AF 447 Thread No. 6
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That more complexity and that more work and attention may not be obvious to a casual observer, but it is there, even if hidden by the huge reduction in electronics components dimensions, huge advance in electronics integration, and modularization, or by the physical character of the components - software - and the stages and different areas, disciplines, R&D, development or manufacturing facilities in which the attention and work is performed.
Last edited by airtren; 4th Oct 2011 at 17:14.
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K.I.S.S.
Hi,
aitren:
And despite this immense complexity the basic is the same:
When the plane degrades (by any reason) you need:
1) Feel it
2) Aviate it (the same for all models)
And this requires a SIMPLE THING: Known your machine in it's basic config.
A Professional knows everything related and involved in his mission, specially when Murphy Law acts.
aitren:
the modern/current airplanes are hugely more complex
And despite this immense complexity the basic is the same:
When the plane degrades (by any reason) you need:
1) Feel it
2) Aviate it (the same for all models)
And this requires a SIMPLE THING: Known your machine in it's basic config.
may not be obvious to a casual observer
Last edited by Jetdriver; 5th Oct 2011 at 00:57.
Per Ardua ad Astraeus
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Not quite sure how we got to the lift equation in a thread about loc, but I think there may be some confusion growing here between a 'stall' and 'insufficient lift' for flight which can be two completely different phenomena.
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"father of Windows"
DW,
A minor point - Windows appeared on the original Apple Mac well before Bill G. was involved. IIRC it was on the Apple Lisa before that.
I'm told the mouse part of the WIMPs interface (Windows, Icons, Menus and Pointing devices) was a spin-off from a Xerox trackball used in missile guidance well before the Mac.
I mention this only because MS and IBM are often given the credit for the PC. They were well behind.
A minor point - Windows appeared on the original Apple Mac well before Bill G. was involved. IIRC it was on the Apple Lisa before that.
I'm told the mouse part of the WIMPs interface (Windows, Icons, Menus and Pointing devices) was a spin-off from a Xerox trackball used in missile guidance well before the Mac.
I mention this only because MS and IBM are often given the credit for the PC. They were well behind.
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@SandyYoung - hence the capitalised W in "Windows" (implying the product, not the concept). Xerox invented it, Apple nicked it, Microsoft copied it - but the best early implementation was Workbench on the Commodore Amiga. Anyway - back to the regular scheduled programming...
Power outta a stall? Speed versus AoA?
Thanks, BOAC. ANd speed is a huge part of the lift equation, like a "squared" component.
So if I hold the same gee ( read lift you can feel in wings level flight), and I increase speed, then I can use a lower AoA for the same amount of lift.
Lowering AoA is the faster solution - get outta the part of the Cl curve that shows less lift and you also reduce induced drag. And for those jets with the underslung motors, adding power is not a good idea in some cases due to the nose up pitch moment.
For the swept wing jets the induced drag is a lot more evident that in the straight wings. The deltas were the worse ( or most low aspect ratio wings), then the good wings we developed in the 70's and 80's had much more gentle stall entries and less buffet and better directional control at high AoA. This is an insidious feature of the better wing designs we now have that may have contributed to the AF447 crew's failure to recognize their state and take appropriate corrective action. The lack of a good AoA indication also comes into play. That string taped to the side of the cockpit window would have been more helpful than the ambiguous stall warnings and such that the crew dealt with.
After talking with several folks here offline, I am suspecting a management influence on all the "laws" and "protections" and Otto functions versus "neat" features that the pilots demanded. The jet appears to be very well designed and easy to fly even with all the "old" mechanical/hydraulic control systems. And that is what bugs many of we old dinosaurs. I can't speak for all of us, but I would guess we would all like a very clear control system implementation we could hang our hats on when all the Otto functions and bank angle limits and pitch angle limits and such go away.
If we, the SLF, wish to have "systems managers" up front versus folks that can fly the jet with little "help", than I'll cease to be SLF. Scares the hell outta me.
So if I hold the same gee ( read lift you can feel in wings level flight), and I increase speed, then I can use a lower AoA for the same amount of lift.
Lowering AoA is the faster solution - get outta the part of the Cl curve that shows less lift and you also reduce induced drag. And for those jets with the underslung motors, adding power is not a good idea in some cases due to the nose up pitch moment.
