AF 447 Thread No. 6
Mr Optimistic
RF4 thanks. Only one comment: no rudder?
RF4 thanks. Only one comment: no rudder?
The yawing and the problems of the PF to reestablish wings level flight was imho caused by using ailerons at that high AOA.
One interesting paragraph i forgot in the above post, it is from the introduction part and should have been on the top:
Note the thing about tactile feedback.
All modern jet transports are certified to exhibit adequate warning of impending stall to give the pilot opportunity to recover by decreasing the angle of attack. Whether this warning is by natural aerodynamic buffet or provided by a stick shaker or other warning devices, it warns the pilot when the angle of attack is getting close to stall. Moreover, the warning is required to be in a form other than visual. The pilot need not look at a particular instrument, gauge, or indicator. The warning is tactile: the pilot is able to feel the stall warning with enough opportunity to recover promptly. Pilots need to be especially cognizant of stall warning cues for the particular airplanes they fly. The onset of stall warning should be taken as an indication to not continue to increase the angle of attack.
Given the very high AoA during the descent, it is surprising that the ailerons were effective enough for roll to be (reasonably) controlled. Not much point looking at how well teh PF controlled roll under these circumstances, at least in terms of judging his sidestick touch. Presume the ailerons were acting as drag modulating devices rather than Cl adjusters. Not so very much more and the wing would have been going backwards (AoA >90 degrees).
Interesting quotes though, so thanks again.
Interesting quotes though, so thanks again.
Join Date: Jul 2011
Location: Northern Hemisphere
Posts: 195
Likes: 0
Received 0 Likes
on
0 Posts
AlphaZulyRomeo,
At a re-read of your text, that last paragraph of my post is to be ignored. Originally I was not 100% if my reading of your text was correct, and at a re-read I realize that it was a misunderstanding.
At a re-read of your text, that last paragraph of my post is to be ignored. Originally I was not 100% if my reading of your text was correct, and at a re-read I realize that it was a misunderstanding.
Join Date: Aug 2011
Location: Grassy Valley
Posts: 2,074
Likes: 0
Received 0 Likes
on
0 Posts
AlphaZuluRomeo
Yes, I was speaking of Alpha protections lost. I was party of a very long discussion on Rudder/Vertical Stabiliser issues long ago, and understand reasonably well the RTLU.
The PITCH is protected "IN" 'g' ? OR "BY" 'g'? Its PROT is time discrete, as it prevents transient exceedance of PITCH loads.
It demonstrably does not prevent high angles of Attack see: "the climb"
In fact, as long as the a/c rotates within a 'g' envelope, there seems to be no functional limit of PITCH UP.
Now here is the problem with that, as I see it.
447 entered the climb without a STALL protection, and STALLED. She climbed at a rapidly inceasing PITCH value, but with a controlled RATE OF CHANGE.
Wasn't PF using 'g' prot as his NORMAL LAW "stand-in"? No immediate and seat crushing PITCH UP, but a steady excursion toward the STALL AoA?
So I see "G" PROTECTION as a de facto airframe limiter, which not only prevents over load, but allows LOC, and in Losing Control, "G" PROT, having allowed it, prevents recovery "FROM IT".
How can I say that? Because the TRIM started to LOAD the airframe, in STALL, when to unload it, or allow it to be unloaded, would facilitate recovery.
Nothing Earthshattering about this, it is a point of view. Will you attempt to see it that way for purpose of understanding?
Climbing UP, PF had an airframe that appeared NORMAL, but was rotating to absurd PITCH UP. By that I mean, his climb was incremental, and indicated no disaster in the offing. (possibly).
If PILOT/PLANE communication is critical, wouldn't the a/c have annunciated to the crew[/I] that pilot input was being g managed?
In a perfect world, one then says "but he should have known this", no denying. Was there an clear alert that instructed the manual pilot that basic, and life protecting systems were operating the Plane, and not he?
I have a sinking feeling that the PF was possibly unaware "g" was molding his inputs to an incremental PITCH UP that he may have sussed was not potentially very hazardous. Otherwise, why the gruff Stick demands?
add. "Attitude" and 'g' PROT are not related. There can be (have been) circumstances where 'g' PROT might have wanted to be sent packing?
The chronic application of PITCH UP by this pilot is made easier to understand (by me), when one imagines the environment, the lack of "Response", and the inappropriate nature of some of the cueing.
THS. There is a command in medicine, that applies to the inappropriate automatic application of TRIM:
"First, do no harm"...... perhaps engineers should have a short 101 in patience at onset of disaster, as well as Physicians.
Yes, I was speaking of Alpha protections lost. I was party of a very long discussion on Rudder/Vertical Stabiliser issues long ago, and understand reasonably well the RTLU.
The PITCH is protected "IN" 'g' ? OR "BY" 'g'? Its PROT is time discrete, as it prevents transient exceedance of PITCH loads.
It demonstrably does not prevent high angles of Attack see: "the climb"
In fact, as long as the a/c rotates within a 'g' envelope, there seems to be no functional limit of PITCH UP.
Now here is the problem with that, as I see it.
