AF 447 report out
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Originally Posted by noland3
to suggest the flight crew did not understand Alternate law is ridiculous
I see no evidence that they tried to manually trim the aircraft
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We have a multitude of examples over the years (AB & Boeing) When the flight crew have pulled instead of pushed, or become completey disorientated.
The functions & limitations of Normal, Alternate & Direct law are taught well before any Airbus pilot begins line flying.
Perhaps the various laws seem like wizadry to someone unfamiliar with the A3xx. A trained crew or anybody with even a basic knowledge of the aircraft will understand what happens when you revert from Normal to Alt and Direct law.
The functions & limitations of Normal, Alternate & Direct law are taught well before any Airbus pilot begins line flying.
Perhaps the various laws seem like wizadry to someone unfamiliar with the A3xx. A trained crew or anybody with even a basic knowledge of the aircraft will understand what happens when you revert from Normal to Alt and Direct law.
Last edited by NOLAND3; 10th Jun 2013 at 10:49.
Oakape - understand your views now, (and concur), thank you.
BOAC, I certainly don't want to let the oozlum bird out of it's cage - however, the contribution of the THS, as discussed by aeronautical engineers here and elsewhere, was not such that the airplane was rendered uncontrollably nose-high once the THS was at its maximum NU deflection of -13.5deg.
In other words, had the stick been placed in the ND position so as to reduce the AoA and unload the wing, (as, I think, Machinbird, said a long time ago, - I know you know this last point - just referencing past work), the elevators, which were still flying, would have brought the nose down and, if the SS were held, (for about 40" in my own sim experiment), the wing would have unstalled.
PJ2
BOAC, I certainly don't want to let the oozlum bird out of it's cage - however, the contribution of the THS, as discussed by aeronautical engineers here and elsewhere, was not such that the airplane was rendered uncontrollably nose-high once the THS was at its maximum NU deflection of -13.5deg.
In other words, had the stick been placed in the ND position so as to reduce the AoA and unload the wing, (as, I think, Machinbird, said a long time ago, - I know you know this last point - just referencing past work), the elevators, which were still flying, would have brought the nose down and, if the SS were held, (for about 40" in my own sim experiment), the wing would have unstalled.
PJ2
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Oozlum permitted, PJ,
(and I did say "Diverting to a larger issue" rather than 447 alone) but do you agree there is little logic in allowing an autotrim to trim ANY tailplane into a setting where it is never normally going to go without saying something to someone and asking 'Are you sure?' My point is that by asking it should trigger the 
in the pilot's mind - "Do I really want to be doing this?" After all, we have t/off config warnings for mis-set trim.
(and I did say "Diverting to a larger issue" rather than 447 alone) but do you agree there is little logic in allowing an autotrim to trim ANY tailplane into a setting where it is never normally going to go without saying something to someone and asking 'Are you sure?' My point is that by asking it should trigger the in the pilot's mind - "Do I really want to be doing this?" After all, we have t/off config warnings for mis-set trim.
- as ridiculous as holding a large amount of back stick well above max permitted altitude? I refer you to Oakape's views.
coffin corner was not actually the issue here
Flight planned altitude was FL 350 with a planned climb to 380 at some point (which due to temp not developing as forecast was apparently not viable at some point before the stall)
To make sure I am clear, had they begun at, say, FL 300 and held back stick for as long as they did, stalling somewhere baround FL 330 - FL 350, the aircraft would still have stalled, and not because of a max altitude broken.
While I appreciate the impact on lift creation of variations in altitude, I don't recall from the report that a service ceiling was busted, but rather that the problem was holding a attitude too high, for too long, to maintain lift.
What am I mis-reading in BOAC's and Clandestino's previous (recent) posts on the matter of "maximum altitude" regarding the report and the series of actions and events that led to achieving minimum altitude?
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'Coffin corner'??? What has that to do with this accident? Now, depending on your meaning of 'Service Ceiling' (eg 100fpm residual rate of climb, max alt for oxygen considerations or max altitude according to WAT limits), I don't know if they bust 1. They did not bust 2 but they did bust 3.
