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Cockpits: Flying Wheel VS Joystick..  
User currently offlinervA340 From Mexico, joined Jan 2006, 69 posts, RR: 0
Posted (1 year 5 months 1 week 2 days 13 hours ago) and read 10949 times:

Hi everybody, Im not a pilot and probably I might be a bit ignorant obout this subject, but I was wondering, how efficient or how good idea is to control big commercial airplanes with joysticks.

I was Reading a report about af447 accident and at one crucial point, both, Captain an First Oficer where flying the A330 at the same time at opposite directions, with no visual reference between them of who was acctually flying the plane and in what direction, leading to confussion and no control. Something that I believe might not happened on a Boeing(Flying Wheel).
On other subject I imagine flying the A380 with only one hand.. really..? I cant even imagine myself driving on the freeway at 180Km/h with a joystick..instead of a driving wheel.. so, lately when im starting to preffer flying on a Boeing jet rather tan on an Airbus jet.. Waht do you think.

Greetings!

116 replies: All unread, showing first 25:
 
User currently offlineBoeingGuy From United States of America, joined Dec 2010, 3157 posts, RR: 7
Reply 1, posted (1 year 5 months 1 week 2 days 12 hours ago) and read 10821 times:

Quoting rvA340 (Thread starter):
Hi everybody, Im not a pilot and probably I might be a bit ignorant obout this subject, but I was wondering, how efficient or how good idea is to control big commercial airplanes with joysticks.

I was Reading a report about af447 accident and at one crucial point, both, Captain an First Oficer where flying the A330 at the same time at opposite directions, with no visual reference between them of who was acctually flying the plane and in what direction, leading to confussion and no control. Something that I believe might not happened on a Boeing(Flying Wheel).
On other subject I imagine flying the A380 with only one hand.. really..? I cant even imagine myself driving on the freeway at 180Km/h with a joystick..instead of a driving wheel.. so, lately when im starting to preffer flying on a Boeing jet rather tan on an Airbus jet.. Waht do you think.

Oh boy! This one opens a big can of worms.

Actually, quite frequently the pilot of a Boeing airplane will only have one hand on the control wheel also, especially if the autothrottle is off. So the argument for only having one hand flying an A380 is not valid. You hand fly a 747-8 or 777-300ER with one hand frequently also.

Bottom line is that Airbus and Boeing have many different flight deck philosophies, of which many of us could probably describe in detail. Both have good points. There are valid arguments for preferring either. Obviously each manufacturer thinks theirs are superior, but recognizes the other guys make excellent airplanes too.


User currently onlineSOBHI51 From Saudi Arabia, joined Jun 2003, 3503 posts, RR: 17
Reply 2, posted (1 year 5 months 1 week 2 days 12 hours ago) and read 10749 times:
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I once asked an American pilot friend that same question his respond was (if i don't have a long driving wheel between my legs i will never fly that plane) Those are his words.   


I am against any terrorist acts committed under the name of Islam
User currently offlineBoeingGuy From United States of America, joined Dec 2010, 3157 posts, RR: 7
Reply 3, posted (1 year 5 months 1 week 2 days 12 hours ago) and read 10673 times:

Quoting SOBHI51 (Reply 2):
I once asked an American pilot friend that same question his respond was (if i don't have a long driving wheel between my legs i will never fly that plane) Those are his words.

Yep, a former US Air pilot told me the same thing. Likes having a nice big long thing between his legs when he flies.

That person clearly had a strong preference for which type of airplane he preferred, having flown both A and B.  


User currently offlinecbphoto From United States of America, joined Dec 2003, 1567 posts, RR: 6
Reply 4, posted (1 year 5 months 1 week 2 days 12 hours ago) and read 10655 times:

It honestly depends on who you ask! To address the flying with one hand part, every pilot flies their airplane with one hand, as to always keep one hand on the throttle/power levers, regardless of the control wheel in front of them.

Many pilots prefer the control wheel, because generally speaking, while the airplane in on autopilot the pilot can get feedback through the control wheel. A joystick generally however cannot get feedback of what the airplane is doing and many pilots don't like that. However, from an ergonomics point of view, the joystick frees up a lot of much needed space in the flight deck and makes those long flights that much more enjoyable for the pilot. I have talked to many pilots who say they will never bid off of a Boeing aircraft, to guys who absolutely love the Airbus. So it really depends on the pilot and their preference. Is the control wheel safer then the joystick? Absolutely not, they just require slightly different techniques that all the pilots will get in training!

Boeing even explored the idea of putting a joystick in the 777 when they were designing it, but United said keep the control wheel in, as they were the launch customer of it. Who knows what Boeings line would be like today if United had said yes to the joystick??

Quoting SOBHI51 (Reply 2):
I once asked an American pilot friend that same question his respond was (if i don't have a long driving wheel between my legs i will never fly that plane) Those are his words.



Well, wish your American pilot friend the best of luck making it to the major airlines. What is he going to tell United or American if they put him in the Airbus? Thanks for the job offer at my dream airline, but I don't fly planes with joysticks??    



ETOPS: Engines Turning or Passengers Swimming
User currently offlineBoeingGuy From United States of America, joined Dec 2010, 3157 posts, RR: 7
Reply 5, posted (1 year 5 months 1 week 2 days 11 hours ago) and read 10485 times:

Quoting cbphoto (Reply 4):
every pilot flies their airplane with one hand, as to always keep one hand on the throttle/power levers, regardless of the control wheel in front of them.

This isn't entirely true. A lot of pilots take their hands off the throttles at V1 and put both on the yoke for rotation and climbout, until the engage the autopilot. That's with the autothrottle engaged, of course. Likewise, if the F/O is the pilot flying a takeoff, they'll usually have both hands on the yoke the entire time because the Captain's hand is on the throttle until V1.


User currently offlinecbphoto From United States of America, joined Dec 2003, 1567 posts, RR: 6
Reply 6, posted (1 year 5 months 1 week 2 days 10 hours ago) and read 10257 times:

Quoting BoeingGuy (Reply 5):
This isn't entirely true. A lot of pilots take their hands off the throttles at V1 and put both on the yoke for rotation and climbout, until the engage the autopilot. That's with the autothrottle engaged, of course. Likewise, if the F/O is the pilot flying a takeoff, they'll usually have both hands on the yoke the entire time because the Captain's hand is on the throttle until V1.

You are correct and I should have emphasized during the arrival and landing phase, the pilot flying's hand is always on the throttle, that's where I was going with that comment! Most Airbus drivers I have observed during the takeoff, instead of putting their other hand on the yoke (which of course there is non) end up putting their other hand on there lap or knee after V1. I guess there really is no other use for that hand until the autopilot is engaged!



ETOPS: Engines Turning or Passengers Swimming
User currently offlineN766UA From United States of America, joined Jul 1999, 8309 posts, RR: 23
Reply 7, posted (1 year 5 months 1 week 2 days 9 hours ago) and read 10208 times:

Quoting rvA340 (Thread starter):
n other subject I imagine flying the A380 with only one hand.. really..? I cant even imagine myself driving on the freeway at 180Km/h with a joystick..instead of a driving wheel.. so, lately when im starting to preffer flying on a Boeing jet rather tan on an Airbus jet.. Waht do you think.

You often only fly a traditional yoke with 1 hand (the other's on the throttles), so a sidestick isn't REALLY a big difference, and I don't have a problem with it, per se. My issue is, as you mentioned, that Airbus' physical cockpit controls, the stick, the throttles, etc, don't react commensurately with the operation of a system. If the autothrottle changes throttle setting, the throttle levers don't move, for example. Or, as you stated, the Captain and F/O have essentially completely independent sidesticks. This is an issue for me, because I think you should have as much tactile, easily-discernable information available to you as possible, especially in an emergency when you're not thinking straight. If you reach for the throttle levers, and they're full forward, the airplane SHOULD be at 100%+ power. On an Airbus, that may not be so, and so you're required to verify with your eyes and the instruments, and that's a very "heads-down" philosophy that a LOT of pilots have a problem with, myself included.

In a Boeing, you can close your eyes and put your hands on any button, switch, or knob and know what it's doing. On an Airbus, you generally have to look at something. Boeing uses a lot more toggle/rocker switches, Airbus uses those push-in switches that feel the same regardless of the setting. Other manufacturers are somewhere in between. I think the better choice is obvious, but that's just my opinion. Boeing tends to build pilot's airplanes, Airbus tends to build engineer's airplanes. It's all about philosophy.



This Website Censors Me
User currently offlinepilotpip From United States of America, joined Sep 2003, 3150 posts, RR: 11
Reply 8, posted (1 year 5 months 1 week 2 days 6 hours ago) and read 10091 times:

Nothing is being said about the bicycle yoke. What about those?  

I have way too much time in Embraer products.

[Edited 2013-05-17 18:13:42]


DMI
User currently offlinepilotpip From United States of America, joined Sep 2003, 3150 posts, RR: 11
Reply 9, posted (1 year 5 months 1 week 2 days 6 hours ago) and read 10084 times:

Quoting rvA340 (Thread starter):
I cant even imagine myself driving on the freeway at 180Km/h with a joystick..instead of a driving wheel

Bet you wouldn't imagine steering at that speed with your feet, either. But that's what you're doing in an airplane regardless of the manufacturer.



DMI
User currently offlinefreeze3192 From United States of America, joined Oct 2006, 164 posts, RR: 0
Reply 10, posted (1 year 5 months 1 week 2 days 5 hours ago) and read 10063 times:

Quoting BoeingGuy (Reply 5):

This isn't entirely true. A lot of pilots take their hands off the throttles at V1 and put both on the yoke for rotation and climbout, until the engage the autopilot. That's with the autothrottle engaged, of course.

That's a company required item. At V1 you're committed to going flying no matter what happens so you remove your hands from the throttles to remove the itch to abort if an abnormal situation develops.

Some airplanes are so heavy on the controls (especially at higher speeds) that you almost need two hands on the yoke to put the airplane where you want it.

Quoting BoeingGuy (Reply 5):

Likewise, if the F/O is the pilot flying a takeoff, they'll usually have both hands on the yoke the entire time because the Captain's hand is on the throttle until V1.

That's not entirely true either. It's company specific. At my company the FO keeps their hand on the power levers throughout the takeoff until V1. If there's an abort, they're expected to execute after the CA calls for it.



"A passenger bets his life that his pilot is a worthy heir to an ancient tradition of excellence and professionalism."
User currently offlineStarlionblue From Greenland, joined Feb 2004, 17068 posts, RR: 66
Reply 11, posted (1 year 5 months 1 week 2 days 5 hours ago) and read 10058 times:

Quoting rvA340 (Thread starter):
On other subject I imagine flying the A380 with only one hand.. really..? I cant even imagine myself driving on the freeway at 180Km/h with a joystick..instead of a driving wheel.

Flying a plane and driving a car are very different when it comes to the feel and response of the controls. Just like most cars, airliners have augmented controls, meaning you're not using muscle force to move the surfaces. Muscles are used to move the yoke or stick, and these inputs are either carried via cables and rods, but hydraulically augmented, or transmitted electronically. So the amount of force required is limited and you can be very subtle. It is actually more physical work to fly a light twin than a 747 because in a light twin your muscles are moving the surfaces without augmentation. Anyone who has done a multi checkride will remember how much muscle it takes to keep the thing going straight with an engine out.

Another big difference is that in a car, especially in traffic, you are continually changing direction and often making quite large inputs. In an airplane, it is much more about gentle manipulation. The King Private Pilot course says in one of the first lessons that "flying is a series of small corrections". Seldom do you make large inputs, and if you do they should be smooth. You can be remarkably subtle with one hand, even the off-hand. Making corrections of a degree or two to a heading, or ten feet to your altitude, takes practice but it is something which all pilots must be able to do if they expect to pass their instrument checkride.

Finally, unlike cars, planes want to go straight ahead very badly. In a car, especially one not built for high speeds, you get a lot of instability as you go faster and a small input can lead to loss of control. In a plane, if you make even a large input, the plane will want to go back to where it was. This resistance to input makes fine control easier.

Quoting pilotpip (Reply 9):
Bet you wouldn't imagine steering at that speed with your feet, either. But that's what you're doing in an airplane regardless of the manufacturer.

:D Then again planes aren't the most agile on the ground.



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlinePGNCS From United States of America, joined Apr 2007, 2833 posts, RR: 45
Reply 12, posted (1 year 5 months 1 week 2 days 4 hours ago) and read 10034 times:

Quoting SOBHI51 (Reply 2):
I once asked an American pilot friend that same question his respond was (if i don't have a long driving wheel between my legs i will never fly that plane) Those are his words.

Is his nationality or airline American? If he is an American Airlines pilot I am sure he prefers the yoke because I feel confident he has no experience operating a FBW Airbus. (Very few current AMR pilots have time in the FBW Airbus.)

Quoting BoeingGuy (Reply 3):
Yep, a former US Air pilot told me the same thing. Likes having a nice big long thing between his legs when he flies.

That person clearly had a strong preference for which type of airplane he preferred, having flown both A and B

Fine. I've flown both extensively (Airbus, Boeing, Lockheed, and McD products) and would never fly with a yoke again given the choice.

Quoting cbphoto (Reply 4):
It honestly depends on who you ask!

Exactly. It's normally (not always) the people who have never flown the FBW Airbus products that feel most strongly about the yoke I find.

Quoting cbphoto (Reply 4):
To address the flying with one hand part, every pilot flies their airplane with one hand, as to always keep one hand on the throttle/power levers, regardless of the control wheel in front of them.

Exactly. While sometimes pilots end up with both hands on the yoke, there are times when we all must fly with one hand on the yoke of SSC. It's irrelevant to discuss that skill.


User currently offlinebueb0g From United Kingdom, joined Jul 2010, 648 posts, RR: 0
Reply 13, posted (1 year 5 months 1 week 1 day 22 hours ago) and read 9939 times:

Quoting rvA340 (Thread starter):
Captain an First Oficer where flying the A330 at the same time at opposite directions

This is actually a very overblown fact and not quite true. A lot of people act as if the person in the RHS on AF 447 was pulling all the way back, while the person in the LHS was pushing all the way forward and the aircraft therefore took the median and stayed in the stall. This isn't true - the entire crew was confused, none of them realised they were stalled until it was too late.

There were one or two simultaneous inputs but these were mainly with relation to roll, rather than pitch. Indeed, for much of the descent, the other pilots were calling for the PF to "go up!", so I think the contribution of the sidesticks has been massively overstated by a lot of people when it comes to AF 447.

If they had been in a 777 it's quite possible that the capt and the PM would still have thought that the PF was doing the right thing. I mean it's not as if a Boeing has never stalled before...



Roger roger, what's our vector, victor?
User currently offlineairmagnac From Germany, joined Apr 2012, 316 posts, RR: 52
Reply 14, posted (1 year 5 months 1 week 1 day 17 hours ago) and read 9815 times:

Quoting N766UA (Reply 7):
If you reach for the throttle levers, and they're full forward, the airplane SHOULD be at 100%+ power.

And the Airbus will, as IIRC the autothrust will be disconnected if one lever is beyond MCT detent or both beyond CLIMB. So if both levers are full forward, there is no ambiguity on what thrust is being commanded.

Quoting N766UA (Reply 7):
In a Boeing, you can close your eyes and put your hands on any button, switch, or knob


Apart from not being too sure about the difference between comparable A and B aircraft (say, 777 and A330), I kind of wonder how you can reliably "feel" the position of a knob or switch which is significantly smaller than your hand (and thus does not require much muscular movement to hold and move), and which is positioned on the overhead panel (so you have to extend your arm in a not-very-comfortable position to reach). But as a non-pilot, I'll take your word for it !  



Anyway the crux of the matter is, the position of the switches/knobs/throttle levers/yoke/side-stick only gives you information on what commands are being sent to the various aircraft systems, in particular the flight controls (yoke/SSC) and engines (thrust levers). They do not indicate what the actual setting is. And therein lies the issue.

A decision loop should be something on the lines of
1) Gathering information on your current, real situation, and establish an assessment of said situation
2) Compare the situation to what you want it to be, and determine whether a correction is required
3) Decide on the best strategy to make that correction
4) Compute the necessary command(s) and sent them to the machine
5) Verify that real situation evolves as expected in response to the command, and start loop again

Note the emphasis on "real situation" not "commanded situation" in step 1). If all is well, both should be the same. But in case of a problem with the system (engine failure for example), they will diverge. Actually that is how you would detect the problem, by noticing a divergence between command and actual behaviour.

So what's important is to asses what the plane is actually doing ; if you base your decisions on what you asked it to do, you may be lured into a false sense of security. Because even though you can "feel" that everything is positioned properly, there may be an issue that prevents the machine from answering properly.
Obviously, no one makes decisions based only on throttle position/yoke position ; it may be subconscious, but I'm pretty sure you work on real data, even if you do "augment" it with lever/yoke/switch positions. The Airbus layout just forces you to make your decisions based on the real situation, and not based on the commands, and this eliminates the potential ambiguities.
As an illustration, in the case of the flight controls on FBW aircraft, what is important is not what attitude your colleague is commanding with his yoke/side-stick, but what is the current actual attitude of the airplane. Which you obtain by looking outside, or by checking the big screen that is staring you in the face, otherwise known as a PFD.
[which the PNF of AF447 was obviously looking at between 2:10'25'' and 2:10'40'', as he reacted 3 times to improper control inputs by his colleague. So he did know what was going on IMO. Why he remained passive afterwards remains a mystery, but I will not elaborate here. The point is, the thesis that he did not know what PF was doing because of the Airbus layout does not hold ]

Now, there is a valid objection to all this. In my explanation above, I completely separated the "commands" from the "situational feedback". Actually, it is arguable that the commands are also useful "feedback" when making a decision. Knowing what commands are being sent to the airplane would allow you to predict how the plane will react, and thus predict the future situation and prevent a possible future problem.
Thus it might be interesting to have linked yokes/side-sticks to know what attitude is being commanded by the other pilot, and if he is making a mistake you can react much sooner than if you waited for the situation to evolve and be displayed on the PFD. Same for knowledge of what is being commanded by the AP (moving yoke/stick) or by the ATHR (moving levers)
Except that in the case of the attitude control loop (pilot/AP + control-augmented flight controls + feedback via PFD or Mk1 eyeball) or the thrust control loop (pilot/ATHR + FADEC + feedback via the engine display), the time constant of the loops (= the time it takes to complete one full decision loop) is very short, on the order of a few tenths of a second. At the most, maybe a couple of seconds. The worst case is the full change from IDLE to TOGA thrust in 5 to 8 seconds, as seen at Habsheim, but that is a relatively exceptional case.
In parallel, you need time to notice a movement of your yoke or thrust levers, compute what the reaction will be and understand that something will go wrong. The human brain is a wonderful thing, but it still needs a couple seconds accomplish all that. Which is the same order of time as the control loop.
So by the time you are ready to take action based on your predicitons, the situation might have already evolved and you could have just reacted to the observed evolution. Which would be much more reliable than acting based on quick predictions. Therefore, the predictive loop is kind of useless, and in particular, all the moving parts and engineering required to provide that feedback are useless.
Then again, as I said, the time constants are just about the same, so you could also consider that in some cases it will be useful to have the predictive capacity. And therefore install means to provide feedback of the commands.

