AF 447 Thread No. 11
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Originally Posted by busTRE
An airbus can stall in normal law
An outfit I am 'familiar with' had just such an incident, full back stick on receipt of the hard 'pull up' just saved them (rad alt at the peak around 40ft).
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CONFiture
Yeah, I said an airbus CAN stall in normal law!
Don't know if the report is in the public domain. But I do know that the investigation team produced profiles for the escape maneuvre which included 'average' airline wide profiles for comparison which didn't clear the terrain.
Yeah, I said an airbus CAN stall in normal law!
Don't know if the report is in the public domain. But I do know that the investigation team produced profiles for the escape maneuvre which included 'average' airline wide profiles for comparison which didn't clear the terrain.
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Originally Posted by busTRE
You think a guy nudging the stick shaker is flying a max alpha manuevre as efficiently as one nailing alpha-max with EFCS?
Don't know if the report is in the public domain. But I do know that the investigation team produced profiles for the escape maneuvre which included 'average' airline wide profiles for comparison which didn't clear the terrain.
Of course you cannot fly as accurately by just triggering the stick shaker as you could fly with an actual AOA indicator directly in front of you, but if you had an AOA indicator and used it, your performance should not be far different than the EFCS max AOA performance.
In the situation just mentioned by CONF iture, there would be unreasonable AOA values staring you in the face as you decelerated. You would have to be asleep to miss it.
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Inhibition of stall warning. Well Ok, see where the designers where going...
Now, can we accept that alpha probes need to have some airflow to work reliably or do we keep on harping that they have to work perfectly from zero kt to Mmo, which is quite a wishful thinking?
Affirm mode by changing some colours on the FD ? In a crisis I am supposed to notice and swing my mind around to that ?
Let the THS go way beyond normal limits and not scream about it ?
Have a SOP which says blank FD when the software could automatically do it ?
Need to crowbar the logic in some situations.
How about a 'Ghastly Silence' mode
The pilots need effectively to understand 2/3 'philosophies' - slightly different 'rules of flying' in each law, and to be able to 'switch' seamlessly from one to the other, probably when the is hitting the fan. An easy task for a 'HAL' with loads'a lines of code, but for we mere mortals....................
why was the stick subsequently held back, do you think?
An Airbus is not worse than any other design, but it is not better just because of its design either.
I don't want to enter the statistics debate again, but another FBW design has a better safety record.
I have flown the AB, the T7 and the MD11. All of them FBW
It is this myth of some invulnerability of Airbus that cultivates pilots who fly escape manoeuvres with full stick back in any situation.
A start would be to stop with such dumb assertions that Airbus does this and that better than others.
What we need is a simple independent back-up to all the electronics like i.e. a pneumatically (wind) driven gyroscopic horizon and a unprocessed access to the flight controls.
I guess he thought that since he was definitely airborne that it was necessary to pull fully back.
It's low level windshear encounter.
What does it have to do with cruise, beats me. Lest you want to suggest that it is indeed difficult to tell the difference between low level maneuvering and cruise flight.
We dinosaurs were taught to "respect the stick shaker" during these manoeuvres. Airbus doesn't fit one
just another audio warning on top of constant "C chord" altitude deviation warning.
Just need two AoA probes to freeze at a similar angle
High angle protection no more but normal law still.
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How do I know they had no ATT info?
Another AoA disciple speaks
I welcome USMC to the fray. Seems to be from the "next generation" from 'bird and I, but has the same feelings/beliefs about AoA as RetiredF4 and other folks here that have used HUDs and AoA indicators for thousands of landings ( not hours, considering our mission lengths),
It is true that you can use the FPV relatonship to the ship's "boresight" to determine AoA. But why go thru that when you can have a simple display that shows your AoA WRT to stall or best approach AoA ( speed will vary depending upon gross weight and configuration)?. My leading edge flap failure video is old and grainy, but you can easily see it WRT to the pitch lines, and both are related to the real world via an inertial system, with no regard for frozen speed/altitude sensors. AoA doofers are still working. We can laugh at my mistakes near the end, but I corrected enough to save the jet and my skinny butt. The AoA is that braket below the FPV, and had I tried to reach the dersired AoA for normal approach, I would have lost roll authority, so I flew at a lower AoA. As with the A-7, F-14, F-16, F-15, AV-8, F-18, F-22, and now F-35 you pull to get the braket even with the FPV, or push. My upward FPV change near the end was due to extra power, as I had started down quickly when putting out speed brakes from habit ( not good).
http://www.sluf.org/misc_pages/lef-landing.m4v
So much for the basics of using AoA and FPV.
I'll guarantee that the AF447 troops would have noticed their FPV WRT to the pitch lines and realized that the FPV was not going up and that AoA was above the stall AoA. Pitch attitude be damned.