So, that expression is meaningless. Surely any pilot, knowing that he has climbed above his WAT limit would lower the nose, wouldn't you? That is what we mean by 'Max Altitude' and it is probably labelled something similar in the FMC.
So, that expression is meaningless. Surely any pilot, knowing that he has climbed above his WAT limit would lower the nose, wouldn't you? That is what we mean by 'Max Altitude' and it is probably labelled something similar in the FMC.
Hi BOAC - yes, concur with some system that makes auto-trimming of the THS sensible, (IIRC, the A320 auto-trim system on the Perpignan accident stopped trimming when the stall warning occurred, but I'd have to go back to the report and the data - I also recall that it reached 13deg at the same time the stall warning occurred so it may be coincidental - I couldn't find anything in either type's AMM that indicates that the THS stops with a stall warning.
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to suggest the flight crew did not understand Alternate law is ridiculous.
A trained crew or anybody with even a basic knowledge of the aircraft will understand what happens when you revert from Normal to Alt and Direct law.
Surely any pilot, knowing that he has climbed above his WAT limit would lower the nose
Unfortunately the days are long gone where one can assume that, just because an individual is an airline pilot, he/she is capable, well trained & competent.
max altitude according to WAT limits
How is it that WAT has entered the conversation?
Why is "they climbed too high caused the stall" rather than "the AoA was held and maintained too high as airspeed/energy bled off so they stalled?"
What am I missing here?
Go back to the illustration I provided.
Had they begun at FL300, and pulled the same stunt (Held pitch 11-15 degrees and AoA increasing), the maintenance of that high AoA, and subseqent bleeding of energy still stalls them whether or not they reach FL380, or whatever WAT limit for the day was.
That they began closer to the limit was of course a contributing factor.
Why the shift in emphasis?
I do not believe from the report that exceeding the WAT is the cause of the stall.
Let me pose this another way. Were these gents in the goo at 20,000 feet, and held too high of an AoA, and bled energy off without remedy, they'd stall before reaching an altitude limit.
Right?
Originally Posted by ATC Watcher
Accidents such as AF447 or TK1951 to take 2 recent ones, but also the incidents we see in ATC today,( especially those involving STCA and TCAS) strongly point out to a discrepancy between humans operators and automated systems, also programmed by humans, and how both interact with one another.
However, this doesn't imply that those crying "Bad pilots!" are right.
Originally Posted by Lonewolf 50
Why is "they climbed too high caused the stall" rather than "the AoA was held and maintained too high as airspeed/energy bled off so they stalled?"
You are correct in saying that such a severe pitch demand would cause them to run out of energy below MAX REC if they started a few levels lower but it is also true that they would have hit stall warning if they used smaller pitch but insisted on climbing, it would have merely postponed reaching of stall warning AoA.
Further reading: Pinnacle 3701, West Carribean 708, Pulkovo 612.
Originally Posted by Lonewolf 50
What am I missing here?
Originally Posted by Oakape
OK, next question. Is there any indication that the flight crew on AF447 aware that they were in alternate law?
Originally Posted by BOAC
I suspect yes, they knew they were in Alternate Law but did not know what it meant and I'm sure had the 'AB will look after you if you just pull back' message running through their heads.
Originally Posted by BOAC
do you agree there is little logic in allowing an autotrim to trim ANY tailplane into a setting where it is never normally going to go without saying something to someone and asking 'Are you sure?'
Originally Posted by PJ2
IIRC, the A320 auto-trim system on the Perpignan accident stopped trimming when the stall warning occurred,
Originally Posted by PJ2
If they missed it "in the confusion", that is an indication of incompetence
Originally Posted by Oakape
I believe that the crew were of below average flying ability, were inadequately trained & had no business being in the flightdeck of a jet transport aircraft.
Folks, pilots trying to keep the nose up to stall and in it is something we have since there were pilots. Wolfgang Langewiesche described such a case seventy years ago. About eighty years ago, there was young cadet who spun his training glider into ground by holding the stick firmly against the back stop. Fortunately, low wing loading meant he hit with moderate RoD so survived, which was most unfortunate for those who were later caught in sights of his Me-109 over Spain or during the Battle of Britain. His name was Adolf Galland. Would you call him "incompetent" or state he was of "below average flying ability"?
