![]() |
jcjeant, as the BEA is still working on the case, you cannot write that just now IMO. ;)
If nothing is said about the SS after the final report is published, then you can - think that the discussion about SS is moot or - that the BEA didn't want to stress a point that calls into question the ergonomic / philosophical choices of Airbus. I think this particular topic should be covered by the human factor workgroup, whose creation was announced on sept. 7, 2011 (here). |
right,as i said in my last post.we must know the fact ,that the cpt gave command to the younger f/o was taken by the other one.
i am sure there were underlying human issues. |
jcjeant:
So the BEA accepts this situation and therefore also agrees that this event happens again with the risks that entails Remind that BEA (the experts) analyse the accidents and release conclusions and recommendations for improve safety when necessary. So it seems that the discussion about SS is moot Unfortunately, don't we have to wait for the process to slowly and methodically grind its way to a formal conclusion? The BEA "human factors" study seems to indicate them recognising and addressing significant CRM issues. I thought it significant that they thought perhaps cockpit video be made available. Will we ever know what instrument indications PF had at all stages of the last 4 minutes? Hopefully in their report they'll fully address the equipment and operational issues exhaustively as well. I hope AF have already learnt lessons and applied better procedures. I hope other airlines have also (there seem to be a lot of A330 customers in scope). I'm eager for the A330 to be a safer tube to fly in asap (and any A3xx) and so have expections on Airbus itself but I guess formality requires a patience it is sometimes difficult to exercise at this stage of an investigation. For me, I guess I will still step aboard an A330 of almost all airlines (and did so recently, enjoyed it). |
sorry,this was a response to DW 1379
|
Side-stick use in an auto - this has been referred to a couple of times. Firstly we only need control in a single dimension in a car (left/right), unlike an aircraft where we'd like left/right and up/down. There is also the simplicity factor - even with power-steering, basically the deflection of the steering column, results in a directly proportional deflection at the wheels. Trying to do this another way would undoubtedly be more complicated and (more significantly) cost more. You can be pretty certain that a 'better' way of controlling a car would have made it's way into the Formula 1 world at some point over the last 20 years, given the multi-million $$$ world that is. To date, there has been no fundamental change with respect to the use of a steering wheel.
|
GarageYears You can be pretty certain that a 'better' way of controlling a car would have made it's way into the Formula 1 world at some point over the last 20 years, given the multi-million $$$ world that is. To date, there has been no fundamental change with respect to the use of a steering wheel. |
Machinbird Quote: Someone mentioned that the SS does offer feel. Yes, it does offer feel, but not feedback. Maybe I'm just "ham handed", but the feel offered by the Airbus SS is of little value to me. Once you break out of center, I don't feel much difference between part and full deflection. But more importantly, the FBW system prevents me from feeling the controls I.e. "feedback". In an MD80, I can feel a wing start to drop (thru the yoke) before it happens. In the Airbus, I have to see the wing drop on the ADI, make a corrective control movement, watch the ADI again to verify the control was successful. IOW, with feedback, I never had to think or process a control input. My hands felt the controls and sent the message straight to flying part of my brain which returned the correct input to the control yoke. No cognitive process involved TTex600, I could be wrong, but what I think you are perceiving is the time lag in your perceive-act cycle. An aircraft like the MD-80, you see the slightest of movement and you apply the slightest of pressure automatically and the wings stay level. If you have to perceive a bit of movement, and mentally process it, before making a correction on the 'Bus, then the response is going to be a bit delayed. One of the early visual flight simulators for the A-4 Skyhawk had a bit of lag in the visual display of about 0.3 seconds. No problem to fly it 'visually' as long as the control movements and rates were small. But if the rates were high enough, the lag caused a disconcerting overshoot and could generate a PIO, normally