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Hi,
This forum is titled "Tech Log" as it is normal that all the technical assumptions are discussed here. Many hypothesis have been advanced .. so that even someone qualified can be confused by their number and diversity. There's just a fact that caused all these technical discussions .. it's the pilot performance in the first seconds after the autopilot go off This in my opinion is the most important fact Does this fact is explained by all the technical assumptions in posts? I doubt it strongly. As I said earlier - the BEA can be said to have handled a single AF/Airbus incident "badly", though personally speaking I wouldn't have wanted any part in that political minefield. That incident was 23 years ago and they're still dealing with the damage that did their reputation today. It would be utter madness for them to try to do so again, so I say again, give them a chance. They have this chance .. but they already begin to ruin it by the release of their last note. And this chance was again badly wounded by the statement of a member of the french political body (Mr Mariani directly involved in the following of AF447 cause his position in the government) |
Originally Posted by wallybird7
(Post 6521843)
Just for the record, the mission of EVERY investigating body, is to gather the facts and make a determination of Probable Cause and to recommend a fix, but NOT to affix blame, fault, or liability, which is left to legal venues.
However, I don't see anywhere in the post you quoted where I referred to "blame". I was very careful in the word I chose, and said "finding", using the language common to the AAIB, NTSB et al. As a pilot all I want is all the given facts and then I can make my own conclusion regarding what to do about it. In this case avoid thunderstorms at all costs. Period. Seriously though, when they've got facts worthy of release - I suspect they'll release them. It has long been common practice in aviation accident investigation to cover as much ground as they can so that as much can be learned as possible - that's the reason it tends to take a while. For example, the AAIB's final report on the BA038 incident took 2 years and one month to produce. In that case, they had the entire airframe more-or-less intact, both flight recorders and the QAR to hand, as well as the entire crew and passenger list available for interview - but the lack of evidence regarding icing on the heat exchangers meant that there was a significant hole in the available data and thus there was a seemingly "inexplicable" element to the incident. The BEA produced their initial interim report on AF447 with small fragments of wreckage, a set of ACARS messages and no flight recorder data. Now that they have more wreckage and the flight recorders they are probably going to have to do a lot of rewriting of their assumptions, as well as a whole battery of human factors testing in relation to what they've learned from the CVR. As an aside, the discussion on BA038 on here went back and forth for those entire two years, and speaking for myself I learned a lot of new and surprising things from that discussion - but at no point did any contributor demand that the raw data traces were released or chide the AAIB for not doing so. Now was that because it was the AAIB doing the investigation and not the BEA? Was it because the aircraft involved was a Boeing 777 and not a member of the Airbus FBW family? Or was it because there's an understanding that these things take time and should not be rushed. Being on here for as long as I have, I suspect it was a combination of all three. Finally, there were theories doing the rounds (that ended up in the BBC/NOVA "Lost" documentary on AF447 back in 2009) that the thunderstorm cells were obscured on radar by a smaller cell in front of the cell they entered - what do you do in that situation if avoidance beomes impossible? when in fact they won’t even allow pilots to practise “hand flying” in the simulator at altitude, let alone in the airplane.
