AF447 wreckage found
Joined: Sep 2010
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From: Netherlands
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.
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.
Joined: Sep 1999
Posts: 930
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From: United Kingdom
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.
Joined: Jun 2001
Posts: 3,991
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From: UK
I have a Master in aerospace engineering and am working on my PhD (in the area of aerodynamics).
I probably know more than you about stalls.
Joined: May 2011
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From: here
When the media, AF, the investigation and the courts start using those 2 words, i expect an apology ZBMAN.
Joined: May 2011
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From: here
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 !!!
Joined: Jun 2001
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From: UK
Please, refrain from ad hominem attacks, and focus on arguments instead.
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.
Joined: May 2011
Posts: 7
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From: United States
To TheShadow:
Your analysis is based on wrong assumptions:
They know very well, see the repport.
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.
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?)
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.
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 analysis of Flight Safty makes much more sense.
Joined: May 2011
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From: United States
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.
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.
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.
Joined: May 2011
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From: here
He obviously misspoke, because they were in Alternate law, not Abnormal law.
Joined: Nov 2010
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From: formally Cyprus, now UK
I found this CNN report interesting
CNN.com International - Breaking, World, Business, Sports, Entertainment and Video News
CNN.com International - Breaking, World, Business, Sports, Entertainment and Video News
Joined: Jun 2009
Posts: 85
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From: Belgium
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.
Joined: May 2011
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From: United States
Quote:
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.
He obviously misspoke, because they were in Alternate law, not Abnormal law.
Joined: Jun 2009
Posts: 2,167
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From: Australia
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
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.
Joined: Jun 2009
Posts: 2,167
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From: Australia
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*
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*
Joined: Jul 2009
Aviation Qualifications: PPL
Posts: 167
Likes: 56
From: France
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.
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.