447 entered the climb without a STALL protection, and STALLED. She climbed at a rapidly inceasing PITCH value, but with a controlled RATE OF CHANGE.
Wasn't PF using 'g' prot as his NORMAL LAW "stand-in"? No immediate and seat crushing PITCH UP, but a steady excursion toward the STALL AoA?
So I see "G" PROTECTION as a de facto airframe limiter, which not only prevents over load, but allows LOC, and in Losing Control, "G" PROT, having allowed it, prevents recovery "FROM IT".
How can I say that? Because the TRIM started to LOAD the airframe, in STALL, when to unload it, or allow it to be unloaded, would facilitate recovery.
Nothing Earthshattering about this, it is a point of view. Will you attempt to see it that way for purpose of understanding?
Climbing UP, PF had an airframe that appeared NORMAL, but was rotating to absurd PITCH UP. By that I mean, his climb was incremental, and indicated no disaster in the offing. (possibly).
If PILOT/PLANE communication is critical, wouldn't the a/c have annunciated to the crew[/I] that pilot input was being g managed?
In a perfect world, one then says "but he should have known this", no denying. Was there an clear alert that instructed the manual pilot that basic, and life protecting systems were operating the Plane, and not he?
I have a sinking feeling that the PF was possibly unaware "g" was molding his inputs to an incremental PITCH UP that he may have sussed was not potentially very hazardous. Otherwise, why the gruff Stick demands?
add. "Attitude" and 'g' PROT are not related. There can be (have been) circumstances where 'g' PROT might have wanted to be sent packing?
The chronic application of PITCH UP by this pilot is made easier to understand (by me), when one imagines the environment, the lack of "Response", and the inappropriate nature of some of the cueing.
THS. There is a command in medicine, that applies to the inappropriate automatic application of TRIM:
"First, do no harm"...... perhaps engineers should have a short 101 in patience at onset of disaster, as well as Physicians.
Last edited by Lyman; 21st Aug 2011 at 14:51.
Join Date: Dec 2006
Location: Florida and wherever my laptop is
Posts: 1,350
Likes: 0
Received 0 Likes
on
0 Posts
Only THS made NU effective?
Quote Clandestino:
Originally Posted by Rudderrudderrat
In ALT LAW, when he relaxed back pressure, the aircraft maintained it's nose up attitude as the speed washed off.
Just when did he relax the backpressure? You are acquainted with sidestick traces from 3rd intermediate report, aren't you? A couple of times stick goes forward but quickly gets behind neutral again and stays there before elevators even have the chance to get to neutral.
Originally Posted by Rudderrudderrat
In ALT LAW, when he relaxed back pressure, the aircraft maintained it's nose up attitude as the speed washed off.
Just when did he relax the backpressure? You are acquainted with sidestick traces from 3rd intermediate report, aren't you? A couple of times stick goes forward but quickly gets behind neutral again and stays there before elevators even have the chance to get to neutral.
If (as suggested earlier) the THS had remained at NEUTRAL rather than chasing the NU input during a stall, would the PF NU inputs have been enough with elevator alone to maintain nose up into a deep stall? Was it only the added authority of the THS that allowed the aircraft to be kept in the stall?
Perhaps with elevators alone and a THS neutral the aircraft would have dropped its nose, then (had PF kept NU) after getting flying speed its nose would come back up. Perhaps PF was expecting this nose drop 'nodding' behavior? Its what would happen in a lot of gliders and light aircraft and he was glider qualified. The lack of this nose drop possibly convinced PF that the aircraft could not be in a stall.
Was there any training or flight envelope information available to A330 crews that told of the possibility of deep stall? There seems to have been quite a lot on 'spurious' stall warnings.
So without any knowledge of deep stall, with THS having sufficient authority to hold the aircraft in a stable deep stall so no nodding ND, and previous information about spurious stall warnings: everything seems to be set up for a confused PF.
Join Date: Nov 2010
Location: FR
Posts: 477
Likes: 0
Received 0 Likes
on
0 Posts
Lyman,
Let's go step by step:
- I do agree that the autotrim going full UP is a bad idea. Re-read my previous posts (discussion with airtren) on the subject.
- I do agree that AoA/stall (hard) protection and pitch (hard) protection were lost on AF447. That's the very raison d'être of the Alternate Law: when the plane can no more grant full protection, it reverts to Alternate (or Direct, if failures are more than what allows Alternate to be invoked).
You're saying - unless I'm mistaken - that "g demand" flight controls are dangerous and "unknown" of the pilot?? May I remind you that the Normal Law is also g demand? May I remind you that, apart from Dassault's Falcons, all FBW civilian aircraft use the g demand philosophy? There is no need of being in a perfect world for hoping that pilots know that!!
Yes there was. ALT LAW (PROT LOST) on the ECAM means just that. And this was acknowledged by the crew (see CVR transcript).
On a side note, I wouldn't call the g protection (nor the whole g demand law) "life protecting systems". They're:
- structural protecting systems for the g protection
- standart way of flying the aircraft for the g demand law.
