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AF447 Thread No. 3

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AF447 Thread No. 3

Old 12th Jun 2011, 23:02
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Cool

Hi,

The passengers would have felt the 40 degree rolls, but I do agree with this "The cockpit voice recorder transcripts will be telling. It will be interesting to see if the vernacular involved is about flying the airplane or system observations."
Instead felt .. can they have seen ???
That's not seat TV screens installed in the Air France A330 ?
This in flight video system (info channel about the flight) was functioning or not ?
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Old 12th Jun 2011, 23:24
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I think a 40 degree bank would have made me put my drink down and tighten the belt.
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Old 12th Jun 2011, 23:25
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Gums,
Somewhere in the cobwebs of this old brain it seems that temperature is a big player to get true mach, especially up high. An SR-71 buddy of mine reminded me of this awhile back, but what do WE know?
I suggest you have a look at this interesting and well documented internet site you kindly gave us in one of your previous posts: "The Blackbird Archive". SR-71 Online - SR-71 Flight Manual: Section 1, Page 1-135
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Old 12th Jun 2011, 23:47
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Originally Posted by jcjeant
Hi,
Instead felt .. can they have seen ???
That's not seat TV screens installed in the Air France A330 ?
This in flight video system (info channel about the flight) was functioning or not ?
we don't know yet, but I am sure this vital parameter is recorded in the FDR data and will be in the next report - if not, I suggest it's a major regulatory failure that you should take up with the relevant authorities! Furthermore, I suggest urgent investigation is needed into whether or not said info channel samples and displays air data often enough and accurately enough to indicate a 10k fpm ROD, whether or not it correctly relays stall warnings, and whether or not said warnings are inhibited below 60kts IAS.
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Old 13th Jun 2011, 00:04
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RetiredF4 - small note. Could you change the subject, "tail was falling faster than the nose"? It conjures visions of a plane split in two, which didn't happen until impact. Without breaking the plane in two the tail can only fall faster than the rest for a short time. When it hits 90 degrees, or sooner, it must then fall at the same rate as the rest.
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Old 13th Jun 2011, 00:28
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My take so far

My take so far.

Hoping to not offend every person on the site. If I do not then I have failed.

I’m just starting to formulate my pretty close to final assessment on the crash. Not much different than all previous feelings.

The Pprune blogs and discussions raise some interesting points and while careful to not ruffle any sensitive feathers, the bulk of what I’ve read so far is pretty much way out of line and off base but nevertheless informative in getting a handle on what the outside world feels about it.

The problems I see are that when you get too deep into the minutiae you miss the forest for the trees.

Among the problems (in no particular order) are the events themselves;

1) In icing which in turn causes pitot tube failures – all 3 of them. So, a triply redundant system fails all at once.
2) This airplane, so reliant on the info from the probes simply shuts down – robbing the pilots from desparately needed information upon which to take action.
3) The auto-pilot and auto throttle click off.
4) The pilots are left with no cogent understanding of which system is controlling the aircraft and unable to figure out the level of control they do have.

The bloggers have a different opinion on the same systems and no one seems to know for sure what controls what on the airplane, and who is doing what to whom.
Further, they have the luxury of sitting in a warm comfortable chair looking at a computer for days and weeks on end trying to analyze what the pilots should have done at the very time they are dis-organized, scared, bouncing around in the middle of the night in a horrendous storm, who must act within literally seconds to analyze and figure what went wrong, what works and what doesn’t, and hopefully do something right.
The test pilots themselves stated that they never contemplated a plane going into a deep stall, and therefore were never able to train pilots to deal with it. Even in the safety of a simulator which never leaves the ground. The emphasis always was to train pilots to veer away from the “approach to a stall”. Simple enough.


5) What has never been addressed is to me the key element: the 7000 ft per minute climb to close to 38,000, when the plane itself could barely maintain it’s maximum level of 35,000 (even though they mentioned wanting to climb to a higher altitude but could not because the temps at their altitude were too warm.)

Note: A normal climb in instrument conditions is a moderate 1000 feet per minute climb. Which I do not know if the plane could attain at that altitude and weight.
A 7000fpm climb could only occur if the pilot nosed up and traded speed for height. First of all an insane maneuvar If it was intentional. Because the result would be running out of speed and altitude at the top which in fact it did.

Alternatively to me it is likelier that an updraft pushed the airplane up. Note in the meteorologists analysis he speculated that there were updrafts that could be as high as 60-70kts which translate to 6000-7000 feet per minute. Whether or not in fact that was the case.

I do know (know?) that powerful thunderstorms are capable of very strong force winds that can easily toss a plane around a lot. Many crashes attest to that.
I’ve personally been involved in strong winds that I could barely overcome. But fortunately in anticipation always carry excessive speed and so far successfully evaded them. But this is close to the ground where the air is thicker and therefore more responsive.