in the roll axis. This may be an analog to what the PF on AF447 experienced in Alt 2 law with the higher than accustomed roll rate. Maybe my problem here is that my swept wing experience comes from opposite ends of the spectrum. Lears, both Longhorn and tip tank, and the DC9 series are both cable controlled, steam gauge airplanes. Then I went to the Airbus 319/320/321. Any reasonable experienced Lear/DC9 pilot can give you a fairly accurate estimate of airspeed using nothing more that control response for input. I thought that was flying 101. Heavy controls = fast, mushy controls = slow. Maybe I expect too much out a transport category airplane, I guess I am just spoiled. Back to AF447, Why do some of you insist upon damning the pilots because "the instruments were giving normal indications the last three minutes"? How were the pilots to KNOW the the indications were normal? I've worked the UAS/ADR scenario in the sim and it takes far more than three mins to decipher the good data from the bad data. I agree that the PF pulled and continued to pull, but I won't damn him for that even though we can find no reasonable justification for doing so. We know NOW, that the speeds returned to normal and that everything else never deviated from normal, the crew didn't have that luxury. They went from a known attitude with bad indications to an unknown (self induced) attitude with good instruments which added more uncertainty to the equation. Regardless, they had twenty seconds to figure out what we've had twenty months to study. Yes, if they had just flown pitch and power (lyman appears to believe that pitch info was also suspect which leaves us basically unrecoverable, but I'll assume now that pitch info was accurate),,,,,,if they had just flown pitch and power, they would have had time to decipher the conflicting info and determine their true situation. Be that as it may, he made a mistake thirty some odd seconds into the event and pulled. After that, the combination of UAS - stall warning sounding as speed increased, no tactile feel to provide clues, etc, prevented the crew from understanding the situation. Anyone not familiar with most all modern transport category/high tech airplanes can't really understand, but when one recognizes that everything presented to him is computer generated - including pitch info- and then suffers a failure leading to misleading information, he is faced with two choices. 1. pick the most likely correct instrument and use it to judge the others and hope you choose wisely or 2. assume that NONE of them are correct and methodically work your way through a troubleshooting flow chart (on paper or from memory, either way). Methodical, step by step, procedures take time and require you start from some known. The limited info we have regarding the crews actions the last three mins. would seem to indicate that they were anything but methodical and deliberate. That points to training. Put yourself in the AF447 cockpit, you've made one mistake, a mistake you don't yet recognize, and find yourself out of control. Your instruments are confusing, your master warning/caution system demands attention, bells and whistles are ringing, You know that something is terribly wrong, you don't know what. What do you do? In this case, one mistake caused an accident - pulling for no reason. The Airbus philosophy would appear to be one of protecting the airframe from the pilot. Somehow this went horribly wrong. IMHO, Airbus didn't realize that the pilot could damage the airframe in more ways than just flying too fast or too slow, than just pulling too hard, than just banking too much. He could be confused to the point of error and they didn't anticipate that. If I could go and change one thing and prevent this accident, I would say that would be: train the pilots to ignore everything but pitch and power in the event of any instrument abnormality. If I could go and change any one thing to have helped them recover from this accident, it would be: put the stall warning system on WOW (weigh on wheels, or air/ground) switch so that it would not bias out at taxi speed and below.(I realize that more needs to be done than just a simple WOW, but I'm trying to keep this example simple) Putting myself in the dead crews place, I imagine that the most confusing input was the stall warning activation that returned, twice, as the airplane trended to recovery. |
@TTex600
BRAVO!!! :D |
on the one hand it surely sounds crazy that three people were not able to realize a stalled situation and recover from this high altitude. we could think that everybody of us would have done better.