So what I'm saying is : there is no clear-cut best solution, we're at a limit. Both Airbus and Boeing ways are acceptable.
And no, the better choice is not obvious at all  

And I now realize what a long, abstract post I just wrote...



Quoting N766UA (Reply 7):
Boeing tends to build pilot's airplanes, Airbus tends to build engineer's airplanes

Could be, it all depends on how you define "pilot" and engineer". Using typical Hollywood stereotypes, am I to understand that people flying a Boeing will always be wearing Ray-Bans, a silk scarf and a beautiful uniform and have a stewardess sitting on their lap the whole flight (i.e. "pilots"), while Airbus requires slobs with an open shirt, sandals, a bushy beard and curly hair, who play World of Warcraft whenever they have a spare minute (i.e. "engineers") ?     



One "oh shit" can erase a thousand "attaboys".
User currently offlinePihero From France, joined Jan 2005, 4597 posts, RR: 77
Reply 15, posted (1 year 5 months 1 week 1 day 17 hours ago) and read 9809 times:
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Quoting SOBHI51 (Reply 2):

I once asked an American pilot friend that same question his respond was (if i don't have a long driving wheel between my legs i will never fly that plane)

Another proof that being an airline pilot is not proof of intelligence...   

Quoting BoeingGuy (Reply 3):
Yep, a former US Air pilot told me the same thing. Likes having a nice big long thing between his legs when he flies.

... or sexual happiness in one's life ...   

Quoting N766UA (Reply 7):
If you reach for the throttle levers, and they're full forward, the airplane SHOULD be at 100%+ power.

...and with one or more failed engine in this case, where is your famous tactile feedback ?
If your statement was always true, why did - Kegworth comes to mind, but there plenty more axamples - some crews shut down the wrong engine ?
And, BTW, if you push the T/Ls fully forward, you have full TOGA thrust on an Airbus.

Quoting N766UA (Reply 7):
In a Boeing, you can close your eyes and put your hands on any button, switch, or knob and know what it's doing.

That's one of the best ways to fail a check ride : Standard practice demands that one always checks the result - generally on the forward instrument panel - of one's action on *any* switch, button, knob... whatever.
BTW, the "Dark Cockpit" concept, with switchlights does partly away with the above requirement : Depressing one switchlight causes its illumination into the status it has gone into : *OFF* / *ON* / *ARMED* etc...

Quoting N766UA (Reply 7):
Boeing tends to build pilot's airplanes, Airbus tends to build engineer's airplanes. It's all about philosophy

Ah ! The big hairy American pilot concept, flying big American areoplanes tailored to his ego !.. Another falsity... See below.

Quoting rvA340 (Thread starter):
On other subject I imagine flying the A380 with only one hand.. really..?

Yes, really and it's quite easy and natural.
As a matter of fact, pilots have been flying all sorts of jets with only their fingers. People seem to have forgotten that, starting with the Boeing 707, nearly sixty years ago, with A/P on, they had on the pedestal a set of two little wheels each dide of a big knob : the wheels for pitch control, the knob for roll ( actually it was for VS and HDG change, but it amounts to the same )... you wouldn't be driving your car with those controls either, I bet, but all pilots on the 707 /727 did and later generations still did, with even smaller wheels and buttons.
See here on the pedestal :


View Large View Medium
Click here for bigger photo!

Photo © Braccini Riccardo - Aviopress



and on the A/P panel :


View Large View Medium
Click here for bigger photo!

Photo © Robert Domandl



[Edited 2013-05-18 07:57:28]

[Edited 2013-05-18 08:37:24]


Contrail designer
User currently offlineDavid L From United Kingdom, joined May 1999, 9524 posts, RR: 42
Reply 16, posted (1 year 5 months 1 week 1 day 14 hours ago) and read 9756 times:

Quoting N766UA (Reply 7):
Boeing tends to build pilot's airplanes, Airbus tends to build engineer's airplanes. It's all about philosophy.

That one always irks me. It's a nice catch-phrase but, just once, I'd like to see it backed up by some credible evidence. Everything I've seen, read and heard about the way Airbus designs its aircraft indicates that there's just as much input from pilots than with any other manufacturer.

Quoting N766UA (Reply 7):
If the autothrottle changes throttle setting, the throttle levers don't move

But if you want to compare commanded thrust to actual thrust, and any other engine parameter, you only need to look in one place.

If no-one moved the boundaries, we'd still be living in caves and walking everywhere and there would be no A.net where we could discuss such matters.  
Quoting PGNCS (Reply 12):
It's normally (not always) the people who have never flown the FBW Airbus products that feel most strongly about the yoke I find.

   Without a doubt.


User currently offlineBoeingGuy From United States of America, joined Dec 2010, 3157 posts, RR: 7
Reply 17, posted (1 year 5 months 1 week 1 day 6 hours ago) and read 9596 times:

Quoting freeze3192 (Reply 10):
That's not entirely true either. It's company specific. At my company the FO keeps their hand on the power levers throughout the takeoff until V1. If there's an abort, they're expected to execute after the CA calls for it.

Really? I knew that it varies with who sets power for takeoff - at some airlines the Captain always does it and the F/O never touches TO/GA or the throttles; at others the F/O sets takeoff power and then the captain reaches over and puts his/her hands on the throttles.

Quoting freeze3192 (Reply 10):


That's a company required item. At V1 you're committed to going flying no matter what happens so you remove your hands from the throttles to remove the itch to abort if an abnormal situation develops.

Yep. There's one exception though. The Captain is allowed to abort above V1 if in his/her opinion the airplane simply is not capable of safe flight.


User currently offlinecobra27 From Slovenia, joined May 2001, 1019 posts, RR: 0
Reply 18, posted (1 year 5 months 1 week 22 hours ago) and read 9531 times:

I think you can get accustomed really quickly, if it is classic Yoke, Embraer yoke or Joystick, fighter yoke.

I don't like the Airbus yoke because you fly right or left handed depending where you are seating


User currently offlinebueb0g From United Kingdom, joined Jul 2010, 648 posts, RR: 0
Reply 19, posted (1 year 5 months 1 week 22 hours ago) and read 9530 times:

Quoting BoeingGuy (Reply 17):
Really? I knew that it varies with who sets power for takeoff - at some airlines the Captain always does it and the F/O never touches TO/GA or the throttles; at others the F/O sets takeoff power and then the captain reaches over and puts his/her hands on the throttles.

As at yet others, the Capt sets the throttles and then the FO takes them once thrust is set. There are a select few however that allow FO's to have the throttle throughout the whole takeoff, although I think there are many more that mandate some kind of Captain's input.

Quoting BoeingGuy (Reply 17):
Yep. There's one exception though. The Captain is allowed to abort above V1 if in his/her opinion the airplane simply is not capable of safe flight

  

Or if he/she deems there is enough runway remaining, such as if you're flying a small aircraft on a big runway, or are a positioning flight and can easily stop/land on the runway remaining.

There was a BMI Baby 737 that rejected a takeoff in the UK a few years back, at about 20 knots over V1. The FO was flying and couldn't get the nose off the ground with normal back pressure, the Capt took control and found he couldn't either and judging that they had sufficient runway remaining, rejected and stopped the a/c safety, making some weaving S-turns down the runway as they decelerated. AAIB later concluded that it was a trim problem that they could have overcome with enough pressure on the yoke but, at the time, the crew considered it unflybable.



Roger roger, what's our vector, victor?
User currently offlineStarlionblue From Greenland, joined Feb 2004, 17068 posts, RR: 66
Reply 20, posted (1 year 5 months 1 week 21 hours ago) and read 9484 times:

Quoting cobra27 (Reply 18):

I think you can get accustomed really quickly, if it is classic Yoke, Embraer yoke or Joystick, fighter yoke.

I don't like the Airbus yoke because you fly right or left handed depending where you are seating

Same on Embraer, Boeing, Cessna or Piper. You fly with your left hand in the left seat, right hand in the right seat.

This is only a big deal for people who have not tried it.



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offline9VSIO From United Kingdom, joined Dec 2006, 724 posts, RR: 2
Reply 21, posted (1 year 5 months 1 week 19 hours ago) and read 9460 times:
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Quoting Starlionblue (Reply 20):
You fly with your left hand in the left seat, right hand in the right seat.

That leaves you no hands to fly with! :P



Me: (Lining up on final) I shall now select an aiming point. || Instructor: Well, I hope it's the runway...
User currently offlinePihero From France, joined Jan 2005, 4597 posts, RR: 77
Reply 22, posted (1 year 5 months 1 week 18 hours ago) and read 9437 times:
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I find it amusing, more than 25 years after the A320, people still bashing the *Airbus* sidestick.
Fact is that there is a definite trend away from the yoke which will be soon a solution for the minority : Except Boeing and Embraer, all new designs incorporate sidesticks : Bombardier, Dassault, COMAC, Sukhoi... have gone to the sidestick.

American hairy pilots and their aéroplanes will be soon in the minority.

How about that ?

I for one think that the era of the Ford Trimotor and the Junkers G-38 is long time passed.

After all, in most parts of the world, we are in the year 2013 in flight control design.   



Contrail designer
User currently offlinemandala499 From Indonesia, joined Aug 2001, 6926 posts, RR: 76
Reply 23, posted (1 year 5 months 1 week 17 hours ago) and read 9425 times:

Quoting PGNCS (Reply 12):
Exactly. It's normally (not always) the people who have never flown the FBW Airbus products that feel most strongly about the yoke I find.

I guess they'll just go nuts when they meet pilots here who moved from the yoke to the sidestick...

And interestingly, sidestick aircraft here have a much lower accident or incident rate per 10,000 departures than yoke equipped aircraft (limited to part 121 airlines only).

Quoting cobra27 (Reply 18):
I don't like the Airbus yoke because you fly right or left handed depending where you are seating

But you don't fly it... so how do you know what it's like? It's just your prejudice right?



When losing situational awareness, pray Cumulus Granitus isn't nearby !
User currently offlinepilotpip From United States of America, joined Sep 2003, 3150 posts, RR: 11
Reply 24, posted (1 year 5 months 1 week 17 hours ago) and read 9420 times:

Quoting Pihero (Reply 22):
Except Boeing and Embraer, all new designs incorporate sidesticks

Embraer's bizjets have gone to a side stick as well. The Legacy 450 will incorporate one.



DMI
User currently offlinePihero From France, joined Jan 2005, 4597 posts, RR: 77
Reply 25, posted (1 year 5 months 1 week 16 hours ago) and read 9711 times:
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Quoting pilotpip (Reply 24):
Embraer's bizjets have gone to a side stick as well. The Legacy 450 will incorporate one.

Didn't know that.

Thanks for the info,Pp.

Cheers !

Quoting cobra27 (Reply 18):
I don't like the Airbus yoke because you fly right or left handed depending where you are seating

So, of course, when you're a captain and right handed, you fly the aircraft with your right hand and operate the throttles with your left hand, right ?



Contrail designer
User currently offlinebueb0g From United Kingdom, joined Jul 2010, 648 posts, RR: 0
Reply 26, posted (1 year 5 months 1 week 15 hours ago) and read 9676 times:

Quoting 9VSIO (Reply 21):
That leaves you no hands to fly with! :P

Huh?

Quoting Pihero (Reply 22):
Except Boeing and Embraer, all new designs incorporate sidesticks : Bombardier, Dassault, COMAC, Sukhoi... have gone to the sidestick.

Not true, Mitsubishi's MRJ has a yoke.



Quoting mandala499 (Reply 23):
And interestingly, sidestick aircraft here have a much lower accident or incident rate per 10,000 departures than yoke equipped aircraft (limited to part 121 airlines only).

That's a fallacious point and you know it. There's much more at play than the control column, which has next to no impact on flight safety. Due to the almost ubiquitous adoption of FBW in airliners, your average sidestick equipped aircraft is likely to be newer and more advanced than your average yoke equipped aircraft (which is not to say that yoke equipped aircraft can not be new and advanced, obviously). The fact that the 727 has a higher accident rate than the A320 is not an indictment or an endorsement of the yoke or sidestick, it is an irrelevancy. If you take a *comparable* yoke and side-stick aircraft, ie 777 and the A330 / A340, you know full well that there is not a difference.

We can argue pilot preference, practicalities and cleanliness of design... But safety wise, the design of the control column (yoke or stick) is not important.



Roger roger, what's our vector, victor?
User currently offlineStarlionblue From Greenland, joined Feb 2004, 17068 posts, RR: 66
Reply 27, posted (1 year 5 months 1 week 12 hours ago) and read 9685 times:

Quoting bueb0g (Reply 26):
Quoting 9VSIO (Reply 21):
That leaves you no hands to fly with! :P

Huh?

He was making a joke based on what I said.

Quoting 9VSIO (Reply 21):
Quoting Starlionblue (Reply 20):
You fly with your left hand in the left seat, right hand in the right seat.

That leaves you no hands to fly with! :P

If you take what I said literally, the left hand would be IN the left seat and the right hand IN the right seat. Thus no hand on the controls.



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlineBoeingGuy From United States of America, joined Dec 2010, 3157 posts, RR: 7
Reply 28, posted (1 year 5 months 1 week 6 hours ago) and read 9562 times:

Quoting cobra27 (Reply 18):
I don't like the Airbus yoke because you fly right or left handed depending where you are seating

And your point is? All yoke driven aircraft are exactly the same. You know which of A vs. B I favor, but your argument is incorrect. Airbus joystick or yoke airplanes (A300 or A310) are no different than Boeing or any other airplanes in this regard. On the 787 if you're in the left seat you fly with your left hand and use your right hand for throttles when hand flying. That's basically the same as on an Airbus joystick airplane.

Quoting mandala499 (Reply 23):
And interestingly, sidestick aircraft here have a much lower accident or incident rate per 10,000 departures than yoke equipped aircraft (limited to part 121 airlines only).

That's a ludicrous point and you know it. Older generation airplanes statistically have a higher accident rate, and they were all yoke driven. The world of aviation have all gotten a lot smarter in the last 30 years so there a thankfully far fewer accidents all the way around. All airplanes are statistically safer in the last 30 years, but that includes the only joystick airplanes out there.

Tell me about how the 777, 767 and 757 yoke equipped airplanes are less safe. How many passengers have ever died on board a 777 in 19 years? A big fat ZERO. The over 1000 757s in 31 years have NEVER had a fatal accident that was the fault of the airplane (they were all maintenance errors, pilot errors or 9/11); and the 767 has only ever had one (BKK) in which the technical issue was immediately fixed and never reoccurred. The rest were sabotage, hijackings, CFITs or 9/11.

Bottom line is that I'd venture to say that no-one at A or B who is intelligent about airplanes thinks the other guys' airplanes aren't safe. Sure, everyone has their preferred philosophies, but I've never met anyone who is well educated about airplanes who doesn't respect that an A32x, A330 or A340 is also a very safe good airplane. An certainly no-one from either company enjoys it when the other brand has a bad a day and there is an accident. Kind of like AS and WN having a healthy respect for each other. That's the way it should be.

Quoting mandala499 (Reply 23):
I guess they'll just go nuts when they meet pilots here who moved from the yoke to the sidestick...

I know pilots who regularly go back and forth between the C-17 which is stick equipped (in front of the pilot,not sidestick) equipped and Boeing airplanes with a yoke. They could fly a C-17 for the USAF Reserves one day (or a Boeing ferry flight) and fly say a 787 the next. They tell me it's no biggie. An airplane is an airplane.


User currently offlineJoeCanuck From Canada, joined Dec 2005, 5476 posts, RR: 30
Reply 29, posted (1 year 5 months 1 week 6 hours ago) and read 9565 times:

Ok...I'm going to add my two cents in here. I've flown piston singles with yokes and gliders with sticks and the monkey part of the human brain, (at least in my case), doesn't seem to know or care about the difference. I find it a lot like going from a car to a motorcycle to a plane. Once you know how to drive them, their controls are pretty much automatic. If you have to be thinking about what action it takes on your part for a certain action by the vehicle, you probably should be walking.

As for the Boeing/Airbus/engineer/pilot thing...all I can add is; it seems to me that engineers design and build aircraft for pilots to fly...no matter the name on the door.


Some pilots prefer Airbus, some Boeing, but I'll bet anybody that their absolutely favourite plane is the one they get paid the most to fly.



What the...?
User currently offlineBoeingGuy From United States of America, joined Dec 2010, 3157 posts, RR: 7
Reply 30, posted (1 year 5 months 1 week 6 hours ago) and read 9550 times:

Quoting JoeCanuck (Reply 29):
Some pilots prefer Airbus, some Boeing, but I'll bet anybody that their absolutely favourite plane is the one they get paid the most to fly.

Or people prefer the manufacturer's philosophies that help pay our mortgage and grocery bills.  