6) One more question I’ve never seen addressed is, when things go awry, or components fail, with time permitting we have checklists that spell out what to do and in what case. Of course some things occur that require instant action, but here with so many things going wrong, it is essential to do the right thing at the right time.

A more comprehensive read out of the Voice Recorder will give us clues to what they were thinking and trying to do.

(note- Not sure if you are familiar with a Quantas A-380 that landed in Australia with multiple failures. They had 5 qualified check captains in the cockpit and it still took 45 minutes to resolve all of the failures and run all the checklists. It ain’t simple.)

(I must respond to the Ministry of Transportation’s analogy of the flat tire: It is more likened to not a flat tire, but the car rolling over and over and the driver covered in blood and then trying to navigate a road with the bridge out. What does he do and when?)

7) Finally to me one thing is certain. If they didn’t fly head on into a thunderstorm, none of this would have happened. Cost more money? Perhaps. Take more time? Perhaps.
Fly a different route? Why not? Land at an alternate? Cost money, Takes time, but ask the passenger, what does he think?

And finally again for a bigger question: What to do about all of this? Scrap the airplane? Scrap the technology? Impossible. And way too costly.

However, there are some homilies that apply. Be careful. Any port in a storm. Better safe than sorry. Penny wise and pound foolish.
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Old 13th Jun 2011, 00:34
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bearfoil, I missed this the first time I read it. When I was reading RetiredF4 reply to you this quote REALLY bugged me: "This is a heavy a/c with beaucoups energy to sustain a short climb of 3k feet?"

What does mass have to do with the price of altitude in terms of speed change?

Kinetic energy is 1/2 mV^2. Potential energy is mgh. So the mass washes out of the equation. So a 3000' climb would give "gh" = 1/2 v^2 = 96000 ft^2/s^2 equals about a 438 '/s velocity change or about 300 MPH.

Of course a clean heavy aircraft will have this simple equation modified less by air friction than might a nerf ball. But somehow I figure military fighter jets are not nerf balls either. I'd expect the military jet tradeoff to be pretty close to the AirBus tradeoff in terms of altitude gain and velocity lost.

But, then, what do I know? I'm just an engineer.
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Old 13th Jun 2011, 00:40
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Originally Posted by rr_ndb
Pitot´s failure (e.g. at cruise) are not sudden ("digital"). They start to be transformed, in altimeters for example, gradually. Thiells 727 (NW N274US) showed this gradual deterioration. I think that an encounter of a dangerous icing condition when cruising, is also gradual, technically allowing a warning (of this crucial info) before "law switching" by the Systems.
RR_NDB, please meet BEA Release, especially the rather highlighted piece of the report.

Originally Posted by BEA Release
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).
A "sharp fall" is not a gradual drop.
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Old 13th Jun 2011, 00:48
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Mr. Optimistic, please review the Tim Vasquez plots of the storm and the plane's position in the storm. Check the visibility of the Moon at that time and location.

In order to see you need clear air, a light source, and something to see. I submit that they had two of them at some point but never had all three. I'm not sure such starlight as might have managed to get through the upper layer obstructions would have been enough.

edit: Specifically the half Moon was in its last 40 minutes before it went down. They were well into the storm. Maybe enough Moonlight was able to get through to show some glints on the ocean surface. The Moon was on a line with the line of clouds, though.

Last edited by JD-EE; 13th Jun 2011 at 01:22.
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Old 13th Jun 2011, 01:00
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Henra,
I think it is not acceptable to post this kind of rubbish about what you call a sub-standard aircraft configuration based on the limited amount of data we have at the moment.
There was a really good discussion going on about the technical aspects.
Can we please refrain from spoiling this with this kind of drivel ?!
Drivel? You got to be kidding me! The only drivel is this that produced by this quasi accident investigation from the BEA.

It is perfectly acceptable to suggest that the aircraft configuration was sub-standard. The BEA report is so vague and ambiguous that it is obviously only possible to make sense of it by some process interpretation, and it is obvious what interpretation was intended. In the course of releaseing such an incomplete picture, it seems that it is perfectly acceptable for the media to insinuate that the pilots were substandard despite the aircraft switching off its warnings and dynamically changing its behaviour during what would be the upset recovery phase of that flight.
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Old 13th Jun 2011, 01:01
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Savrin, this is from the June 2009 report:
FCPC2(2CE2)/WRG:ADIRU1 BUS ADR1-2 TO FCPC2 (2 h 10)
ATA: 279334
Source: *EFCS1
Identifiers: *EFCS2
Class 2, HARD

This message indicates that FCPC 2 no longer considers as valid the information that is delivered to it by ADR 1 (via bus 2). The ATA code beginning with 27 indicates that the fault was not detected by any other FCPC during the three seconds that followed (otherwise this message would have been classified ATA 34). This message has not been fully explained at this stage of the investigation.
This is from the 30 November 2009 report:
FCPC2 (2CE2)/WRG:ADIRU1 BUS ADR1-2 TO FCPC2 (2 h 10)
ATA: 279334
Sou rce: *EFCS1
Identifiers: *EFCS2
Class 2, HARD
It is possible to explain this message by the rejection of ADR 1 by FCPC 2. It is correlated with the MAINTENANCE STATUS EFCS 1 and EFCS 2 messages.
Neither believes this is a wiring problem. What makes you insist WRG means wiring rather than warning? I realize there are WRN and WRG messages. There does not seem to be a distinction between them as listed by BEA.

