the nose.
:confused: The aircraft is stalled in Alternate Law, it is obvious they had icing, why did the PF use aerolons to recover the wing drop? Inducing a cross control stalls. Correct method, as always been taught, use rudder to recover a wing drop.


-I am sure engine anti-ice would have been on, but did anyone select Wing Anti-ice? Further note, tailplane was probably heavily iced as well not helping stall recovery.


HKPAX You're obviously not a A330 pilot or never hand flown your aircraft high altitude and don't know much about about the plane you "fly". EVEN in alternate law the pitch is a G request, so softly pushing on the stick at high altitude will give the same effect as sofly pushing on the stick at sea level. I know this to be true, as I have had to fly in Alternate law at FL340 because of a dual FMGC failure. If we were talking Boeing, you'd be right. But we are not! Second, a change from level flight to a 7'000ft/min climb then a 10'000ft/min descent in such a short time is definitely gonna be noticed by all as high Gs are involved.

Engine-eer I assume you are an engineer, so I don't expect you know about the auto trim operation on an Airbus, like you wouldn't expect me to know how to change an engine on one.
The auto trim function only ceases when:
-Alpha Floor is engaged (Not available in Alternate or Direct law)
-Below 50ft RA
-Load factor drops below 0.5g
-Aircraft in high speed protection (Not so as aircraft was stalled)
-Pilot manually over rides via trim wheel

Note: In alternate mode. Pitch is load factor and roll is direct.

opherben
28th May 2011, 16:15
Nojwod wrote," As expected reading the last few pages, the usual crowd of perfect pilots comes on to disparage those pilots who were imperfect, the only difference between the perfect pilots and the rest are that the perfect pilots strut around here like a bunch of cockerels, the imperfect pilots are out there facing the real world scenarios...

Anyway that aside, to me what was said and the actions of the PF, with no real dissent from either of the other two imperfect pilots who were there, indicate that something either in the instrumentation or the plane's response to inputs was diametrically opposed to what the crew expected to see or experience. Unless you perfect pilots believe that all three highly trained pilots on the flight deck on that dark night were so grossly incompetent that they could not follow basic airmanship as a matter of course, then there must be some factor(s) that the data recorders have not been able to provide and which may never be known.

As for the dogmatic statements by some perfect pilots above that the crew shouldn't have flown into the storm or flew a perfectly serviceable aircraft into the sea, your comments are beneath contempt, not only for their insensitivity but also for their gross simplification of a situation that you in reality know absolutely nothing about. "

I beg to differ in approach:
a. You should expand your horizons by going through the NTSB database of fatal accidents, to find out what mistakes pilots make.
b. That should lead you and everyone taking control of an aircraft to the understanding that if you are not a perfect pilot, quickly get away and never come back. I have seen enough in 36 years of flying, you can trust what I say.

engine-eer
28th May 2011, 16:15
Yes, while in alternate law (and with the AA over 40º, abnormal attitude law) auto-trim is disabled. However my comment was in regard to the scenario Yipoyan referred to with the Chinese A300 Go-Around. In this instance, had a nose down input recovered the stall, and thus normal law returned, the auto-trim would have moved nose down.

Sorry I thought you were referring to this case.

What does it take to have the FC system return to normal law? Does the system do that automatically after it has decided that the AS sensors were previously declared as faulted, or does it have to be reset manually? Is there any indication that the system returned to normal law or that the autotrim system moved the trim from 3 to 13 degrees?

takoon
28th May 2011, 16:32
Really do feel for the pilots on this A330, they called the situation wrong and paid the ultimate price.

Question is how does an A330 or to that matter any airbus behave in a 'deep' stall. Do standard stall recovery techniques still work ? Actually has anyone experienced a deep Stall condition in a FBW airbus ?

Count Niemantznarr
28th May 2011, 16:38
Enjoy

YouTube - &#x202a;Tarom Inccident a/c YR-LCA ROT381 Airbus 310-325 (Paris, Orly) 3D Flight Reconstruction&#x202c;&rlm;

Well the wings stayed on!

flyer146
28th May 2011, 16:58
Sorry to say but lot of crap on these threads.
Let's wait more details.