For the swept wing jets the induced drag is a lot more evident that in the straight wings. The deltas were the worse ( or most low aspect ratio wings), then the good wings we developed in the 70's and 80's had much more gentle stall entries and less buffet and better directional control at high AoA. This is an insidious feature of the better wing designs we now have that may have contributed to the AF447 crew's failure to recognize their state and take appropriate corrective action. The lack of a good AoA indication also comes into play. That string taped to the side of the cockpit window would have been more helpful than the ambiguous stall warnings and such that the crew dealt with.
After talking with several folks here offline, I am suspecting a management influence on all the "laws" and "protections" and Otto functions versus "neat" features that the pilots demanded. The jet appears to be very well designed and easy to fly even with all the "old" mechanical/hydraulic control systems. And that is what bugs many of we old dinosaurs. I can't speak for all of us, but I would guess we would all like a very clear control system implementation we could hang our hats on when all the Otto functions and bank angle limits and pitch angle limits and such go away.
If we, the SLF, wish to have "systems managers" up front versus folks that can fly the jet with little "help", than I'll cease to be SLF. Scares the hell outta me.
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In no other a/c but the A330 is it more important to isolate NORMAL LAW from everything else. The type is trained to NL, and there is a disconnect in making anything except NORMAL LAW available in emergent or off standard flight path.
Except basic aero. Basic. It is counter intuitive to think other Laws in some sort of descending order will be helpful in an odd, or rare condition.
The a/c is dependable enough to eliminate the need for anything other than DIRECT LAW in such circumstances... Nothing but trouble if Pilots have to remain current in several ways to approach unusual conditioons.
As we see here.
Except basic aero. Basic. It is counter intuitive to think other Laws in some sort of descending order will be helpful in an odd, or rare condition.
The a/c is dependable enough to eliminate the need for anything other than DIRECT LAW in such circumstances... Nothing but trouble if Pilots have to remain current in several ways to approach unusual conditioons.
As we see here.
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If we, the SLF, wish to have "systems managers" up front versus folks that can fly the jet with little "help", than I'll cease to be SLF. Scares the hell outta me.
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Thanks for confirming it 
As for the maths: I'm sorry, I'm not fond of maths, I must say. Logic is enough to me
For that reason, I won't comment on your formula.
You may be unstalled (i.e. your wing is flying, producing lift & allowing control) but not have a CI big enough to support your weight. Then, you're descending. But no more stalled.
I wrote : "the gain of speed is a mean to lower AoA (all other parameters equals)" (my underlining)
Reverse: For the same velocity vector, your AoA is lower if you fly quick than if you fly slow.
That's why I wrote that if you fly quicker, you'll lower your AoA. Note that it was the spirit of the (now discarted IIRC) "approach to stall" procedure: To escape "falling" into an actual stall with more speed ; Without loosing altitude (<= maintaining the (level) velocity vector)
My point is : Speed is a consequence. AoA is what matters.
If stalled (or nearly stalled), you must lower AoA, be it by altering flight path (velocity vector => push the damn stick) or by gaining more speed (*)
The former is more efficient, as pitch control is a direct AoA control. That doesn't mean a bit more speed won't help: it will. But what you seeks, ultimately, is not more speed but less AoA.
(*) which, as shown above, will allow you a lesser AoA for the same flight path, or a higher flight path with the same AoA.
As for the maths: I'm sorry, I'm not fond of maths, I must say. Logic is enough to me
For that reason, I won't comment on your formula.
You may be unstalled (i.e. your wing is flying, producing lift & allowing control) but not have a CI big enough to support your weight. Then, you're descending. But no more stalled.
Reverse: For the same velocity vector, your AoA is lower if you fly quick than if you fly slow.
That's why I wrote that if you fly quicker, you'll lower your AoA. Note that it was the spirit of the (now discarted IIRC) "approach to stall" procedure: To escape "falling" into an actual stall with more speed ; Without loosing altitude (<= maintaining the (level) velocity vector)
My point is : Speed is a consequence. AoA is what matters.
If stalled (or nearly stalled), you must lower AoA, be it by altering flight path (velocity vector => push the damn stick) or by gaining more speed (*)
The former is more efficient, as pitch control is a direct AoA control. That doesn't mean a bit more speed won't help: it will. But what you seeks, ultimately, is not more speed but less AoA.
