Air France 447 - On topic only!

[TeeVee]

Maybe a possible solution to help disorientated pilots is to include a 2nd line on the stall warning lights that says "Push nose forward", or an audible alarm with stall alarm that says "Stall! Push nose forward". Yes may will not apply in all situations. but since the plane failry knows what condition it is in, some checklist features can be auto inserted to start trouble shooting of and get the pilots into recovery mode quicker. just a thought.

not completely crazy. after all, the terrain alarm says, "terrain. pull up, pull up."

better yet, as has been mentioned in this thread before, why not build the logic into the bus's idiot proof system? just like the plane won't allow you to do stupid things like exceed a certain bank angle, it can take over and self-recover from a stall or approach to stall--in every "law"

[Gabriel]

Well, the "in every law" is the problem.

The plane was already in abnormal alternate law, where enough information was lost as to loose redundancy in a way that most of the envelope protections were not possible to remain in place anymore.

It's quite obvious that in direct law, where you've lost your flight control computers and you are left only with an analog transducer of the postition of the joystick that sends analog signals to the actuactors, that (or anything automatic) would be not possible at all.

I honestly don't understand why / if in this case it would have been impossible too. Apparently, the plane has 3 ADR computers (air data), each of these computers collects total pressure (from the pitot tubes), static pressure, outside air temperature and angle of attack. When the three ADRs gave different readings of total pressure, all three ADRs were declared unreliable, and not only the total pressure. That's why it triggered that the AP and AT dissengaged, and that the flight director was unusable too.

On the other hand, the inertial systems were still 100% reliable so the flight computers had enough information close the loop to transform the sidestick input in a load factor output.

One could question why the wholoe ADR and not just the total pressure reading was declared unreliable, but one should know enough of the systems arquitechture in that plane, and I certainly don't. In any event, probably a mod to include the proposed feature (that the stall protection remains active in any law) would not mean just a software upgrade, but a full review of the systems arquitechture and a major re-certification of the plane.

I, on the other hand, vote for pilots that had a good primary instruction in a Cessna 172. That would protect against this accident in this plane in in the vast majority of the airliners flying today which are not FBW and could hardly be modified to include the anti-stall feature.

[3WE]

...good primary instruction in a Cessna 172...

Apply full power.
Maintain climb attitude.

[Gabriel]

Okay, make it a Piper Tomahawk then.

[snydersnapshots]

Maybe a possible solution to help disorientated pilots is to include a 2nd line on the stall warning lights that says "Push nose forward", or an audible alarm with stall alarm that says "Stall! Push nose forward". Yes may will not apply in all situations. but since the plane failry knows what condition it is in, some checklist features can be auto inserted to start trouble shooting of and get the pilots into recovery mode quicker. just a thought.

Why don't we just build an airplane with a system in which both pilots can see which way the stick is being pushed? Oh, wait. Boeing already does that! I guarandamtee you that if the guy in the left seat had a control column hauled back into his...well, you get the idea...he would have slapped the other guy up aside the head and made him push forward to break the stall!

A sidestick in a single pilot airplane is great...the guy flying ALWAYS knows which direction the stick is being pushed. A sidestick in an two-pilot cockpit is idiotic. Or maybe I'm just a biased Boeing kinda guy...

[starchyme]

Why don't we just build an airplane with a system in which both pilots can see which way the stick is being pushed? Oh, wait. Boeing already does that! I guarandamtee you that if the guy in the left seat had a control column hauled back into his...well, you get the idea...he would have slapped the other guy up aside the head and made him push forward to break the stall!

A sidestick in a single pilot airplane is great...the guy flying ALWAYS knows which direction the stick is being pushed. A sidestick in an two-pilot cockpit is idiotic. Or maybe I'm just a biased Boeing kinda guy...

It's been mentioned before, and I agree with, that the "feel" of flight is lost with the joysticks type controls, on the side. In the "kid in the cockpit" air crash investigation, all the boeing pilots had to was to release hold of the control column and the plane would have corrected itself.