Nor the g protection, nor the g demand controls alone will prevent any pilot to do what he wants with his plane (even stalling it, or recovering it from stall).
It will only - if needed - prevent him to do it too fast for the aircraft structure to cope with. The aircraft will retain its wings. Good idea, isn't it?
On the whole, I don't get it. What are you trying to prove? That a pilot must know its plane? I took that for granted...
I do agree that a PPL being thrown in AF447's cockpit could have difficulties with the g demand law. But we're talking of a professional crew, here, with ATPL & type rating licences.
Let's go step by step:
- I do agree that the autotrim going full UP is a bad idea. Re-read my previous posts (discussion with airtren) on the subject.
- I do agree that AoA/stall (hard) protection and pitch (hard) protection were lost on AF447. That's the very raison d'être of the Alternate Law: when the plane can no more grant full protection, it reverts to Alternate (or Direct, if failures are more than what allows Alternate to be invoked).
On a side note, I wouldn't call the g protection (nor the whole g demand law) "life protecting systems". They're:
- structural protecting systems for the g protection
- standart way of flying the aircraft for the g demand law.
Nor the g protection, nor the g demand controls alone will prevent any pilot to do what he wants with his plane (even stalling it, or recovering it from stall).
It will only - if needed - prevent him to do it too fast for the aircraft structure to cope with. The aircraft will retain its wings. Good idea, isn't it?
On the whole, I don't get it. What are you trying to prove? That a pilot must know its plane? I took that for granted...
I do agree that a PPL being thrown in AF447's cockpit could have difficulties with the g demand law. But we're talking of a professional crew, here, with ATPL & type rating licences.
Join Date: May 2011
Location: here
Posts: 131
Likes: 0
Received 0 Likes
on
0 Posts
Was there any training or flight envelope information available to A330 crews that told of the possibility of deep stall? There seems to have been quite a lot on 'spurious' stall warnings.
Join Date: Feb 2011
Location: Nearby SBBR and SDAM
Posts: 875
Likes: 0
Received 0 Likes
on
0 Posts
The "inputs" PF (and crew) received
Hi,
dufc,
The "information" (we don't have it) PF received (when a/c was operating outside* it's design) led him to an "strange behavior". We need more info to understand PF persistent NU.
When 3 qualified pilots fail, even to "understand timely", probably we have something very serious in the a/c (design, cert, training, operation, etc). The very basic info MUST be absolutely reliable and presented in real time by the a/c resources to the crew. Complex machines may fail in this aspect. And should not...
(*) F-GZCP at that night, operated "outside design":
1) Facing WX (icing)
2) Too high (briefly)
3) Stalled
dufc,
The "information" (we don't have it) PF received (when a/c was operating outside* it's design) led him to an "strange behavior". We need more info to understand PF persistent NU.
...suggests to me that in essence they had no idea what was going on or where to start to resolve things.
(*) F-GZCP at that night, operated "outside design":
1) Facing WX (icing)
2) Too high (briefly)
3) Stalled
Vielen Dank, Franzl, for posting "Pilot guide to aeroplane upset recovery". It is very useful reading, learning lessons from it might save someone's flying rear yet but I do not think it is applicable to AF447 case. It mentions that definition of aeroplane upset includes unintentional.
Beyond any doubt, pulling the aeroplane into stall was not intentional, however aeroplane did just what she was commanded to. Looks as if 447's crew simply forgot how to fly an aeroplane. So crashed.
My sincerest apologies, sir. I was under distinct impression I was debating with professional pilot, rated on FBW Airbus. I mistakenly believed that we share some common background so there would be no need for me to go into details that are ingrained in basics of airline pilots training, such as technique of instrument flying. I now see that by omitting the details I believed would be familiar to you, my answers came across as quite harsh, snobbish and disrespectful. It was not my intention. From now on I'll try to dumb it down to level of high school physics.
Most important and most often checked information in "blind flying" is attitude. If one cannot read it properly or cannot maintain it properly, the rest of instrument scan is in vain.
When pilot is handflying by sole reference to instruments, it is important to keep movement smooth and precise to avoid unnecessary maneuvering that might upset pilot's sense of balance and induce illusions of turning or banking. Pilots who, when without outside visual reference, start flying by their senses instead by their instruments, get far more often killed than not. That is known fact that is with us since there were first instrument flights and no amount of sophistication and automation is able to isolate us from it, as was correctly, in more general terms, predicted by Antoine de Saint-Exupery.
So, as instrument rated pilot, I don't fly by feeling Gs, I fly by reference to my instruments.
Non, monsieur. You are mistaking the angle of attack and pitch. Pitch is angular difference between aeroplane's longitudinal axis and horizon. Angle of attack. in the most layman's terms, is angular difference between where nose of the aeroplane is pointing and where aeroplane is travelling to through air (velocity vector), measured in aeroplane's vertical plane. So AF447 was traveling at 2.5° cruise AoA and recieved first two stall warning as it was pitching up in turbulence, they were quite short and only transient and stopped promptly. It is also important to understand that stall warning sounds before actual stall takes place. It is certification requirement, purpose of which is for pilots to have enough time to make corrective actions before actual stall takes place.