-What do u think about sidestick philosophy in unusual attitude ?

Now, the PNF is really missing important feedback : what is the colleague doing on his stick ???
Normal flight, you have feedbacks on PFD : attitude etc... but here : with attitude of 40° up, stalled, you don't have a clue of what HE IS DOING !
You can assume he is pushing down BUT YOU DON'T KNOW ! Instruments won't tell you !

Now, the table was certainly out at CRZ, so you see NOTHING of the colleague stick...

I like AB but I would prefer 2 CONNECTED STICKS with VISUAL FEEDBACK on this scenario and if i see that the other one is keeping it fully AFT for too long, I WOULD CERTAINLY NOT LET HIM DO.

Now to think that a normal pilot pulls full aft stick sooooo loooong.... hard to believe...

What u think ??

Count Niemantznarr
28th May 2011, 17:00
If my memory serves me correctly, even the dear old VC10 had AoA sensors.

Also there was a Northwest Orient 727 crew who crashed because they forgot to switch on the pitot - static heat before take off.

On the climb out their indicated airspeed was increasing and in response they simply increased pitch to correct the "overspeed", until the jet went into an unrecoverable super stall.

Most swept wing aircraft in a deep stall will pitch up and increase the AoA. Perhaps a stick pusher is required? No VC10 was ever lost to a super stall.

engine-eer
28th May 2011, 17:05
Touch'n'oops

Sorry, I confused Alternate Law with Direct Law. In direct law autotrim is disabled. That is what occurred in the Air New Zeland crash, where the trim was left at the last autotrim position (near stall) and the aircraft then pitched up as airspeed increased and stalled which they did not recover from.

If the aircraft was in alternate law then the autotrim was enabled. If that is the case, then can we assume that the change in trim from 3 degrees nose up to 13 degrees nose up was commanded by the auto trim system? If you push nose down, how long does it take for the autotrim to respond? As somebody asked earlier, could this high pitch trim setting made the aircraft unrecoverable?