It cannot be difficult for the airbus engineers in this case to install an auto recovery mode, where everything is operational except the airspeeds (and pilots in this case). As many posts state, set cruise speed, and correct angle of attack, and the pilots can then troubleshoot the conditions that are faulty. But because they did not have a feel for the plane, due to many factors, they kept overriding the systems. Get them to fly cessna, or other planes once and a while as part of their training to keep them on par with feel-of-flight. and yeah, I know visual cues are needed for reference, but clouds, and lightning at night could have helped that fateful evening, maybe. Besides the blank-out of the pilots, the aircraft had enough information to make this a preventable accident as stated by posters, if basics of flights could have been set. If the pilots don't do it, the computer must periodically try to set it for them if "correct" action is not taken. Who knows, maybe they are working on something already. Let's see what the future holds.

[Gabriel]

Seriously, guys, we are discussing how the smart plane should kill the stupid pilot.

We have to make a choice. Who is in charge? Until we have pilotless planes, I don't see this happening.

Why don't we require the 737, 757, 767, 747, etc to nanny-guard against stupid pilots like we ask Airbus to do? These planes have the same ammount of info than the Aribus: AoA, total pressure, static pressure, air temp, accelerations and angular orientation.

Why are we asking Airbus to include features that we don't requiere for Boeings and are not required in the regs?

Answer: The regs and Boeing assume that there are two pilots in charge. And know what? Airbus assumes that too. The problem is that we expect Airbus to put the plane above the pilot. And apparently some Airbus pilots too.

To put more power on the plane and less in the pilots would be a mess for certification. The computer software becomes terribly complex, and you would have to prove that there is no mistake in it's design and code. You don't need to prove that for a human (because it's already known that we are imperfect).

If anything, I criticize Airbus for NOT making the plane more pilot-friendly, not for not making it more pilot-independent:

The sidestick design in which what one pilot is doing it's not evident for the other pilot.
The AP that moves the control surfaces without actually moving the controls as a pilot would do (when a Boeing's AP adds trim you see the trim wheel turning, and when the AP rolls you see the yoke being turned).
The same for the AT: The thrust levers don't move like in Boeings.
The control laws clearly violate the speed stability requirements in the FAR (which imply an AoA stability too), which require a pull to slow down and a push to speed up. I don't know how Airbus managed to go around this requirement, but I guess that they said that the envelope protection gave an equivalent or better level of safety. And I'd agree. Except that in abnormal alternate law the stall and speed protections are lost but the control law still lacks the speed stability requirements.

For some reason, the "what is it doing now" seems to happen more often in the Airbus line than in the B-777, which is also fly-by-wire but with a philosophy that remains loyal to the traditional airplane feel, including all of the above.

[Gabriel]

I add: Not that any of the above had anything to do with this particular accident. As I've said several times before, the pilots reaction to this event (actively pulling up into an aggressive and unsustainable climb and then, when the stall warning sounded, pulling hard up again and keeping pulling up) would have equally stalled an A330, a B777, a DC-8 or a Cessna 172.

The only "but" is that perhaps the PNF was not aware of what the PF was doing with the sidestick, while he would have been aware with any of the other types mentioned.

[TheKiecker]

YAY !!!!

Joysticks to be visible to all in the cockpit !!

[Deadstick]

Sullenberger on AF 447

http://www.youtube.com/watch?v=kERSSRJant0

[3WE]

Okay, make it a Piper Tomahawk then.

Are you trying to say that the little opposed 4-banger is not powerful enough to power out of a stall.

[3WE]

...Get them to fly cessna, or other planes once and a while as part of their training to keep them on par with feel-of-flight...

After much consternation, I've come to feel that the vast majority of pilots do not need this training and that these aggressive pull ups tend to be done by a very small fraction of folks who somehow slipped through the cracks and forgot (or never got) the AOA/stall concept.

...and for the most part, stalls mostly kill private pilots who are diving on their girlfriends houses, or turning steeply to final approach (or who takeoff and turn into a tailwind without enough momentum)...airliner folks have to worry much more about flying into the ground during an approach to minimums, or an engine failure on takeoff. And, intstead of getting out of a stall, I have to overwhelmingly state that the best way to avoid a stall is to maintain adequate airspeed and a healthy attitude- not to fully stall out and then recover.