Old unreliable airspeed procedure directed pilots to fly 2.5° attitude and power from table. New procedure, valid at time of AF447 final dive, called for setting 5° pitch with climb power for a couple of seconds, while PNF takes out the table of pitch-against-power from QRH and then power and attitude are set accordingly. 2.5° pitch is fine if you know your cruise power by heart. With climb power it would likely result in overspeed.
I would expect them to do exactly that as UAS procedure valid at the time of crash demands it. Page 59 of accident report refers. Your gut feeling is correct, I have explained why a few pages ago.
Demanded load factor was met by elevators alone. Reason? High dynamic pressure at start of the climb.
They maintain attitude when stick is pitch neutral. In normal and altn law they are programmed to meet G demand set by sidestick.
One only needs to look int Flight Crew Operation Manual (FCOM) to see that info. Pilot input is always G managed, except in direct law.
Only if one is purposefully set on breaking up the aeroplane in midair through overstress. Absolutely not applicable to AF447. Aeroplane never came close to G limits.
People who don't understand that if they pull and nose doesn't come up (EDIT: sorry, I wrote that terribly wrong the first time), there are 99.99% chances they are stalled, are usually not allowed to go solo in gliders, microlights or light aeroplanes, let alone climb the ladder to professional aviation. 0.01% caters for airframe failures, control circuit failures, etc.
There is absolutely no NEUTRAL position as such on any THS fitted to any aeroplane, anywhere. There is neutral position for speed, altitude, weight, balance and configuration. It can be anywhere within stabilizer operating range.
No. It would be a lie. Airbus 330 is not prone to deep stall/ superstall/ locked-in condition.
In other words, the aircraft is not doing what it was commanded to and is approaching unsafe parameters.
Originally Posted by CONF iture
Attitude is the objective, but 36 ways to reach that goal, how smooth or not you can or want to be is the director of your inputs.
Clandestino, if you start feeling Gs do you still pull harder or you just relax … ?
Clandestino, if you start feeling Gs do you still pull harder or you just relax … ?
Most important and most often checked information in "blind flying" is attitude. If one cannot read it properly or cannot maintain it properly, the rest of instrument scan is in vain.
When pilot is handflying by sole reference to instruments, it is important to keep movement smooth and precise to avoid unnecessary maneuvering that might upset pilot's sense of balance and induce illusions of turning or banking. Pilots who, when without outside visual reference, start flying by their senses instead by their instruments, get far more often killed than not. That is known fact that is with us since there were first instrument flights and no amount of sophistication and automation is able to isolate us from it, as was correctly, in more general terms, predicted by Antoine de Saint-Exupery.
So, as instrument rated pilot, I don't fly by feeling Gs, I fly by reference to my instruments.
Originally Posted by CONF iture
Except that 5 degrees of AoA on AF447 and stall warning is already warning, stall itself is just about.
what about a more common sense 2.5 deg pitch ?
what about a more common sense 2.5 deg pitch ?
Old unreliable airspeed procedure directed pilots to fly 2.5° attitude and power from table. New procedure, valid at time of AF447 final dive, called for setting 5° pitch with climb power for a couple of seconds, while PNF takes out the table of pitch-against-power from QRH and then power and attitude are set accordingly. 2.5° pitch is fine if you know your cruise power by heart. With climb power it would likely result in overspeed.
Originally Posted by HazelNuts39
I agree with PJ2 and others that going to 5 degrees pitch is not what one would expect a seasoned pilot to do, and is not the right thing to do in the circumstances. Depending on how quickly the airplane is rotated to 5 degrees pitch, the AoA would probably temporarily exceed the stall warning threshold of about 4 degrees, and in any case the 'stabilized' AoA in still air would move closer to the stall than with 2.5 degrees pitch. On the other hand I believe, based on 'gut feeling' rather than a numerical analysis, that if CLB power had been set and attitude had increased to but not exceeded 5 degrees pitch, that the airplane would not have stalled.
Originally Posted by Lyman
Why then, no "compensation" for the elevator position? The stick is held back sufficiently to command autotrim, but none shows.
Originally Posted by ruderruderrat
The FBW computers are programmed to maintain attitude, so more nose up from the elevator is required.
Originally Posted by Lyman
If PILOT/PLANE communication is critical, wouldn't the a/c have annunciated to the crew that pilot input was being g managed?
Originally Posted by Lyman
There can be (have been) circumstances where 'g' PROT might have wanted to be sent packing?
Originally Posted by Lyman
The chronic application of PITCH UP by this pilot is made easier to understand (by me), when one imagines the environment, the lack of "Response"
Originally Posted by Ian W
If (as suggested earlier) the THS had remained at NEUTRAL
Originally Posted by Ian W
Was there any training or flight envelope information available to A330 crews that told of the possibility of deep stall?
Last edited by Clandestino; 21st Aug 2011 at 18:08. Reason: Flatulens cerebralis
Join Date: Jan 2005
Location: France
Posts: 2,315
Likes: 0
Received 0 Likes
on
0 Posts
It's a matter of terminology, further confused by the early "locked-in stall" accidents of some of the early T-tails being referred to as "deep stalls".