JJFFC
28th May 2011, 17:43
2 - ANALYSIS

2.1 ATC Actions
The aircraft left its cruise level late, on instruction from the ATC. The IAF, the MEL VOR, was flown over at an indicated speed greater than 300 kt whereas speed is limited to 250 kt below level 100. ATC asked the flight crew, who announced a vertical speed of 4,000 feet per minute, to accelerate its descent to level 60, which, according to standard procedure, should be reached 7 NM after passing MEL.
Heading 330 given by approach control tended to bring the aircraft practically to the FAF for immediate interception of the ILS. Heading 310 reduced the closing angle for the aircraft's route in relation to the ILS axis. This angle was still too wide for the aircraft to align comfortably on the ILS and follow it immediately, all the more in that the indicated speed was still about 235 kt on interception.
This type of procedure is a practice that allows for traffic to be accelerated when meteorological conditions are favorable, which was the case. The flight crew could, however, in compliance with regulations, express its disagreement if they considered headings given would lead the aircraft to intercept the ILS too close to the final descent point. They did not do so.
There was no radio communication exchanged during the incident itself.
After the aircraft came out of the stall, the controller suggested to the flight crew that they stay on heading 180. This complies with the operational instruction aimed at keeping any aircraft with reduced maneuverability to the south of Orly. They were then left the choice of heading to return to their final approach as they wished.
New clearance for landing was given at 10 h 49 m 54 s. Note that no superfluous requests as to the cause of the incident were made by the controller.
2.2 Incident Sequence
The CVR transcription does not indicate an approach briefing. The Captain was performing an automatic approach.
In level flight at 3,000 feet, the aircraft crossed the glide slope before intercepting the localizer. The flight crew seems to have attributed non-capture of glide to automatic pilot system malfunction, whereas the system logic subordinates it to that of the localizer, and disconnected the automatic pilot. The systems configuration then became AP OFF and ATHR ON. The aural warnings announcing disconnection of the AP and downgrading from CAT 3 to CAT 1 of the system landing capability were not commented on by the flight crew.
The aircraft was now in being flown manually and locked onto the localizer at an angle of 52° at 210 kt. It was high in relation to the glide slope and to the north of the localizer axis. Aligned and set to descend, the speed was too high and the indicator for deviation in relation to the descent glide slope showed one point. The vertical speed was not commented on.
At about 2,750 feet, when the “altitude alert” signal sounded, the co-pilot selected 4,000 feet as the altitude to reach in the event of aborted approach, in order to cut off the warning signal.
This selection, before the capture of runway alignment, was premature and its value was greater than the level-off altitude following a go around.
Although the throttle levers had been in “flight idle” position, the speed remained high, the aircraft being two hundred feet above the glide slope. The Captain decided to put it in landing configuration. On each of the successive extensions of slats, flaps and landing gear, the speed was close to the maximum authorized value.
The flaps were positioned at 20 degrees as soon as the speed of 195 kt, that is VFE, was reached. A temporary and minimal excess of VFE (two knots for two seconds), perhaps on going through turbulence, was recorded. The speed protection logic then triggered mode reversion, thus initiating CLB mode due to the altitude selected being higher than the aircraft's altitude.
This change was not noted by the flight crew who were apparently not reading the FMA and did not notice the LVL CHG pushbutton illuminated on the FCU. They did not comment on the “triple click” signal.
While the throttle levers were advancing at their nominal speed on automatic by one degree per second, an action, which seems to have been unintentional and unconscious by one of the pilots, on the elevator trim control button led to deflection of the THS, at constant angular velocity, over ten seconds, up to the maximum value of thirteen degrees nose up. Although the characteristic "whooler" aural alarm was heard continuously for ten seconds, it was not commented on by the flight crew and led to no reaction from them.
This was probably the Captain's responsibility, who was at the controls. It may be explained :
either by incorrect positioning of the left hand on the control column which would have caused the thumb to press the trim control button,
or following confusion between two buttons, that of the trim control and that of the instinctive AP disconnect. This pilot has considerable experience on the BAC 111, an aircraft on which the pushbutton on the left control column horn is the automatic pilot instinctive disconnection control. We may surmise that when he sought to counter the aircraft's tendency to pitch up without understanding its origin, confusion could have set in and having reverted to old reflexes in seeking to disconnect the automatic pilot (already disconnected) he operated the control located in the same place as the AP disconnection on BAC 111.
