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davepoth
19,884 posts
68 months
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james_tigerwoods said: Lol above.
However - how many are there? Is there not a backup way of determining speed such as GPS? GPS doesn't really help - the number the pilots are really interested in is the speed of the air passing across the wings, which can be a lot different to the ground speed.
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fido
9,384 posts
124 months
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davepoth said: GPS doesn't really help - the number the pilots are really interested in is the speed of the air passing across the wings, which can be a lot different to the ground speed. Wouldn't it still be helpful to know? And you could estimate the wind speed from the ground speed. Clearly, if you could establish that your pitot wasn't working properly in the first place .. i'm just postulating.
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Apache
38,242 posts
153 months
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It is interesting to postulate, it's also interesting to consider how different the outcome could have been with mechanically linked flying controls or control columns, the 'playstation cockpit' that was alluded to earlier seems to have been little help in this case. I remember the old Victor K2s I worked on had artificial feel built in called Q Feel which gave a feedback proportional to the loads imposed on the controls....do modern, sidestick controlled aircraft not have something similar
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croyde
8,745 posts
99 months
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Someone posted a video on another thread showing an Airbus pilot on approach and I, along with many others, were amazed how the small joystick is waggled about with seemingly no reaction from the aircraft. I have held the control column of a small aircraft in flight once so I am no pilot but surely a mechanical system is better than all this fly by wire stuff.
I don't like power steering systems that distance you from the feel of the road which in some cars cases seem completely disconnected from the front wheels and I really don't like the idea of throttle by wire systems on some modern motorbikes.
I know I'm getting on but it just does not seem right.
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just me
5,904 posts
89 months
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croyde said: Someone posted a video on another thread showing an Airbus pilot on approach and I, along with many others, were amazed how the small joystick is waggled about with seemingly no reaction from the aircraft. I have held the control column of a small aircraft in flight once so I am no pilot but surely a mechanical system is better than all this fly by wire stuff.
I don't like power steering systems that distance you from the feel of the road which in some cars cases seem completely disconnected from the front wheels and I really don't like the idea of throttle by wire systems on some modern motorbikes.
I know I'm getting on but it just does not seem right. Yes, I don't like them either, in motorbikes, cars, or airplanes. There has to be a proportional force feedback mechanism built in. In this case, not sensing the stall, and not having the stall warning, was deadly.
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mrloudly
2,163 posts
104 months
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just me said: croyde said: Someone posted a video on another thread showing an Airbus pilot on approach and I, along with many others, were amazed how the small joystick is waggled about with seemingly no reaction from the aircraft. I have held the control column of a small aircraft in flight once so I am no pilot but surely a mechanical system is better than all this fly by wire stuff.
I don't like power steering systems that distance you from the feel of the road which in some cars cases seem completely disconnected from the front wheels and I really don't like the idea of throttle by wire systems on some modern motorbikes.
I know I'm getting on but it just does not seem right. Yes, I don't like them either, in motorbikes, cars, or airplanes. There has to be a proportional force feedback mechanism built in. In this case, not sensing the stall, and not having the stall warning, was deadly. Don't quite understand that with regards to cars and bikes? "Fly by wire" on cars and bikes still use a return spring on the throttle pedal/grip, the deflection of such is just digitised not expressed via a cable, so where's the difference?
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Apache
38,242 posts
153 months
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mrloudly said: Don't quite understand that with regards to cars and bikes? "Fly by wire" on cars and bikes still use a return spring on the throttle pedal/grip, the deflection of such is just digitised not expressed via a cable, so where's the difference? Have you not noticed how some modern cars seem to have a delay on the throttle so when you change up the revs seems to pause before they drop? annoys the s  t out of me, other examples seem to have a delay when you floor it
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mrloudly
2,163 posts
104 months
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To be fair, yes! The R8 is really bad whilst scaring Saxo drivers at traffic lights :-) Whilst on the move there is zero lag though. Even when "heel and toeing" can't notice it!
Do agree at standstill though, there is a weird disconnection between throttle and revs.
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davepoth
19,884 posts
68 months
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croyde said: Someone posted a video on another thread showing an Airbus pilot on approach and I, along with many others, were amazed how the small joystick is waggled about with seemingly no reaction from the aircraft. I have held the control column of a small aircraft in flight once so I am no pilot but surely a mechanical system is better than all this fly by wire stuff.
I don't like power steering systems that distance you from the feel of the road which in some cars cases seem completely disconnected from the front wheels and I really don't like the idea of throttle by wire systems on some modern motorbikes.
I know I'm getting on but it just does not seem right. When it works properly FBW is brilliant - no matter what you do to the controls the plane will effectively refuse to fall out of the sky if you ask it to. Unfortunately the "what if it breaks?" question hadn't been thought through all the way to this conclusion.
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Ian Lancs
564 posts
35 months
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davepoth said: croyde said: Someone posted a video on another thread showing an Airbus pilot on approach and I, along with many others, were amazed how the small joystick is waggled about with seemingly no reaction from the aircraft. I have held the control column of a small aircraft in flight once so I am no pilot but surely a mechanical system is better than all this fly by wire stuff.
I don't like power steering systems that distance you from the feel of the road which in some cars cases seem completely disconnected from the front wheels and I really don't like the idea of throttle by wire systems on some modern motorbikes.