on the other hand, like TTex600 described very good, its a different story to discuss it aftermath or being in such a situation for real. they went through the night, thunderstorms in the vicinity , systems shut down one after another. the copilots confused and start to loose orientation. the captain needs time back to the cockpit but cannot help much. the pilots had no visual reference what pitch they have, the stall warning wents off when you pull further and goes on when you push so vice versa you normally would expect... ( because at very low IAS it seems to inhibit) . the captain seemed to be the only who had a feel for a possible stall, he advised several times not to pull- until the gpws went on and they tried the last instinctive pull without any result in a stalled condition of course. i think you can blame airbus that the stallwarning is not designed to inform a pilot firmy about a stall in any event, even with frozen probes and false speed indications. the second thing of course to blame airbus is that the instruments at all went erratic. the crew of course lacked to realize the true problem and , when not manouvering so that they will not reach a stalled situation, to recover the stall. from that high altitude the stall from a technical point of view should be recoverable. |
systems shut down one after another. the pilots had no visual reference what pitch they have i think you can blame airbus that the stallwarning is not designed to inform a pilot firmy about a stall in any event the second thing of course to blame airbus is that the instruments at all went erratic. |
TTex600, you are absolutely correct that yokes connected to a stearing surface offer direct feedback from the very surface. While this is true in a DC-9 or a Boeing 737, this is no longer the case in any wide body aircraft since the last 40 years or so.
The DC-10 was the very first aircraft that had no direct mechanical connection to the stearing surfaces anymore. A lot of conservative pilots (i.e. most pilots) were crying out loud, but since then everyone took over this technology. With the only exception, that AI (not AB, AB is Air Berlin) replaced the cables to the hydraulic servos by wires and control computers. So imaging yourself being in a DC-10 and having pulled fully up at FL350, you would have most probably experienced the exact same problem as AF447. When the captain in his pijama would have come back to his station, and the FO said "I cannot figure it out" and see him his yoke more or less in neutral, he also couldn't make any sense out of it. I think that in a stalled 777 you would also feel nothing during your glide down. Because the yoke's feedback unit is not designed to give feel during stall. The only thing you would get would be the stick shaker/pusher (don't know if 777 has this feature). Having to fight against those two "poor man's protections" is way more difficult than against nuissance warnings. |
lyman appears to believe 1. pick the most likely correct instrument and use it to judge the others and hope you choose wisely or 2. assume that NONE of them are correct and methodically work your way through a troubleshooting flow chart (on paper or from memory, either way). The Airbus philosophy would appear to be one of protecting the airframe from the pilot. Somehow this went horribly wrong. If I could go and change one thing and prevent this accident, I would say that would be: train the pilots to ignore everything but pitch and power in the event of any instrument abnormality. If I could go and change any one thing to have helped them recover from this accident, it would be: put the stall warning system on WOW (weigh on wheels, or air/ground) switch so that it would not bias out at taxi speed and below. |
aerobat77, and everyone else for that matter. I am not willing to place blame for this accident on any single person. I can't even speak to the training provided by AF,
With that said, I'm leaning toward blaming airline managements for shortchanging the pilots in training. I absolutely know that my carrier's management used the "a monkey can fly this thing" so we can put a 200 hour pilot in it logic. On the other hand, I've seen some of the training given/knowledge required by USAirways and United Airlines and I believe that their training departments were very thorough. If this accident does nothing more than force the business side of the office to fund more training, we will all be better off. I spent countless hours droning along in a simulator flying non-precision approaches when I transitioned from DC9's, but never trained for UAS until after this accident. This forum has been a far better training class than my GS. Thanks to everyone. BTW, the training dept at my carrier - Spirit - is completely different from when I went through. It's yet to be determined if the new guys will be more thorough. |