The co-pilot's phrase “take over manually” is not sufficiently explicit. As the aircraft was no longer on automatic pilot, it would have been more appropriate to say “disconnect the auto-throttle”. This may also mean that the co-pilot believed that one automatic pilot had remained active.
In any event, deflection of the THS created a strong nose up force to the aircraft that the pilot countered by energetic efforts on the elevators, which put the aircraft in a totally out of trim situation.
This out of trim situation was the second crucial feature in the sequence of events in the incident, the first having been the AFS mode reversion.
It seems that the flight crew was unaware of this total out of trim situation. They did not carry out the instructions provided for in the event of “High Pitch Force” or “Abnormal pitch behavior” that provide a response to this situation.
As the auto-throttle was still in operation, the pilot overrode it by manually moving the throttle levers to flight idle for ten seconds before suddenly pushing them back to the maximum thrust position. Four seconds later, he moved them rapidly to flight idle for two seconds, before again pushing them to maximum thrust.
To try and explain the first positioning of the throttle levers to maximum thrust, we can propose two hypotheses :
the Captain, noticing the strong reduction in the VC trend, may have thought that the speed was going to decrease significantly. He may have advanced the throttle to avoid stalling,
the Captain, noticing the problem in the pitch attitude, which would prevent him from continuing his landing, seems to have decided to climb so as to obtain more favorable conditions to deal with the problem. No reason was found for the two other movements of the throttle levers and interviews with the flight crew did not contribute to an understanding of this. It is also clear that the crew, after such a stressful event, could neither remember all their actions, often probably of an instinctive nature, nor even less explain them.
Under the aerodynamic effect of THS deflection and under the mechanical effect of thrust, the aircraft was thus subjected to a nose up force that could not be controlled by elevators. It rapidly assumed an extreme pitch attitude and angle of attack.
The level of force applied on the elevators with just the left hand, while the right hand was maneuvering the engine throttle levers, induced load on the aileron controls. The aircraft then went into a regular and slow roll.
The flight crew was thus confronted by four problems, with the need to:
Hold the aircraft on a descending path
Counter the nose up tendency and control thrust
Pilot the aircraft by switching to instrument flight
Analyze and decide. The Captain reached a point of saturation and so announced a MAYDAY situation, meaning he indicated that he was in a critical situation. It should be noted here that the flight crew neither acted in a coordinated manner nor relied on rules for dealing with an emergency situation. The Captain did not delegate any task or action to the co-pilot who, in turn, proposed no emergency action. Any notion of managing the flight crew seems to have been forgotten.
The FD indications on the pitch attitude to be followed to reach an altitude of 4,000 feet could only be interpreted with great difficulty by the flight crew. Also, due to high pitch attitudes, the PFD was automatically purged, to leave essential information only.
The aircraft thus reached an altitude of 4,100 feet on the verge of a stall, with a minimum recorded speed of about 35 kt. The protection system against high angles of attack cut in and reduced THS deflection from –12.7 to –8.8 degrees, and as a result, the angle of attack from 42 to 30 degrees. The PF does not seem to have noticed the THS pitch down movement, particularly given that a movement of the THS commanded by the automated systems is not announced by the “whooler”. This triggered a reduction in pitch attitude. The aircraft did, however, stall; the “Cricket” stall warning signal and stick shaker were only activated later during descent (see paragraph 2.3.2 below).
Immediately before, during and after the stall, due the unreliability of the total pressure, the ADC no longer provided speed data, resulting in automatic disconnection of the ATHR, with the throttle levers remaining in the maximum thrust position.
Just before the stall, the Captain pulled the control column fully back, bringing the elevator to 23 degrees nose up. He then pushed it fully forward, while continuing to counter the roll of 75 degrees to the right with the ailerons. The statistical data shows that, when confronted by a stall, in 80% of cases, pilots pull back the control column, in a sort of reflex movement, which continues the loss of control.
The aircraft was subjected to a series of four full and rapid rolls. The first was attributed to the force brought to bear by the pilot on the left part of the control column; the following ones were due to pilot overcompensation on the roll then the stall. Having pulled the control column fully back and thus caused maximum nose up pitch, the pilot rectified this by pushing the control column fully forward. The aircraft dipped, with its nose going under the horizon by 32°. The roll-off from +50 to –32° in seven seconds was remarkable.