I would have called AF447 a "deep stall" in the general sense, in that it was a persistent, fully developped stall, with a few nasty contributing factors (no airspeed, THS, confused meatware), which lasted until FL000....
Maybe you could suggest some 'formal' terminology?
Join Date: Aug 2011
Location: Grassy Valley
Posts: 2,074
Likes: 0
Received 0 Likes
on
0 Posts
AlphaZuluRomeo Thank you so much for your response.
First, whether 'g' or mechanical, (RTLU or 'g' airframe) we speak of a direct and powerful LIMIT. The type of limiting is not relevant, suffice to say, the limit exists to prevent airframe damage.
ALPHA PROT is a FLIGHT PATH Protection. 'g' limit is an airframe protection.
From a design point of view, some things of note: Any Limit is considered as a boundary, not subject to mitigation, it is on, or it is off. It is not a function, nor is it a method, of Flight Path control.
So no one has addressed my opinion that the climb up was a function of "g" inhibition of the THS. I hear that "Control (stick) was not sustained", "thus the THS remained unmoving." This same argument is used on the descent, "All he had to do....." etc.
My Point? 'g' limiting was the source of the shape of the climb curve, along with the PF input at the stick.
It was the PNF who SAID: "SO, WE HAVE LOST THE SPEEDS.........ALTERNATE LAW".
WHY? Because I think PF was flying thinking he was in NORMAL LAW, NOT ALTERNATE LAW, hence the REMINDER.
With 'g' values wandering above and also below thresholds for THS TRIM,
'g' was flying the Aircraft; the PF was inputting stick, and the results were derived from 'g', via the Computer FCS. NO THS TRIM, it is inhibited in this window(s). An increase in AoA allowed by 'g' sensing, not the Pilot.
This is mode confusion. Call the Pilot flying whatever you will, IF he thought he had one Law, and didn't (couldn't) relate it to basic control, it does not matter whether he was Yeager, Yogi, or YODA, the a/c was not sussable. "THE AIRCRAFT DID WHAT IS WAS DIRECTED TO DO."
My point, simply...SIMPLY is this.
This is a FLAW. All Pilot derived? I DON"T CARE. The a/c got to be a mystery, and it was lost.
There is not one pilot here who can honestly say he could have done better. PERIOD. And it does not matter for purpose of this discussion, imo.
ICE is not PROVEN. IT IS NOT EVEN A CONCLUSION SUBJECT TO, PROOF.
PITOTS failure is not PROVEN.
1. The aircraft STALLED
2. The aircraft did not recover.
At the STALL, the THS was full UP.
My proposition is this. All three pilots could have been TIRE, TIRE, TIRE! from the outset. Because the THS was FULL UP, the NOSE COULD NOT BE LOWERED.
IF THE THS had been neutral, the pilots could have pulled TIRE TIRE TIRE!
and the a/c would have recovered in spite of the wrong input. Had they continued their pull, it would have STALLED AGAIN.
Do you see? The a/c prevented a recovery.
NOW. How did it cause LOC? Because the Pilot got incremental nibbles of NOSE UP, as it would have in NORMAL LAW. And it STALLED at nil AS.
Discard 'g' protection (for the moment). The Pilot gets a BUNCH of NU elevator, and the a/c Stalls, immediately. The nose drops, he recovers (hopefully), and all is well.
Do you see this? I am not judgiing, moralizing, or defending. I am saying that for whatever the reason, the DIRECT cause of this disaster is the aircraft itself.
If you can patiently entertain that pov, let's discuss. Too many PPL's here stroking themselves on the graves of professional pilots, methinks (ok, that is a judgment).
Clandestino, either for reasons of ignorance or conceit, you continue to "misunderstand" or dismiss with great prejudice the posting of others. Anyone who snubs someone who has engaged you, with a picture of a book and a "read this" is too arrogant to waste my time in response.
btw. In the descent, the STALL WARN returns, and the PF is accused of NU. Several times. Why would the STALL WARNING trigger? And what effect would this have on 'g' Prot?
I'll wait, whoever sees where I'm going will likely be better at explaining why the PF "PULLED UP".............
First, whether 'g' or mechanical, (RTLU or 'g' airframe) we speak of a direct and powerful LIMIT. The type of limiting is not relevant, suffice to say, the limit exists to prevent airframe damage.
ALPHA PROT is a FLIGHT PATH Protection. 'g' limit is an airframe protection.
From a design point of view, some things of note: Any Limit is considered as a boundary, not subject to mitigation, it is on, or it is off. It is not a function, nor is it a method, of Flight Path control.
So no one has addressed my opinion that the climb up was a function of "g" inhibition of the THS. I hear that "Control (stick) was not sustained", "thus the THS remained unmoving." This same argument is used on the descent, "All he had to do....." etc.
My Point? 'g' limiting was the source of the shape of the climb curve, along with the PF input at the stick.