(*) which, as shown above, will allow you a lesser AoA for the same flight path, or a higher flight path with the same AoA.
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The beauty of it is that it can embed a certain logic in an abstract way in an equation, allowing reference to the logic, or its elements, just by way of referring to the equation, and its elements...
You may be unstalled (i.e. your wing is flying, producing lift & allowing control) but not have a CI big enough to support your weight. Then, you're descending. But no more stalled.
Exactly!
The explanation helped seeing that I've missed your implicit reference to the speed vector's scalar (magnitude) as a constant element, with the changes of the vector's direction coinciding with the AoA changes, and vector axial components changes.
With the rephrasing, I think we're in sync (unintentional rime).
The "speed change” I was referring to “is a consequence of change of AOA" , with both energy conservation and momentum conservation playing their roles.
My point is : Speed is a consequence. AoA is what matters.
With the rephrasing, I think we're in sync (unintentional rime).
The "speed change” I was referring to “is a consequence of change of AOA" , with both energy conservation and momentum conservation playing their roles.
Last edited by airtren; 5th Oct 2011 at 13:00.
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Originally Posted by DozyWannabe
Also, CONF is a long-time hater of everything the 'bus stands for, so of course he's going to say that.
Originally Posted by DozyWannabe
If the protections were gone, your hero Asseline would not have been alive to lie about the aircraft in the first place.
That I look "little ridiculous" in your eyes is OK to me.
If you are at the end of the rope for your argumentation, I cannot help you.
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Sorry, who was Asseline employed by? What was his rank in the company?
'Reality' is a boulevard with a reciprocal. It cuts both ways.
The company beverage at Airbus is 'KoolAde'...tm
'Reality' is a boulevard with a reciprocal. It cuts both ways.
The company beverage at Airbus is 'KoolAde'...tm
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Hi,
And another news (transparency and credibility .. we said .. ?)
Rio-Paris: l'Agence européenne de la sécurité aérienne a-t-elle quelque chose à cacher ? - Libération
Google Traduction
And another news (transparency and credibility .. we said .. ?)
Rio-Paris: l'Agence européenne de la sécurité aérienne a-t-elle quelque chose à cacher ? - Libération
Google Traduction
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Hi,
I just made a little review of the French press this past October 5 dealing with the matter of legal side AF447
I think that I am right in reckoning that the process will be in 10 or 15 years (St Odile and Concorde style) and no doubt many players will disappear naturally before those days (even the "experts") and everything will be already a "souvenir" in the shadow
It goes without saying that this does not show the famous independence .. the famous transparency .. the famous search for the truth .. very credible to the general public
I just made a little review of the French press this past October 5 dealing with the matter of legal side AF447
I think that I am right in reckoning that the process will be in 10 or 15 years (St Odile and Concorde style) and no doubt many players will disappear naturally before those days (even the "experts") and everything will be already a "souvenir" in the shadow
It goes without saying that this does not show the famous independence .. the famous transparency .. the famous search for the truth .. very credible to the general public
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airtren
We're on synch indeed.
Except perhaps re-the beauty of maths, but it's a religious matter for me (joking).
jcjeant
How interesting! Let's hope the "technical constraints" may be soon solved...
We're on synch indeed.
Except perhaps re-the beauty of maths, but it's a religious matter for me (joking).
jcjeant
How interesting! Let's hope the "technical constraints" may be soon solved...
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Rank ? Not sure, but I have seen at least one reference to him being (ironically) one of those who were consulted by Airbus in the flight control system design. Since there are some here who believe Airbus didn't consult pilots on the design... that would imply Asseline was not a pilot.
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Also, so does Boeing (777, not sure on 787 but believe it is the same). Secondary mode on 777 is very similar to alt law on bus - still the same control laws but no protections (which on 777 are "soft" only and operate through the artifical feel). 777 also has direct mode too.
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“I’ve lost VSI,” the junior co-pilot said of the Airbus’s vertical-speed indicator, according to a recording detailed in the report from court-appointed experts. In fact, the instrument was functioning normally, its analog needle immobilized at the lower limit because the plane was hurtling toward the ocean at 15,000 feet a minute, the document seen by Bloomberg News shows.