During the descent, the pilot, helped by the automatic setting of the THS to –8.8 degrees, reduced angle of attack, gained speed by reducing drag, performed a gentle pull-out (load factor of 2 g for five seconds) and adjusted power. The aircraft came out of the stall at a height of eight hundred feet, still out of trim. The flight parameters were apparently stable thanks to thrust modulation.
Alpha-trim protection was automatically cancelled as soon as the aircraft came out of the stall : the THS returned to its previous deflection of –12.7 degrees. This automatic movement, without a “whooler”, seems to have gone unnoticed by the Captain. The Captain flew the aircraft, still totally out of trim, on a slightly rising trajectory, and set thrust to around 60% of N1. The speed decreased regularly and reached 140 kt. This situation carried a high potential risk : in the event of an increase in thrust for any reason, the aircraft would inevitably have started climbing with a high angle of attack.
The co-pilot, reading the ECAM, announced “Pitch trim off”. In fact, the drifting caused by the rolls had disturbed angle of attack assessment and led to their automatic disconnection. The co-pilot re-engaged them and performed tests by deflection in both directions. The “whooler” was identified and the co-pilot declared the trim setting system to be operational. He reduced deflection to –8.4 degrees. This action to reduce the THS angle was beneficial. It nevertheless remains an example of simultaneous piloting, performed without the knowledge of the pilot flying.
On an outward leg on heading 120, the aircraft at 195 kt and at 2,000 feet was now only slightly out of trim (THS –8.4 degrees nose up; pitch 8° nose down).
The Captain at first refused to use THS trim. About eighty seconds later, inputs recorded on the FDR and selector noises on the CVR show that he used it but without announcing it, by short touches identical to his way of using trim before the event was triggered. Five minutes after total deflection of the THS, the aircraft was correctly trimmed and piloting had returned to normal.
Landing took place in configuration with slats and flaps 20 , which in the final approach, led to the announcement “too low flaps” from the GPWS. LOC interception took place by visual alignment with the runway axis. The aircraft crossed the glide slope, remained above then, finally, went below it. These deviations were not announced. The “glide slope” aural warning was heard on final approach.
On final approach, on reducing speed, the AFS triggered a mode reversion from VS to SPD. As the auto-throttle was disconnected and the flight crew was getting ready to land, this new mode reversion went unnoticed.
To summarize, this second approach was neither prepared nor stabilized.
Note : the CVR shows no attempt to determine the anomaly felt on the longitudinal attitude control system, THS and pitch. More generally, there would not seem to have been actions which could be called “return to basics” on the part of the flight crew. In the present case, this would have involved:
setting the aircraft trim, if necessary using the mechanical control wheel,
returning to standard flight situation, normal visual flight circuit, briefing and check .list,
possibly reactivating certain elements of the AFS, after consulting the ECAM. As soon as the situation seemed to have stabilized, conversations resumed in the cockpit. Neither the auto-throttle, nor THS deflection, nor the variations in thrust were mentioned. Neither was mode reversion from VS to LVL CHG brought up. The conversation mainly concerned the AP. The flight crew did not carry out a briefing for the new approach.
2.3 Operation of AFS Protection
2.3.1 Protection of Speed Envelope
The aircraft speed exceeded VFE before capture of ILS. Note that in these circumstances, protection against an overspeed is ensured according to the two following thresholds:
when the speed becomes equal to VFE, by switching to LVL CHG mode.
when the speed reaches VFE + 4 kt, by sounding a Continuous Repetitive Chime. The choice of LVL CHG as protection against excess speed led, in the circumstances of the incident, to an increase in thrust at a moment where the goal was to reduce speed, this being incompatible with the goal sought.
We may note that, if the automatic pilot had been active, it would have caused a nose up attitude, which would also have surprised a flight crew in the middle of intercepting a localizer and whose first objective was to reach the runway.
2.3.2 Analysis of the Stall Protection Logic
Stall protection is organized around three angle of attack thresholds, that for Alpha-floor, that for Alpha-trim and that for triggering the stall warning (see 1.16.1.4).
Alpha-floor protection could not play its role as, when angle of attack of 14.5° was reached, the throttle levers were already on maximum thrust.
Alpha-trim protection was triggered at a value for angle of attack of slightly less than 15° in conditions where the flight dynamics were close to the extreme. It should be noted that it also functioned after coming out of the stall by giving the opposite order to the THS.
The stall warning did not sound and the stick shaker did not operate in the flight phase prior to the stall. When questioned, the aircraft manufacturer indicated that the cause for non-operation of these two warnings was the disturbance of the angle of attack sensors due to the dynamics of the aircraft's movements, with the speed having dropped below 60 kt before the angle of attack reached 17.5°. The flight crew had, however, been warned of the approach of a stall by buffeting.
3 - CONCLUSIONS