Dani TTex600, you are absolutely correct that yokes connected to a stearing surface offer direct feedback from the very surface. While this is true in a DC-9 or a Boeing 737, this is no longer the case in any wide body aircraft since the last 40 years or so. Dani The DC-10 was the very first aircraft that had no direct mechanical connection to the stearing surfaces anymore. A lot of conservative pilots (i.e. most pilots) were crying out loud, but since then everyone took over this technology. With the only exception, that AI (not AB, AB is Air Berlin) replaced the cables to the hydraulic servos by wires and control computers. MAN SLEW Selector Provides manual control, when elevator feel selector is at MAN and changes the Q variable load feel input of the elevator controls. Elevator feel must be manually changed by use of the MAN SLEW selector to maintain ELEV-FEEL-REF IAS in agreement with air plane IAS. DECR—Holding the selector at the first dot provides manual electrical control of one of two electrical motors to decrease the reference air speed indication and elevator load feel. Holding the selector at the second dot performs the same function if the first motor has malfunctioned. INCR—Functions identical to the DECR position except in the INCR direction. ELEV-FEEL Indicator: Indicator pointer follows up indicated airspeed within±15 Knots when the system is operating in the automatic mode. Used as an aid for providing proper maneuvering control force gradient throughout the flight envelope when operating in the manual mode. So imaging yourself being in a DC-10 and having pulled fully up at FL350, you would have most probably experienced the exact same problem as AF447. When the captain in his pijama would have come back to his station, and the FO said "I cannot figure it out" and see him his yoke more or less in neutral, he also couldn't make any sense out of it. |
All of those aircraft have an artificial airspeed dependent control force. OK, it might even help, because the yoke force would be so strong that even the dummy FO would be unable to pull up to 15° nose-up... :suspect: |
Dani very true, but what do they do if speed is lost or - even worse - showing complete nonsense? |
Never heard of such techology in an airliner. Anyone?
If you would have additional sources of speed pick-up, you could use it to compare them with the unusual (the wrong) speed signal. |
Yokes, sticks and feedback
I do not believe any of the commercial jets last 30 years had a pneumatic doofer to provide some feedback for the yoke/stick. As RF4 said, the Voodoo and Phantom had a ram air bellows that increased the aft stick force according to dynamic pressure. It was not "feedback", and only served to keep us from ripping the wings off if we pulled too hard too fast, heh heh.
I also do not believe there was a lotta direct feedback via the cables, push rods and such for most airliners since the 777 and 'bus series. Could be wrong. If we pilots insist upon a great "feel" with the new FBW systems, it is not a big deal. The force or "deflection angle" sticks/yokes can easily be modified to use sensed "q" and even actuator/control surface position to "vibrate" the controls or increase force requirements according to "q" and so forth. Hell, the jet would feel like a huge Sopwith Camel! Besides all the confusing warnings and the perceived unreliable readouts the AF crew dealt with, they also did not have obvious "feel" of the jet's condition. So I think that the 'bus has very good aero characteristics and that the remaining FBW features helped keep the jet from entering a spin or having extreme roll moments. The delta's had very good directional stability, and little buffet once past a useable AoA. Biggest clue was the vertical velocity pegged downward and the altimeter unwinding faster than you can believe. Ask a Concorde pilot or one that flew the F-102, F-106, J-35, Mirage, et al. So some form of "feedback" via the sidestick could be in order. Actual control surface feedback, a "buzz" to indicate stall or approach to stall, etc. |
The 'feel' debate strikes me as a red herring sorry to say. Once again it comes down to knowing your machine and what it does. What you can do with the controls - being a professional pilot in fact (this is not a comment on the flight crew of AF447). Being disciplined enough to scan your instruments properly and pay attention to the information they give. These will be a more reliable indicator of what an aircraft is doing than feel. A pilot has to trust his instruments first and himself second - he is the random element.
|
"If you compare it with AF447 the yoke would have been in his lap. If the captain would have not seen this, he most probably would have his blinds still in front of his eyes."
