AlphaZuluRomeo

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).

philip2412

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.

LandIT

jcjeant: jcjeant: Maybe that is rather premature judgement on BEA, because they released preliminary findings, not their final report and recommendations yet. Lots of us are eager to see some concrete results and improvements to various things that we believe we can see are blindingly obviously in need of changing and improving.

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).

philip2412

sorry,this was a response to DW 1379

GarageYears

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.

RetiredF4

Concerning flying, military fighters use SS. But the equivalent of formula 1, like Red Bull air racing, or the machines flown in Reno-air races............??

TTex600

No, I am not perceiving the time lag. When I have a tactile connection to the airplane, I FEEL the aircraft. You are limiting me to sight, just as the airbus limits me to sight, and I reject that condition. Actually, in the Bus, I have no choice to accept it, but I don't like it.

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.

Organfreak

@TTex600

BRAVO!!!

aerobat77

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.

jcjeant

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.

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.

Zorin_75

I don't think anybody including himself really knows what he believes, in any case most of the time he's just making up stuff. Steer clear if you want to maintain any level of sanity.

I agree we're not seeing much of option 2 here, but I also have a hard time imagining indications that rationally should have lead to the inputs made. Perhaps we need to consider 3. Freeze and stare into the headlights. A very natural reaction to a dangerous situation, deeply hardcoded into our reptile brain, no matter how smart you are. Only to be overcome by training...

Well, in this case (like any other old a/c) there were no more hard protections, period. This reversion was based on the assumption that a computer acting on unreliable data is much worse news than a well trained pilot trying to make sense of the situation. I assume out of context of this incident most here would have wholeheartedly agreed with this?

Though one would have hoped that this was already the most basic piloting instinct...

Certainly a good idea, though it should be noted that they had almost a minute of proper stall warning (plus there not being any need to stall the plane at all). I can't think of any reason not to improve the stall warning logic, but if you're that slow and in the air you probably need a lot more than a reliable stall warning to get out of this...

TTex600

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.

RetiredF4

True, but it is no argument here. All of those aircraft have an artificial airspeed dependent control force. It´s not relevant how the feel is generated, wether by cabels and pulleys or by speed augmented springs or weights.

A very unfortunate example. All the DC 10 had also an airspeed dependent control force feedback. The feedback could be used in manual mode (the feedback could be manually increased or decreased) or in AUTO mode.

The artificial feel system of FBW-AB is a constant spring mode feel and therefore no feedback.

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.

Dani

very true, but what do they do if speed is lost or - even worse - showing complete nonsense?

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...

RetiredF4

Those speed corrections are normally derived from seperate sources (like a ram air inlet in the horizontal stabilizer in the F4). No rocket science or electrical signaling necessary.

Dani

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.

gums

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.

Old Carthusian

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.

bubbers44

"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?