It was the PNF who SAID: "SO, WE HAVE LOST THE SPEEDS.........ALTERNATE LAW".
WHY? Because I think PF was flying thinking he was in NORMAL LAW, NOT ALTERNATE LAW, hence the REMINDER.
With 'g' values wandering above and also below thresholds for THS TRIM,
'g' was flying the Aircraft; the PF was inputting stick, and the results were derived from 'g', via the Computer FCS. NO THS TRIM, it is inhibited in this window(s). An increase in AoA allowed by 'g' sensing, not the Pilot.
This is mode confusion. Call the Pilot flying whatever you will, IF he thought he had one Law, and didn't (couldn't) relate it to basic control, it does not matter whether he was Yeager, Yogi, or YODA, the a/c was not sussable. "THE AIRCRAFT DID WHAT IS WAS DIRECTED TO DO."
My point, simply...SIMPLY is this.
This is a FLAW. All Pilot derived? I DON"T CARE. The a/c got to be a mystery, and it was lost.
There is not one pilot here who can honestly say he could have done better. PERIOD. And it does not matter for purpose of this discussion, imo.
ICE is not PROVEN. IT IS NOT EVEN A CONCLUSION SUBJECT TO, PROOF.
PITOTS failure is not PROVEN.
1. The aircraft STALLED
2. The aircraft did not recover.
At the STALL, the THS was full UP.
My proposition is this. All three pilots could have been TIRE, TIRE, TIRE! from the outset. Because the THS was FULL UP, the NOSE COULD NOT BE LOWERED.
IF THE THS had been neutral, the pilots could have pulled TIRE TIRE TIRE!
and the a/c would have recovered in spite of the wrong input. Had they continued their pull, it would have STALLED AGAIN.
Do you see? The a/c prevented a recovery.
NOW. How did it cause LOC? Because the Pilot got incremental nibbles of NOSE UP, as it would have in NORMAL LAW. And it STALLED at nil AS.
Discard 'g' protection (for the moment). The Pilot gets a BUNCH of NU elevator, and the a/c Stalls, immediately. The nose drops, he recovers (hopefully), and all is well.
Do you see this? I am not judgiing, moralizing, or defending. I am saying that for whatever the reason, the DIRECT cause of this disaster is the aircraft itself.
If you can patiently entertain that pov, let's discuss. Too many PPL's here stroking themselves on the graves of professional pilots, methinks (ok, that is a judgment).
Clandestino, either for reasons of ignorance or conceit, you continue to "misunderstand" or dismiss with great prejudice the posting of others. Anyone who snubs someone who has engaged you, with a picture of a book and a "read this" is too arrogant to waste my time in response.
btw. In the descent, the STALL WARN returns, and the PF is accused of NU. Several times. Why would the STALL WARNING trigger? And what effect would this have on 'g' Prot?
I'll wait, whoever sees where I'm going will likely be better at explaining why the PF "PULLED UP".............
Last edited by Lyman; 21st Aug 2011 at 18:25.
Join Date: Jul 2009
Location: Not far from a big Lake
Age: 82
Posts: 1,454
Likes: 0
Received 0 Likes
on
0 Posts
Franzl,
A very pertinent series of points.
I suspect the "unload" term may be strange to those who have never flown tactical aircraft. It literally means to take the load off of the wings (which puts you into a ballistic trajectory).
It is usually not absolutely necessary to perfectly hit zero g to unload.
One tenth of a g keeps things planted on the floor and is thus a safer thing to do when carrying passengers.
Example:
If your aircraft has a 180 knot clean stall speed at 1 g, then your stall speed at .1 g will drop to 57 knots. Very useful for maintaining control of the wing attitude (even though you are on a ballistic trajectory).
Airtren's comments re the Interflug A310 Incident, near Moscow, in 1991
allowed me to find the following youtube posting which makes a whole range of relevant points among which I find the comments regarding the problems with keeping the pilots in the loop while the computers fly the aircraft to be particularly relevant to AF447.
Blackbox - 05 - Blaming the Pilot - Part 5 of 5 - YouTube
A very pertinent series of points.
I suspect the "unload" term may be strange to those who have never flown tactical aircraft. It literally means to take the load off of the wings (which puts you into a ballistic trajectory).
It is usually not absolutely necessary to perfectly hit zero g to unload.
One tenth of a g keeps things planted on the floor and is thus a safer thing to do when carrying passengers.
Example:
If your aircraft has a 180 knot clean stall speed at 1 g, then your stall speed at .1 g will drop to 57 knots. Very useful for maintaining control of the wing attitude (even though you are on a ballistic trajectory).
Airtren's comments re the Interflug A310 Incident, near Moscow, in 1991
allowed me to find the following youtube posting which makes a whole range of relevant points among which I find the comments regarding the problems with keeping the pilots in the loop while the computers fly the aircraft to be particularly relevant to AF447.
Blackbox - 05 - Blaming the Pilot - Part 5 of 5 - YouTube
Originally Posted by Lyman
Clandestino, either for reasons of ignorance or conceit, you continue to "misunderstand" or dismiss with great prejudice the posting of others.