Originally Posted by jcjeant
(Post 6521877)
Just a tought
They have this chance .. but they already begin to ruined it by the release of their last note. And this chance was again badly wounded by the statement of a member of the french political body (Mr Mariani directly involved in the following of AF447 cause his position in the government) The problem is that there are some on here that remain wedded to the idea that the BEA will always try to find against the pilot before anything else - something that is not supported by any evidence gathered over the last 20 years at least. Yes, their paycheques are ultimately signed by an entity that has a controlling stake in the manufacturer and airline involved, but the same was true to some degree of the old UK AIB (in the days when the UK made airframes and BA was state-owned), as well as the NTSB prior to the mid '70s (Boeing/McD-Douglas and Lockheed were privately owned, but heavily dependent on government/military contracts). |
Finally, there were theories doing the rounds (that ended up in the BBC/NOVA "Lost" documentary on AF447 back in 2009) that the thunderstorm cells were obscured on radar by a smaller cell in front of the cell they entered - what do you do in that situation if avoidance beomes impossible? Regards |
Deficient Documentary
Dozy:
Finally, there were theories doing the rounds (that ended up in the BBC/NOVA "Lost" documentary on AF447 back in 2009) that the thunderstorm cells were obscured on radar by a smaller cell in front of the cell they entered - what do you do in that situation if avoidance beomes impossible? |
Hi,
"Badly wounded" how? They released all the information they could determine after just a few days looking at the data The note released it's just some fragments of the CVR record. Unless the CVR had recording problems ... we can't tell the BEA released all the information provided by the CVR This is why all those posts trying to fill the gaps open by this incomplete release. If I quote one of your message incompletely .. you will complain of context .. ♫♪la la la♪♫ Same for a incomplete BEA release .... |
A half truth is a whole lie (yiddish proverb)
Hi,
They had time to carefully select and release the "right information" taking into account all all possible implications. Trying to secure a big and comfortable "room to maneuver". 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 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. 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 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...The PF made an input on the sidestick to the left and nose-up stops, which lasted about 30 seconds..." And in emphasizing persistent NU commands seems as to considering as the "major cause", coherent to LF leak, deviating the focus from plane malfunction(s). This was IMO a tentative to gradually prepare public opinion and timely to the big "interests involved in Paris Air Show". The seriousness because the LF leak was too early (IIRC in the Monday subsequent the first analysis during the weekend). Probably an opportunistic attitude from one(s) representing the huge interests" behind. With risk (and probably, intentions) in creating a "frame" for BEA "output". Human machine interface issues, "software issues", etc. would be considered "machine faults"? System processing of "ridiculous Pitot redundancy" has chances to be considered "machine fault"? All this are "against crew" and makes easier the work of the "high rocks" at FR government and it´s personnel (including BEA top managers). Most of us yet now could imagine the Report and it´s recommendations. Certainly BEA is "ahead of the schedule" on that. They seems to be navigating very well in this turbulent weeks since wreckage location. |
Originally Posted by Graybeard
(Post 6521936)
I just want to repeat that documentary was rubbish. Just reading the pilot's guide for the Wx radar on 447 would have given them real info about the radar capabilities. Instead, they went off on an ill-founded theory about the "storm behind the storm."
Originally Posted by jcjeant
(Post 6521961)
I disagree about this
The note released it's just some fragments of the CVR record. Unless the CVR had recording problems ... we can't tell the BEA released all the information provided by the CVR This is why all those posts trying to fill the gaps open by this incomplete release. If I quote one of your message incompletely .. you will complain of context .. ♫♪la la la♪♫ Same for a incomplete BEA release .... Case in point - I remember an accident described in the "Black Box" book* that accompanied the C4 series of the same name in 1996. The investigators in that case released CVR data where the pilots were complaining of being tired - this got picked up by the press and the accident was written up as fatigue-induced pilot error. Another angle they were working at the time was that the altimeter fitted to the aircraft in question was known to occasionally misread by up to 1,000 ft and there was plenty of evidence that this had indeed happened. As such, they recommended replacing that model of altimeter, but because public perception had already accepted the "fatigue" explanation, the regulator wasn't interested. This is about the fifth time I've asked this question and I've yet to get an answer - why are there demands for raw data being made of the BEA in this instance from some quarters on this forum, when to my memory no such demands have ever been made of the NTSB or AAIB? @RR_NDB : I note that when journalistic "tittle-tattle", as it applies to piloting and aircraft operations, is brought up on here it tends to be treated with the scorn it deserves, except in very exceptional circumstances. Why should press hearsay about the motivations of the BEA and the French government be any different? [EDIT : Just had a quick squiz on Google, and as far as I can see the "Paris Air Show" connection was made at the end of a paragraph in a Flight International article, and all that said was that the timing of the discovery "could have come out of a film script" - no connection to the possible release of information to protect Airbus or Air France has been made outside of the speculation on this forum.] * - The book was heavily oversimplified and wasn't really all that - but my local Waterstone's was getting rid of it for 2 quid... |
Re: A Half Truth
RR_NDB
Perhaps a more appropriate saying: Do not be desirous of having things done quickly. Do not look at small advantages. Desire to have things done quickly prevents their being done thoroughly. Looking at small advantages prevents great affairs from being accomplished. |
This was actually predated by the noted Far Eastern scholar, Wo Phuc, who noted:
"If you want it badly, you'll get it badly." |
Invisible Thunderstorms
Dozy:
What do you do about the thunderstorm you can't see? Was it that the AF pilots didn't receive adequate training in use of their Wx radar? Was it that AF didn't upgrade to the latest radar that has special processing for tropical storms? Do you believe there are thunderstorms with no rainfall or ice pellets? |
@Graybeard : The context of my question is that if enough people thought it was a possibility, even if it doesn't turn out to have much of a bearing on the case, would it not be a good idea to look into remedying the situation - whether that be via training or technology?