Still, I have to question the rote training of full power and climb attitude without at least a little discussion that sometimes...sometimes, you might want to think about lowering the nose...just a little, since you can theoretically stall an airplane at any airspeed and attitude, even including a healthy climb out with giant-ass, powerful turbofan engines that would chew up a 172 and spit it out as a puff of smoke.

[Black Ram]

Sullenberger on AF 447

http://www.youtube.com/watch?v=kERSSRJant0

Sullenberger is a hypocrite. He also reacted by frantically pulling up in the final seconds and it was the bus protections that prevented a catastrophic stall.
I don't think it adds anything positive to the discussion when certain people go beyond their field of understanding, no matter how competent they might be in that field. Sullenberger is (was) a pilot and is also an important figure in the pilot's union - those who despise the airbus way of doing things. It is the NTSB who investigate and write reports. Sullenberger was very cynically anti-airbus and kept trying to play down the bus's role in the accident. Still he hasn't explained what would have substituted the airbus's auto trim and alpha protection...
So don't believe everything he says, just because he is a great airman.
Plus, many more accidents have happened prior to the introduction of the sidestick. And the Colgan crash happened without involving sidesticks.

[Deadstick]

Sullenberger is a hypocrite. He also reacted by frantically pulling up in the final seconds and it was the bus protections that prevented a catastrophic stall.
I don't think it adds anything positive to the discussion when certain people go beyond their field of understanding, no matter how competent they might be in that field. Sullenberger is (was) a pilot and is also an important figure in the pilot's union - those who despise the airbus way of doing things. It is the NTSB who investigate and write reports. Sullenberger was very cynically anti-airbus and kept trying to play down the bus's role in the accident. Still he hasn't explained what would have substituted the airbus's auto trim and alpha protection...
So don't believe everything he says, just because he is a great airman.
Plus, many more accidents have happened prior to the introduction of the sidestick. And the Colgan crash happened without involving sidesticks.

Wow. Let's see, "he went beyond his field of understanding no matter how competent he might be in that field." That's a little circular, or something. Sully may not be an active airline pilot anymore, but he's still a pilot, and I would believe he has valid comparisons in his multi thousand hours between Boeing style and Airbus style aircraft. "So don't believe everything he says just because he's a great airman?" I guess if he said an airplane can fly without a tail or wings I could suppose he's talking about a rocket, but your comment is a tad confusing. He's a great airman but don't believe him in his analysis of aircraft he's flown? I don't think I can get there mang.

And just one other quick thingy, he "frantically pulled up in the final seconds?" Considering the side stick throw is only a couple of inches, I don't know where frantically comes from, other than maybe you're a little worried about being the PIC in an airliner about to splash down in the Hudson. I never heard "frantic" in his radio transmissions. I guess I'd want the nose up a little too before hitting the water. Everyone survived. I know there was a huge luck factor, but I think there was just a slightly larger experience and skill factor involved as well.

Are you drunk or just Jeff Skiles?

[Gabriel]

He also reacted by frantically pulling up in the final seconds and it was the bus protections that prevented a catastrophic stall.

Leaving the "frantically" adjective at a side, the above is true.
He run out of airspeed too soon and too high ("too" here doesn't mean "a lot", just more than what would have been good), so the airplane descended into a somehow higher than ideal sink rate towards the water, and Sully attempted to prevent a hard touchdown by pulling up, and the stall protections had to intervene to prevent a stall.

On the other hand, maybe Sully was counting with this feature and pulled full aft knowing that the protections would limit the AoA to just below stall, thus delivering the max performance and achieving the smoother landing that was possible at that point (that he had already run out of airspeed too soon and to high), which is an optimal solution vs a pilot trying to find that exact point manually and risking pulling up less than as much as he would have been able to (and hitting the water with more than the minimum possible sing rate) or pulling up more than he should have and stalling, again hitting the water with more than the minimum possible sink rate.

In the end, intentional or not, and at that moment when he had already run out of airspeed too soon and too high, pulling fully aft was the best that he could have done IN THIS PLANE that had the stall protections in place. (It would have not been the right thing to do in a Boeing or in an Airbus in alternate law).