Air France Flight 447 - finally solved.

[sundevil777 93]

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>The Airbus design doesn't lack feedback and coupling just by accident or oversight. My
>memory is that it lacks those features because there are design/engineering issues
>that prevent their implementation.

While I am sure it was cheaper and easier to avoid implementing force feedback, there are no design/engineering issues that prevent such features from being installed in aircraft. Much smaller aircraft with much smaller cockpits (i.e. the F35B) use such systems. Heck, you can get a Microsoft game joystick with force feedback for $99.

If anything it was a cost tradeoff. A reliable force feedback system is expensive.

Thanks for correcting me, I must have not been around there in the flight deck design group at that time after all. There couldn't be anything about having a 2 person crew in a civilian airliner that could be different than an F-35.

It was definitely not a cost tradeoff.

People are sick and tired of being told that ordinary and decent people are fed up in this country with being sick and tired. I’m certainly not, and I’m sick and tired of being told that I am

[billvon 2,400]

>There couldn't be anything about having a 2 person crew in a civilian airliner that
>could be different than an F-35.

There are a lot of differences. None of them would prohibit the same sort of sidestick installation that an F-35 has.

>It was definitely not a cost tradeoff.

Then what was it?

[Calvin19 0]

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The SR22 is becoming the successor to the Bonanza as the "doctor killer" in GA. I'm sticking with my Mooney.

Just read a study that said the SR22, even with the chute, is middle of the road in accident and fatality rates. The Mooney is a little worse, but I say no fault of either machine. It's all in the pilot's judgement.

Was it the one on Cirrus' website?
I read a few that claim "average safety".
Accident rate and fatal accident rate are different things

Everything I have read said "its fatal accident rate is ~1.6/100,000 hours, higher than the US general aviation rate average of 1.2-1.3"


"The Cirrus combined rate (SR20 and SR22) is 1.6,"
http://www.avweb.com/avwebflash/news/Cirrus_Safety_Record_Average_205914-1.html

"Lifetime of the fleet: 1.63"
http://www.cirruspilots.org/Content/CirrusSafety.aspx

"the rate has barely climbed to 1.8." " Just pulling the parachute more often would help. "(old one, but a funny article.)
http://www.cirruspilots.org/blogs/pull_early_pull_often/archive/2008/11/27/trends-in-cirrus-fatal-accident-rates.aspx

The mooney: 1.18 fatal accidents per 100,000 flying hours.
http://www.mooneyland.com/Mooney%20Accident%20List.htm

[billvon 2,400]

>I never agree with the thinking that prohibits the pilot from pushing an override
>button and taking control of the damn airplane.

You can shut down the computers and revert all the way back to manual mode if you want, where you have direct control of pitch (via the elevator trim tab) and yaw (via direct control of the rudder.) I believe you can also shut down just the primary computers and revert to direct law, which is stick deflection = control surface deflection.

But it's going to be very rare for a pilot to try this. It would be placing the aircraft into a mode they're not very familiar with, which is something that is generally unlikely to make things better during an emergency.

[Calvin19 0]

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>It was definitely not a cost tradeoff.

Then what was it?

I would venture to say they did not think they needed it, and the way the FBW system is programed it should not be "needed" These guys are not flying these planes very much, a TON of the flight, (probably more than 95%) is done by the computer. It has been stated to me by my various airline pilot friends, as well as in this thread, that flying by hand, even if it is all done legally, gets you in trouble by your airline.

Putting myself in the shoes of the engineers, I can see why they would not put a feedback into it. The computer does not do a linear surface deflection like a hard-rigged (non flyby wire, hard surface link) control system does. The computer makes a ton of decisions and "changes" between the control stick and the surface. Full aft stick at 400kts does not move the surface the same as full aft stick at 130kts because FBW think it is too much input.

These planes were not designed for creative evasive maneuvering, even if that is needed and vital. With well trained pilots, feedback is not needed.

[theonlyski 3]

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The SR22 is becoming the successor to the Bonanza as the "doctor killer" in GA. I'm sticking with my Mooney.

Just read a study that said the SR22, even with the chute, is middle of the road in accident and fatality rates. The Mooney is a little worse, but I say no fault of either machine. It's all in the pilot's judgement.

The SR20/22 is a slick plane, likes to go fast, and with minimal inputs required. (as I recall) The propeller pitch is linked to the throttle, it's very aggressive to control inputs... I know of at least one instance where a steep turn turned into a spinning to the ground (and LOW) by a VERY experienced, VERY competent and current CFI.

I'd take a mooney/cessna over a cirrus any day of the week.

"I may be a dirty pirate hooker...but I'm not about to go stand on the corner." iluvtofly
DPH -7, TDS 578, Muff 5153, SCR 14890
I'm an asshole, and I approve this message

[billvon 2,400]

>I would venture to say they did not think they needed it . . .