I've got no answers to your other questions, other than a nagging suspicion that for all our knowledge, nature will always find a way of surprising us - sometimes not in a good way. |
Thanks OK465,
That is the message, very concise. :ok: |
Originally Posted by DozyWannabe
The BEA were the ones who released that information publicly when their initial interim report was released a couple of years back - if they really wanted to "stitch up" the pilots then they would never have released that information.
Originally Posted by RR NDB
Probably an opportunistic attitude from one(s) representing the huge interests" behind. With risk (and probably, intentions) in creating a "frame" for BEA "output".
http://i25.servimg.com/u/f25/11/75/17/84/af447_10.jpg Three lies in one single image :
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Originally Posted by CONF iture
(Post 6522305)
Did they have any choice really when ACARS + Air Caraibes report were all over the Net … FIRST.
Three lies in one single image :
Let me know what you think of the stuff I PM'ed you! |
Harry Hawker to his designers
To RR_NDB's (post 4/150), should be added Harry Hawker's suggestion to his designers:
"Simplify, and add lightness." ( I'll try to remember that, if I post again :~? ) |
Three lies in one single image :
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I will repeat my opinion that the release by BEA was 'mischievous'. As I have said, they have the CVR and FDR. By limiting the CVR info they neatly 'imply' that PF pitched to 10 deg, and climbed 3000' (above optimum and possibly above max) without a single word being said by either pilot about it. Either that is the case, which I positively doubt, or there is some reason why this part of the conversation has not been released. It would have saved pages of PPRune. Without it we are all guessing in the dark
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Hi BOAC,
I will repeat my opinion that the release by BEA was 'mischievous'. Something similar happened with the B777 at LHR 2008 pprune discussions. It's not the BEA who are mischievous - it's us - the pprune posters. http://www.pprune.org/rumours-news/3...crash-lhr.html |
Originally Posted by BOAC
I will repeat my opinion that the release by BEA was 'mischievous'
As a minor detail, BEA said : "The airplane's pitch attitude increased progressively beyond 10 degrees ..." (to 13 degrees according to my 'simulation'). |
Originally Posted by BOAC
(Post 6522558)
I will repeat my opinion that the release by BEA was 'mischievous'
|
ACARS message "NAV ADR DISAGREE"
That message, time stamped 2:12, was received at 2:12:51. At that point in time the airplane was already in a full stall, with all airspeeds probably misreading due to pressure errors at the pitots and at the static sources due to the high AoA. I wonder if that could tell us anything about the speed displayed on PFD2 prior to stall, but can't figure it out. Anyone?
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Originally Posted by HN39
based on the entirely arbitrary assumption that the pilots observed the departure in pitch, v/s and altitude and discussed it
|
Was the PNF possibly too busy/engrossed/distracted with pages of ECAM warnings and alerts to notice what the plane was doing?