User currently offlineSmittyOne From , joined Dec 1969, posts, RR:
Reply 31, posted (1 year 5 months 6 days 17 hours ago) and read 9354 times:

Quoting Pihero (Reply 25):
So, of course, when you're a captain and right handed, you fly the aircraft with your right hand and operate the throttles with your left hand, right ?

I would like to see that!


User currently offlineairmagnac From Germany, joined Apr 2012, 316 posts, RR: 52
Reply 32, posted (1 year 5 months 6 days 16 hours ago) and read 9328 times:

Quoting bueb0g (Reply 26):
Quoting Pihero (Reply 22):
Except Boeing and Embraer, all new designs incorporate sidesticks : Bombardier, Dassault, COMAC, Sukhoi... have gone to the sidestick.

Not true, Mitsubishi's MRJ has a yoke.

I had done some research last year on control device choices for FBW aircraft, for a small project. Here's what I found at the time (I can't guarantee the links are still active)
[I think I had posted this in a thread back then, but I'm too lazy to do a search...]


------------
AIRBUS
sidesticks

------------
BOEING
yokes

------------
BOMBARDIER

- Bombardier CSeries : sidesticks
http://www.flycseries.com/deck.asp

- Bombardier Global 7000/8000 : yokes,
chosen more for commonality with Global 5000/6000 rather than ergonomics (sidesticks were considered, as used on the CSeries)
http://www.flightglobal.com/news/art...-new-bombardier-global-duo-354669/
http://www.flightglobal.com/news/art...biggest-bombardier-globals-363207/

------------
EMBRAER

- Embraer E-Jets : yokes

- Embraer Legacy : sidesticks
http://www.flightglobal.com/news/art...fly-by-wire-executive-jets-348254/

------------
DASSAULT

- Dassault Falcon 7X : sidesticks
http://www.dassaultfalcon.com/aircraft/7x/avionics.jsp

------------
SUKHOI

- Sukhoi Superjet 100 : sidesticks
http://sukhoi.org/eng/planes/projects/ssj100/
http://www.airliners.net/photo/Sukho...d=247f1dd28849e0097f709af896940bb3

------------
MITSUBISHI

- Mitsubishi MRJ : yokes
http://www.flightglobal.com/news/art...mrj-cockpit-and-structures-225636/

------------
GULFSTREAM

- Gulfstream 650 : yokes
http://www.flightglobal.com/news/art...es/g650-as-good-as-it-gets-316577/
"so that pilots would be aware of control inputs being made by the autopilot."
Yet the wiki article suggests that the yokes are preserved for commonality with the G550

------------
COMAC

- COMAC 919 : sidesticks (actually the cockpit should be shared with the CSeries)
http://www.flightglobal.com/news/art...-cseries-c919-co-operation-369766/
------------


I left the Antonov 148 out, even though it is FBW + yokes, because the design process took 20 years following the end of the USSR so I am not sure the design choices are really representative.)


===> So apart from A&B, only 2 out of 7 companies (Gulfstream and Mitsubishi) choose to go with a column instead of sticks. Embraer and Bombardier currently use yokes, but they are moving towards side-sticks on their newer designs.



One "oh shit" can erase a thousand "attaboys".
User currently offlinemandala499 From Indonesia, joined Aug 2001, 6926 posts, RR: 76
Reply 33, posted (1 year 5 months 6 days 16 hours ago) and read 9335 times:

Quoting bueb0g (Reply 26):
That's a fallacious point and you know it. There's much more at play than the control column, which has next to no impact on flight safety. Due to the almost ubiquitous adoption of FBW in airliners, your average sidestick equipped aircraft is likely to be newer and more advanced than your average yoke equipped aircraft (which is not to say that yoke equipped aircraft can not be new and advanced, obviously).
Quoting BoeingGuy (Reply 28):
That's a ludicrous point and you know it.

Let me put another one then... All sidestick aircraft vs all the 737NGs in the Indonesian register... still, the sidestick has lower accident and incident rates.

Is it ludicrous? OF COURSE IT IS! Same with a lot of talk on why sidestick isn't safe.
Is it a sidestick vs yoke issue? No... it's a training and company safety policy issue. I know that you guys know that I know that...

Quoting BoeingGuy (Reply 28):
They tell me it's no biggie. An airplane is an airplane.

Exactly! No biggie...
I wonder why some make it into a biggie... (not you...)
An airplane is an airplane... as long as it makes money for the airline... I dun care if it's yoke, sidestick, joystick, reversible, non-reversible, FBW, FBL, or mind-controlled flight control system...   

And the references to AF447... well, the history of pulling the nose high despite hearing the stall warning isn't limited to sidestick aircraft.



When losing situational awareness, pray Cumulus Granitus isn't nearby !
User currently offlineBoeingGuy From United States of America, joined Dec 2010, 3157 posts, RR: 7
Reply 34, posted (1 year 5 months 6 days 15 hours ago) and read 9316 times:

Quoting mandala499 (Reply 33):
Let me put another one then... All sidestick aircraft vs all the 737NGs in the Indonesian register... still, the sidestick has lower accident and incident rates.

Again, that wasn't my point. Newer airplanes, with newer training methods and newer safety equipment have better safety records. All airplanes prior to about the last 30 years were yoke airplanes. Those times and airplanes have a higher accident rate. That is going to statistically make yoke driven airplanes have a higher accident and incident rate.

If you look airplanes manufactured during the time when sidestick airplanes have actually existed, I don't believe that sidestick airplanes have a higher accident rate (not counting hijacking and sabotage).

The 757, 767 and 777 have about 3000 total airplanes out there and each have an almost flawless safety record (not counting 9/11 and other hijakings) given the number of years of service (the 777 does have a flawless fatal accident record over 19 years) - all yoke airplanes. But yeah, the 737 data can be skewed by the number of less experienced operators and the sheer number of airplanes out there, and the fact that jillions of older 737s were manufactured since 1967, long before the A32x was even a glean in someone's eye.

All this skews the data, making your sidestick vs yoke accident rate like comparing apple to oranges (or beer to wine).


User currently offlinevikkyvik From United States of America, joined Jul 2003, 10103 posts, RR: 26
Reply 35, posted (1 year 5 months 6 days 14 hours ago) and read 9269 times:
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Quoting BoeingGuy (Reply 3):
Likes having a nice big long thing between his legs when he flies.

  

Quoting JoeCanuck (Reply 29):
Once you know how to drive them, their controls are pretty much automatic. If you have to be thinking about what action it takes on your part for a certain action by the vehicle, you probably should be walking.

Hmmm. I probably shouldn't drive automatic transmission cars then. I always end up slamming my left foot into the floorboard!  
Quoting SmittyOne (Reply 31):
Quoting Pihero (Reply 25):
So, of course, when you're a captain and right handed, you fly the aircraft with your right hand and operate the throttles with your left hand, right ?

I would like to see that!

This reminds me of a friend of mine who drives a stick shift. I've seen him sometimes answer his phone while driving (shouldn't do that, but anyway...). He'd hold the phone with his right hand, which meant he had to reach over with his left hand to shift gears. Never made sense to me....



"Two and a Half Men" was filmed in front of a live ostrich.
User currently offlineJoeCanuck From Canada, joined Dec 2005, 5476 posts, RR: 30
Reply 36, posted (1 year 5 months 6 days 8 hours ago) and read 9141 times:

Quoting mandala499 (Reply 33):
Is it ludicrous? OF COURSE IT IS! Same with a lot of talk on why sidestick isn't safe.

That's pretty much it in a nutshell.



What the...?
User currently offlinePGNCS From United States of America, joined Apr 2007, 2833 posts, RR: 45
Reply 37, posted (1 year 5 months 6 days 4 hours ago) and read 9096 times:

Quoting cobra27 (Reply 18):
I don't like the Airbus yoke because you fly right or left handed depending where you are seating

Just like in an aircraft with a yoke...

Quoting BoeingGuy (Reply 28):
Quoting mandala499 (Reply 23):I guess they'll just go nuts when they meet pilots here who moved from the yoke to the sidestick...I know pilots who regularly go back and forth between the C-17 which is stick equipped (in front of the pilot,not sidestick) equipped and Boeing airplanes with a yoke. They could fly a C-17 for the USAF Reserves one day (or a Boeing ferry flight) and fly say a 787 the next. They tell me it's no biggie. An airplane is an airplane.

Correct, BoeingGuy. I was for a while current on both the DC-9 and A-320 at the same time, and would sometimes fly both in a single day. I was extremely familiar with them both, and never had a problem flying either. Later on I was current on both the B-757/767 and B-747-400 at the same time and actually found that more difficult as much of the automation was very similar but not identical.

Bottom line: if you are well trained it's an airplane and neither concept is especially difficult. I don't mind anyone who has preferences about any airplane as long as their opinions are informed by fact (and for pilots, experience in type.)


User currently offlineBoeingGuy From United States of America, joined Dec 2010, 3157 posts, RR: 7
Reply 38, posted (1 year 5 months 6 days 4 hours ago) and read 9087 times:

Quoting PGNCS (Reply 37):
Later on I was current on both the B-757/767 and B-747-400 at the same time and actually found that more difficult as much of the automation was very similar but not identical.

Yep, I relate to that. Even though the functionality is mostly the same for the autothrottle and autopilots, the 757/767 mode annunciations are somewhat different than on the 747/777/787. Like FLCH is annunciated as an autothrottle mode on the 757/767 but a pitch mode on the 747/767/777.

It's EPR or N1 mode on the 757/767 and THR REF on the newer airplanes......etc.

I assume this is what you are referring to.

BTW, I can guess what airline you flew for, given your listings of airplanes you flew - before and after the merger.  


User currently offlinemandala499 From Indonesia, joined Aug 2001, 6926 posts, RR: 76
Reply 39, posted (1 year 5 months 6 days 3 hours ago) and read 9090 times:

Quoting BoeingGuy (Reply 34):
Again, that wasn't my point. Newer airplanes, with newer training methods and newer safety equipment have better safety records.

The A320 entered our registry some 10 yrs ago temporarily, and only came back in 2005...
The NG entered our registry in 2005, and in much larger numbers...

I was merely pointing out to the "I hate sidesticks coz I think yokes are safer" gang that the accident/incident rate per 10,000 flights, are lower on the 32X than on the NG, and that the key issue here is not whether it's a yoke or not, but in the training and the degree of safety culture embedded in the operators...

On a lighter note, the fact that one now closed operator didn't have a fatal accident on the 32X is actually a miracle given how badly the safety culture (flying 150hrs a month regularly), training (hey, they weren't even given charts OK!) and maintenance was (single IRS flight on a 320 on IFR and carrying passengers anyone?), and how on earth did the EU gave that airline an exemption to its ban really baffles everyone!

So I by all means agree with a plane is a plane... as long as one gets trained on it... doesn't matter if sidestick or yoke...

Quoting BoeingGuy (Reply 38):
BTW, I can guess what airline you flew for, given your listings of airplanes you flew - before and after the merger.

I spent a few years wondering where he flies... now I figured it out too... Thanks !   
*ducks and hides*



When losing situational awareness, pray Cumulus Granitus isn't nearby !
User currently offlinePGNCS From United States of America, joined Apr 2007, 2833 posts, RR: 45
Reply 40, posted (1 year 5 months 5 days 16 hours ago) and read 8882 times:

Quoting BoeingGuy (Reply 38):
BTW, I can guess what airline you flew for, given your listings of airplanes you flew - before and after the merger.
Quoting mandala499 (Reply 39):
Quoting BoeingGuy (Reply 38):BTW, I can guess what airline you flew for, given your listings of airplanes you flew - before and after the merger.
I spent a few years wondering where he flies... now I figured it out too... Thanks !
*ducks and hides*

Oh I never say, but I have been on multiple certificates for multiple operators...I like to keep the mystery alive!  

My best always you two!  


User currently offlineBoeingGuy From United States of America, joined Dec 2010, 3157 posts, RR: 7
Reply 41, posted (1 year 5 months 5 days 15 hours ago) and read 8867 times:

Quoting PGNCS (Reply 40):
Oh I never say, but I have been on multiple certificates for multiple operators...I like to keep the mystery alive!

Hmmm, when I think of a carrier who flew DC-9s and A320s in recent past, one comes to mind. The 757/767 and 747-400 wouldn't be the same carrier since that DC9/A320 operator never flew 767s, but the carrier who took them over sure does fly a large fleet of 757/767s and inherited 747-400s from the DC-9/A320 operator (cough cough...widgets).   Am I getting warm?


User currently offlinePGNCS From United States of America, joined Apr 2007, 2833 posts, RR: 45
Reply 42, posted (1 year 5 months 5 days 15 hours ago) and read 8867 times:

Quoting BoeingGuy (Reply 41):
Quoting PGNCS (Reply 40):Oh I never say, but I have been on multiple certificates for multiple operators...I like to keep the mystery alive! Hmmm, when I think of a carrier who flew DC-9s and A320s in recent past, one comes to mind. The 757/767 and 747-400 wouldn't be the same carrier since that DC9/A320 operator never flew 767s, but the carrier who took them over sure does fly a large fleet of 757/767s and inherited 747-400s from the DC-9/A320 operator (cough cough...widgets). Am I getting warm?

I doubt you are considering that my DC-9 experience was years ago and my A-320 experience started in the early 1990s; you also seem to have forgotten I have L-1011 time from over a decade ago as well.

Like I said, I have been on multiple certificates with multiple airlines...


User currently offlinercair1 From United States of America, joined Oct 2009, 1327 posts, RR: 52
Reply 43, posted (1 year 5 months 4 days 19 hours ago) and read 8634 times:
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Quoting airmagnac (Reply 14):
Actually, it is arguable that the commands are also useful "feedback" when making a decision.

I don't think it is arguable at all. The sense of touch and tactile feedback is a useful sense.

I think most of the posters here are missing the point entirely - and the point is not about sidesticks versus yokes - but lack or presence of feedback - specifically haptic feedback as an input to the 'control loop'.

What would be a more interesting study than the # of aircraft with sticks versus yokes but the # of aircraft which incorporate haptic feedback versus not. BTW - a standard rate spring is not haptic feedback.

By ignoring the tactile sensation we are requiring the pilot to utilize only visual cues as to performance. It is a valid question that should looked at, not dismissed.

Other 'industries" are utilizing haptic feedback extensively to improve interaction with machines. Why should aviation be so dismissive of that factor. Heck - my cell phone uses it. It 'vibrates' when I 'touch' a button on the touch screen to simulate a physical button press. Games use it. Robotic surgery uses it.

It is not about the physical location or structure of the control - but the behavior of the control and whether or not that behavior can be useful to the pilot (or misleading - and it can be both).

Quoting airmagnac (Reply 14):
So what I'm saying is : there is no clear-cut best solution, we're at a limit. Both Airbus and Boeing ways are acceptable.
And no, the better choice is not obvious at all

Obviously. And obviously neither is inherently safe or unsafe. Both have advocates and detractors.

Quoting David L (Reply 16):
That one always irks me. It's a nice catch-phrase but, just once, I'd like to see it backed up by some credible evidence. Everything I've seen, read and heard about the way Airbus designs its aircraft indicates that there's just as much input from pilots than with any other manufacturer.

As a pilot, and an engineer, I can see both arguments in play. While I've never designed aircraft, I've worked extensively in user interface design and have had many a heated argument with both users and engineers about that design.

Quoting David L (Reply 16):
If no-one moved the boundaries, we'd still be living in caves and walking everywhere and there would be no A.net where we could discuss such matters.  

What are you talking about? Are you stating that any aircraft that uses a yoke cannot be a step forward or have any advancement.

Quoting JoeCanuck (Reply 29):
As for the Boeing/Airbus/engineer/pilot thing...all I can add is; it seems to me that engineers design and build aircraft for pilots to fly...no matter the name on the door.

Yes. Sometimes with more success, sometimes with less.



rcair1
User currently offlineDavid L From United Kingdom, joined May 1999, 9524 posts, RR: 42
Reply 44, posted (1 year 5 months 4 days 18 hours ago) and read 8606 times:

Quoting rcair1 (Reply 43):
What are you talking about? Are you stating that any aircraft that uses a yoke cannot be a step forward or have any advancement.

No and, to be honest, I'm not sure how you inferred that from what I said. I'm saying you can't take a particular methodology at a particular point in time and expect all future aircraft to be designed in the same way.


User currently offlineairmagnac From Germany, joined Apr 2012, 316 posts, RR: 52
Reply 45, posted (1 year 5 months 4 days 11 hours ago) and read 8510 times:

Quoting rcair1 (Reply 43):
I don't think it is arguable at all. The sense of touch and tactile feedback is a useful sense.

I think most of the posters here are missing the point entirely - and the point is not about sidesticks versus yokes - but lack or presence of feedback - specifically haptic feedback as an input to the 'control loop'.

What would be a more interesting study than the # of aircraft with sticks versus yokes but the # of aircraft which incorporate haptic feedback versus not


You make it sound like haptic feedback must always be provided, even if it's just for the heck of it, because it's a good thing. I do not disagree with tactile clues being a good thing - and I'd bet no one here does either. But the question is, what should it be used for ? Or more exactly, what information should be provided via haptic feedback ?

The usual argument, that David was refering to, is something like : "there has always been haptic feedback via the yoke, that's how it's always been done and that's how it always should be done on a proper airplane"
The problem with that argument is that it implies that the yoke on a 737 or a 767 and the yoke/sidestick on FBW aircraft serve exactly the same purpose, and therefore should be used the same way. But they are in fact fundamentally different devices. They may look the same, but what's going on behind them is not even remotely similar.

