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AF447 wreckage found

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AF447 wreckage found

Old 29th May 2011, 08:05
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I really wasn't going to reply again but... like a tickle...

fullforward, people like me? I have a Master in aerospace engineering and am working on my PhD (in the area of aerodynamics). I don't appreciate being labeled 'people like you'. I probably know more than you about stalls.

The fact is, and this is an indisputable FACT, the plane was fully functioning and the pilots crashed this plane into the ocean. Talking about auto-trim, psychological anomalies or design flaws are the conspiracy here, not me stating the obvious that the pilots didn't know how to fly the plane. Don't shoot the messenger.
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Old 29th May 2011, 08:09
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A good post shadow. Interesting in that on a few occasions in the little bus on a normal go around the a/c some times over pitches with the speed reducing below VLS Airbus then had to change some control protections to include a mod to the speed reversions. Having said that disconnecting the auto guidance & applying some fwd stick puts things back to normality. I have not had that problem with the big bus. However a pilot must realise that the automatics are not infalable just like pilots aren't either.
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Old 29th May 2011, 08:12
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I have a Master in aerospace engineering and am working on my PhD (in the area of aerodynamics).
but, wafelbolletjes, with all respect, are you a pilot?

I probably know more than you about stalls.
That may, or may not, be true but that doesn't mean you would/could do any better than these pilots in the situation they found themselves.
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Old 29th May 2011, 08:13
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When the media, AF, the investigation and the courts start using those 2 words, i expect an apology ZBMAN.
He won't owe you one. This isn't about you turning out to have been right or not. This is about you jumping to conclusions and condemning people without the knowledge and the facts to back it up.
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Old 29th May 2011, 08:17
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but, wafelbolletjes, with all respect, are you a pilot?
Please, refrain from ad hominem attacks, and focus on arguments instead.
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Old 29th May 2011, 08:24
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Will the pilot be aware that he's in abnormal Law? (and the portents of that)" The answer might well be: "Probably not" (there's nothing to promote awareness of this being the case i.e. no aural annunciation - and thus we arrive at: what now needs to be done that's essential for recovery?)
AH no??? The PF announces Alternate Law when he takes manual control of the aircraft. It is in one of the first lines in the BEA communication !!!
He's talking about Abnormal law, not Alternate law. The relevant difference here being autotrim not working in Abnormal law.
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Old 29th May 2011, 08:26
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Please, refrain from ad hominem attacks, and focus on arguments instead.
abovethesky, it wasn't an attack, merely a request for information!

It is relevant to the matter under discussion. Whilst having every respect for those having technical qualifications far superior than a mere mortal pilot, such as I, unless you have done or are doing the job as a pilot you really have little appreciation of what these pilots were faced with.

There is too much condemnation going on here of the pilot's actions, especially when we don't know all the facts.
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Old 29th May 2011, 08:26
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To TheShadow:
Your analysis is based on wrong assumptions:

Three questions: 1. "Will the pilot be aware that he's in abnormal Law? (and the portents of that)" The answer might well be: "Probably not" (there's nothing to promote awareness of this being the case i.e. no aural annunciation - and thus we arrive at: what now needs to be done that's essential for recovery?)
They know very well, see the repport.
2. "Does the elevator alone have sufficient authority to unstall the wings at max power or at idle?" The answer is probably not, at least not while the superior trim authority of the THS at 13 degs n/up holds sway.... and particularly not whilst at TOGA power.
3. "Why doesn't the elevator have sufficient authority to unstall?"
The whole design premise of the THS is to reduce trim drag and allow the elevator to become more of an active trim and less of a primary flight control. This ideation works well 99.99% of the time and it's used in all models of airliners to some degree. They need the capability of coping with large CofG ranges to accommodate loading, fuel burn-off and configuration changes. Some aircraft augment this capability with tail-located fuel trim-tanks. However this minimalistic elevator design feature in the A330 apparently won't "work" in the progression of events that AF447 underwent.
The PF didn't even try nose down. He wanted nose up. So all the speculation whether we would have been capable of bringing the nose down (elevator, trim) is mood.