I suspect that's a big part of it; I suspect they thought something like "we don't really need it and it's not worth the cost, weight and complexity to add it." After all, there are aircraft (like the F-16) that have no force feedback at all and seem to do OK. (Indeed the original F-16 stick didn't move at all! It was a rigid stick.)

>With well trained pilots, feedback is not needed.

Also agreed. Neither are cockpit windows (at least in flight) aural warnings or caution/warning indicators. But all of those things can help when the shit hits the fan, as in this case.

The field of haptics has really taken off lately because (I think) people are starting to see the value of providing feedback via the methods humans are used to getting it. We have hardwiring that lets us pick stuff up without breaking or dropping it, and that lets us manipulate objects in a three-dimensional world. This hardwiring is why force feedback works so well - and why it's becoming more common in user interfaces.

[kallend 1,623]

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The SR22 is becoming the successor to the Bonanza as the "doctor killer" in GA. I'm sticking with my Mooney.

Just read a study that said the SR22, even with the chute, is middle of the road in accident and fatality rates. The Mooney is a little worse, but I say no fault of either machine. It's all in the pilot's judgement.

The SR20/22 is a slick plane, likes to go fast, and with minimal inputs required. (as I recall) The propeller pitch is linked to the throttle, it's very aggressive to control inputs... I know of at least one instance where a steep turn turned into a spinning to the ground (and LOW) by a VERY experienced, VERY competent and current CFI.

I'd take a mooney/cessna over a cirrus any day of the week.

I haven't flown a SR22 but I have flown a SR20. Very fancy avionics but I can't say I liked the way it handled. I can see how people get in trouble with it.

...

The only sure way to survive a canopy collision is not to have one.

[JerryBaumchen 1,048]

Hi bill,

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people are starting to see the value of providing feedback

Many, many years ago, when I was in college, I had a part-time job working in the test lab at Freightliner Corp. About that time we added pneumatic throttles to the trucks. Then the drivers said that they simply did not have a 'feel' for the amount of throttle that they were giving the engine via their foot. So we added a small spring under the foot pedal to give them some feedback on just what they were doing.

This is not a new phenomena.

JerryBaumchen

[sacex250 0]

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Remember the early Airbus crash where the plane just descended into the trees during an airshow flyby ? The computer was confused, the pilots were confused, the whole thing stunk ! Early version of the system, I think.
I never agree with the thinking that prohibits the pilot from pushing an override button and taking control of the damn airplane.

In that crash, the computer wasn't confused. The computer did exactly what it was supposed to do and did exactly what the pilot asked it to do. The crash was completely pilot error because the pilot put the airplane into a situation in which there wasn't enough time to accelerate in order to climb.

It's all been said before, no sense repeating it here.

[JohnMitchell 14]

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So we added a small spring under the foot pedal to give them some feedback on just what they were doing.

This is not a new phenomena.

Back in the day, my dad helped design the feel systems for the Boeing 727. Otherwise the yoke would have felt just like moving a hydraulic lever.

[sundevil777 93]

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>There couldn't be anything about having a 2 person crew in a civilian airliner that
>could be different than an F-35.

There are a lot of differences. None of them would prohibit the same sort of sidestick installation that an F-35 has.

>It was definitely not a cost tradeoff.

Then what was it?

My responsibility was for switch panels in the flight deck, not the controllers, so I did not have first hand knowledge of the issues. I do remember conversations with those that were responsible for that in my design group, but I will probably misrepresent the concerns because I was not directly involved and because accuracy of such hearsay memory is often of low quality.

Boeing would not consider implementing sidestick controllers unless they were coupled, and by the nature of the physical layout of sidestick controllers, coupling by physical linkages was not practical (not just a cost issue). The coupling would therefore have to be simulated, and this brought up severe concerns by the human factors design group (I believe human factors design was for the first time treated as a separate discipline on the 777 project) and unacceptable results during the failure mode and effects analysis (the 777 had very high standards for the acceptable probability of severe or catastrophic events, perhaps higher than a military program such as the F-35 might allow). The list of issues preventing implementation was likely much longer than this.

In my earlier post, I said, "The Airbus design doesn't lack feedback and coupling just by accident or oversight." I was saying that in the sense that the two features would be implemented together. The implementation of just feedback without coupling could be a different story.

Also, I said that there were issues that prevented the implementation of feedback and coupling. I would not claim that it is impossible, but I think it wrong to characterize it as a cost issue. I am trying to convey what I know without claiming to have the details.

I think the controller vs wheel issues/tradeoffs/philosophy is interesting and worthy of further discussion, but I think it is wrong to think that Airbus made the decision not to implement either feedback or coupling without grappling with very tough issues and complicated tradeoffs other than just cost.