No doubt the unreliable speed was a factor, as was trusting the "protections" when in a back-up flight control law. But inertial vectors and operable AoA displays would possibly have saved the day.
It is true that you can use the FPV relatonship to the ship's "boresight" to determine AoA. But why go thru that when you can have a simple display that shows your AoA WRT to stall or best approach AoA ( speed will vary depending upon gross weight and configuration)?. My leading edge flap failure video is old and grainy, but you can easily see it WRT to the pitch lines, and both are related to the real world via an inertial system, with no regard for frozen speed/altitude sensors. AoA doofers are still working. We can laugh at my mistakes near the end, but I corrected enough to save the jet and my skinny butt. The AoA is that braket below the FPV, and had I tried to reach the dersired AoA for normal approach, I would have lost roll authority, so I flew at a lower AoA. As with the A-7, F-14, F-16, F-15, AV-8, F-18, F-22, and now F-35 you pull to get the braket even with the FPV, or push. My upward FPV change near the end was due to extra power, as I had started down quickly when putting out speed brakes from habit ( not good).
http://www.sluf.org/misc_pages/lef-landing.m4v
So much for the basics of using AoA and FPV.
I'll guarantee that the AF447 troops would have noticed their FPV WRT to the pitch lines and realized that the FPV was not going up and that AoA was above the stall AoA. Pitch attitude be damned.
No doubt the unreliable speed was a factor, as was trusting the "protections" when in a back-up flight control law. But inertial vectors and operable AoA displays would possibly have saved the day.
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Originally Posted by Clandestino
Obviously, my umpteen attempts at explaining the protections were just too technical. Let me try it this way: why do you think Airbus pilot needs to understand what you have labeled "2/3 philosophies"? Why would the Airbus pilot need to know anything about protections at all (besides them being covered in FCOM and there being legal requirement to know one's manuals)?
Regarding AoA and the Oozlum bird. Forget the AoA. It would take enormous training input and costs no-one will justify, and can easily be 'missed' in a panic too - yet another gauge. All we need is pilots who understand basic flying, and that a PITCH attitude of 17 degrees at 38000' is just silly. I believe they never went below 5 degrees? 3 instruments already there, apparently working, displaying this, and used for 'basic flying'. End of? The challenge is 'why'?
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BOAC
Agree. Introducing AoA would add a layer of complexity that will probably produce more problems than it solves.
Natstrackalpha
What utter balloney. You know nothing of the sort and how the hell do you know the real attitude was different from that on the ATT indicator? Please do tell.
It's embarrassing sometimes.
Show us the exact quote from the report
Agree. Introducing AoA would add a layer of complexity that will probably produce more problems than it solves.
Natstrackalpha
How do I know they had no ATT info?
Because the PFD said S&L and the nose was pointing up wards.
Because the PFD said S&L and the nose was pointing up wards.
It's embarrassing sometimes.
Show us the exact quote from the report
Last edited by busTRE; 17th Jun 2013 at 09:42.
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Are we talking about AF over Atlantic in bad wx that disappeared and was pulled out some time later . . . ? A330?
Now read this carefully. WHERE IN THE REPORT DOES IT SAY THAT THE PFD WAS READING S&L WITH THE NOSE POINTING UP. Show me where it says that because I can't find it.
Last edited by busTRE; 17th Jun 2013 at 09:51.
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Originally Posted by Natstrackalpha
- Well, where did I get this from?
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Originally Posted by BOAC
The pilots need effectively to understand 2/3 'philosophies' - slightly different 'rules of flying' in each law, and to be able to 'switch' seamlessly from one to the other, probably when the 
is hitting the fan. An easy task for a 'HAL' with loads'a lines of code, but for we mere mortals....................
is hitting the fan. An easy task for a 'HAL' with loads'a lines of code, but for we mere mortals....................I don't want to interfer to much in your discussion with HN39, abut still I'm puzzled by your comment about the different laws.
I mean, aren't crew supposed to be able to adapt to slightly different 'rules of flying'? Isn't that the very purpose of "keeping" crews and not letting computers alone in the front end?
- Crews are able to understand (and manage) an engine failure, resulting in slightly different 'rules of flying': less thrust available and dissimetry.
- Crews are able to understand (and manage) a fuel leak or a depressurization, resulting in slightly different 'rules of flying': range is shortened, altitude is limited (if depressurization).
Why would crews not be able to understand (and manage) the slightly different 'rules of flying' that some sensor failure may cause, such as the loss of protections caused by law reversion?
I fail to see the fundamental difference you seem to see between those different failures.
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Why would crews not be able to understand (and manage) the slightly different 'rules of flying' that some sensor failure may cause, such as the loss of protections caused by law reversion?
Its not the crew, the airlines or the training. All airlines train and all crews are trained - it is the type of training that needs to be reviewed.