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Was the PNF possibly too busy/engrossed/distracted with pages of ECAM warnings and alerts to notice what the plane was doing? GB Not noticing is something humans are very good at, unlike computers :) |
Hi,
The context of this note should be taken into account: the BEA was under pressure to anticipate their analysis of the newly recovered DFR/CVR, some results were leaked and Airbus was already claiming that the analysis of the recorded data had shown that the plane was not the problem. The BEA reacted strongly to this claim, making clear it is the only authorized entity to establish new facts about the AF 447 accident, that those leaked/unauthorized informations were not helping the families who had lost a relative, that it will soon release a first set of new facts derived from the recorders and an interim report by the end of july. A bone to gnaw, waiting for the main course. BEA reacted strongly for support the Airbus claim Indeed for "le citoyen" lambda people the note of the BEA (and emphasized in newspapers) the pilot error is what made fall the plane. Even the minister Mariani confirmed this after the BEA release. The seed is planted |
This whole "pilot error" discussion puts me in mind of the deceptive term "pilot induced oscillation" which is actually an airframe problem. PIO is often known as Pilot in the Loop Oscillation or also Aircraft Pilot Coupling, but the key point is that it is more an aircraft design problem-not so much a pilot technique issue.
I can already see that the AF447 cockpit was not well designed for pilot situational awareness in the type of flight conditions encountered by the AF447 crew: No direct AOA indications, no old fashioned steam gage altimeter unwinding, no bell or clacker on the trim wheel to draw attention to its motion, too many competing alarm sounds in the cockpit. Then there are training issues surfacing and also fundamental how do you fly the 'Bus issues that are surfacing. We are left with three core issues relating to piloting and aircraft systems.
|
Dozy, the Lufthansa preceding, and the Iberia and Air France following, on the same airway as AF447 that night 'saw' the Cbs and deviated, AF459 rather dramatically with its zig-zagging total of about 100 NM to the left and right of the track. Dispatch had sent AF447 a message regarding satellite observation of Cbs vicinity of ORARO and TASIL well before AF447 reached ORARO.
Until the full CVR is released, we won't know what the crew of AF447 saw (or failed to see) on their radar after ORARO. |
SaturnV (liking the handle!):
Absolutely - I wasn't trying to imply one way or the other - I was just expressing the opinion that the investigation should be thorough. jcjeant: BEA reacted strongly for support the Airbus claim |
Machinbird;
Apart from the ice particles that blocked the pitots, do you think that the weather played an important role in this accident? |
One thing that has puzzled me, in the interaction between the two copilots. If the Junior one was flying and the senior one thought he was screwing up in a big way, I can see an advisory call of the problem followed by "I have the aircraft" if the senior guy still was not happy with the other man's performance. (And proper CRM says the reverse can happen too). But this apparently did not happen. Was the senior copilot not concerned with the junior one's performance? Or was he too busy with other things?
Is there something exclusively in the interaction between copilots that would act to inhibit this type of takeover of control. Perhaps Captains orders who was to fly a segment? |
Originally Posted by Graybeard
Was the PNF possibly too busy/engrossed/distracted with pages of ECAM warnings and alerts to notice what the plane was doing?
Originally Posted by BEA
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.
Originally Posted by BEA
At 2 h 10 min 16 The airplane’s pitch attitude increased progressively beyond 10 degrees and the plane started to climb. The PF made nose-down control inputs and alternately left and right roll inputs. The vertical speed, which had reached 7,000 ft/min, dropped to 700 ft/min and the roll varied between 12 degrees right and 10 degrees left. The speed displayed on the left side increased sharply to 215 kt (Mach 0.68). The airplane was then at an altitude of about 37,500 ft and the recorded angle of attack was around 4 degrees
Originally Posted by BEA
At 2 h 10 min 51 , the stall warning was triggered again.
Originally Posted by BEA
At around 2 h 11 min 40 ... During the following seconds,
all of the recorded speeds became invalid and the stall warning stopped.
Originally Posted by BEA
...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.