A coincidence that would cause an AIRINC bus to quit working in only one direction would be surprising. And if it's not an AIRINC bus (or multiple AIRINC busses) then it's a multipin connector with inputs and outputs on the same connector. Why would only one direction fail? Why would it fail only in modest turbulence and not be discovered before that turbulence? That's too many hard failures at once for my tastes.
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Old 13th Jun 2011, 01:04
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Heathrow Flyer - sure the leaks stopped. AirBus has no incentive to leak anymore.
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Old 13th Jun 2011, 01:45
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Chill ma'am, have a cocoa. You insinuate with a broad brush that Airbus has no further need to 'leak'. Does that mean you have begun to look a bit askance at the player(s)? I think 447 is entitled to negotiate energy for altitude, No?

Wait, what is the net deltaE? Can I say that? From 0.82M to tail slide in 60 seconds? At an average velocity of (Reported) 4,000fpm? Both engines were running at cruise thrust, I can't see where my opinion deserves such savagery.

Explain? Small Data, Bold imagery?


edit. I should let RR speak for himself, but you miss the logic in his example.

He speaks of Onset, Emergence, and Presentation. Gradual, it is an ok thing.

Are you thinking the airdata was bunk? That the reads were bogus? They could have been actual, which would explain the attenuation of the cricketSTALL <60knots. And its reacquisition for the "Real" cricket Stall.

The a/c thought it was ok to climb, it helped. It trimmed while the PF worked the elevators. At the top, the elevators were exhausted, and the THS was 'stuck' (to include PE, possibly)?

Last edited by bearfoil; 13th Jun 2011 at 01:58.
 
Old 13th Jun 2011, 02:32
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Cool

Hi,

infrequentflyer789

we don't know yet, but I am sure this vital parameter is recorded in the FDR data and will be in the next report - if not, I suggest it's a major regulatory failure that you should take up with the relevant authorities!
You can be sarcastic (if I well understand your intention) .. it's not a problem .. and I like also black humor
Nevertheless .. be sure that the families lawyers will try to know by all means if the passengers suffered before their final fate ( knowing they were to dying)
It's a important point for lawyers .. as the financial compensation will be far more substencial if they can establish that the passengers suffered before dying .....
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Old 13th Jun 2011, 03:09
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Wow - you go away for a few days and the thread almost goes belly-up. From what I see there are now attempts to argue that the BEA's press "note" should be treated as a report, and thus the BEA deserve to be slammed for not releasing enough information (which is IMO utterly ludicrous - why do I get the feeling that the NTSB or AAIB would not be under this much scrutiny?), people still trying to blame the aircraft and systems based on the flimsiest of theories, and many of the same people arguing that to do otherwise somehow equates to "blaming the pilot". Full marks to PJ2 and others who've been trying to keep things shiny-side to the sky.

Originally Posted by Svarin (emphasis mine)
But the initial 3000 feet climb, 10 degrees and more pitch-up is unlikely to be "pilot error", even though some powers that be, and hordes of blindly faithful technology worshippers would prefer it to be so.
I'd love to know how you've come to that conclusion. I've been reading the therad from the start and I'm pretty sure that other than a couple of interjections, no-one has been arguing that the accident was the result of "pilot error" and leaving it at that. In fact the only people I've seen trying to apportion blame on this thread are the people who are constantly looking for ways to blame the aircraft and the manufacturer based on their own personal agendas. Pretty much everyone else has (wisely IMO) said "wait and see". As I said, very few other air accident investigation units tend to release CVR transcripts until a final report is written - why the undue pressure from some on here towards the BEA?

Originally Posted by wallybird7
I’m just starting to formulate my pretty close to final assessment on the crash. Not much different than all previous feelings.
Isn't that a bit cheeky, seeing as all we have is a press note and a lot of speculation?

2) This airplane, so reliant on the info from the probes simply shuts down – robbing the pilots from desparately needed information upon which to take action.
Not unique to this aircraft, as has been said countless times. When this happens the correct thing to do is fly pitch and power. Not that this is necessarily easy when you've got a bunch of warnings going off, of which at least some may be spurious, but eminently do-able.