3.1 Findings
The flight crew was properly licensed to conduct the flight. A third pilot undergoing familiarization was in the observer's seat.
The meteorological conditions were excellent.
The aircraft was normally certified and maintained. No non-availability of equipment (with the exception of the FDR) was noted. Ground checks after the incident, and subsequent flights of the aircraft showed no evidence of any operating anomaly.
The Captain, at the controls, started an automatic approach.
Approach control asked the aircraft to shorten its path, which led to ILS interception closer to the runway than provided for by standard procedure.
According to the systems logic, the glide, encountered before the localizer, was not automatically captured . The Captain then disconnected both automatic pilots, leaving the auto-throttle in operation.
An altitude of 4,000 feet was selected before establishment of the aircraft on ILS as go around altitude. The go around altitude in the procedures is 2,000 feet.
When flaps were selected at 20 degrees, the speed was slightly greater than VMAX, which activated speed protection, leading to reversion of VS mode to LVL CHG mode.
Due to the altitude selected being greater than that of the aircraft, the auto-throttle commanded an increase in thrust. The pilot maintained the aircraft on descent.
He accidentally caused the trim to its electrical stop at thirteen degrees nose up, which put the aircraft in a totally out of trim situation.
To counter the effect of THS deflection, he moved the elevator control to its mechanical stop of fifteen degrees nose down, by effort applied on the control column.
A sudden increase in thrust was commanded manually.
Under the effect of the additional force, the aircraft pulled up rapidly. The pilot continued to counter by continuous effort on pitch and by temporarily holding the thrust levers in the idle position. He neither corrected trim, which remained on pull-up stop nor disconnected the auto-throttle.
The aircraft took a path with a very steep slope, with roll angle reaching extremely high values. It climbed to an altitude of 4,100 feet and minimum speed recorded was 35 kt. Alpha-trim protection reduced the THS deflection by four degrees.
Under the effect of strong drift on full and rapid rolls, the angle of attack sensors were disturbed, which led to automatic disconnection of the two pitch-trims. The auto-throttle was inhibited for the same reasons.
Due to the dynamic of the aircraft's movements, the stall warning and the stick shaker did not function in a preventive manner.
The flight crew regained control of the aircraft after the stall. 3.2 Probable Causes
The direct causes of the unusual attitudes and the stall to which the aircraft was subjected were a movement of the THS towards the full pitch-up position and a rapid increase in thrust, both of which maneuvers were the due to the Captain, following an AFS mode reversion which was not understood. The pitch-up force caused a sudden change in attitude that the flight crew was unable to contain with the elevators.
The following elements contributed to the incident:
Too rapid an approach, due to a late start in the descent, followed by a reduction of the standard procedure.
Inadequate crew resource management.
Premature selection of the go around altitude and precipitous setting of the configuration with slats and flaps at 20-20, which led to activation of the speed protection.
Difficulty in understanding the action of the auto-throttle increasing thrust in its overspeed protection function. 4 - RECOMMENDATIONS