On the mechanically-linked aircraft, the yoke controls the deflection of flight-control-surfaces. On most FBW aircraft, the flight control computers are in charge of converting the attitude command into a surface deflection, a task carried out by more or less consciously by the pilot in classic designs. Ths is called a control-augmentation system. As a result, the yoke or sidestick oon such machines is an attitude control device.
(to complicate matters a bit, the 777 yoke remains a pure surface deflection controller in lateral, and even in longitudinal is not quite an attitude controller due to the airspeed feedback in C*u. So although it is FBW, it does not really have control-augmentation. It's somewhere in between mechanical aircraft and "fully developed" FBW aircraft, for want of a better expression)

On the mechanical aircraft, necessary information regarding the situation of flight control surfaces must be provided to the pilot, so that he can control them properly. Tactile clues given via the yoke are very convenient for this ; it was even a natural feedback on earlier planes (the haptic feedback was artificially generated on later fast & heavy machines). It was much better than giving a visual presentation of the deflection angles, as that would be difficult to generate and exploit (the F/CTL page on ECAM or the equivelent on EICAS are such visual displays, but I doubt anyone would want to use those to fly a plane).
On the FBW planes, the pilot is no longer in charge of the control surface loop, as the computers do that for him. So the surface deflection data is redundant. But he is still in charge of the attitude control, and for that he needs attitude feedback. Which is easy to generate, display and exploit visually with a gyro-based instrument or on a PFD, and not so much via haptic means.

That's for straight feedback from the aircraft. There are however 2 pieces of information that can be conveyed by tactile clues. The first is the attitude order being sent by the AP or the other pilot, which could be transmitted to "verify" that it makes sense. As I have said before, the usefulness of such data is debatable.
The second item is envelope limits. And as you very well know, on an Airbus the actual limit itself is taken care of by the flight control computers. Unless of course they don't work properly for some reason, but in most of those abnormal cases I believe the artifical haptic feedback would not be functional either

So again, I don't think the issue is so much that Airbus "dismisses" haptic feedback ; I just think that there is no data to be beneficially fed back by such means. But all this is theoretical engineering hocus-pocus from a mere PPL-level dude ; I'll admit I lack the perspective of the "human user" (airline pilot) side of the human/machine interface.



One "oh shit" can erase a thousand "attaboys".
User currently offlineSmittyOne From , joined Dec 1969, posts, RR:
Reply 46, posted (1 year 5 months 4 days 11 hours ago) and read 8502 times:

Quoting airmagnac (Reply 45):
But all this is theoretical engineering hocus-pocus from a mere PPL-level dude ; I'll admit I lack the perspective of the "human user" (airline pilot) side of the human/machine interface.

Even so, well written post!

What interests me is the relative level of difficulty/workload presented by "hand flying" say a 757 vs. an A320. Seems to me that the A320 would impose less strain on the pilot by maintaining attitude automatically but maybe it doesn't matter much?

Likewise, what is it like to hand-fly the A320 with the yoke in the most basic mode?

Happy to hear from Airbus jockeys about that (explained at the level that a Cessna 172 wannabe would understand)!


User currently offlinercair1 From United States of America, joined Oct 2009, 1327 posts, RR: 52
Reply 47, posted (1 year 5 months 4 days 8 hours ago) and read 8438 times:
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Quoting airmagnac (Reply 45):
You make it sound like haptic feedback must always be provided, even if it's just for the heck of it, because it's a good thing. I do not disagree with tactile clues being a good thing - and I'd bet no one here does either. But the question is, what should it be used for ? Or more exactly, what information should be provided via haptic feedback ?

I think haptic feedback should be provided. Obviously not must - since there are many aircraft flying that don't have it. As for what info - there are lots of cases where the 'feel' of the aircraft can cue the pilot into something is different - and actual cause them to look at the instruments.

Again - feedback is utilized regularly in our society. Most cars have a variable power steering - specifically to preserve the "feel" of the steering as speed and conditions change. One of the most common complaints of early power steering systems is that they lacked that.

My opinion - using all of our senses in an intelligent way to decrease workload and focus attention is good, not bad. It is easy to dismiss because there are plenty of a/c that do not have it, but that does not make it the best option.

In fact, that can turn into confirmation bias - we've got airplanes working just fine without it - so we don't need it. It is certainly cheaper and simpler to not have it. To take it to the extreme, both Columbia and Challenger failures had aspects of "success bias" - where we had gotten away with it before so it must be okay. And don't insult us by assuming I'm comparing those clear failures to aircraft that don't have haptic feedback. I'm simply using extremes to make a point. (too bad you have to explain that kind of stuff at a.net.)



rcair1
User currently offlinePITrules From United States of America, joined Jun 2000, 3212 posts, RR: 6
Reply 48, posted (1 year 5 months 4 days 7 hours ago) and read 8426 times:

Quoting rcair1 (Reply 43):
Quoting airmagnac (Reply 14):
Actually, it is arguable that the commands are also useful "feedback" when making a decision.

I don't think it is arguable at all. The sense of touch and tactile feedback is a useful sense.

I think most of the posters here are missing the point entirely - and the point is not about sidesticks versus yokes - but lack or presence of feedback - specifically haptic feedback as an input to the 'control loop'.

What would be a more interesting study than the # of aircraft with sticks versus yokes but the # of aircraft which incorporate haptic feedback versus not. BTW - a standard rate spring is not haptic feedback.

By ignoring the tactile sensation we are requiring the pilot to utilize only visual cues as to performance.

I think what airmagnac is saying is that tactile feedback is fine, but should not be relied upon as a final confirmation of a commanded change; and I agree with that.

There was a 727 freighter that was approaching ORD at night several years ago. It was on initial descent (thrust levers at idle) when the cockpit lost most of its lighting and other electrical components went unpowered. The crew suspected complete electrical failure, other than battery backup. The crew ran electrical system checklists to no avail. After several minutes the Flight Engineer leaned forward and said something to the affect of "this might be a dumb question, but are the engines running?" Turns out all 3 engines had flamed out, which is what caused all 3 generators to pop offline.

Point being, just because the switch (or thrust levers in the above situation) are in the expected position does not mean the system is operating as expected or as commanded.

Tactile sensation is fine, but should not be the only cue to verify performance.

When a switch is moved (including the illuminating or extinguishing its switch light), the configuration change is only rumor. It is confirmed by the EICAS (or ECAM). So requiring a pilot to utilize visual cues is only a good thing IMHO.


Another factor not yet mentioned in this debate is the ability to move your legs to improve blood circulation. While you can still stretch your legs straight ahead in a Boeing, you have much more range of movement (such as being able to cross your legs) in an Airbus because you don't have this big clumsy control column in your way. Ideally you want to get up and move around to prevent blood clots but its not always possible. Some cockpits have very little room to get up and move around, such as the 737 which is now routinely doing long flights.

Having flown both Airbus and Boeing, the increased comfort alone that the Airbus affords makes it preferable to me.


So if an airline has both Boeing and Airbus, which do pilots prefer?

The correct answer is the one that has better pay, schedules, layovers, and bases considering your relative seniority.

[Edited 2013-05-22 18:55:22]


FLYi
User currently offlinercair1 From United States of America, joined Oct 2009, 1327 posts, RR: 52
Reply 49, posted (1 year 5 months 4 days 6 hours ago) and read 8412 times:
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Quoting PITrules (Reply 48):
I think what airmagnac is saying is that tactile feedback is fine, but should not be relied upon as a final confirmation of a commanded change; and I agree with that.

And so would I. However, the fact that it is not the only cue does not mean it is not a valuable cue.

Try assembling something small and fine with tape on your fingers. Can you? Yes. It is optimal? No.



rcair1
User currently offlinepilotpip From United States of America, joined Sep 2003, 3150 posts, RR: 11
Reply 50, posted (1 year 5 months 4 days 2 hours ago) and read 8369 times:

Quoting SmittyOne (Reply 46):
Happy to hear from Airbus jockeys about that (explained at the level that a Cessna 172 wannabe would understand)!
Quoting rcair1 (Reply 47):
I think haptic feedback should be provided. Obviously not must - since there are many aircraft flying that don't have it. As for what info - there are lots of cases where the 'feel' of the aircraft can cue the pilot into something is different - and actual cause them to look at the instruments.

Again - feedback is utilized regularly in our society. Most cars have a variable power steering - specifically to preserve the "feel" of the steering as speed and conditions change. One of the most common complaints of early power steering systems is that they lacked that.

My opinion - using all of our senses in an intelligent way to decrease workload and focus attention is good, not bad. It is easy to dismiss because there are plenty of a/c that do not have it, but that does not make it the best option.

I quoted both of these for a couple reasons. First, while the fundamentals of flying an airplane remain the same regardless of size, there are a couple important things to remember. First, the airline world is based in the world of IFR. In this world, you fly the instruments. Flying by the seat of your pants can kill you because your senses betray you without those visual cues. Second, jets are flown by the numbers. Because of widely varying weights, icing speeds, etc pitch pictures and speeds can vary greatly. Again, this is why we rely on instruments. There have been many crashes where the crew elected to ignore correct instrumentation and allowed spacial disorientation to kill them.

Quoting PITrules (Reply 48):
Another factor not yet mentioned in this debate is the ability to move your legs to improve blood circulation. While you can still stretch your legs straight ahead in a Boeing, you have much more range of movement (such as being able to cross your legs) in an Airbus because you don't have this big clumsy control column in your way. Ideally you want to get up and move around to prevent blood clots but its not always possible. Some cockpits have very little room to get up and move around, such as the 737 which is now routinely doing long flights.

What about the 747, 767, 777, and other long-haul aircraft that have been doing long legs with a yoke for years? Pilots aren't stapled to the seat. It's not unusual to get up and stretch on a flight. I would do it on anything longer than 2 hours. Long haul flights have extra crew so there is ample opportunity to get up and move around. Also, there is a lot more room to stretch out than you think. Adjust the seat, adjust the pedals and your legs have plenty of space.

As for workload, proper use of automation is a much bigger workload reducer than any FBW system, side stick or yoke.

Bottom line, yoke vs stick, isn't really an issue for anyone flying the line. I've yet to meet a pilot who would refuse an assignment because of one or the other. The biggest factor is quality of life and pay. After that, an airplane is an airplane when it's your job.



DMI
User currently offlinePITrules From United States of America, joined Jun 2000, 3212 posts, RR: 6
Reply 51, posted (1 year 5 months 3 days 20 hours ago) and read 8310 times:

Quoting pilotpip (Reply 50):

What about the 747, 767, 777, and other long-haul aircraft that have been doing long legs with a yoke for years?

What about them? Great airplanes, but just because they have been doing it for years does not mean they are better at it from a health and comfort standpoint.

Quoting pilotpip (Reply 50):
Pilots aren't stapled to the seat. It's not unusual to get up and stretch on a flight. I would do it on anything longer than 2 hours. Long haul flights have extra crew so there is ample opportunity to get up and move around.
Quoting pilotpip (Reply 50):
Also, there is a lot more room to stretch out than you think. Adjust the seat, adjust the pedals and your legs have plenty of space.


Moving seat/rudder pedal position while seated, and getting up and moving around (more ideal to prevent blood clots) are two different things. You may think standing up with no room to move in the tiny little jumpseat area of an E-170 during your 2 hour hop would also suffice on a 6+ hour flight.. but I disagree. Then there is the matter of being seated during the last 40 min or so of a long haul flight during descent preparation. Bottom line, the Airbus offers more leg room while seated.

Try a 10 hour flight and compare the ergonomic advantages of an Airbus vs. Boeing pilot seat position, even with a third crew member break, then maybe you will appreciate the extra space.

[Edited 2013-05-23 05:33:08]


FLYi
User currently offlineSmittyOne From , joined Dec 1969, posts, RR:
Reply 52, posted (1 year 5 months 3 days 19 hours ago) and read 8231 times:

Quoting pilotpip (Reply 50):
I quoted both of these for a couple reasons. First, while the fundamentals of flying an airplane remain the same regardless of size, there are a couple important things to remember. First, the airline world is based in the world of IFR. In this world, you fly the instruments. Flying by the seat of your pants can kill you because your senses betray you without those visual cues. Second, jets are flown by the numbers. Because of widely varying weights, icing speeds, etc pitch pictures and speeds can vary greatly. Again, this is why we rely on instruments. There have been many crashes where the crew elected to ignore correct instrumentation and allowed spacial disorientation to kill them.

I understand all of this.

What I'm asking is, if you are flying a visual approach by hand (pilots still do that, right?) - what is it like in the Airbus due to the FBW? From what little I understand of it, the pilot doesn't need to worry about elevator trim or keeping the wings level (the banes of my existence back when I took flight lessons in Cessnas LOL)...is that true? Is that better?


User currently offlinebikerthai From United States of America, joined Apr 2010, 2155 posts, RR: 4
Reply 53, posted (1 year 5 months 3 days 13 hours ago) and read 8120 times:

Quoting Pihero (Reply 22):

American hairy pilots and their aéroplanes will be soon in the minority.

Unlike popular perception even hairy Americans do evolve and not devolve 

My two cents from my knot hole?

The stick is the way of the future. Even modern ships uses stick as opposed to the old wheel.

If you remove the feed back argument, and the FBW argument, and the control logic argument, as none of these are specific to one or the other, you come down to ergonomics and manufacturing cost. Both of which favors the stick.

Boeing is trapped with it's design as it tries to keep the pilot rating similar to the legacy aircraft. If given the opportunity, I would put my money on Boeing designing a stick airplane for completely new design. After all they do have the C-17 experience.

Now, someone will pull up a picture of the Sonic Cruiser cockpit to show a wheel and blow my theory away . . .  

bt



Intelligent seeks knowledge. Enlightened seeks wisdom.
User currently offlineairmagnac From Germany, joined Apr 2012, 316 posts, RR: 52
Reply 54, posted (1 year 5 months 3 days 12 hours ago) and read 8099 times:

Quoting PITrules (Reply 48):
tactile feedback is fine, but should not be relied upon as a final confirmation of a commanded change

Spot on.

Quoting rcair1 (Reply 47):

I think haptic feedback should be provided. Obviously not must - since there are many aircraft flying that don't have it. As for what info - there are lots of cases where the 'feel' of the aircraft can cue the pilot into something is different - and actual cause them to look at the instruments.

I was concentrating on normal flight parameters feedback, as that is the usual point of debate. But if I understand right, you are suggesting here to use haptic means to provide attention-getters and warnings. No general objection there, but it would have to be a warning associated with manual flying, as that's the only time the pilot will have his hands on the stick and/or throttle levers. That limits the scope.
[ I think the A380 and A350 have stick-shaking in case of dual input, but I have a sudden doubt about that and I can't find evidence to back it up. Anyone know if I'm making stuff up, or if it's actually true ?    ]

Quoting rcair1 (Reply 47):
Most cars have a variable power steering - specifically to preserve the "feel" of the steering as speed and conditions change. One of the most common complaints of early power steering systems is that they lacked that.

A justified complaint. The driver is still directly commanding the wheels and thus needs feedback from the wheels to apply proper control.
But that would be comparable to advanced mechanically linked aircraft (what DP Davies would call "the big jets"), in which the pilot still controls the flight control surface deflections, but the movement itself is powered by hydraulic components. In this case, force feedback was generated artificially by dedicated systems, just like in your example.
But in a control-augmented aircraft, the man/machine interface is at a different "level", it does not deal with the movement of the control surfaces due to various forces, but rather with the attitude of the whole vehicle, which is a more abstract concept based on angles. The relation between attitude and surface deflection is still simple enough to be managed by the pilot in light aircraft with relatively small operating envelopes. It's not so trivial on large, fast aircraft with flexible structures.
This is where the comparison with a car breaks down, because the relation between direction of travel, main axis of the vehicle and steering angle of the wheels is extremely straightforward in most driving conditions (exceptions would be high-speed driving using counter-steering, or driving on ice, for example)

Quoting rcair1 (Reply 47):
And don't insult us by assuming I'm comparing those clear failures to aircraft that don't have haptic feedback. I'm simply using extremes to make a point. (too bad you have to explain that kind of stuff at a.net.)


I do not mean to insult you in any way. If I did my posts would be much shorter ! And personally I am not interested in comparing aircraft X and Y ; I prefer to see justifications for the solutions chosen for each one. There is no single best solution, so any difference does not immediatly translate into "better"/"safer" or "worse". Nor does it allow any post hoc justification, as you said.

As an interface designer, I'm sure you know that providing too much information is just as bad as not giving enough. It justs confuses or overwhelms the receiver and prevents him from analysing the relevant data. And the data that you do provide must be clear, non-ambiguous and easily absorbed by the receiver. With those two principles in mind, I just don't see what information could be conveyed through haptic means which would not be confusing or redundant or ambiguous.
Again - my opinion only.



One "oh shit" can erase a thousand "attaboys".
User currently offlinercair1 From United States of America, joined Oct 2009, 1327 posts, RR: 52
Reply 55, posted (1 year 5 months 3 days 9 hours ago) and read 8053 times:
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Quoting airmagnac (Reply 54):
I do not mean to insult you in any way.

And you did not. I was just anticipating somebody (not particularly you) taking me to task for supposedly relating the Challenger and Columbia disasters to haptic feedback in a/c controls.   Both those disasters had more to do with politics than any engineering.

Quoting airmagnac (Reply 54):
As an interface designer, I'm sure you know that providing too much information is just as bad as not giving enough.

   The right information, at the right time, in the right way. There are lots of examples of both lack of information and too much information - or even the right information presented badly - has caused problems.

Quoting airmagnac (Reply 54):
With those two principles in mind, I just don't see what information could be conveyed through haptic means which would not be confusing or redundant or ambiguous.
Again - my opinion only

One that come to mind - the stick shaker. Of course - if I understand correctly - Airbii (except the 300) do not have stick shakers. Hmmm



rcair1
User currently offlineKlaus From Germany, joined Jul 2001, 21486 posts, RR: 53
Reply 56, posted (1 year 5 months 3 days 9 hours ago) and read 8055 times:

(Speaking from a non-aviation systems/automation background.)

Quoting rcair1 (Reply 43):
What would be a more interesting study than the # of aircraft with sticks versus yokes but the # of aircraft which incorporate haptic feedback versus not. BTW - a standard rate spring is not haptic feedback.

That's the thing – Airbus FBW is designed in a way that the spring in fact already represents proper feedback of what the stick is supposed to do: Stick deflection commands a proportional acceleration in the respective direction, thus also corresponding to the counterforce imposed on the stick by the spring.

Most of the posts above revolve around the assumption that Airbus just removed feedback and left it at that, but in fact they completely changed the control behaviour so that servo feedback wouldn't even make sense in the first place.