I agree with this statement about the captain not knowing the PF had been pulling full back on the SS for some time causing the upset in the first place. Who would expect any pilot to do that or the PNF to allow it? |
I agree with this statement about the captain not knowing the PF had been pulling full back on the SS for some time causing the upset in the first place. Who would expect any pilot to do that or the PNF to allow it? It is quite clear in my mind: regardless of all the "Once again it comes down to knowing your machine and what it does. What you can do with the controls - being a professional pilot in fact"-type comments, the SA of the PNF would have been much-enhanced (quite probably to the point of being able to do something positive early on) if he had a control column in front of him, not to mention the skipper when he appeared. Whether the cost-savings of having independently-moving, hidden-from-view side-sticks is worth 228 lives: that is the question. |
Capn Bloggs
Having a control column is another of those 'red herrings' I am afraid. It wouldn't have made a blind bit of difference on that night. You will recall from the BEA interim reports that the PNF could understand what was going on but didn't intervene sufficiently (a precis I agree but accurate enough). CRM was another thing lacking with poor definition of roles and this was much more significant. The side stick is not the issue here but how the crew responded to the situation. I refer you to the numerous accidents in the past where PNFs could see what the control column was doing but didn't intervene. Know your aircraft - that is all. |
gums
As RF4 said, the Voodoo and Phantom had a ram air bellows that increased the aft stick force according to dynamic pressure. It was not "feedback", and only served to keep us from ripping the wings off if we pulled too hard too fast, heh heh. I´ve flown more than 3000 hours in that bird in all flight conditions, and the feedback was like natural in all flight conditions from stall to Mach 2.2 (yes, the RF-4E was going that fast in clean configuration). The expierience of a bellows failure demonstrated well enough how vital this system was for flight. I speak out of first hand expierience here. Wether the system is a pure mechanical one or a computerized one like in the concorde, is imho secondary to this discussion. It was deemed necessary for decades and serves well until today. Boing deemed something alike necessary for it´s newest models 777 and 787. Note: I´m not intending to value A v B, i was only trying to answer Dani´s input concerning feedback in the last years. |
i have been wondering who thought taht out:
speed 60 mph or less - no s/w b/c at that speed the ac could`nt be in the air speed 61 mph - s/w b/c now the ac is in the air. mostly we can only speculate,but i thought from the beginnung taht when the s/w did no act that way the ac could very well have been saved. the "logic" of the s/w definetly confused the pos. you do the right thing and the computers are telling you,you`re wrong ! |
Did the PNF know? If you ask me, I don't know, if you ask me, *should* he have known, I strongly affirm. These guys happened to experience the worst case of instrument failure, and what do you do when you have that? Looking out of the window? Smoking a cigarette? Chatting with your cabin attendant? Sorry for being so bitterly sarcastic but this is not a question of Airbus or fbw or any other question, this is gross neglect of primary pilots duty. You don't leave your eyes from the instruments until your aircraft is stable and checklist work is initiated. And this means all four eyes. But they never left the initial confusion state until impact. |
Originally Posted by Capn Bloggs
He perhaps knew the nose was up a bit (not grossly high, mind you),
Likewise
Originally Posted by Dani
These guys happened to experience the worst case of instrument failure
|
Joysticks in cars
Has been done (1992 apparently):-
The Saab 9000 drive-by-wire ‘Joystick’ project Google for [saab joystick steering] turns up quite a few hits. I did once see a Mini parked on the road that was apparently steered by a tiny (RC model sized) joystick on the floor. I assumed it was for the use of someone with no or non-functional arms. It must have cost a *fortune* at the time. I think I saw the car in the 1970s and it was a 1960s mini in utterly pristine condition. |
i think the PNF knew that the PF gave upstick inputs since - when the publication of the last conversation is true- the PF stated that he pulled back full for a while. and does the ac not have a stick input indication on the pfd?
i personally do not think that the sidestick concept is an answer why it happened, look how many a320/330/340 fly every day and everything works . it stays a mysteria why he pulled that much , put the aircraft in a stall and none of the three realized it and recovered. |
aerobat, I completly agree with you that the PNF knew exactly what the other did, they both agreed upon the procedure. Only the procedure was wrong, because everyone told them, that you just have to pull on an Airbus and you are safe.