4.1 Measures Taken
After the incident and on the basis of the first facts established as communicated by the BEA([3] (http://www.bea.aero/docspa/1994/yr-a940924a/htm/yr-a940924a.htm#_ftn3)), the French Civil Aviation Authority (Direction Générale de l'Aviation Civile) informed French operators of the Airbus A 310 and A 300-600 (these two types have identical protection). It asked them in particular first to draw the attention of flight crews to the need to respect limit speeds provided for different aircraft configurations and, secondly, to ensure they are fully informed as to the logic of the protection system in the event of abnormal speed.
The DGAC also warned the civil aviation authorities of the countries using these aircraft, recommending them to take similar action with the operators under their authority.
4.2 Intermediate Recommendation
Following several accident investigations in which the Bureau Enquêtes-Accidents participated, the following recommendation was issued on 24 January 1995:
Various incidents or accidents (see list below) involving public transport aircraft show the following common characteristics:

Configuration: Automatic Pilot and/or auto-throttle lever (or auto thrust) in operation.
Circumstances: pilot flying overrides (voluntarily or involuntarily) the Automatic Flight System, or acts contrary to the indications of the Flight Director.
Aggravating circumstances:
a) the pilot flying is not always aware of his action in opposition with the Automatic Flight Systems and never perceives the consequences thereof,
b) the pilot not flying (even instructors) is not aware of the conflict between the pilot at the controls and the Automatic Flight Systems.
Consequences:


the reaction of the Automatic Flight Systems leads to potentially dangerous configurations: out of trim, engine thrust incompatible with the trajectory chosen by the pilot, etc.
Flight crew, either is not aware of the situation, and thus cannot take corrective measures,
or observes the aircraft configuration without understanding the causes. This incomprehension (also related to limited knowledge of systems) leads to a loss of time in analyzing the situation, or even to an erroneous analysis, generally associated with a lack of adequate communication between crew members
This has led to highly dangerous attitudes: extreme attitudes or rolls, loss of speed (including stalls) or excess speed, etc.



As a result, the Bureau Enquêtes-Accidents recommends:
- that a study be launched so that the pilot's priority over all Automatic Flight Systems is maintained in all circumstances.
This could be done :
a) by the disconnection of Automatic Flight Systems (automatic pilot and auto .throttle lever or auto thrust) in the event of conflict between the pilot's actions and those of the Automatic Flight System or Flight Director.
b) and/or by clear information in the cockpit (possibly an alarm) warning the flight crew of such a conflict.
List of events:


Incident to an A 300 .B4 on approach to Helsinki (Finland) on 9 January 1989
Accident to the A320 .231 VT .EPN at Bangalore (India) on 14 February 1990
Incident to the A310 D .ADAC on approach to Moscow on 11 February 1991
Accident to the B747 .400 F .GITA at Tahiti .Faaa on 13 September 1993
Accident to the A310 .300 F .OGQS near Novokuzniesk (Siberia) on 22 mars 1994
Accident to the A300 .600 B1816 at Nagoya on 26 April 1994
Incident to an A310 .325 on approach to runway 26 at Orly on 24 September 1994

4.3 New Recommendations
4.3.1 Speed Protection System Activation Display
The flight crew noticed neither the initiation of the flight envelope speed protection nor the mode change which resulted from it. Further, we may note that the denomination "LVL CHG" is inappropriate to indicate activation of speed protection. LVL CHG is the process used and not the goal.
The BEA considers that recommendation 4.4.2 issued in the context of the investigation into the accident that occurred on 20 January 1992 near Mont Ste Odile corresponds to the problem identified here. It is repeated below, with the grounds given:
In its analysis of this accident, the commission has been led to note deficiencies in the effectiveness of the display to the flight crew of the various active modes, the references used, actions in progress and targets pursued with regard to the Autopilot devices, notably in the vertical plane. Most particularly, in the opinion of the commission, the total information presented is inadequate in terms of its likelihood of alerting a crew, who at a given moment have an incorrect mental picture of the state of the automatic devices. In practice, a good number of observations made by the commission apply to one degree or another to all new-generation aircraft …
Consequently, the commission recommends that for all new-generation aircraft:
- consideration should be given by the competent authorities and organizations with a view to improving, in a standardized fashion on an international basis, the presentation and the symbols for displays and information relating to the different Autopilot active modes, notably in the vertical plane.

misd-agin
28th May 2011, 17:47
JJFFC - Do you agree to this test ?
In a test, any pilot who ears a stall alarm who hadn't nose down within a quarter of a second should be fired.

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Disagree.

1. maintain aircraft control
2. analyze the situation
3. take appropriate action

A reaction to a stall warning, absent other confirming indications, is inappropriate. Maintiain aircraft control(#1) sometimes means 'do nothing immediately or drastic', verify a/c performance state(#2) and then proceed to ignore waring(if false) or reduce AOA if warning/stall is confirmed (#3).

wiggy
28th May 2011, 17:50
Agree with you entirely when you mention cognitive dissonance - it's involved somewhere.