As far as I'm aware, when you command a climb acceleration of 0.2g by pulling the stick aft by a certain amount (and always by that same amount!), you feel a proportional spring counterforce and with little latency the plane in fact accelerating upwards by that commanded amount for as long as you hold the stick deflected, accompanied by a corresponding change of the indicated climb rate. What kind of additional feedback beyond the spring would even make sense there?

The flight computers do in fact hide the control loop from you which automatically chooses the surface deflection required at the given weight, speed and configuration to give you the acceleration you've requested as precisely as possible. But what actually useful information does that hide from you? Would it in fact improve your actually useful situational awareness if you were in that low-level loop instead of just telling the aircraft where to go and leaving the side effect compensation to the flight computers?

Additional points I think are relevant:

Normal Law as described applies only to unimpaired standard flight; The system automatically transitions from and to conventional proportional surface deflection during takeoff and landing (see Airbus Flight Control Laws).

• As far as I'm aware, at least some other FBW manufacturers (notably with Boeing's exception) seem to have followed the Airbus flight control model, so this should largely apply to those as well.

• Envelope protection (or its absence) is an exceptional edge case in either model and with both systems it seems to hold specific problems and/or advantages depending on the situation that got you there.

• Failure modes of both the automatic Airbus system (see link above) and the feedback-driven Boeing system (to use these exemplary) are nontrivial in both cases – properly annunciated flight control law degradation in an Airbus might be similarly distracting and potentially problematic as malfunctioning backdrive servos or yoke linkage problems in a Boeing.


User currently offlineDavid L From United Kingdom, joined May 1999, 9524 posts, RR: 42
Reply 57, posted (1 year 5 months 3 days ago) and read 7949 times:

Quoting airmagnac (Reply 45):
The usual argument, that David was refering to, is something like : "there has always been haptic feedback via the yoke, that's how it's always been done and that's how it always should be done on a proper airplane"

Yes, that and the thrust levers not being back-driven (which is actually what prompted my remark). Anyway, my remark seems a little redundant after your excellent contributions.

Quoting rcair1 (Reply 55):
Of course - if I understand correctly - Airbii (except the 300) do not have stick shakers. Hmmm

True but there is an aural "Stall... Stall..." warning which, it could be argued, is less ambiguous. Yes, I know it didn't help AF447 but there was no shortage of other issues in that one and stick-shakers don't always get their message across either. In Normal Law there isn't much point in a stall warning.

(I tried to post this last night but I think Klaus's post broke the internet.    )


User currently offlinebueb0g From United Kingdom, joined Jul 2010, 648 posts, RR: 0
Reply 58, posted (1 year 5 months 2 days 20 hours ago) and read 7901 times:

Quoting SmittyOne (Reply 46):
Likewise, what is it like to hand-fly the A320 with the yoke in the most basic mode?

The A320 will handle exactly like any conventionally controlled aircraft in direct law.

Quoting SmittyOne (Reply 52):
What I'm asking is, if you are flying a visual approach by hand (pilots still do that, right?) - what is it like in the Airbus due to the FBW? From what little I understand of it, the pilot doesn't need to worry about elevator trim or keeping the wings level (the banes of my existence back when I took flight lessons in Cessnas LOL)...is that true? Is that better?

It's broadly similar - because of the nature of the implementation of FBW on an Airbus, whereby you command an attitude change and not control surface deflection, less movement of the controller is required, and you'll see less of the massive movements in opposite directions that you might see in an older aircraft in gusty conditions.

It doesn't really affect the workload of hand flying too much, the basic idea is the same. On keeping the wings level, yes, that's easier because when you let go of the stick, you're commanding zero roll, not zero control deflection.

However, on coming through 100 feet or so, this goes away and you're essentially back in direct control to avoid pilots over-controlling close to the ground and to let them make minute adjustments for the touchdown.

Quoting bikerthai (Reply 53):
Even modern ships uses stick as opposed to the old wheel.

They have both normally.



Roger roger, what's our vector, victor?
User currently offlinebikerthai From United States of America, joined Apr 2010, 2155 posts, RR: 4
Reply 59, posted (1 year 5 months 2 days 18 hours ago) and read 7875 times:

Quoting bueb0g (Reply 58):

They have both normally.

I must have missed the wheel when watching that Discovery Chanel about a large catamaran ferry 

bt



Intelligent seeks knowledge. Enlightened seeks wisdom.
User currently offlineKlaus From Germany, joined Jul 2001, 21486 posts, RR: 53
Reply 60, posted (1 year 5 months 2 days 18 hours ago) and read 7872 times:

Quoting David L (Reply 57):
(I tried to post this last night but I think Klaus's post broke the internet.    )

Oops!   


User currently offlineBoeingGuy From United States of America, joined Dec 2010, 3157 posts, RR: 7
Reply 61, posted (1 year 5 months 2 days 12 hours ago) and read 7798 times:

Quoting David L (Reply 57):
Quoting rcair1 (Reply 55):
Of course - if I understand correctly - Airbii (except the 300) do not have stick shakers. Hmmm

True but there is an aural "Stall... Stall..." warning which, it could be argued, is less ambiguous. Yes, I know it didn't help AF447 but there was no shortage of other issues in that one and stick-shakers don't always get their message across either. In Normal Law there isn't much point in a stall warning.

Have you ever seen the Boeing Stick Shaker? I would very much disagree with your assessment. It's pretty hard to miss. It's very loud and the control column vibrates very unmistakeable. Also in several model, there is a very obvious pull on the column as the FBW or Stick Pusher system tries to push the nose down.

I'd argue this is far more unambiguous than a voice aural and the non-feedback flight controls.


User currently offlineSmittyOne From , joined Dec 1969, posts, RR:
Reply 62, posted (1 year 5 months 2 days 10 hours ago) and read 7743 times:

Quoting bueb0g (Reply 58):

Thanks! Makes sense to me...


User currently offlineDavid L From United Kingdom, joined May 1999, 9524 posts, RR: 42
Reply 63, posted (1 year 5 months 2 days 9 hours ago) and read 7740 times:

Quoting BoeingGuy (Reply 61):
I would very much disagree with your assessment. It's pretty hard to miss.

Fine, except I didn't make an assessment that it's not hard to miss. I don't seem to be coping very well with the old "common-language barrier" in this thread.  
Quoting BoeingGuy (Reply 61):
Also in several model, there is a very obvious pull on the column as the FBW or Stick Pusher system tries to push the nose down.

A stick pusher is a different matter, of course.


User currently offlinePihero From France, joined Jan 2005, 4597 posts, RR: 77
Reply 64, posted (1 year 5 months 1 day 16 hours ago) and read 7593 times:
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Quoting BoeingGuy (Reply 61):
Have you ever seen the Boeing Stick Shaker? I would very much disagree with your assessment. It's pretty hard to miss. It's very loud and the control column vibrates very unmistakeable.

That "Boeing" stick shaker has been going on since the 707 came into service, 55 yeras ago... I would have thought that there could be some progress in this respect.
Problem is there are countless instances where it was disregarded. The most recent accidents involving that sort of stall protection :
- Colgan 3407 in which the pilot 1/ disregarded the warning ( unmistakable, you say... ) and, 2/ fought the stick pusher ;

- The Turkish 1951 at AMS where the pilots 1/ ignored the stalling state ( 40 kt below Vref is no small matter ) and, 2/ fought against both the throttles and the control yoke.

One of the problems with haptic feedback, visual or tactile clues is that humans do deal with them and humans have many valid reasons to disregard important cues which do not suit their perception of the situation they are at. The China Airlines 006 incident is very interesting in this respect : although the crew knew #4 engine had flamed out, the control wheel ( the *yoke* ) was at full left deflection, as well as the rudder pedals, on disconnecting the autopilot, they managed to put themselves into a right spiral dive !

It is of some important note that after TY 1951, Boeing themselves stressed through an AD the importance of instrument monitoring.

From the above, you can gather that I'm certainly not as sure as you are of the case for the moving throttles and the tactile and visual cues given by back driven controls.
There is a corollary in your defense of the stall shaker : it's one of the main references to stall, yes... but think of a windshear escape : without a stick shaker the manoeuvre is left to your flying the pitch limit indicator on your ADI, which is just about unreadable because of vibrations, so in fact, the in-and-out of the stick shaker method becomes your only way to deal with a major emergency... consider then that the effort on the control column are more than doubled (because of the soft limits you could override but at a greater force ! )... you are not in your best day, I can assure !
Years ago, on this very forum I said that it would be criminal for any manufacturer who to not follow the Airbus windshear escape philosoiphy.
I am glad that at last, it is the case for the 787.

Quoting SmittyOne (Reply 52):
if you are flying a visual approach by hand (pilots still do that, right?) - what is it like in the Airbus due to the FBW? From what little I understand of it, the pilot doesn't need to worry about elevator trim or keeping the wings level

Complement to buebog's # 58 post, you have to consider that on a 'Bus, one flies a trajectory that is quite visually obvious. Very few corrections are needed, one has a direct control of the nose movement and position. Then, the aircraft stays at the bank / pich attitude one has put it in with the stick at neutral : if 10° of bank is required, there one commands it - and leave the stick at neutral - and there it stays until one changes it ; Same thing with the pitch angle. The variations around these values due to turbulence are smoothened out by the system : one doesn't fight the airplane.

Quoting bueb0g (Reply 58):
However, on coming through 100 feet or so, this goes away and you're essentially back in direct control

It's a bit more complicated, but you've got the gist of it. Roll control remains in normal law until tyhe ground roll.

Quoting pilotpip (Reply 50):
there is a lot more room to stretch out than you think. Adjust the seat, adjust the pedals and your legs have plenty of space.

I would certainly not recommend such practice : Doing so will prevent you from having any action on the flight controls should you need to have one. In fact it would make me very angry.

[Edited 2013-05-25 08:51:55]


Contrail designer
User currently offlineKlaus From Germany, joined Jul 2001, 21486 posts, RR: 53
Reply 65, posted (1 year 5 months 1 day 15 hours ago) and read 7580 times:

Quoting BoeingGuy (Reply 61):
Have you ever seen the Boeing Stick Shaker? I would very much disagree with your assessment. It's pretty hard to miss. It's very loud and the control column vibrates very unmistakeable. Also in several model, there is a very obvious pull on the column as the FBW or Stick Pusher system tries to push the nose down.

I'd argue this is far more unambiguous than a voice aural and the non-feedback flight controls.


The problem with AF447 was not that the pilots missed the stall warning but that they didn't know what to do about it, even though that would have been possible with the information they had.

When you've already abandoned situational awareness and CRM while the automatic systems still protect you, you get completely lost very quickly as soon as that technical protection falls away for some reason.

When there's no realistic mental model of the situation connected to your hands and ears (and if you're unable to reconstruct one on demand), stick shakers or aural warnings become useless.


User currently offlineDavid L From United Kingdom, joined May 1999, 9524 posts, RR: 42
Reply 66, posted (1 year 5 months 1 day 12 hours ago) and read 7536 times:

Quoting BoeingGuy (Reply 61):
I'd argue this is far more unambiguous than a voice aural and the non-feedback flight controls.

In my haste to point out the misinterpretation of what I said, I managed to miss this. All I can say is that I think we have very different ideas of what "less ambiguous" means. One system tells you "hey, remember what you were trained to do when I do this..." while the other says "you're in danger of stalling". If you've been trained well I'd agree that you probably would remember what you were trained to do when it did that but I think the best you can say is that it's almost insignificantly more ambiguous than a voice telling you specifically what the issue is.

And to put my initial comment into perspective, I was responding to a statement that FBW Airbuses don't have stick-shakers (correct, so far), but with the addition of a "Hmmm", which I wasn't exactly sure how to interpret.  
Quoting Pihero (Reply 64):
Problem is there are countless instances where it was disregarded.

   Even when it has been the first indication that something was wrong. The AF447 crew were already immersed in a cascade of issues before the stall warning sounded.

[Edited 2013-05-25 12:27:59]

User currently offlinepacksonflight From Iceland, joined Jan 2010, 382 posts, RR: 0
Reply 67, posted (1 year 5 months 1 day 8 hours ago) and read 7469 times:

Quoting BoeingGuy (Reply 61):
Have you ever seen the Boeing Stick Shaker? I would very much disagree with your assessment. It's pretty hard to miss. It's very loud and the control column vibrates very unmistakeable. Also in several model, there is a very obvious pull on the column as the FBW or Stick Pusher system tries to push the nose down.

The AF447 report 3 or 4 similar previous crashes. The aircrafts involved where B757 B707 and DC9. Last time I checked those aircrafts had no FBW system or flimsy sidestick, but all of them had the old dependable control wheel.


User currently offlineSmittyOne From , joined Dec 1969, posts, RR:
Reply 68, posted (1 year 4 months 4 weeks 1 day 23 hours ago) and read 7280 times:

Quoting Pihero (Reply 64):
Complement to buebog's # 58 post, you have to consider that on a 'Bus, one flies a trajectory that is quite visually obvious. Very few corrections are needed, one has a direct control of the nose movement and position. Then, the aircraft stays at the bank / pich attitude one has put it in with the stick at neutral : if 10° of bank is required, there one commands it - and leave the stick at neutral - and there it stays until one changes it ; Same thing with the pitch angle. The variations around these values due to turbulence are smoothened out by the system : one doesn't fight the airplane.

Interesting, thanks! So one final question (again, coming from a guy with the most basic understanding of flight via Cessna 172...). If you are in level flight with say two degrees nose up pitch, and then decrease the throttles, what happens? Does the airplane start to decelerate at the same pitch angle? Does it pitch down and continue to fly at the same airspeed (the way a trimmed Cessna would)?

Or do you always just use autothrottles and dial in the desired speed? In that case, in the same scenario above, if you decrease ordered speed but still have the nose set at two degrees up, would you start to descend at that attitude?

Just trying to get a better sense of what it would be like to fly one of these planes.

[Edited 2013-05-27 02:06:21]

User currently offlinePihero From France, joined Jan 2005, 4597 posts, RR: 77
Reply 69, posted (1 year 4 months 4 weeks 1 day 21 hours ago) and read 7279 times:
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Quoting SmittyOne (Reply 68):
If you are in level flight with say two degrees nose up pitch, and then decrease the throttles, what happens?

With the stick free, the aircraft will decelerate, keeping your attitude... you'll get a warning *SPEED SPEED SPEED !*, that advises you that you're in a low energy state. If You keep on doing nothing, the trim will stop and the airplane will start descending at a constant AOa - called *Alpha Prot(ection) and the safe speed correspondent to that AoA, called Vaprot. On the PFD it's just above the black-yellow range of the speed tape.
If you'd insist on pulling the stick back and the speed still decays, you'll reach the *Alpha floor* zone, at which point, the A/THR will trigger TOGA and you'll gently climb at a constant low speed.

Quoting SmittyOne (Reply 68):
Or do you always just use autothrottles and dial in the desired speed? In that case, in the same scenario above, if you decrease ordered speed but still have the nose set at two degrees up, would you start to descend at that attitude?

With the A/THR on, you will not go below Vls (lowest selectable speed) for your configuration even if you've dialled a speed below Vls. Vls is visually displayed at the top of the yellow band of the speed tape.



Contrail designer
User currently offlineSmittyOne From , joined Dec 1969, posts, RR:
Reply 70, posted (1 year 4 months 4 weeks 1 day 19 hours ago) and read 7248 times:

Quoting Pihero (Reply 69):

That's pretty slick!

I've read the book "Fly By Wire" but it obviously left me with some questions   Thank you for taking the time to school me up on the Airbus system...

Edit: OK, one more question...

Does the Airbus system work the same way (generally) for all models other than the A300s? So if you are experienced with the A320 the A330/A380 would be roughly the same?

[Edited 2013-05-27 05:41:45]

User currently offlinePihero From France, joined Jan 2005, 4597 posts, RR: 77
Reply 71, posted (1 year 4 months 4 weeks 1 day 19 hours ago) and read 7241 times:
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Quoting SmittyOne (Reply 70):
Does the Airbus system work the same way (generally) for all models other than the A300s? So if you are experienced with the A320 the A330/A380 would be roughly the same?

Yes, up to the A380. Don't know about the A350, but I'd doubt there would be any major changes.



Contrail designer
User currently offlineBoeingGuy From United States of America, joined Dec 2010, 3157 posts, RR: 7
Reply 72, posted (1 year 4 months 4 weeks 1 day 13 hours ago) and read 7139 times:

Quoting SmittyOne (Reply 68):
If you are in level flight with say two degrees nose up pitch, and then decrease the throttles, what happens? Does the airplane start to decelerate at the same pitch angle? Does it pitch down and continue to fly at the same airspeed (the way a trimmed Cessna would)?

On a Boeing airplane it would depend on which pitch mode is selected. Several pitch modes are "Speed through Elevators" modes, meaning the autothrottle is commanding thrust to maintain a climb rate or a commanded thrust (e.g. the calculated takeoff thrust). The autopilot will vary the pitch to maintain the selected speed.

Several other modes, the autothrottle will adjust thrust to maintain speed and the autopilot will command a pitch to achieve a desired vertical speed or path.

Quoting Pihero (Reply 69):
With the A/THR on, you will not go below Vls (lowest selectable speed) for your configuration even if you've dialled a speed below Vls. Vls is visually displayed at the top of the yellow band of the speed tape.

Boeing airplanes also will not command an autoflight command outside a safe envelope. If you dial down the speed to 120 knots, say, and that's well below stall speed, the autothrottle won't let you get below minimum maneuvering speed.

Further, the 777, 787, 747-8 and some 747-400s have a feature called "autothrottle wake up". If the autothrottle are off (as long as they are still armed) and the airplane drops below a safe speed, the autothrottle will automatically engage and command the last safe selected speed.


User currently offlinebueb0g From United Kingdom, joined Jul 2010, 648 posts, RR: 0
Reply 73, posted (1 year 4 months 4 weeks 1 day 9 hours ago) and read 7100 times:

Quoting bikerthai (Reply 59):
I must have missed the wheel when watching that Discovery Chanel about a large catamaran ferry 

I said normally. Most modern ships retain a conventional style helm or tiller while also incorporating various back-up or manoeuvring controllers, which are likely sticks.

