Air France 447 - On topic only!

[Myndee]

As I am a bit of a simpleton (certainly compared to the vastness of expertise from others around here), I still confess myself confused. Is your point that Capt Cox is/was immune to weather?

Not that I know of. In the Nova video he said that something to the effect that pilots would never fly into a thunderstorm. I was just saying that normally I agree with him all of the time, but in this instance, I do not. I really feel like I was on death's door that night. Another thought that was in my mind then was the terrain beneath us. With mountainous terrain in that area and the massive losses of altitude, well, you can see that it was frightening. Windshear was also something that popped into my head. That, and a lot of prayers. I have honestly never been so scared in my life. I was actually more afraid then than I was when I survived a tornado. Maybe I have nine lives?

Thanks for the Airbus info and answering my questions guys. I appreciate you taking the time. I seem to have drifted the on topic only thread off topic, so I will turn it back over to you.

[Evan]

Take roll for example. Up to 35° the roll rate is proportional to the stick displacement, which already means that the displacement of the ailerons depends not only on the displacement of the stick but also on other parameters such as speed. But then, above 35° the logic changes, and the computers will try to return to 35°, the more you are beyond 35° the harder that the computers will try to return to 35°, to the point that the roll rate is reduced to zero by 62° even with full stick deflection, and past 62° it even is inverted. In a simplified model: (AD= aileron deflection, SD= stick deflection)

AD = k1 * SD * k2/speed, for 0° AD = k1*SD * k2/speed * k3*(62°-bank)/(62°-35°) for bank>35°

I'm not an engineer (or any good at algebra), so you lost me on the equations.

I am simply trying to point out to Myndee (and others who perpetuate this myth), that there is no ghost in the machine or HAL9000 or potentially malevolent A.I. going on here. I am stating that the computer does not initiate original commands, like 'land now', but rather acts to limit (or trim) pilot commands which exceed the safe operating envelope.

But since we are talking about the 1% disagreement, I concede that, technically speaking, acting to limit is a command, yes.

For instance, in Normal Roll Law, to exceed 33° of bank angle you have to maintain pressure on the sidestick or it will return to 33°. It will not return to 33°, however, if you maintain pressure, so the pilot has full authority as long as he is applying the command. At maximum deflection, the computer will roll to and maintain a maximum of 67°, and therefore limit pilot command. Thank god.

With pitch, the computer will make corrections to maintain 1G (I've already conceded this), but these are subtle trim issues as opposed to distinctly original commands. If you roll beyond 33°, the pitch trim function (Positive Spiral Static Stability) is inhibited and you have full authority up to the designed limitations.

Meaning that you have, in the heat of an emergency, turn five guarded switches of to override the computers? (ok, I guess that with 4 you'll be in direct law already, and that you need at least 1 of them to "read" the sidestick signals)

I believe taking two PRIM computers off-line will get you to DIRECT law (causing the third to rule itself unreliable), or three at the most. Yes, there are extended consequences to doing this, as we have discussed elsewhere (when I advocated a guarded switch to defeat only the Alpha Prot features instead), but a properly trained crew will be able to stabilize the aircraft manually in DIRECT law before dealing with those consequences.

The computers can be overridden. It is not some kind of impenetrable A.I., as the myth suggests. It does not have a mind of its own. A 'haywire' computer did not bring AF447 down. This is my point.

[Evan]

Not that I know of. In the Nova video he said that something to the effect that pilots would never fly into a thunderstorm. I was just saying that normally I agree with him all of the time, but in this instance, I do not.

Here, I agree with you. Pilots do indeed fly into thunderstorms and take unnecessary, even reckless, chances from time to time. I've been through it as well. It needs to stop. There needs to be a higher authority on weather restrictions, especially the decision to land, then the PIC. Overconfidence and task-orientation are human weaknesses that can infect pilot judgment. Not every pilot is trained to deal with them. I've also had this argument on this forum to no avail.

And this concern is not at all off-topic here.

[Curtis Malone]

There needs to be a higher authority on weather restrictions, especially the decision to land, then the PIC.

Are we talking God, Buddha, Krishna or what? Also, since you don't trust the pilot (you've made that abundantly clear), why would you trust that "higher authority" which ostensibly would be everywhere, but in the airplane?

[guamainiac]

Isn't there something in each "company ops manual" that would say something like .. "intentional flight into thunderstorm activity is strictly prohibited" ..

I guess you can't vary from where some controller is telling you where to go but don't they steer you around even when you don't request it?

[Myndee]

Are we talking God, Buddha, Krishna or what? Also, since you don't trust the pilot (you've made that abundantly clear), why would you trust that "higher authority" which ostensibly would be everywhere, but in the airplane?

I'm not sure if you are being facetous, but I think he means like FAA regulations or something. I guess right now it is not a terribly high priority on the reinforced rules? Some pilots might be great men of skill, but mother nature really can't be underestimated, ie Delta 191.