People are sick and tired of being told that ordinary and decent people are fed up in this country with being sick and tired. I’m certainly not, and I’m sick and tired of being told that I am

[billvon 2,400]

>Boeing would not consider implementing sidestick controllers unless they were
>coupled, and by the nature of the physical layout of sidestick controllers, coupling by
>physical linkages was not practical (not just a cost issue).

I don't understand this. Boeing's yokes aren't physically coupled in most of their aircraft (witness the events leading up to the EgyptAir Flight 990 crash) - why would they insist that their sidesticks were?

The important thing in any case is not that they are physically coupled - the important thing is that they FEEL like they are. If, as Robert had pushed forward on the stick, Bonin had felt the stick "fight back" - and if Robert had felt strong resistance, as if Bonin were pulling back as hard as he could (which he was) Robert they would have realized much earlier that there was something seriously wrong with what the other pilot was doing. And had he realized that at 15,000 feet instead of at 2000 feet, he would most likely have been successful at recovering the aircraft.

[Calvin19 0]

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Boeing's yokes aren't physically coupled in most of their aircraft (witness the events leading up to the EgyptAir Flight 990 crash)

Not a Boeing expert here, But I think the yolks are coupled on the '67s like the one from flight 990. But they have a disconnect safety so that were one of the controls to get jammed they would still have the other. Meaning that if one pilot pulled up and the other pushed with enough force, the yolks would disconnect and go into separated surface mode.

[Rookie120 0]

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I don't understand this. Boeing's yokes aren't physically coupled in most of their aircraft

What do you mean by this? I do not understand?They are coupled but I dont understand what you mean by physically?

If you find yourself in a fair fight, your tactics suck!

[Calvin19 0]

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I don't understand this. Boeing's yokes aren't physically coupled in most of their aircraft

What do you mean by this? I do not understand?They are coupled but I dont understand what you mean by physically?

He means by a physical connection, like a torque/push rod as opposed to a computerized actuated connection.

[Rookie120 0]

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Not a Boeing expert here, But I think the yolks are coupled on the '67s like the one from flight 990. But they have a disconnect safety so that were one of the controls to get jammed they would still have the other.

I think it's called a "break over 'check"? I remember doing the op's check on that. Basically the tech in left seat pulls and tech in right pushes and we measure the force need to it. I think thats what the op's check is called.I have only done it twice.

If you find yourself in a fair fight, your tactics suck!

[Rookie120 0]

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He means by a physical connection, like a torque/push rod as opposed to a computerized actuated connection.

OK, If i remember im trying to visualize the foward column and I think one side acts like the master and the other is slaved in. but they connerct to the same control column mechanism.

If you find yourself in a fair fight, your tactics suck!

[Calvin19 0]

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He means by a physical connection, like a torque/push rod as opposed to a computerized actuated connection.

OK, If i remember im trying to visualize the foward column and I think one side acts like the master and the other is slaved in. but they connerct to the same control column mechanism.

Is it the same on real '67s as it is in the UA Sims at old Stapleton in Denver? Because I think I remember looking at that.

[sundevil777 93]

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I don't understand this. Boeing's yokes aren't physically coupled in most of their aircraft

Yes they are. As others have said, they also decouple when there is an excessive force difference.

People are sick and tired of being told that ordinary and decent people are fed up in this country with being sick and tired. I’m certainly not, and I’m sick and tired of being told that I am

[mpohl 1]

Why not leave the AF447 bantering to professional airline pilots? For example, pprune.org.

Most people on here can't even fly a canopy!

[CSpenceFLY 1]

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Why not leave the AF447 bantering to professional airline pilots? For example, pprune.org.

Most people on here can't even fly a canopy!

Two professional airline pilots put the damn thing in the water. See you in 6 months for another angry drive by.

[mpohl 1]

Just need date and time. Drive by, if your dare!

Chilled beverages and food will be waiting for you and Julie. Too bad you are stuck in middle GA. :)

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Two professional airline pilots put the damn thing in the water. See you in 6 months for another angry drive by.

[Rookie120 0]

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Is it the same on real '67s as it is in the UA Sims at old Stapleton in Denver? Because I think I remember looking at that.

I dont know. Only Sim's I have been in were in Houston and I was too busy having the instructor take away my hydraulics, steering, and throwing an engine fire at me at the same time. Never got to see what it looked like inside.

If you find yourself in a fair fight, your tactics suck!

[lawrocket 3]

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Why not leave the AF447 bantering to professional airline pilots? For example, pprune.org.

Most people on here can't even fly a canopy!

I'm a student pilot who wants to know how in the world this sort of thing can happen. There's a lot to learn about exactly how. "Trust your instruments." Instruments aren't working. "Then check for outside cues." There aren't any. "Trust your instinct" Instinct says pull up.

There are some fundamental issues that plenty of us are very interested in.

My wife is hotter than your wife.