3) The auto-pilot and auto throttle click off.
4) The pilots are left with no cogent understanding of which system is controlling the aircraft and unable to figure out the level of control they do have.
Uh, if a pilot is incapable of working out that upon A/P disconnect that the system that is controlling the aircraft is in fact them, then there's something seriously wrong in their training, surely?

The bloggers have a different opinion on the same systems and no one seems to know for sure what controls what on the airplane, and who is doing what to whom.
Again, those on here who are either FBW Airbus pilots or who have systems-level knowledge seem to know exactly what's going on. Most of the confusion has been engendered by people throwing theories in either from a position of relative ignorance or because they have an agenda.

The test pilots themselves stated that they never contemplated a plane going into a deep stall, and therefore were never able to train pilots to deal with it. Even in the safety of a simulator which never leaves the ground. The emphasis always was to train pilots to veer away from the “approach to a stall”. Simple enough.
Wrong again. The "test pilots" would have been quite capable of taking the aircraft to a genuine stall as part of certification testing. You're confusing line pilot stall/incipient stall training (which certainly looks deficient with 20/20 hindsight) with Airbus's own testing of it's aircraft and systems.

(note- Not sure if you are familiar with a Quantas A-380 that landed in Australia with multiple failures. They had 5 qualified check captains in the cockpit and it still took 45 minutes to resolve all of the failures and run all the checklists. It ain’t simple.)
That's an apples/oranges comparison. There's a major difference between troubleshooting an engine failure on a relatively new aircraft type with all-new engine technology and getting things ready to come in for a landing, and diagnosing a pitot probe blockage/loss of airspeed data on an aircraft that's been in service for over a decade.
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Old 13th Jun 2011, 03:10
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Bearfoil
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Chill ma'am, have a cocoa. You insinuate with a broad brush that Airbus has no further need to 'leak'. Does that mean you have begun to look a bit askance at the player(s)? I think 447 is entitled to negotiate energy for altitude, No?
Bearfoil, do you ever stop to take a breath? Your logic was flawed and the engineer pointed that out. You should really review your thoughts a bit before posting.
And FYI, AF447 never did a tail slide as you seemed to infer. I suggest you read/re-read Davies "Handling the Big Jets" for comprehension.
If you don't want the engineers and physicists to pounce on you, try to avoid stomping all over Newton's laws and relevant facts that BEA has released. Of course, if all you wish is attention, carry on.
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Old 13th Jun 2011, 03:23
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Bearfoil

Oi mate! ..."The a/c thought it was ok to climb, it helped."

The aircraft is nuts and bolts, circuits and wires and magic copper coils.... but it doesn't think.
GIGO, and you know it.

...and where are you getting that the THS was "stuck"?
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Old 13th Jun 2011, 03:52
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PF Action in Last 30 secs - Did He Increase Thrust?

Quote:
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.

I have deduced from all the learned comments here that nose down inputs were probably made during the last 30 seconds of flight. Do we know whether increased thrust was initiated by the pilot who took over in those last 30 seconds and if not would it have made any difference ? Was the AoA still too high for the aircraft to gain enough air speed for adequate lift ?
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Old 13th Jun 2011, 04:14
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System "Pitot DSP are amplifying" Pitot problems?

Hi,

BEA sequence is: AP quits, AT quits, RH roll, PF action, SW, SW... Sharp fall from LH Pitot then a few moments later from ISIS Pitot

I suspect the "processing" of Pitot data (signal conditioning, voting, etc.) is amplifying Pitot problems. Probably (to be confirmed by FDR) AP, AT quit before ISIS showed lower speed.

The speed falling seems typical of stagnation point and not drain. And the event seems to be "short lived". Question? The a/c System needs this kind of sensitivity? Why can not during short duration failures remain alive? Well, this was discussed earlier and IIRC they are developing a "band aid" to deal with this "short term" Pitot failures.

In summary, my rationale is:

1) An EW seems to be simple to implement and may be could be useful (as a band aid) to alert to something more serious.
2) May be the a/c System can still operate properly using "improved" algorithms or even also using alternate data (while Pitot´s during short period are not delivering same output).
3) We need to power modulate Pitot´s with extra Watts (last but not least) while waiting R&D, Cert. and perhaps new type of sensors for "real redundancy".
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Old 13th Jun 2011, 04:42
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"The speed falling seems typical of stagnation point and not drain."

I agree. However, if the drain plugged first, the first invalid excursion of a/s would be an increase. If the aperture plugged up with the drain, stagnation, and "frozen" sense of "a/s" read while both holes remain plugged. If the drain unplugged before the Aperture, the ias would approach zero.

So, if these pitots plugged in this fashion, and close to the same time, the A/S would be reported as "accurate", and faster than she was actually flying.

Also, a rapid and consistent increase in a/s could trigger WindshearAlert. It could also trigger OverSpeed alert, etc. These artifacts are present in the ACARS.
 

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