The plane turned the stall warning OFF when it had no good reason to do so. So what's this nonsense BEA has been spouting that the plane is not at fault? The plane has a critical design flaw in its software that conditions pilots to do the wrong thing even when they know better. In the past four days worth of posts on catch-up reading I've seen nothing to change my view in this regard. |
HN-39
Apart from the ice particles that blocked the pitots, do you think that the weather played an important role in this accident? Those that wish to add a large turbulence/updraft element to this loss of control seem to be putting unnecesary sauce on the stew. Occam's Razor applies. There appears to be sufficient explanation in the pitch angle achieved to account for the climb to FL380. |
JD-EE:
You're not taking the training around loss of air data into account. One of the things quickly learned from the pitot/static failure accidents in the 1990s was that aural warnings generated were confusing, thus the correct thing to do is to disregard them and fly pitch-and-power until the speed readings become valid again. This is not something peculiar to the A330, it is common to all advanced jetliners. If the pilot were simply reacting to those warnings, when he had visual cues in the form of the ADI in front of him and the power settings - neither of which requires air data to function, and are therefore likely to be correct - telling him that he was too nose-high for the power he had selected at that altitude, then he was either not adequately trained for this scenario, or so thrown by the sudden onset of the situation that the training went out the window. |
Originally Posted by machinbird
If the Junior one was flying and the senior one thought he was screwing up in a big way, I can see an advisory call of the problem followed by "I have the aircraft" if the senior guy still was not happy with the other man's performance. (And proper CRM says the reverse can happen too). But this apparently did not happen. Was the senior copilot not concerned with the junior one's performance? Or was he too busy with other things?
|
The pilot made a nose down input. |
Originally Posted by DozyWannabe
(Post 6523403)
jcjeant:
The way I read it the BEA were actually a bit annoyed at Airbus for jumping the gun, so they released the "note" to calm the press, which naturally went into something of a feeding frenzy as soon as the recorders made it back to Paris. You *could* read it as the BEA supporting Airbus's statement, but alternatively it could simply mean that while Airbus jumped the gun, their information was solid. All I have / recall is Airbus release (I believe approved by BEA) that no action was required for 330 operators yet - on the basis of analysis of the data at that point. That got turned by the media into "plane not at fault", along with other leaks leading to headlines like "no pilot in the cockpit" and other idiocy. BEA release was to stamp on the media leak/bulls**t fest - which it laregly did. AFAICS neither Airbus or BEA can possibly come out and say the plane wasn't at fault - because the pitots (brand / model) were (and still are) held to be at fault. Airbus might not have built the pitots, but they approved them for the a/c (and maybe because they are French...), so they are on the hook. The fact that they advised AF to replace them 2yrs before the crash, and AF blocked it, may get Airbus back off the hook (certainly doesn't make AF look good) but the plane is clearly still part of the cause. And that is before we even get into any possible human factors issues in the control system design, warnings systems, THS etc. |
That nose-down command between 2:10:16 and 2:10:50 reduced the vertical speed from 7000 fpm to 700 fpm and AoA to (less than - in my simulation) 4 degrees (reducing v/s implies less than 1g, hence reduced AoA) - no stall warning at that point. Then a nose-up command must have followed calling for about 1,1 g and an AoA that exceeded the stall warning threshold, and ultimately the stall AoA. The 1,1 g increased the vertical speed from 700 fpm (to about 2500 fpm in my simulation). Look at BEA's "3D view" for the partial level-off followed by a steepened final climb just before the apogee. The airplane stalled before the apogee. |
By now the PF was "conditioned". He was rewarded for NU and punished for ND. The frigging plane turned the stall warning OFF when it had no good reason to do so. So what's this nonsense BEA has been spouting that the plane is not at fault? The plane has a critical design flaw in its software that conditions pilots to do the wrong thing even when they know better. UAS is known to be a situation where alarms, alerts and warnings can be misleading - training dictates fly pitch and power until speed indications recover. Which in flight, unless I'm seriously off-target, they have proven to always do (excepting situations were pitots have been blocked due to human error or bees - never did like bees). I'm sure that the BEA and Airbus will be looking at the stall warning behavior very closely, but let's not loose sight of a couple of key issues that are VERY UNLIKELY to be the aircraft's fault: 1) Flying THROUGH the CB area was the initiating and fundamental cause. All other flights on the same airway track deviated. Had they done the same we would not be here. 2) The reaction to the stall warning was NOT the initiating problem. The problem was how they arrived at the stall condition in the first place, i.e. pitch and power at the loss of airspeed indication would not lead to this. Therefore I would suggest that the real work needs to be focused on why they elected to NOT deviate. Everything else falls out in turn. I think it fair to say that 99.9% of pilots would claim to have NEVER flown through a CB - because it is known to be a very, very bad thing to try. There are a few stories around from those few that made that mistake and sadly the majority end badly. The fact that the pitots iced in this situation was a prior issue, one that Airbus had already issued a warning, that for whatever reason AF was slow to action. Whether the appropriate regulatory authorities should set in when there is a potential safety of flight concern, is another topic worth discussion. |
Originally Posted by GarageYears
(Post 6523623)
I think it fair to say that 99.9% of pilots would claim to have NEVER flown through a CB - because it is known to be a very, very bad thing to try. There are a few stories around from those few that made that mistake and sadly the majority end badly.