I know I'm getting on but it just does not seem right. When it works properly FBW is brilliant - no matter what you do to the controls the plane will effectively refuse to fall out of the sky if you ask it to. Unfortunately the "what if it breaks?" question hadn't been thought through all the way to this conclusion. I disagree - the FBW did exactly what it was designed to do. It wasn't designed to have two pilots making polar opposite inputs!
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Chuck328
510 posts
36 months
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Some of you on here have a complete failure to grasp just what fly by wire is....
Garbage in garbage out. Heard of the saying before?
FBW is simply a step up from mechanical to add an extra element of protection. Is it perfect? Course not.
It does however do its job very well when the inputs are correct. It's just a computer using algorithms, logic circuits and what ever else to drive it. When data collection to it becomes corrupted, it realises this, tells you it can no longer make sense of anything and throws it out. This is what happened to AF442.
It then falls to the human to analyse an diagnose the problem and action the corrective response. Tragically in this case BOTH humans failed to do this, for what ever reason the analytical side of their brains came to a grinding halt.
Had that aircraft been an A310 or B767 with results may have been exactly the same. Fail to deal with unreliable airspeed correctly and go hauling back on the stick. STALL STALL STALL.
If I could change one element here, it would be to make the side sticks vibrate ( no jokes here lol) like a stick shaker on a conventional control column. Hearing is often the first thing that goes when the brain is under extreme stress/concentration. Perhaps that might have helped with the diagnosis with what was really going on....
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davepoth
19,884 posts
68 months
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Ian Lancs said: I disagree - the FBW did exactly what it was designed to do. It wasn't designed to have two pilots making polar opposite inputs! Nope, the FBW was in "alternate rule" and therefore not functioning properly. Had the pitot head been functioning and providing the airspeed information the plane would not have not allowed the stall.
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just me
5,904 posts
89 months
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Ian Lancs said: I disagree - the FBW did exactly what it was designed to do. It wasn't designed to have two pilots making polar opposite inputs! That's the point, the designers should have foreseen this as one of many possible human error cases, and established a protocol that would allow the system to deal with it without compromising safety.
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Apache
38,242 posts
153 months
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What FBW was designed to do originally was to allow an aircraft to perform in a way that a human couldn't control alone. The guy whose seminar I attended in Bristol Uni was from BAe and described it perfectly. Imagine your AC is a broom handle, to move it around conventionally you hold it at the top, it is balanced by it's inertia, you move your hand to change position and it follows, sluggishly due to it's inertia. Now balance it in the palm of your hand, it is unbalanced, and you have to make many corrections to keep it balanced, but you can move it far faster. This is what FBW was designed for.
Its use in commercial jets is probably because of something far more basic, cost.
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Ian Lancs
564 posts
35 months
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Apache said: What FBW was designed to do originally was to allow an aircraft to perform in a way that a human couldn't control alone. The guy whose seminar I attended in Bristol Uni was from BAe and described it perfectly. Imagine your AC is a broom handle, to move it around conventionally you hold it at the top, it is balanced by it's inertia, you move your hand to change position and it follows, sluggishly due to it's inertia. Now balance it in the palm of your hand, it is unbalanced, and you have to make many corrections to keep it balanced, but you can move it far faster. This is what FBW was designed for.
Its use in commercial jets is probably because of something far more basic, cost. Out of curiosity, can you remember who that was - someone from Jaguar FBW / EAP by any chance?
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Apache
38,242 posts
153 months
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Ian Lancs said: Apache said: What FBW was designed to do originally was to allow an aircraft to perform in a way that a human couldn't control alone. The guy whose seminar I attended in Bristol Uni was from BAe and described it perfectly. Imagine your AC is a broom handle, to move it around conventionally you hold it at the top, it is balanced by it's inertia, you move your hand to change position and it follows, sluggishly due to it's inertia. Now balance it in the palm of your hand, it is unbalanced, and you have to make many corrections to keep it balanced, but you can move it far faster. This is what FBW was designed for.
Its use in commercial jets is probably because of something far more basic, cost. Out of curiosity, can you remember who that was - someone from Jaguar FBW / EAP by any chance? Could have been, it was around 90/91, course was called active flying control technology
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mrloudly
2,163 posts
104 months
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just me said: Ian Lancs said: I disagree - the FBW did exactly what it was designed to do. It wasn't designed to have two pilots making polar opposite inputs! That's the point, the designers should have foreseen this as one of many possible human error cases, and established a protocol that would allow the system to deal with it without compromising safety. My point above... Then I seem to remember an Airbus planting itself in trees because the computer decided it was landing.... There has to be a happy medium somewhere though...
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davepoth
19,884 posts
68 months
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mrloudly said: My point above... Then I seem to remember an Airbus planting itself in trees because the computer decided it was landing.... There has to be a happy medium somewhere though... That was the very first one in service IIRC - The pilot had not really done much flying with FBW and FADEC, and thought he could get away with flying low, and then pulling up in a bit of a zoom climb while ramming the throttles wide open so they'd spool up well before he stalled. What actually happened was that he came along a runway that had taller trees at the end of it, went lower and slower than he was aiming for, and then the FBW decided that he didn't have enough speed for the zoom climb and stopped him from pulling up until the engines had spooled. Which didn't happen because he crashed first. All the FBW in the world won't stop a CFIT.
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moles
600 posts
113 months
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Anyone see the ch4 program on tonight?.
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schmalex
Original Poster
8,660 posts
75 months
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Had to record it as the TV got commandeered for X Factor and Downton Abbey 
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