Quoting Pihero (Reply 64):
- The Turkish 1951 at AMS where the pilots 1/ ignored the stalling state ( 40 kt below Vref is no small matter ) and, 2/ fought against both the throttles and the control yoke.

I don't think they fought the yoke, and the warning wasn't disregarded. They obviously didn't react to the speed loss or RA fault initially, but once the stick shaker went off, they immediately pushed the yoke forward and the throttles up (the second time they had pushed the throttles forward), but it was too late to avoid the accident. I think the comment about fighting the throttles is also misplaced although, of course, if TK1951 had been an A320, and the RA fault had occurred, the aircraft would have shouted "retard" but would not have actually done anything with the thrust.

Quoting BoeingGuy (Reply 72):
Boeing airplanes also will not command an autoflight command outside a safe envelope. If you dial down the speed to 120 knots, say, and that's well below stall speed, the autothrottle won't let you get below minimum maneuvering speed.

And yet it happened on TK1951, even with (and indeed, because of) the autothrottle. Obviously this is a different situation to the one you are describing, as the AT had gone into IDLE mode but that accident is proof that the autoflight system on a Boeing will allow itself to be commanded outside of the safe flight envelope.

Quoting BoeingGuy (Reply 72):
Further, the 777, 787, 747-8 and some 747-400s have a feature called "autothrottle wake up". If the autothrottle are off (as long as they are still armed) and the airplane drops below a safe speed, the autothrottle will automatically engage and command the last safe selected speed.

Could this have saved/helped TK1951 were it a feature on the 737NG, or would the fact that the AT was on and (as far as the a/c was concerned) functioning correctly have stopped it?



Roger roger, what's our vector, victor?
User currently offlineXFSUgimpLB41X From United States of America, joined Aug 2000, 4212 posts, RR: 37
Reply 74, posted (1 year 4 months 4 weeks 1 day 5 hours ago) and read 7077 times:

Quoting BoeingGuy (Reply 72):
Boeing airplanes also will not command an autoflight command outside a safe envelope. If you dial down the speed to 120 knots, say, and that's well below stall speed, the autothrottle won't let you get below minimum maneuvering speed.

Not in V/S mode. If you V/S mode up, the A/T will go to climb power trying to maintain speed, but eventually it will take you to the shaker.



Chicks dig winglets.
User currently offlineBoeingGuy From United States of America, joined Dec 2010, 3157 posts, RR: 7
Reply 75, posted (1 year 4 months 4 weeks 17 hours ago) and read 6985 times:

Quoting XFSUgimpLB41X (Reply 74):
Quoting BoeingGuy (Reply 72):
Boeing airplanes also will not command an autoflight command outside a safe envelope. If you dial down the speed to 120 knots, say, and that's well below stall speed, the autothrottle won't let you get below minimum maneuvering speed.

Not in V/S mode. If you V/S mode up, the A/T will go to climb power trying to maintain speed, but eventually it will take you to the shaker.

Not that I'm aware of. What model are you referring to? I don't know the 737 very well, but I'm pretty sure it's not true on the 767, 777 and 787. It won't go to climb power in cruise. CRZ is the thrust limit mode then.

[Edited 2013-05-28 07:49:07]

User currently offlineXFSUgimpLB41X From United States of America, joined Aug 2000, 4212 posts, RR: 37
Reply 76, posted (1 year 4 months 4 weeks 5 hours ago) and read 6900 times:

Quoting BoeingGuy (Reply 75):
Not that I'm aware of. What model are you referring to? I don't know the 737 very well, but I'm pretty sure it's not true on the 767, 777 and 787. It won't go to climb power in cruise. CRZ is the thrust limit mode then.

It will go to the limit of whatever phase you're in. Regardless, it will take you to the shaker was my point.



Chicks dig winglets.
User currently offlinevikkyvik From United States of America, joined Jul 2003, 10103 posts, RR: 26
Reply 77, posted (1 year 4 months 3 weeks 6 days 14 hours ago) and read 6811 times:
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Quoting bueb0g (Reply 58):
On keeping the wings level, yes, that's easier because when you let go of the stick, you're commanding zero roll, not zero control deflection.

Correct me if I'm wrong, but I believe you're commanding zero roll rate, rather than zero roll. If you already have a bank angle, and you return the stick to neutral, the airplane will remain in that bank angle.

Quoting Klaus (Reply 65):
When there's no realistic mental model of the situation connected to your hands and ears (and if you're unable to reconstruct one on demand), stick shakers or aural warnings become useless.

That's probably the most important point. All the warnings - tactile, audio, or otherwise - become useless if the human mind is not prepared to accept them, based on whatever situation it is in.

Quoting David L (Reply 66):
One system tells you "hey, remember what you were trained to do when I do this..." while the other says "you're in danger of stalling".

Amusingly, I couldn't tell which description referred to which system.  



"Two and a Half Men" was filmed in front of a live ostrich.
User currently offlinebueb0g From United Kingdom, joined Jul 2010, 648 posts, RR: 0
Reply 78, posted (1 year 4 months 3 weeks 6 days 14 hours ago) and read 6795 times:

Quoting vikkyvik (Reply 77):
Correct me if I'm wrong, but I believe you're commanding zero roll rate, rather than zero roll. If you already have a bank angle, and you return the stick to neutral, the airplane will remain in that bank angle.

Correct, that's what I meant, thanks for spotting it.



Roger roger, what's our vector, victor?
User currently offlinebarney captain From United States of America, joined Nov 2001, 970 posts, RR: 13
Reply 79, posted (1 year 4 months 3 weeks 23 hours ago) and read 6453 times:

Sully apparently has concerns about the side sticks role in AF 447.

Captain Sullenberger has a valid point and one that I've often speculated on-a side stick control gives no feed back as to what the autopilot or the other pilot is commanding. A major flaw imo. Now, before I'm accused of AB hating, I think AB makes an amazing airplane. However, having a system where the A/P or other pilots inputs are completely masked from the other crew member is a recipe for disaster. In the case of an AF scenario, if I saw the other pilot with the yoke pulled back in his chest during a stall, I would intervene. In a side stick aircraft, one would have no idea what the other pilot was commanding.

Sully - "AF447 would have been much much less likely in an aircraft without a side stick". Again, I doubt Sully is an AB hater, be he illustrates the point in the sim.


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



...from the Banana Republic....
User currently offlinercair1 From United States of America, joined Oct 2009, 1327 posts, RR: 52
Reply 80, posted (1 year 4 months 3 weeks 18 hours ago) and read 6401 times:
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Quoting bueb0g (Reply 73):
And yet it happened on TK1951, even with (and indeed, because of) the autothrottle. Obviously this is a different situation to the one you are describing, as the AT had gone into IDLE mode but that accident is proof that the autoflight system on a Boeing will allow itself to be commanded outside of the safe flight envelope.

The RA feeding the information to the A/T had failed and was telling the a/c it was at ground level. That means, the a/c systems 'thought' they were doing exactly the right thing - and they were not commanding flight outside the envelope. As far as 'it' knew - it was inside the envelope for an a/c touching down. Garbage in- garbage out.

Quoting bueb0g (Reply 73):
Could this have saved/helped TK1951 were it a feature on the 737NG, or would the fact that the AT was on and (as far as the a/c was concerned) functioning correctly have stopped it?

I don't know - but I think not - again because the data going to the computers was incorrect. These kind of protections must be disabled at some point because if they are not - you'd never get the a/c to stop on the runway.



rcair1
User currently offlinebarney captain From United States of America, joined Nov 2001, 970 posts, RR: 13
Reply 81, posted (1 year 4 months 3 weeks 14 hours ago) and read 6347 times:

The video link below show Captain Sullenberger's take on how the side stick may have played a roll in AF447. This is something I've long speculated on as well. I'm sure Sully isn't an AB hater and neither am I. However, I see an inherent issue with any side stick design in that; any input that the other pilot or in fact, the A/P commands, is completely masked from the other pilot (or pilots). With a control wheel a/c, whatever inputs the A/P or other other pilot commands are immediately evident.

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



...from the Banana Republic....
User currently offlinebarney captain From United States of America, joined Nov 2001, 970 posts, RR: 13
Reply 82, posted (1 year 4 months 3 weeks 14 hours ago) and read 6345 times:

The video link below show Captain Sullenberger's take on how the side stick may have played a roll in AF447. This is something I've long speculated on as well. I'm sure Sully isn't an AB hater and neither am I. However, I see an inherent issue with any side stick design in that; any input that the other pilot or in fact, the A/P commands, is completely masked from the other pilot (or pilots). With a control wheel a/c, whatever inputs the A/P or other other pilot commands are immediately evident.


...from the Banana Republic....
User currently offlineDavid L From United Kingdom, joined May 1999, 9524 posts, RR: 42
Reply 83, posted (1 year 4 months 3 weeks 13 hours ago) and read 6314 times:

Quoting barney captain (Reply 79):
In the case of an AF scenario, if I saw the other pilot with the yoke pulled back in his chest during a stall, I would intervene.

It's often claimed that the PF was holding the stick full aft from early on - I don't know if you're going from that or from the sidestick traces of the DFDR. Although the PF's inputs were "generally nose-up", the stick wasn't held full-aft until quite late in the sequence of events. I also feel obliged to bring up again the point that, in the absence of situational awareness, a yoke "in the chest/lap/groin" has occasionally not elicited an appropriate response in previous accidents. I have no reason to doubt that most pilots would react as you would, in either set-up.

Quoting barney captain (Reply 79):
having a system where the A/P or other pilots inputs are completely masked from the other crew member is a recipe for disaster

As a non-pilot, I confess I'm struggling a bit to tally that with the CVR excerpts. The other two told the PF more than once that he was "going up" and that he needed to stop "going up" and "go down" instead. In fact, the PM did intervene but he didn't push the stick forward and keep it there.


User currently offlinebarney captain From United States of America, joined Nov 2001, 970 posts, RR: 13
Reply 84, posted (1 year 4 months 2 weeks 5 days 1 hour ago) and read 6110 times:

..All, I apologize for the multiple posts. The forum wasn't behaving correctly and for a few days, none of those posts were showing up. I've alerted the mods.


...from the Banana Republic....
User currently offlinePihero From France, joined Jan 2005, 4597 posts, RR: 77
Reply 85, posted (1 year 4 months 2 weeks 2 days 20 hours ago) and read 5954 times:
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Quoting barney captain (Reply 82):
The video link below show Captain Sullenberger's take on how the side stick may have played a roll in AF447. This is something I've long speculated on as well.

...and Captain Sullenberger conveniently forgets that aircraft with yokes have crashed in similar situations.
A list that's certainly not exhaustive :
- 01.12.74 : NWA 727
- 06.02.96 : Birgerner 757
- 02.10.96 : Aeroperu 757
- 22.12.96 : Airborne Express DC-8
- 14.10.04 : Pinnacle CL-600
- 10.08.05 : West Caribbean MD-82
- 12.02.09 : Colgan Q-400...



Contrail designer
User currently offlinebarney captain From United States of America, joined Nov 2001, 970 posts, RR: 13
Reply 86, posted (1 year 4 months 2 weeks 2 days 11 hours ago) and read 5874 times:

Quoting Pihero (Reply 85):
...and Captain Sullenberger conveniently forgets that aircraft with yokes have crashed in similar situations.

Of course - and that (unfortunately) will always be a possibility. But even Sully - an ex-AB driver - acknowledges the issue of not seeing what input the other pilot is commanding. AF 447 had repeated, long term aft control inputs over a significant period of time that in all probability, only the PF knew about. Not good.

l'll state it again, any system that masks the A/P and/or the PF inputs from the crew is an issue.

Ironically, the fact that Sully was in an AB that day on the Hudson likely saved lives. We've attempted low altitude dual engine failures in the sim, and without the benefit of an auto-deploying RAT, you're left in manual reversion, with only battery power and likely a very different outcome.



...from the Banana Republic....
User currently offlinercair1 From United States of America, joined Oct 2009, 1327 posts, RR: 52
Reply 87, posted (1 year 4 months 2 weeks 2 days 8 hours ago) and read 5847 times:
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Quoting Pihero (Reply 85):
and Captain Sullenberger conveniently forgets that aircraft with yokes have crashed in similar situations.

No - he did not say it caused the crash - he said it may have contributed.

Quoting barney captain (Reply 86):
Ironically, the fact that Sully was in an AB that day on the Hudson likely saved lives.

Cactus 1549 was a marvelous aircraft flown by a marvelous pilot - but somehow I think he would have put a 737 down with the same grace and control.

There are, in fact, some who believe that the automation on modern aircraft hindered a pilot like Sullenberger. For instance, there has been discussion that the FADEC on the engines purposely limited their output to prevent further damage (a maintenance issue) and that with manual reversion he may have been able to get more power. I think the general conclusion is that this is false - the engines may have produced more power - but not enough and not for long enough. I'm not an expert in turbines or FADEC so I have no opinion - I only note the discussion.

I also remember that he could not achieve the ideal angle of entry at the last moment because the alpha protections would not allow it. To achieve it - he would have had to dive to pick up speed first. Again - I really don't have an opinion.

Quoting barney captain (Reply 86):
We've attempted low altitude dual engine failures in the sim, and without the benefit of an auto-deploying RAT, you're left in manual reversion, with only battery power and likely a very different outcome.

He started the APU immediately. He could have done that on many aircraft.



rcair1
User currently offlinePihero From France, joined Jan 2005, 4597 posts, RR: 77
Reply 88, posted (1 year 4 months 2 weeks 2 days 6 hours ago) and read 5836 times:
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Quoting barney captain (Reply 86):
Ironically, the fact that Sully was in an AB that day on the Hudson likely saved lives. We've attempted low altitude dual engine failures in the sim, and without the benefit of an auto-deploying RAT, you're left in manual reversion, with only battery power and likely a very different outcome.

They had a completely intact electrical power generation.
And the RAT can be deployed manually.

Quoting rcair1 (Reply 87):
No - he did not say it caused the crash - he said it may have contributed.

He could also have said that the yokes on the accident I cited contributed - may have - to the crashes. But he didn't.

Quoting rcair1 (Reply 87):
I also remember that he could not achieve the ideal angle of entry at the last moment because the alpha protections would not allow it.

Incorrect. Below 100 ft rad alt there is no alpha floor protection any more. They've never been in a low energy situation for Alpha Prot to engage.



Contrail designer
User currently offlineDavid L From United Kingdom, joined May 1999, 9524 posts, RR: 42
Reply 89, posted (1 year 4 months 2 weeks 1 day 21 hours ago) and read 5782 times:

Quoting barney captain (Reply 86):
AF 447 had repeated, long term aft control inputs over a significant period of time that in all probability, only the PF knew about. Not good.

Then I'm still puzzled as to why the Captain and PNF kept telling the PF to stop doing something if they didn't know he was doing it and why the PNF felt the need to take the controls. The stick movements were such that many have speculated that the PF was targeting a certain pitch, as recommended for UAS, but it was the wrong pitch.

With all due respect, I'm still inclined to stick with the version of events depicted in the official report. And don't get me wrong, Barney Captain. I do respect your contributions. I only took you off my Respected Users list some time ago because you hadn't posted for a while and there was a waiting list.  
Quoting Pihero (Reply 85):
A list that's certainly not exhaustive :

Well, that's another thing that continues to puzzle this non-aviation person. Why is the Airbus control system plucked out of the multitude of significant issues involved in one accident and wielded as some kind of smoking gun while any mention of several similar results in aircraft with yokes is often met with a muffled cough and a change of subject? That isn't aimed at anyone in particular - it happens in every discussion involving Airbus FBW.

At the risk of sounding like a broken record, it's been 25 years, a quarter of a century, with over 7,000 FBW aircraft delivered. Where is the data to show that Airbus FBW aircraft are less safe than Boeings, etc?

Quoting rcair1 (Reply 87):
I also remember that he could not achieve the ideal angle of entry at the last moment because the alpha protections would not allow it.

But he didn't seem to have been prevented from carrying out a superb ditching.


User currently offlineStarlionblue From Greenland, joined Feb 2004, 17068 posts, RR: 66
Reply 90, posted (1 year 4 months 2 weeks 1 day 21 hours ago) and read 5773 times:

Quoting David L (Reply 89):
Why is the Airbus control system plucked out of the multitude of significant issues involved in one accident and wielded as some kind of smoking gun while any mention of several similar results in aircraft with yokes is often met with a muffled cough and a change of subject? That isn't aimed at anyone in particular - it happens in every discussion involving Airbus FBW.

At the risk of sounding like a broken record, it's been 25 years, a quarter of a century, with over 7,000 FBW aircraft delivered. Where is the data to show that Airbus FBW aircraft are less safe than Boeings, etc?

        

Very well put. I think a lot of people, consciously or not, associate "computer control" with the unreliability of a PC. The stigma of computers as unreliable and failure-prone is increasingly misplaced, given how much importance they have in our daily life. The layman hears "computer control" and immediate thinks, "heck, my Windows blue-screened four times last week. Computers can't be trusted." In aviation though, the majority of crashes are in large part caused by the pilots directly or though the mismanagement of a crisis by the pilots. The poor maligned computers do their job and have yet to fail so catastrophically that it has brought down a plane.

I firmly believe that if Boeing had implemented a sidestick and hard limits twenty years ago we wouldn't still be having this discussion.



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlineDavid L From United Kingdom, joined May 1999, 9524 posts, RR: 42
Reply 91, posted (1 year 4 months 2 weeks 1 day 19 hours ago) and read 5749 times:

Quoting Starlionblue (Reply 90):

To be fair, the main bone of contention here seems to be the Airbus side-sticks and thrust levers versus back-driven, interconnected yokes and throttle levers.

Airmagnac's post covers far more than I could even begin to attempt:

Quoting airmagnac (Reply 14):


User currently offlinercair1 From United States of America, joined Oct 2009, 1327 posts, RR: 52
Reply 92, posted (1 year 4 months 2 weeks 1 day 18 hours ago) and read 5734 times:
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Quoting Pihero (Reply 88):
Incorrect. Below 100 ft rad alt there is no alpha floor protection any more. They've never been in a low energy situation for Alpha Prot to engage.