Given enough aggravating circumstances, inappropriate reaction can happen to anyone. That is not to say "we can't do anything about it", trick is to know your aeroplane and know the medium you are flying through so well that when faced with emergency, you can say "Hey, I know how to deal with it" instead of letting the fear coming from inability to understand the predicament you have found yourself in cascade into panic.
While report is disappointingly thin on crews performance in the years preceding the fatal flight, I suspect that investigation did not uncover anything out of the ordinary that would be worth mentioning.
May issue of Aviation Safety World has interesting article. Its title is "Pathological Reactions". Just to give you a sample:
Originally Posted by Wayne Martin, Patrick Murray and Paul Bates
people expect that professional pilots — who
are generally well trained, very experienced
and presumably endowed with
the “right stuff ”15 — will nonchalantly,
competently and flawlessly deal with
critical emergencies to avoid disaster.
Unfortunately, this may not be the case.
Extremely high aircraft reliability
has become the norm, so official findings
after an aircraft accident or serious
incident more often are peppered with
human failings involving the pilots. In
some relatively recent fatal accidents,
the findings showed that flight crews
mishandled critical events and failed
to recover the aircraft [ASW, 8/12, p.
14; ASW, 6/10, p. 32; ASW, 3/10, p. 20;
ASW, 4/11, p. 46]. Typically, there was
some delay in acting, or incorrect action
taken, which exacerbated the problem.
are generally well trained, very experienced
and presumably endowed with
the “right stuff ”15 — will nonchalantly,
competently and flawlessly deal with
critical emergencies to avoid disaster.
Unfortunately, this may not be the case.
Extremely high aircraft reliability
has become the norm, so official findings
after an aircraft accident or serious
incident more often are peppered with
human failings involving the pilots. In
some relatively recent fatal accidents,
the findings showed that flight crews
mishandled critical events and failed
to recover the aircraft [ASW, 8/12, p.
14; ASW, 6/10, p. 32; ASW, 3/10, p. 20;
ASW, 4/11, p. 46]. Typically, there was
some delay in acting, or incorrect action
taken, which exacerbated the problem.
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AF 447
Too much (superfluous) 20/20 fence talking going on here !
No matter what aircraft you fly, holding the stick back WILL lead to a stall
and, if lucky, remain stalled without going into a spin or spiral dive but..............at a high descend rate ! Pilots not interpreting the available information correctly was an unfortunate factor here.
This is what happened here and no theorising is going to change the unfortunate ending of many lives !
No matter what aircraft you fly, holding the stick back WILL lead to a stall
and, if lucky, remain stalled without going into a spin or spiral dive but..............at a high descend rate ! Pilots not interpreting the available information correctly was an unfortunate factor here.
This is what happened here and no theorising is going to change the unfortunate ending of many lives !
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Originally Posted by PJ2
Anyone who thought that the Airbus A320/A330/A340 would be "protected" from the stall in all conditions wasn't paying attention and shouldn't have passed the course. From a 1992 CBT (computer based training) lesson...
CONF iture;
Please...the question is not "either / or"; - we are all much more sophisticated and knowledgable about our craft than that.
There is salesmanship mixed with marketing from airplane makers and everyone else, and then there is the reality of an airplane's design which must be trained, learnt, and understood well.
For me, any pilot who would take the salesmans' view of the airplane's capabilities isn't skeptical enough to learn what the airplane is really about and may end up to be naive as to what it's capabilities are when the chips are down.
Please...the question is not "either / or"; - we are all much more sophisticated and knowledgable about our craft than that.
There is salesmanship mixed with marketing from airplane makers and everyone else, and then there is the reality of an airplane's design which must be trained, learnt, and understood well.
For me, any pilot who would take the salesmans' view of the airplane's capabilities isn't skeptical enough to learn what the airplane is really about and may end up to be naive as to what it's capabilities are when the chips are down.