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AZR - I agree with NTA on that and have said it before many times. I don't know the answer to your question, but in the absence of any logical explanation for AB events such as 447 involving 'failure' of the protection systems, I am asking. A kind of Occam's razor, I suppose?
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Quote:
Why would crews not be able to understand (and manage) the slightly different 'rules of flying' that some sensor failure may cause, such as the loss of protections caused by law reversion?
AZR
Its not the crew, the airlines or the training. All airlines train and all crews are trained - it is the type of training that needs to be reviewed
Quote:
Why would crews not be able to understand (and manage) the slightly different 'rules of flying' that some sensor failure may cause, such as the loss of protections caused by law reversion?
AZR
Its not the crew, the airlines or the training. All airlines train and all crews are trained - it is the type of training that needs to be reviewed
Re quote from Natstrackalpha about the type of training given.
Could not agree more!!!
Forget meaningless time in the sim and trying to land on the piano keys. Fully held off landings seem to be a thing of the past except on 2 airlines mainly crewed by "real pilots". WHY. Try landing an old taildragger without this method and watch the resulting bounce(s)! As a result the U/C gets a pounding. You might float down the R/W a bit but no worry.
In our budget restricted times who wants to shell out on tyres and U/C for clueless but highly educated individuals (poorly trained) who cannot fly.
Seems that all you need for a career is education. WRONG WRONG WRONG. A passion for flying is what you need. Go back to teaching basic piloting skills and not just fly by numbers and the world will be a safer place!!!
Hear endeth the rant
Why would crews not be able to understand (and manage) the slightly different 'rules of flying' that some sensor failure may cause, such as the loss of protections caused by law reversion?
AZR
Its not the crew, the airlines or the training. All airlines train and all crews are trained - it is the type of training that needs to be reviewed
Quote:
Why would crews not be able to understand (and manage) the slightly different 'rules of flying' that some sensor failure may cause, such as the loss of protections caused by law reversion?
AZR
Its not the crew, the airlines or the training. All airlines train and all crews are trained - it is the type of training that needs to be reviewed
Re quote from Natstrackalpha about the type of training given.
Could not agree more!!!
Forget meaningless time in the sim and trying to land on the piano keys. Fully held off landings seem to be a thing of the past except on 2 airlines mainly crewed by "real pilots". WHY. Try landing an old taildragger without this method and watch the resulting bounce(s)! As a result the U/C gets a pounding. You might float down the R/W a bit but no worry.
In our budget restricted times who wants to shell out on tyres and U/C for clueless but highly educated individuals (poorly trained) who cannot fly.
Seems that all you need for a career is education. WRONG WRONG WRONG. A passion for flying is what you need. Go back to teaching basic piloting skills and not just fly by numbers and the world will be a safer place!!!
Hear endeth the rant
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Originally Posted by BOAC
The pilots need effectively to understand 2/3 'philosophies' - slightly different 'rules of flying' in each law, and to be able to 'switch' seamlessly from one to the other,
Situations like low level wind shear and GPWS warning leave no time for thought and just carrying out a drill without hesitation might save the day. In those situations being able to pull without fear of stalling must be an asset.
In AF447 there was no such urgency. The plane would have landed safely in Paris if the pilot had just sat back and 'done nothing'. In that situation there is no need to rely on any protection and the 'rule of flying' in alternate law is no different from that in normal law.
Last edited by HazelNuts39; 17th Jun 2013 at 12:19.
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Natstrackalpha
You haven't the faintest clue what you're on about have you?
but, an aircraft encaked in ice with no flying surfaces active having climbed, stalled and then pitched down, increased speed + therefore lift, ocillating from nose hi low airspeed to nose lo hi airspeed, would have had the equal result of `overspeed` and `stall` together on the descending, without any stick held back - as the effect of the stick would have been ineffective anyway.
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Originally Posted by BOAC
AZR - I agree with NTA on that and have said it before many times.
Originally Posted by BOAC
I don't know the answer to your question
Originally Posted by BOAC
but in the absence of any logical explanation for AB events such as 447 involving 'failure' of the protection systems, I am asking. A kind of Occam's razor, I suppose?
About the logical explanation, there is one in the final report (as to why 447 crew, and more precisely PF, acted as he did) that looks convincing to me. This could led to technical modifications re: FD availability, but I fail to see how a modification to the protection system would be sensible. On that topic, and the existence of the alternate law (that some people judged misleading and/or dangerous), I just read "QF32" by Cpt de Crespigny and found his view on the matter reassuring.
Finally, if I understand correctly, the "go full back stick and trust protections" is teached *only* for low altitude, terrain avoidance events (e.g. CFIT trajectory, windshears...), *not* as a one-fit-all recipe to get out of trouble.
So AFAIK, HazelNuts39 has it right.