btw you only have stick position indicator on ground, not in the air. |
hm... from the last words "but whats happening?" you can imagine they did not knew until impact they are stalled. when you have a high pitch up and simultany a massive descend rate ( more than 10000 fpm!) - what other than a stall should it be ?
i am wondering if its truly so simple, that three pilots until impact believed you cannot stall an airbus and even realizing for minutes that pulling gives no result tried it until the end. i think they were pretty aware they go down like a rock - one pilot says " but why we are going down like this?" maybe... but thats only a quess - an old school solid stick shaker and pusher in this particular situation would have saved more than 200 lives. @ dani : thanks for the information, i have never flown an airbus, so did not knew exactly ! |
Having a wrong procedure and not knowing what's happening thereafter is no logical contradiction. They have been told - according to my assumptions - that if you don't know what's happening to pull, they pulled and found themselves in a completly impossible situation.
Nobody ever told them that a stall would be possible. To the contrary, they have been explained a thousand times: An Airbus cannot be stalled (remember Habsheim!). Giving the readings was impossible to understand under these circumstances. They felt themselves in a not stallable aircraft. The only thought you have in your mind is "why is this happening, what is happening, why are we going down?". |
Nobody ever told them that a stall would be possible. To the contrary, they have been explained a thousand times: An Airbus cannot be stalled (remember Habsheim!). Giving the readings was impossible to understand under these circumstances. They felt themselves in a not stallable aircraft |
But if the pilot doesn't know the fundamentals of his aircraft than he should not be in a seat flying it. |
Nobody ever told them that a stall would be possible. To the contrary, they have been explained a thousand times: An Airbus cannot be stalled (remember Habsheim!). |
when I say that I suspect the AF447 being taught a strange procedure then I don't say that I have ever experienced such. The "pulling procedure" has nothing to do with any official procedure or training syllabus. I have been in some Airbus Training courses, and they teach you that an Airbus "can be flown like any other aircraft", and that's what I learned to happen ever since. I've spent most of my career on conventional aircraft and know what to do in case of high AOA regime and slow speed.
|
Originally Posted by Dani
The "pulling procedure" has nothing to do with any official procedure or training syllabus.
|
None of the pilots flying AF447 had military flying backgrounds. In the past, airlines could rely on a supply of military trained pilots. Now, most of the commercial transport pilots have no military flying background. Although civilian trained pilots would argue that they have equally good training, I think that, if there is a difference, it's that the military training has a greater tendency to filter out people, who would "crack" under pressure, than civilian training. What good is a ball player, who knows everything about american football, if he drops the touchdown pass, when the game is on the line!
The greater flight safety we enjoy, due to technology, is offset by the fact that airlines don't want to filter out the pilots, who would drop the ball, because that would mean less pilots, so they'd need to increase pilot pay. Airline beancounters might claim that training is expensive, but adding a few curve balls and other assorted tricks to their training, to see how a pilot works under pressure, wouldn't be so expensive, but increasing pilot pay, because of the resulting shortage of pilots, would be in the eyes of soul-less accountants, and sociopathic airline executives. Apologies to the many terrific, civilian only trained pilots. I know there are some ex-military pilots who mess up too. |
Coagie, this has been discussed to death: Fighter pilots = better flying skills, civilans = better CRM skills (simplified like your post). That's why "bean counters" count mostly on civilians nowadays.
|
I hope the three AF447 pilots aren't an example of "better" CRM skills! Guess I struck a nerve.
|
"None of the pilots flying AF447 had military flying backgrounds. In the past, airlines could rely on a supply of military trained pilots"
well... fighter pilots, with all respect- are trained to fullfill the mission at every price... in civilian aviation you HAVE NOT to fulffill the mission at every price. i my eyes thats not the point for AF447. we tend to see here on one hand pilots who were not trained on extreme situations on this aircraft and on the other hand an aircraft which was not build for extreme situations. |
| All times are GMT. The time now is 08:39. |
Copyright © 2026 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.