Thanks Pihero - I'll have to go back and see if I can find what the issue was. I know I read a discussion where he could not achieve the ideal angle.

Quoting David L (Reply 89):
But he didn't seem to have been prevented from carrying out a superb ditching.

Indeed not.

Quoting David L (Reply 91):
To be fair, the main bone of contention here seems to be the Airbus side-sticks and thrust levers versus back-driven, interconnected yokes and throttle levers.

I would not characterize it quite that way. You could have coupled side sticks - which would solve much of the issue. Then introduce feedback into those sticks (as opposed to springs). The presence of the stick/yoke is not the issue, it is the behavior.

Regarding back driven throttles - it is adding visual feedback (lever) position to cognitive (look at the gauge and interpret). I believe having both is better than 1.



rcair1
User currently offlineDavid L From United Kingdom, joined May 1999, 9524 posts, RR: 42
Reply 93, posted (1 year 4 months 2 weeks 1 day 16 hours ago) and read 5719 times:

Quoting rcair1 (Reply 92):
I would not characterize it quite that way. You could have coupled side sticks

Well, by "Airbus side-sticks and thrust levers" I mean specifically the side-stick and thrust lever systems used by Airbus. A lot of the argument hinges on the Captain and PNF of AF447 not being able to tell what the PF was doing with the stick yet the data in the official report suggests otherwise, as does the anecdotal evidence of the Airbus TRIs and Captains here and elsewhere.

Again, I think Airmagnac's posts (his Reply 45 is worth a look, too) summarise very well how the current Airbus system suits the C* case while conventional yokes might be preferable for the C*u case. I can recall Pihero making the same point some years ago.


User currently offlineKlaus From Germany, joined Jul 2001, 21486 posts, RR: 53
Reply 94, posted (1 year 4 months 2 weeks 1 day 16 hours ago) and read 5714 times:

Quoting rcair1 (Reply 87):
There are, in fact, some who believe that the automation on modern aircraft hindered a pilot like Sullenberger. For instance, there has been discussion that the FADEC on the engines purposely limited their output to prevent further damage (a maintenance issue) and that with manual reversion he may have been able to get more power. I think the general conclusion is that this is false - the engines may have produced more power - but not enough and not for long enough. I'm not an expert in turbines or FADEC so I have no opinion - I only note the discussion.

Is there really any modern aircraft with manual engine control reversion, overriding the FADECs?

I had assumed so far that the FADECs would only revert to degraded modes similar to the non-normal Airbus control laws, but never go back to actual mechanical control.

Quoting rcair1 (Reply 92):
I would not characterize it quite that way. You could have coupled side sticks - which would solve much of the issue. Then introduce feedback into those sticks (as opposed to springs). The presence of the stick/yoke is not the issue, it is the behavior.

You would still not have any feedback from the aircraft systems, only force coupling between the two pilots.

And for that you would introduce a lot of mechanical complexity with corresponding failure risks.

(My question above what kind of actual system feedback in the Airbus control logic would even make sense still stands unanswered.)

Quoting David L (Reply 93):
A lot of the argument hinges on the Captain and PNF of AF447 not being able to tell what the PF was doing with the stick yet the data in the official report suggests otherwise, as does the anecdotal evidence of the Airbus TRIs and Captains here and elsewhere.

The question is whether the cross-coupling of the sidesticks would have changed anything about the total confusion of both pilots, despite instruments correctly showing rapid descent with a nose-up attitude at full power. What information could a mechanical sidestick linkage really have provided which wasn't already apparent anyway?

And another critical issue is that one cannot just make design changes which retroactively maybe could have prevented one specific accident without also considering how many actually marginal or even uneventful other situations might have been turned into fatal accidents by that same change.

The simplified and low-risk construction of the sidesticks comes with quite a few reliability benefits – introducing additional complexity by adding active servos or mechanical linkages automatically and unavoidably also introduces additional risks. One may indeed gain more safety benefits which make it worthwile, but they would need to clearly exceed the additional risks taken. Would they actually achieve that?


User currently offlineBoeingGuy From United States of America, joined Dec 2010, 3157 posts, RR: 7
Reply 95, posted (1 year 4 months 2 weeks 1 day 16 hours ago) and read 5710 times:

Quoting rcair1 (Reply 87):
Quoting barney captain (Reply 86):
We've attempted low altitude dual engine failures in the sim, and without the benefit of an auto-deploying RAT, you're left in manual reversion, with only battery power and likely a very different outcome.

He started the APU immediately. He could have done that on many aircraft.

On the 777 and 787, the APU also starts automatically if both engines fail, in addition to the RAT automatically deploying.

If it had been a 777 or 787, Captain Sullenberger wouldn't have had to manually start the APU immediately. It would have done so automatically.


User currently offlinebarney captain From United States of America, joined Nov 2001, 970 posts, RR: 13
Reply 96, posted (1 year 4 months 2 weeks 1 day 12 hours ago) and read 5658 times:

Quoting BoeingGuy (Reply 95):
On the 777 and 787, the APU also starts automatically if both engines fail, in addition to the RAT automatically deploying.

VERY cool. When we did this in the 737NG sim, it was a handful. Assuming the first thing you did was reach for the APU, the start-up time is in excess of 2 minutes - an eternity in that situation.



...from the Banana Republic....
User currently offlinePihero From France, joined Jan 2005, 4597 posts, RR: 77
Reply 97, posted (1 year 4 months 2 weeks 1 day 12 hours ago) and read 5660 times:
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Quoting BoeingGuy (Reply 95):
If it had been a 777 or 787, Captain Sullenberger wouldn't have had to manually start the APU immediately. It would have done so automatically.

I think you're incorrect : The engines were running but not delivering a significant amount of thrust. It's only after they tried a relight on both that they coudn't recover # 1.
The APU would not have started automatically.

Quoting rcair1 (Reply 92):
I'll have to go back and see if I can find what the issue was. I know I read a discussion where he could not achieve the ideal angle.

I beg your pardon : They were in Alpha Protection mode for airspeeds significantly below Vls.



Contrail designer
User currently offlineBoeingGuy From United States of America, joined Dec 2010, 3157 posts, RR: 7
Reply 98, posted (1 year 4 months 2 weeks 1 day 10 hours ago) and read 5633 times:

Quoting Pihero (Reply 97):
Quoting BoeingGuy (Reply 95):
If it had been a 777 or 787, Captain Sullenberger wouldn't have had to manually start the APU immediately. It would have done so automatically.

I think you're incorrect : The engines were running but not delivering a significant amount of thrust. It's only after they tried a relight on both that they coudn't recover # 1.
The APU would not have started automatically.

I'm certainly not incorrect about what I stated about the 777 and 787 APUs starting automatically if both engines fail. I may have been incorrect in my interpretation of what happened in the US Air event. I had thought both engines did eventually fail, hence my previous comment.


User currently offlineairmagnac From Germany, joined Apr 2012, 316 posts, RR: 52
Reply 99, posted (1 year 4 months 2 weeks 1 day 10 hours ago) and read 5636 times:

Quoting Klaus (Reply 94):
The question is whether the cross-coupling of the sidesticks would have changed anything about the total confusion of both pilots, despite instruments correctly showing rapid descent with a nose-up attitude at full power. What information could a mechanical sidestick linkage really have provided which wasn't already apparent anyway?

Probably none.
If you look closely at the first 30s of the voice recording, when the aircraft was still inside its envelope, and therefore flyable :
- at first the PNF apparently is looking at ECAM exclusively (he makes several observations on ECAM messages)

- 2 h 10 min 27,0 : he looks up, notices something wrong and calls out fais attention à ta vitesse (watch your speeds). He repeats the call a second later as he can see no change.

- 2h 10 min 30 : PF answers and pushes the stick forward. PNF observes this and simultaneously encourages his colleague, or coments : tu stabilises (stabilise/you're stablising)
note : the english transcript indicates an order, but I think it might also be an observation. Due to the familiar form of grammar used, it might be hard to tell, even by listening to the voices, unless the tone was very imperative

- 2 h 10 min 31,2 : PNF orders/comments the situation once again : tu redescends

- 2 h 10 min 32,2 : PF has pulled back on the stick again, probably in reaction to the FD moving towards the "go up" position. PNF observes this and corrects his colleague with a justification : on est en train de monter
selon lui
(this one says we're climbing)

-2 h 10 min 33,7 : PF again pulls back on the stick, this time probably in reaction to the speed reappearing on the PFD. PNF again notices and corrects his colleague again, this time with a reinforced justification : selon les trois tu montes, donc tu redescends (the 3 say that you're climbing, so go back down)


This sequence clearly shows that the PNF was perfectly capable of observing what his colleague was doing. Either by reading the PFD information or by noticing the movements of hus colleague's arm, he was fully aware of what was going on, and reacted to that information.

Actually, the issue is much deeper : just compare the quantity of vocal exchanges in those first 30s compared to the next minute. Strangely, both pilots become very quiet after 2'10'41". I'd even say passive. Even when they actually stall and the stick is pulled back again. Afterwards, the PNF remains mostly silent, and the few things he says are mostly to repeat something the Captain had just said. It's very strange.

Why both pilots remain so strangely passive is the question...And without an answer, it is hard to say if the PNF would have reacted or not to a tactile cue.
It seems to me he was "incapacitated" for some reason (psychological ? physiological ?), and probably would not have reacted. And that would undermine the argument that he **certainly** would have reacted to a yoke moving against his belly.

Quoting Klaus (Reply 94):
And another critical issue is that one cannot just make design changes which retroactively maybe could have prevented one specific accident without also considering how many actually marginal or even uneventful other situations might have been turned into fatal accidents by that same change.

        
Indeed. With these integrated avionics, there is a non-negligeable chance that a modification will break more things than it fixes. I think there was once a close-call with an A320 in Bilbao, which was partly due to an unintended consequence of a flight control software change, which was of course supposed to correct something in the first place.



Quoting Starlionblue (Reply 90):

I believe that the Airbus FBW myths are due to a number of combined factors, including in no particular order : Airbus being the underdog at the time ; nationalistic BS (including intra-european stuff) ; the violent conflicts over 2- or 3 crewmembers which probably spilled over onto the Airbus FBW (even though it's a seperate topic) ; a slight lack of pedagogy and diplomacy from Bernard Ziegler ; and the natural distrust we humans have for software, and more generally for anything immaterial.

But I think the main issue is that flight controls is a much much more complex topic tham most people realize. After reading many posts on many forums, I believe few people think of how complex mechanical controls were. I see lots of talk about "the simple good ol' cables-and-pulleys", but few mention the designs of mechanical yaw dampers, stick shakers, stick pushers, Mach trim, artifical feedback, and all those other neat gizmos (respect due to the engineers of the time, BTW   ) .Reading Handling the Big Jets is really interesting in this regard.

As a result, I often read about how "complicated" the Airbus system is, whereas in reality it just transformed all those incredibly complicated mechanical devices into lines of code, which really simplifies the whole setup. Of course, Airbus than added some more code, but it's not really that complicated  

The other thing is that flight controls call on very abstract concepts of control theory, communications, and human/machine interfaces. I am the first to admit that my posts in this thread are impossibly abstract. To tell you the truth, after writing them, I decided to arrange all my thoughts on paper...I started over twice already, because I couldn't adequately structure all the ideas. And now my third draft is 21 pages long and I've hardly written the third of what I want to say ! 



One "oh shit" can erase a thousand "attaboys".
User currently offlineStarlionblue From Greenland, joined Feb 2004, 17068 posts, RR: 66
Reply 100, posted (1 year 4 months 2 weeks 1 day 9 hours ago) and read 5624 times:

Quoting airmagnac (Reply 99):
But I think the main issue is that flight controls is a much much more complex topic tham most people realize. After reading many posts on many forums, I believe few people think of how complex mechanical controls were. I see lots of talk about "the simple good ol' cables-and-pulleys", but few mention the designs of mechanical yaw dampers, stick shakers, stick pushers, Mach trim, artifical feedback, and all those other neat gizmos (respect due to the engineers of the time, BTW   ) .Reading Handling the Big Jets is really interesting in this regard.

You said it. When I read Handing the Big Jets I had that same realization. Look at all that immense mechanical complexity in, say, a 747-100. Now a Mach Trimmer is just a software routine. So much more resilient and flexible.



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlinePihero From France, joined Jan 2005, 4597 posts, RR: 77
Reply 101, posted (1 year 4 months 2 weeks 1 day 1 hour ago) and read 5574 times:
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Quoting BoeingGuy (Reply 98):
I had thought both engines did eventually fail, hence my previous comment

...and subsequently mine : Had it been a 777 or a 787, the APU would not - repeat NOT - have started automatically, because both engines were still running.

[Edited 2013-06-10 23:37:07]


Contrail designer
User currently offlineBoeingGuy From United States of America, joined Dec 2010, 3157 posts, RR: 7
Reply 102, posted (1 year 4 months 2 weeks 17 hours ago) and read 5539 times:

Quoting Pihero (Reply 101):
Quoting BoeingGuy (Reply 98):
I had thought both engines did eventually fail, hence my previous comment

...and subsequently mine : Had it been a 777 or a 787, the APU would not - repeat NOT - have started automatically, because both engines were still running.

I am fully aware of that. I stated that.

I'm well familiar with how that feature works on the 777 and 787. I was stating that I mis-understood what happened on Sully's airplane, not that I don't understand how the 777 and 787 work.


User currently offlinercair1 From United States of America, joined Oct 2009, 1327 posts, RR: 52
Reply 103, posted (1 year 4 months 2 weeks 5 hours ago) and read 5448 times:
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Quoting Klaus (Reply 94):
Is there really any modern aircraft with manual engine control reversion, overriding the FADECs?

No - I wasn't stating there was. I was offering the hypothesis that others had postulated that it may have made a difference. As I said - I think the general consensus was it would not have.

Quoting Klaus (Reply 94):
You would still not have any feedback from the aircraft systems, only force coupling between the two pilots.

And for that you would introduce a lot of mechanical complexity with corresponding failure risks.

Not really - servo's could do it. Boeing does it in every aircraft.
There are really two issues - simple coupling so you "feel" the input from the other side stick and haptic feedback, which is a simulated feedback intended to convey what you would have felt with manually coupled controls. You can consider these differently.

For instance, backdrive on throttles. Boeing does, Airbus does not. That is not haptic feedback, it is backdrive. Haptic is much more complex.



rcair1
User currently offlinePihero From France, joined Jan 2005, 4597 posts, RR: 77
Reply 104, posted (1 year 4 months 1 week 6 days 21 hours ago) and read 5413 times:
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About *Haptic Feedback* :
It is just science jargon that exactly describes what we call *Tactile Feedback*, i.e. related to the sense of touch.

- Haptic Feedback is a fallacy right from the beginning of air transport, and even before :
What is the first thing a pilot does on manual flying ?.. Trim out his effort on the flight controls, which means, as a matter of fact, cancelling out the reactions of airplane control surfaces, leaving only the *feel* of the aircraft reactions to the command.

- Haptic feedback is a misinterpretation:
As rcair wrote, it is often confused with *backdrive*

- Haptic feedback can be misleading :
Previous generation airplanes in their majority had some degree of spiral instability : on a 30° right bank – for instance- one’s control wheel could well be inclined 30° to the left. (the 743 was in this respect the worst of the jets ). This is the case for all gliders, the purest form of flying in existence. Pilots have coped with this characteristic for decades, and once again, the most important aspect of piloting is about how the airplane reacts to a command, and certainly not on the return of the control surfaces. It is not reliable.

- Haptic feedback is a gross misunderstanding of C* laws :
On all ‘Buses – and in a slightly different manner on the 777 – the same stick angle will give you the same airplane reaction, be it roll rate or pitch G-demand. The result is that one is in fact piloting a trajectory and not a control surface angle. The increasing efforts one exerts on the stick are enough indicators of the desired command. A sidestick is in no way comparable to any game joystick.

- Haptic feedback is undesirable
… or is a a trick : The example is about increased forces with speed : That went to the point where control column and wheel were as if stuck in concrete, so great were the aerodynamic forces : to manoeuvre a DC-4 above 180 kt required quite a bit of muscle… why trying to reproduce that effort ? And was it really necessary to remain - piloting –wise – stuck in the Ford Trimotor era ?

- Haptic feedback is best given by one’s fundament
One should not care what the control surfaces are doing, the most important is where you intend to go.
As a matter of fact, it is not very different from, in one’s car, braking to exit a motorway : there’s no return from the brake pedal, one just adjusts one’s foot pressure in order to achieve a deceleration to the safe speed required for the slipway transition… the same applies to one’s speed control : you’re not going to observe your throttle pedal, you just feel the engine revving up or down – and observe the RPM indicator… It’s the least you can do.

- Haptic feedback as an induced intellectual dishonesty :
This discussion has always been to me annoying as it is in fact a trial against Airbus, more often than not borne by a total lack of knowledge both of the *philosophy* and the actual realization of the design.
There have been for many years flight control devices that have been totally invisible to the pilots.
An exhaustive list :
• The yaw damper
• The gust alleviation systems
• The Mach trim
• The anti-skid
• The rudder travel limiter
• The nose wheel angle limiter
• The CWS, used most of the time on *manual* flying of the DC-10
• The flap load relief system… and more recently :
• The TAC on the 777, an automatic yaw control of an engine failure
• The tail-strike protection…
…and nobody mentions them in this discussion. Where is the tactile feedback these devices provide the pilots with?