In the air you live and die by the facts, not opinions.
That's what "Handling the big jets" is about.
It's one of those great books written in blood of those who have never put their final flights down in their logbooks.
Join Date: Feb 2011
Location: Nearby SBBR and SDAM
Posts: 875
Likes: 0
Received 0 Likes
on
0 Posts
Real time relevant information to the crew
Hi,
GerardC
I posted earlier on that. And considering the a/c was starting to operate "outside design" (sub heated pitot's) the information of what caused AP/AT out SHOULD BE PRESENTED IMMEDIATELY. Actually the a/c was designed considering a near zero probability of SIMULTANEOUS pitot "failure". And the a/c entered an atmospheric region that caused a (near) simultaneous "failure". And the pitot's (certainly) not failed. Just was operating outside the specs.
IMO the operation of an a/c outside it's design and the fact this info was not (still currently) presented IN REAL TIME to the crew is almost an ABSURD. That may allow you transit from "Normal Law directly to Murphy Law"...
GerardC
I posted earlier on that. And considering the a/c was starting to operate "outside design" (sub heated pitot's) the information of what caused AP/AT out SHOULD BE PRESENTED IMMEDIATELY. Actually the a/c was designed considering a near zero probability of SIMULTANEOUS pitot "failure". And the a/c entered an atmospheric region that caused a (near) simultaneous "failure". And the pitot's (certainly) not failed. Just was operating outside the specs.
IMO the operation of an a/c outside it's design and the fact this info was not (still currently) presented IN REAL TIME to the crew is almost an ABSURD. That may allow you transit from "Normal Law directly to Murphy Law"...
Join Date: Aug 2009
Location: Germany
Age: 67
Posts: 1,777
Likes: 0
Received 0 Likes
on
0 Posts
Ian_W
Transcription de la conférence de presse du 29 juillet 2011
Some answers from Troadec (BEA director)
I think that this may miss the point.
If (as suggested earlier) the THS had remained at NEUTRAL rather than chasing the NU input during a stall, would the PF NU inputs have been enough with elevator alone to maintain nose up into a deep stall? Was it only the added authority of the THS that allowed the aircraft to be kept in the stall?
Perhaps with elevators alone and a THS neutral the aircraft would have dropped its nose, then (had PF kept NU) after getting flying speed its nose would come back up. Perhaps PF was expecting this nose drop 'nodding' behavior? Its what would happen in a lot of gliders and light aircraft and he was glider qualified. The lack of this nose drop possibly convinced PF that the aircraft could not be in a stall.
Was there any training or flight envelope information available to A330 crews that told of the possibility of deep stall? There seems to have been quite a lot on 'spurious' stall warnings.
So without any knowledge of deep stall, with THS having sufficient authority to hold the aircraft in a stable deep stall so no nodding ND, and previous information about spurious stall warnings: everything seems to be set up for a confused PF
If (as suggested earlier) the THS had remained at NEUTRAL rather than chasing the NU input during a stall, would the PF NU inputs have been enough with elevator alone to maintain nose up into a deep stall? Was it only the added authority of the THS that allowed the aircraft to be kept in the stall?
Perhaps with elevators alone and a THS neutral the aircraft would have dropped its nose, then (had PF kept NU) after getting flying speed its nose would come back up. Perhaps PF was expecting this nose drop 'nodding' behavior? Its what would happen in a lot of gliders and light aircraft and he was glider qualified. The lack of this nose drop possibly convinced PF that the aircraft could not be in a stall.
Was there any training or flight envelope information available to A330 crews that told of the possibility of deep stall? There seems to have been quite a lot on 'spurious' stall warnings.
So without any knowledge of deep stall, with THS having sufficient authority to hold the aircraft in a stable deep stall so no nodding ND, and previous information about spurious stall warnings: everything seems to be set up for a confused PF
Some answers from Troadec (BEA director)
Question: there are a lot of airplanes which, when they stall, pitch nose-down including when they have stalled and their last command was to pitch up. This is apparently a phenomenon that many glider or flying school pilots are familiar with. Yet, here we can see that this phenomenon did not occur, that the airplane fell straight while remaining nose-up. Is this a stall mode that is normal or expected?
Jean-Paul Troadec: what was said, is that the airplane stalled from the pilot’s nose-up input. So, mostly the pilot’s inputs were to pitch nose-up, which maintained the stall.
Question: is the way the airplane stalled, that is to say straight while remaining nose-up and not nose-down, is it normal or typical or expected. Let’s say that a lot of airplanes pitch nose-down when they stall.
Jean-Paul Troadec: it’s a point where… Well, I cannot answer your question and say if it is normal or not. It is the situation of this airplane which is perfectly in accordance with the regulations and which was certified.
Jean-Paul Troadec: what was said, is that the airplane stalled from the pilot’s nose-up input. So, mostly the pilot’s inputs were to pitch nose-up, which maintained the stall.
Question: is the way the airplane stalled, that is to say straight while remaining nose-up and not nose-down, is it normal or typical or expected. Let’s say that a lot of airplanes pitch nose-down when they stall.