[Myndee]

I'm not sure if you are being facetous, but I think he means like FAA regulations or something. I guess right now it is not a terribly high priority on the reinforced rules? Some pilots might be great men of skill, but mother nature really can't be underestimated, ie Delta 191.

BTW, not saying that the good crew of 191 knew what they were getting into. They thought they were getting a "little bitty rainshower." I guess in the final minute of the flight is when they saw lightning, and they could have initiated a go-around, but seeing as there was no weather warning and the Lear in front of them made it in okay...I don't think we can fault Capt. Connors and F/O Price in this instance. Just wanted to be clear. I was just saying that mother nature has tricks up her sleeve that the greatest airmen cannot defeat.

[Curtis Malone]

BTW, not saying that the good crew of 191 knew what they were getting into. They thought they were getting a "little bitty rainshower." I guess in the final minute of the flight is when they saw lightning, and they could have initiated a go-around, but seeing as there was no weather warning and the Lear in front of them made it in okay...I don't think we can fault Capt. Connors and F/O Price in this instance. Just wanted to be clear. I was just saying that mother nature has tricks up her sleeve that the greatest airmen cannot defeat.

So, to develop your and Evan's thoughts (assuming that's what they are) a bit further, we need an FAA reg that would protect the flying public from nature's tricks?

[Evan]

So, to develop your and Evan's thoughts (assuming that's what they are) a bit further, we need an FAA reg that would protect the flying public from nature's tricks?

Start here:

http://forums.jetphotos.net/showthread.php?t=51165&highlight=AIRES

[Curtis Malone]

Start here:

http://forums.jetphotos.net/showthre...ighlight=AIRES

Oh, I remember that thread. Definitely a classic.

[Jingogunner]

Flight Data Anomalies

http://www.youtube.com/watch?v=oTQVqCm5eDU&feature=related

the segment about 1.5 cm from the end (don't watch the rest, its torture)

I just watched Air crash Investigations aviation journalist David Learmont (think he was actually a pilot) explain that he thinks the pilots were fixated. There was apparently an anomaly of some kind; the plane transmitted flight data information at regular intervals to the airline and they show that something was wrong. Learmont is speculating that the pilots might have been focused on this and lost situational awareness. Speculation. But is that possible?

When things start to get complicated there should be irritating dramatic music flooding the cockpit to remind pilots they could be heading for Aircrash Investigations.

[Fear_of_Flying]

http://www.youtube.com/watch?v=oTQVq...eature=related

the segment about 1.5 cm from the end (don't watch the rest, its torture)

I just watched Air crash Investigations aviation journalist David Learmont (think he was actually a pilot) explain that he thinks the pilots were fixated. There was apparently an anomaly of some kind; the plane transmitted flight data information at regular intervals to the airline and they show that something was wrong. Learmont is speculating that the pilots might have been focused on this and lost situational awareness. Speculation. But is that possible?

When things start to get complicated there should be irritating dramatic music flooding the cockpit to remind pilots they could be heading for Aircrash Investigations.

Of course the anomolies being referred to are the speed sensor readings followed by the cascade of failures. I'm not sure I buy that the pilots "lost their appreciation of what the airplane was doing - they must have done" as Learmont claims, simply because events happened so precipitously, it's hard to imagine there was any question but that the plane was in distress, descending rapidly. However, his more general point seems to have merit, namely, the pilots could have been more focused - or at least had their attention sufficiently divided - on trying to determine what was wrong with the plane than they were on flying it. I gather this was the point of the segment leading up to the AF447 discussion.

I guess for me the question I would like to have answered by pilots on this forum is how controllable do they think the plane would have been given events as we know them (the loss of speed data followed by the other failures at nighttime, etc.). An Airbus pilot would have the greatest insight here, of course, but to me the answer makes all the difference in understanding which factors may have been most important. "Yes, the pilots should have been able to manage the aircraft despite the loss of systems" versus "Controlling this plane would have been exceptionally difficult even for the best pilots" would be very telling to me. Surely this has now been tried repeatedly in simulators. I wonder how pilots have done.

[Highkeas]

............... However, his more general point seems to have merit, namely, the pilots could have been more focused - or at least had their attention sufficiently divided - on trying to determine what was wrong with the plane than they were on flying it. .....................

This does happen for example on this L-1011

http://aviation-safety.net/database/record.php?id=19721229-0

[BoeingKing77]

When things start to get complicated there should be irritating dramatic music flooding the cockpit to remind pilots they could be heading for Aircrash Investigations.

Oh yeah, irritating music that'll distract them more.

[EconomyClass]

I'm wondering what significance there is at this time, more than a year and a half after the event, that a court is officially beginning an investigation.

http://news.yahoo.com/s/nm/20110317/wl_nm/us_france_airbus