From what I've heard :ok: until you've been involved in an aircraft coming "unglued" you have no idea how quickly your comfy world can turn to a crock of S**** and subsequently just how difficult it can be to metaphorically "step back" and analyse the situation objectively.......

We may well eventually discover what information the AF crew had available to them - we'll sadly never know what they perceived.

JJFFC
28th May 2011, 17:57
You are fired

As 80% of the pilot considering what is said in the report above :
" The statistical data shows that, when confronted by a stall, in 80% of cases, pilots pull back the control column, in a sort of reflex movement, which continues the loss of control.
The aircraft was subjected to a series of four full and rapid rolls. The first was attributed to the force brought to bear by the pilot on the left part of the control column; the following ones were due to pilot overcompensation on the roll then the stall. Having pulled the control column fully back and thus caused maximum nose up pitch, the pilot rectified this by pushing the control column fully forward. The aircraft dipped, with its nose going under the horizon by 32°. The roll-off from +50 to –32° in seven seconds was remarkable."

Don't think. Nose down.

pattern_is_full
28th May 2011, 18:17
Some points:

> Let's not use the term "deep stall" in reference to this accident. A "deep stall" is a specific kind of stall where the attitude of the aircraft is such that the wings block airflow to the horizontal stabilizer, making elevator inputs useless for recovery. Almost always involves a "T"-tail design, which does NOT include any Airbus aircraft. (oopps - edited to include NOT)

This was a pronounced, possibly extreme, and prolonged stall (it appears), but NOT at any time a "deep stall."

> I find huge fault with an audible stall warning system that cuts out as the AoA gets worse, and then cuts back in again during recovery. Yes, a good pilot should be able to recognize a stall by other means than the audible alert - but an alert that a) stops while the situation is still getting worse and b) begins screaming again when the pilot does the RIGHT thing (lowers AoA for recovery) is just ludicrous.

Graybeard
28th May 2011, 18:51
The A/P should have rejected the errant airspeeds, gone into pitch and power hold mode, and stayed in normal law.

BigGrecian
28th May 2011, 19:05
Correct method, as always been taught, use rudder to recover a wing drop.

Really?

Does anyone else disagree with the above post?

I recall the UK CAA sending out a memo around about the use of rudder in stalls...

Right back to the basics ...
Rudder should be used to maintain balance only...

streborc
28th May 2011, 19:08
Perhaps they reacted to winshear, rather than stall.

Full back stick and TOGA, then hold both until the aircraft flies out of the problem.

Not enough thrust at high level, protections not there so the computer cannot stop the pilot holding the aircraft in a stall.

Mind set on the wrong cause of sudden loss of airspeed.

The dreadful fact seems to be that they had a flyable aircraft that they failed to fly.

Manic Moran
28th May 2011, 19:21
With respect to the "we have no valid indications" comment, is it possible that the crew were just so convinced that they were in a nose-down dive (idle throttle, pulling back on stick) that they simply concluded that any instrument which contradicted this belief (such as attitude indicator pointing up) must be wrong?

wallybird7
28th May 2011, 19:21
The way I read the report it continously stated that the plane was in a nose up attitude. And the airspeed very slow. And it seems to me that they had no control over the stabilizer/elevator.

wallybird7
28th May 2011, 19:36
Just for the record the Captain discovered his airspeed was out in the beginning of the TO roll before V1 but elected to go anyway. It's on the CVR.

The taped static port occurred on the Peruvian 757. Unsure if they were aware of it during take-off.

Herod
28th May 2011, 19:50
I can't help feeling there is a bit of the Eastern 401 problem here. If they were dealing with all sorts of other warnings, was anyone looking at attitude, altimeter, R.O.D.? An additional factor; could the PF be inadvertently holding full nose-up control? Unlikely on a conventional aircraft, but could he have been so busy with the other problems that he didn't realise he was doing it? The call at ten thousand is unusual; surely someone would have reacted to that, unless it was a Pavlovian call in the confusion. I don't think we will be able to know much else until the full CVR is made available.