Jean-Paul Troadec: it’s a point where… Well, I cannot answer your question and say if it is normal or not. It is the situation of this airplane which is perfectly in accordance with the regulations and which was certified.
Clandestino
When pilot is handflying by sole reference to instruments, it is important to keep movement smooth and precise to avoid unnecessary maneuvering that might upset pilot's sense of balance and induce illusions of turning or banking. Pilots who, when without outside visual reference, start flying by their senses instead by their instruments, get far more often killed than not. That is known fact that is with us since there were first instrument flights and no amount of sophistication and automation is able to isolate us from it, as was correctly, in more general terms, predicted by Antoine de Saint-Exupery.
So, as instrument rated pilot, I don't fly by feeling Gs, I fly by reference to my instruments
When pilot is handflying by sole reference to instruments, it is important to keep movement smooth and precise to avoid unnecessary maneuvering that might upset pilot's sense of balance and induce illusions of turning or banking. Pilots who, when without outside visual reference, start flying by their senses instead by their instruments, get far more often killed than not. That is known fact that is with us since there were first instrument flights and no amount of sophistication and automation is able to isolate us from it, as was correctly, in more general terms, predicted by Antoine de Saint-Exupery.
So, as instrument rated pilot, I don't fly by feeling Gs, I fly by reference to my instruments
Let me add to that, it is not only refence to the flight instruments, but also to the performance instruments .
It ís in the former mentioned reference upset recovery training at the beginning.
Flying is mainly energy management. With autopilot and autothrust combined with low drag aircraft and strong engines it seems to be a forgotten fact.
It is not understandable to change altitude (intentional or unintentional) without attention to powersetting, speed change and vvi change. Change attitude, change power, except you want to accelerate in diving or decelerate in climbing. No need to wait what the speed will be doing, because that can bring one already behind the aircraft.
Join Date: Feb 2011
Location: Nearby SBBR and SDAM
Posts: 875
Likes: 0
Received 0 Likes
on
0 Posts
Machinbird
And during extreme situations this can be simply vital.
And during extreme situations this can be simply vital.
Join Date: Jul 2009
Location: Not far from a big Lake
Age: 82
Posts: 1,454
Likes: 0
Received 0 Likes
on
0 Posts
That feeling of g
But we do fly with input from our posteriors for the feeling of g.
It isn't a normally a primary input for control of the aircraft, and our internal sense of vertical should be only aircraft referenced (that is, it should not be referenced to the outside world attitude).
That little tactile sensation can feed us a lot of information regarding rate of g onset, level of g achieved, and whether or not the rudder is trimmed properly. It is just when we try to infer up and down relative to the earth that we get in trouble by trying to use it.
Dick Rutan recently gave a very interesting briefing regarding his round the world trip in the Voyager aircraft. At high gross weight, the aircraft had a divergent "pogo" type oscillation that required constant pilot intervention to control. He was controlling the oscillation by visual reference to the wing tips, and it occurred to him, "How am I going to control this thing at night when I can't see the wing tips?" Part of his test flying was to prove that he could control the oscillation by seat of the pants. They covered up the windows with quick remove panels and adequate control was maintained-by "seat of the pants" flying. The rest is history.
It isn't a normally a primary input for control of the aircraft, and our internal sense of vertical should be only aircraft referenced (that is, it should not be referenced to the outside world attitude).
That little tactile sensation can feed us a lot of information regarding rate of g onset, level of g achieved, and whether or not the rudder is trimmed properly. It is just when we try to infer up and down relative to the earth that we get in trouble by trying to use it.
Dick Rutan recently gave a very interesting briefing regarding his round the world trip in the Voyager aircraft. At high gross weight, the aircraft had a divergent "pogo" type oscillation that required constant pilot intervention to control. He was controlling the oscillation by visual reference to the wing tips, and it occurred to him, "How am I going to control this thing at night when I can't see the wing tips?" Part of his test flying was to prove that he could control the oscillation by seat of the pants. They covered up the windows with quick remove panels and adequate control was maintained-by "seat of the pants" flying. The rest is history.
Join Date: May 2011
Location: here
Posts: 131
Likes: 0
Received 0 Likes
on
0 Posts
It's a matter of terminology, further confused by the early "locked-in stall" accidents of some of the early T-tails being referred to as "deep stalls".
I would have called AF447 a "deep stall" in the general sense, in that it was a persistent, fully developped stall, with a few nasty contributing factors (no airspeed, THS, confused meatware), which lasted until FL000....
Maybe you could suggest some 'formal' terminology?
I would have called AF447 a "deep stall" in the general sense, in that it was a persistent, fully developped stall, with a few nasty contributing factors (no airspeed, THS, confused meatware), which lasted until FL000....
Maybe you could suggest some 'formal' terminology?
Now many use it as a synonym for "really bad stall", which unnecessarily confuses people. See Ian's question, "were they told of the possibility of deep stall?"
Uhm, no, it wasn't in the "locked-in" kind and yes, it's got wings so obviously it can stall...
It's a garden-variety stall, do we need a special name for it?