Southern Airways Flight 242 - Wikipedia, the free encyclopedia |
" Before the battle of Verdun, our activity was disturbed by frequent thunder-storms. Nothing is more disagreeable for flying men than to have to fly through a thunderstorm. During the Battle at Somme, a whole English Flying Squadron was forced down behind our lines and became our prisoners of war, because they had all been surprised by a thunderstorm. I had never yet made an attempt to get through thunder clouds, however I could not suppress my desire ' to make the experiment.' During one whole day, thunder was in the air. But in order to look after various things, I had flown over to the nearby fortress of Metz. I had an adventure during my return. After visiting the aerodrome of Metz, I had intended to return to my own base, when an approaching thunderstorm became noticeable. As it approached from the north, its vertical clouds looked like a gigantic . . pitch-black wall. Old, experienced pilots, there, urged me not to fly. However, I had promised to return to my base. I should have considered myself a coward if I had failed to come back because of a silly thunderstorm. Therefore, I meant to try. I was in the air when the rain began falling. I had to throw away my goggles, otherwise I should not have seen anything. The trouble was that I had to travel over the mountains of the Moselle, where the thunderstorm was now raging. And as I rapidly approached the black cloud which reached down to the earth, I said to myself that probably I should be lucky to get through it. As I flew at the lowest possible altitude, I was compelled absolutely to leap over houses and trees with my machine. Very soon . . I no longer knew where I was. The gale seized my machine as if it were a piece of paper and drove it along. My heart sank within me. I could not land among those hills. I was compelled to go on. I was surrounded by an inky blackness. Beneath me the trees bent down in the gale. Suddenly, I saw right in front of me a wooded hill. I could not avoid it. I was able to fly only in a straight line. My Albatross managed to avoid its trees. And now I had to quickly avoid every obstacle that I encountered. My flight became a jumping competition. Purely and simply. I had to jump over trees, villages, spires and steeples, for I had to keep within a few yards of the ground . . otherwise I should have seen nothing at all [ in the dark, obscuring rain and violence. ] The lightning was playing around me. At that time I did not yet know that lightning cannot touch flying machines. I felt certain of my death for it seemed to me inevitable that the gale would throw me at any moment into a village or a forest. Had the motor stopped working I should have been done for. Suddenly, I saw that on the horizon the darkness had become less thick. The thunderstorm had passed, over there. If I were able to get that far, I would be saved. Concentrating all my energy, I steered towards the light. Suddenly I got out of the thundercloud. The rain was still falling in torrents, but still I felt . . saved. In pouring rain, I landed at my aerodrome. Everyone had been waiting for me. Metz had reported my start and had told them that I had been swallowed up by a thunder cloud. Withstanding the dangers during my flight, I had experienced glorious moments . . and I now realize that it was all very beautiful. But I shall never again fly through a thunderstorm . . . . unless the Fatherland should demand it. " Source : Manfred von Richthofen's letters to his family |
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