- The case of the moving throttles.
People forget that there are situations – bar a backdrive failure – where the throttles are fixed : TOGA and IDLE… In these, the FADEC automatically alters the engines output without any crew intervention : changing outside parameters – OAT, local pressure…- or changed configurations – anti-icing, bleed requirements…-In these cases and I daresay critical phases of the flight, an engine (mis) behavior is invisible via the throttle position. There are also cases of more insidious loss of engine thrust control that could well be hidden by the backdriven throttle movements.
The FCTM says :
“Failure of engine or fuel control system components or loss of thrust lever position feedback has caused loss of engine thrust control. Control loss may not be immediately evident since many engines fail to some fixed RPM or thrust lever condition. This fixed RPM or thrust lever condition may be very near the commanded thrust level and therefore difficult to recognize until the flight crew attempts to change thrust with the thrust lever…”

… and we’re back to rcair’s statement : “don’t confuse haptic feedback with backdrive and visual cues.”
I posit that the best indicator of an engine behavior is the ECAM / EICAS indications.
Pïlots transitioning on the ‘Bus learn it very quickly : Commands – either pilot or A/THR generated- are displayed on the N1 /EPR gauge, along with the actual output : One is at all times informed of the engine behavior. It is a *visual* cue that beats the observation of the throttle movements at any time.
And finally,

- The case of the linked sticks.
As I am interested in the airplane attitude and our trajectory, it’s a false problem : my *haptic* fundamental cue, my view of the overall geometry of my trajectory – with the help of the FPV- are enough for me to determine whether my colleague is doing fine or not. In fact, the only time I would look at the other sidestick is when I suspect that what I perceive as” light chop” is not in fact PIO. Then a verbal correction is sufficient.
There was, finally the case of an LH A320 with a cross-wired ( for want of a better term ) captain’s sidestick… Had both sticks been linked, we would have needed a thorough accident investigation on the wreckage of that airplane. As it happened, the first officer just took over, locked his captain’s sidestick out through the priority button , RTB’d and landed without any further incident.

This system takes my vote any time.



Contrail designer
User currently offlineKlaus From Germany, joined Jul 2001, 21486 posts, RR: 53
Reply 105, posted (1 year 4 months 1 week 6 days 19 hours ago) and read 5402 times:

Quoting airmagnac (Reply 99):
This sequence clearly shows that the PNF was perfectly capable of observing what his colleague was doing. Either by reading the PFD information or by noticing the movements of hus colleague's arm, he was fully aware of what was going on, and reacted to that information.

Good points.

Quoting airmagnac (Reply 99):
Why both pilots remain so strangely passive is the question...And without an answer, it is hard to say if the PNF would have reacted or not to a tactile cue.
It seems to me he was "incapacitated" for some reason (psychological ? physiological ?), and probably would not have reacted. And that would undermine the argument that he **certainly** would have reacted to a yoke moving against his belly.

It seems as if both pilots' situational awareness derailed and disconnected when their recognition patterns failed to cope with the combinations of temporarily unreliable airspeed due to pitot icing initially, the onset of the stall and then the unreliable airspeed due to their deepening stall – and they were so far outside of their accustomed control/response loop that they did not find their way back into sync.

When I'm driving a car, I usually keep a marginal awareness alive of emergency situations which could plausibly arise, connected with an anticipation of sensible reactions to get out of those situations again. I can't be certain, but it seems the AF447 pilots at least in that situation had no such "border of the envelope" awareness, at least not at that time, which could have helped them to recognize the situation and to act accordingly.

Quoting airmagnac (Reply 99):
The other thing is that flight controls call on very abstract concepts of control theory, communications, and human/machine interfaces. I am the first to admit that my posts in this thread are impossibly abstract. To tell you the truth, after writing them, I decided to arrange all my thoughts on paper...I started over twice already, because I couldn't adequately structure all the ideas. And now my third draft is 21 pages long and I've hardly written the third of what I want to say !

The conceptual side of it is particularly interesting for me, and I do appreciate your posts in that direction! 
Quoting rcair1 (Reply 103):
Quoting Klaus (Reply 94):
Is there really any modern aircraft with manual engine control reversion, overriding the FADECs?

No - I wasn't stating there was.

Okay; I was really curious about that point.

Quoting rcair1 (Reply 103):
Not really - servo's could do it. Boeing does it in every aircraft.
There are really two issues - simple coupling so you "feel" the input from the other side stick and haptic feedback, which is a simulated feedback intended to convey what you would have felt with manually coupled controls. You can consider these differently.

The Airbus sidesticks and throttles are mechanically extremely simplified with the absolute minimum of mechanical complexity possible – there's simply nothing but just the bare sticks and levers with electronic position sensors. That's it.

I would expect the Boeing implementation to be at least an order of magnitude more complex, with all the additional pulleys, rods, clutches, mechanical failsafes, the backdrive servos and so on. The list gets quite long when you really think it through. None of that exists in a modern Airbus.

Quoting Pihero (Reply 104):
As I am interested in the airplane attitude and our trajectory, it’s a false problem : my *haptic* fundamental cue, my view of the overall geometry of my trajectory – with the help of the FPV- are enough for me to determine whether my colleague is doing fine or not. In fact, the only time I would look at the other sidestick is when I suspect that what I perceive as” light chop” is not in fact PIO. Then a verbal correction is sufficient.

It is probably still a valid argument that in complex situations as on AF447 such cues can be difficult to discern.


User currently offlineBoeingGuy From United States of America, joined Dec 2010, 3157 posts, RR: 7
Reply 106, posted (1 year 4 months 1 week 6 days 16 hours ago) and read 5367 times:

Quoting Pihero (Reply 104):
There have been for many years flight control devices that have been totally invisible to the pilots.
An exhaustive list :
Quoting Pihero (Reply 104):
The flap load relief system… and more recently :
• The TAC on the 777, an automatic yaw control of an engine failure
Quoting Pihero (Reply 104):
Where is the tactile feedback these devices provide the pilots with?

That's not correct. On both the 777 and 787 TAC (Thrust Asymmetry Compensation) backdrives the rudder pedals and displays on the Rudder Trim Indicator. It is not invisible to the pilots. It gives a tactile and visual indication to the pilots.

Load Relief isn't invisible either. The flap position indication shows the revised flap position (e.g. if it is automatically retracted to flaps 20, say) and also annunciates "LOAD RELIEF" on the flap position indication on EICAS.

[Edited 2013-06-12 08:20:47]

User currently offlinePihero From France, joined Jan 2005, 4597 posts, RR: 77
Reply 107, posted (1 year 4 months 1 week 6 days 16 hours ago) and read 5362 times:
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Quoting BoeingGuy (Reply 106):
The flap position indication shows the revised flap position

... and that, of course is the Boeing / Airbus idea of a haptic feedback.  

(OK for the TAC, but only if one has one's feet on the pedals, which is not exactly the case all the time. ---> revert to fundamental feedback... the revised trimposition indicator is not - repeat not - haptic feedback )



Contrail designer
User currently offlineBoeingGuy From United States of America, joined Dec 2010, 3157 posts, RR: 7
Reply 108, posted (1 year 4 months 1 week 6 days 16 hours ago) and read 5359 times:

Quoting Pihero (Reply 107):
(OK for the TAC, but only if one has one's feet on the pedals, which is not exactly the case all the time. ---> revert to fundamental feedback... the revised trimposition indicator is not - repeat not - haptic feedback )

The 777 TAC only gets inputs from the engines and activates if there is a certain percentage assymetry between engine thrusts. The 787 is called ETAC ("Enhanced") and also gets an inertial input detecting if the airplane is actually yawing.

In fact, TAC/ETAC was intentionally designed not to compensate 100% of the asymmetry, so it doesn't completely mask the fact that, say, and engine failed during takeoff. It was intentionally designed to still allow a small amount of yaw so the pilots can still "feel" if an engine failed.


User currently offlineairmagnac From Germany, joined Apr 2012, 316 posts, RR: 52
Reply 109, posted (1 year 4 months 1 week 6 days 13 hours ago) and read 5332 times:

Quoting Klaus (Reply 105):
The Airbus sidesticks and throttles are mechanically extremely simplified with the absolute minimum of mechanical complexity possible - there's simply nothing but just the bare sticks and levers with electronic position sensors. That's it.

To be honest, it's not quite so black and white.
If you ever get to see one pulled outside of its usual emplacement in the cockpit, the sidestick is actually the tip of an impressive iceberg of redundant rods and springs, plus the transducers. The thing has to be reliable...
As Pihero said, it has nothing to do with a gaming joystick.
But on the whole you are probably correct.

Quoting Pihero (Reply 107):
only if one has one's feet on the pedals, which is not exactly the case all the time

Another point which we haven't really covered. Aural signals can come from any direction. Visual cues can come from a wide angle in front of us, and the visual sense can quickly be redirected towards a new target. But for tactile cues, one must be in direct contact with the feedback device. That really restricts the use cases. Or else the pilot must look out for different cues depending on his position in the cockpit, and therefore more or less on the flight phase, which introduces the risk of mode confusion.

When we're discussing coupled yokes, is it actually tactile feedback, or is it rather that the big column moving in front of the pilot is providing a visual cue ?

Quoting rcair1 (Reply 103):
That is not haptic feedback, it is backdrive. Haptic is much more complex.

Just a thought regarding the spring feedback in the sidestick.
The sidestick commands attitude change rates, and the EFCS calculates the corresponding flight control deflections. The exact relation between the two is rather complex (which is precisely the raison d'être of the control laws), but it is valid to state that the bigger the attitude rate, the closer the aircraft will be to its envelope.
IOW : small SS movement = small commanded attitude rate = good ; big SS movement = big commanded attitude rate = not so good. And that's precisely the information provided by the spring.
So why bother with sensors, computers, data communication and reliability & integrity headaches, if the information given is the same ?

Let's call the spring an "open-loop haptic feedback"  



One "oh shit" can erase a thousand "attaboys".
User currently offlinercair1 From United States of America, joined Oct 2009, 1327 posts, RR: 52
Reply 110, posted (1 year 4 months 1 week 6 days 11 hours ago) and read 5294 times:
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Quoting Pihero (Reply 104):
About *Haptic Feedback* :
It is just science jargon that exactly describes what we call *Tactile Feedback*, i.e. related to the sense of touch.

With all due respect Pihero - you characterization of Haptic feedback, while long and detailed is based on a flawed viewpoint in my opinion. You are correct that haptic feedback is about utilizing the sense of touch, or the feedback in the human muscular/nervous system. You are incorrect that the goal is to mimic some ancient behavior of a tri-motor. The idea is to utilize all the human senses to convey information. The basis is that information is useful - really that is a fundamental factor. Tell race car drivers they don't need to 'feel' the steering or brakes - they can simply look at a display on the dash to see if the tires are breaking loose.

Relying on only cognitive information presented visually is limiting. Just as this conversation is limited by the concept that you must read the text an infer much about my attitude. You will probably get it wrong compared to what you would get if we were having a conversation. A failure of my writing or your interpretation - take your pick.

Of course information presented by haptic feedback can be wrong - just as information presented by displays and instruments can be wrong. So don't fall into the trap that if it can be wrong it must useless.

This is a pointless argument - neither you nor I will impact system controls. What may some day is a finding that something caused a accident that drives a change. Change in aviation is slow - despite what some talking about pilotless a/c say.

-Bob



rcair1
User currently offlinePihero From France, joined Jan 2005, 4597 posts, RR: 77
Reply 111, posted (1 year 4 months 1 week 5 days 23 hours ago) and read 5215 times:
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Quoting rcair1 (Reply 110):
You are incorrect that the goal is to mimic some ancient behavior of a tri-motor. The idea is to utilize all the human senses to convey information.

Oh ! No ! Not my thinking at all ; just the argument of all the Airbus haters on this site.
I was just pointing at quite a few drawbacks on relying on that concept ... which, as you and Airmagnac correctly inferred, can be taken out of context and be misleading.

All the titled paragraphs on my previous post have only one intent : point at most of the *errors* or lack of understanding of what is at stake : efficient and safe piloting of an aircraft. Can be achieved in many ways... so why the aggressive antagonism against Airbus ? and only Airbus?

Having been a pilot for forty years or so, with a few thousand hours at the control of quite a few types, each one with its quirks and idiosyncracies, I daresay I am qualified to determine whether the tools given to me are safe and adequate for my needs in flying an airplane. As an example,I did not like the MD-82 flight controls and said so during an evaluation for a previous airline. The reason ? the flight controls were unbalanced and had a definite lag and inertia which came out of synch with the quick corrections commanded by the then modern ADIs.

In this respect, the A sidestick gives me everything I need to achieve a trajectory precision I've only dreamed of before I transitioned on the A320 twenty years ago : I feel the aircraft, I have a feeling of the way it responds to my commands, I always have the right input without the *action/correction/hesitation/action/hesitation/correction*... which used to be the way we piloted.

If I were wrong / biased / over-enthusiastic... the sidestick solution would have died twenty years ago.
That's patently not the case and Boeing is now in the situation of shortly being the only OEM with yokes.

Quoting rcair1 (Reply 110):
This is a pointless argument - neither you nor I will impact system controls.

An argument is never pointless between honest individuals. It is when one side has an agenda or a set of prejudices.
Here, it's about people clamouring the virtues of one design and the vices of the other.
The argument can go into actual dishonesty when as a matter of fact, haptic feedback is reduced or downright eliminated on the beloved product : TAC and ETAC do exactly that and so does an anti-tailstrike device.

And of course, the whole idea goes into the sewers in some critical conditions : An aircraft close to the stall feels - in all axes - mushy, controls are unusually light , right ? Tactile feedback should reflect that... right ?
Wrong. In these conditions, there are airplanes that get increased control forces so not only has the pilot a completely wrong tactile feedback, but his/her work is rendered more difficult by unnatural efforts on the control column... and yet, taking the example of flight 447, they claimed that a yoke could have saved the day. sarcastic 

Quoting rcair1 (Reply 110):
Relying on only cognitive information presented visually is limiting.

Of course it is. I have read many enough accident / incident reports to know that over-reliance on only one set of information does not solve a situation of jeopardy... unless one is the epitomical *born flyer*. That's what SA is about : gathering all the informations at one's disposal in order to build a picture as close as possible to the real situation.

It's eventually back to the discussion you diplomatically refer to : it's about ergonomics and about interfaces and man-machine interaction.

[Edited 2013-06-13 02:14:21]


Contrail designer
User currently offlineDavid L From United Kingdom, joined May 1999, 9524 posts, RR: 42
Reply 112, posted (1 year 4 months 1 week 5 days 22 hours ago) and read 5205 times:

Quoting rcair1 (Reply 110):
Tell race car drivers they don't need to 'feel' the steering or brakes - they can simply look at a display on the dash to see if the tires are breaking loose.

Should we really be comparing the flying of an airliner to racing a car in competition? The rules, objectives and risk acceptance are quite different. If you were to put Airbus-stye control systems into an aerobatic aircraft then I'd have a few questions.  


User currently offlinePihero From France, joined Jan 2005, 4597 posts, RR: 77
Reply 113, posted (1 year 4 months 1 week 5 days 20 hours ago) and read 5182 times:
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The sidestick :

Quoting airmagnac (Reply 109):
If you ever get to see one pulled outside of its usual emplacement in the cockpit, the sidestick is actually the tip of an impressive iceberg of redundant rods and springs, plus the transducers. The thing has to be reliable...
Here is one

Could a nice soul please insert this image in a post as I've lost my photobucket details ?



Contrail designer
User currently offlineKlaus From Germany, joined Jul 2001, 21486 posts, RR: 53
Reply 114, posted (1 year 4 months 1 week 5 days 17 hours ago) and read 5132 times:

This is another version of the schematic:



Apart from some mechanical redundancy and an extremely sturdy design, it's pretty much as simple as I'd have expected it to be.


User currently offlinehivue From United States of America, joined Feb 2013, 1097 posts, RR: 0
Reply 115, posted (1 year 4 months 1 week 5 days 6 hours ago) and read 5053 times:

Quoting airmagnac (Reply 99):
in reality it just transformed all those incredibly complicated mechanical devices into lines of code, which really simplifies the whole setup.
Quoting Starlionblue (Reply 100):
Now a Mach Trimmer is just a software routine. So much more resilient and flexible.

There was a wing tip flutter problem on the 747-8 that was damped by a clever software-only fix:
747-8 Wing Flutter Solution...the Engineer (by bhill Oct 24 2011 in Tech Ops)


User currently offlineeisenbach From Austria, joined Mar 2001, 116 posts, RR: 0
Reply 116, posted (1 year 4 months 1 week 11 hours ago) and read 4719 times:

I have to admit, that I was very sceptical how it would feel to fly an aeroplane with a sidestick, especially with my left ("wrong") hand. It is no problem to drive a car (steering wheel) with my left hand, but I would be not able to use a joystick on my computer with my left hand.

So some time ago a good friend of me (A320 pilot) invited me to the OS full flight simulator in VIE and I was surprised by my experiences I made there:

- It was not a problem at all to use my "wrong" hand to steer the plane at all!!!

- The steering felt very, very natural

- I don't think a "feedback" for the sidestick wouldn't be useful at Airbus, as this would not fit into the Airbus flying experience philosophy (you don't fight against the elements, you just command the plane what to do ... so no feedback necessary in my opinion)

- A stick shaker (stall warning) or a moving sidestick (so that you know what the other guy is doing) is in my opinion also not productive, as it would be more difficult to grab or control the sidestick in a critical situation.

- The thrust levers system was also very simple and intuitive to use. I liked the idea of the fixed thrust settings and also "hand flying" was easy. It is also very intuitive at a TOGA situation or if you need full thrust just to move the levers full forward and that you don't have to press buttons.

- The flight deck is also very ergonomic in my opinion, as you can move the side stick and the arm rest to your ideal position.

====

So, I have also a video of my first landing   with an A320.

http://www.youtube.com/watch?v=cT4B3BseEnQ

As you can see, when hand flying, you still need quiet a lot of inputs to the sidestick, as you have to adjust your directions and glide path during approach. But as I said before, all was very intuitive (I just pulled the stick to much after touchdown).

P.S. As I am no pilot, please consider this just as an opinion of a dummy user of the A320 flight deck   ... and don't flame me, that I didn't go through checklists and messed up the flap settings  



Do228, Saab340, Twin-Otter, C212, Fokker50, AN24, ATR42, ATR72, Dash8-400Q, MD90, MD83, EMB120, A300, A343, B721, B743,.
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