The analysis of Flight Safty makes much more sense.
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Old 29th May 2011, 08:31
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He's talking about Abnormal law, not Alternate law. The relevant difference here being autotrim not working in Abnormal law.
He obviously misspoke, because they were in Alternate law, not Abnormal law.
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Old 29th May 2011, 08:35
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abovethesky, it wasn't an attack, merely a request for information!

It is relevant to the matter under discussion. Whilst having every respect for those having technical qualifications far superior than a mere mortal pilot, such as I, unless you have done or are doing the job as a pilot you really have little appreciation of what these pilots were faced with.

There is too much condemnation going on here of the pilot's actions, especially when we don't know all the facts.
Nobody who isn't a pilot can imagine how it is in such a situation.

Nevertheless, it is a valid question why the PF didn't try to unstall by nose down, and this question is valid no matter who asks it.

See also the link provided by Flight Safty.
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Old 29th May 2011, 08:39
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He obviously misspoke, because they were in Alternate law, not Abnormal law.
That's the point, we don't know (yet) if at some point law switched to abnormal. Low airspeed and high AoA to trigger it were present in any case.
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Old 29th May 2011, 08:40
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I found this CNN report interesting

CNN.com International - Breaking, World, Business, Sports, Entertainment and Video News
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Old 29th May 2011, 08:41
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Nevertheless, it is a valid question why the PF didn't try to unstall by nose down, and this question is valid no matter who asks it.
Imo the most likely explanation is that they did not believe or realise they were actually stalled. Not until it was too late, anyway.
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Old 29th May 2011, 08:43
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face down *** up thats the way planes like to ****!

It's also how you recover from a stall.
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Old 29th May 2011, 08:46
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Quote:
He obviously misspoke, because they were in Alternate law, not Abnormal law.
That's the point, we don't know (yet) if at some point law switched to abnormal. Low airspeed and high AoA to trigger it were present in any case.
Leaving aside wired conspiracy theories, we know very well. Abnormal law enables only in case of extreme attitude, which definitely wasn't the case.
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Old 29th May 2011, 08:55
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Gee and I thought this was the "Professional Pilots rumor network"

There is no "Abnormal" Law on the FBW Airbus.

Normal
Alternate 1
Alternate 2
Direct

Ok.

got it?

Good


Correction.........see below

Last edited by nitpicker330; 29th May 2011 at 09:09.
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Old 29th May 2011, 09:02
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Ok, Let me re-post the Quick Reference Handbook information on just what these guys faced. This info was available long before this accident. It may also help to explain to those that don't fly the Airbus.

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*
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Old 29th May 2011, 09:03
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There is no "Abnormal" Law on the FBW Airbus.
There is. But it happens only under a so exotic condition that it's usually not mentioned.
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Old 29th May 2011, 09:07
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Above the sky....... Yes I must apologize you are correct. I just looked at FCOM 1 and it applies during abnormal attitudes.......

I'll take my foot out of my mouth now
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Old 29th May 2011, 09:11
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1. This crew got killed in their frantic struggle with an erroneous system. There are flaws in the system that prevented them from correctly recognizing the situation.
Air France Pilots Were Probably Confused by Cockpit Instruments in Crash - Bloomberg
"The data and cockpit voice recording suggest the pilots never realized that the plane had stalled, BEA Chief Investigator Alain Bouillard said in an interview. “They hear the stall alarm but show no signs of having recognized it,” he said. “At no point is the word ‘stall’ ever mentioned.”

2. The PF did try to pitch down. The system acknowledged this effort with a renewed stall warning. He did probably not try again.

Criminal neglect is to blame at this stage somebody who is not here anymore to explain his actions, instead of questioning the entire system including training.
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