How safe is (airbus) fly by wire? Airbus A330/340 and A320 family emergency AD
Dozy,
You say that, contrary to my post, "BZ would not have been responsible for implementation details such as whether to interconnect controls or not - that would have fallen to the aeronautical and pilot engineering teams to hash out."
To indulge in thread drift: whom do you have in mind?
Around 1986, when we were discussing the feature in study groups, we were told informally that it had been insisted on by BZ. After all, he was the senior vice-president for engineering around that time, and we understood he was in charge of the FBW project. He was himself an experienced test pilot, and former chief test pilot of Airbus.
Gordon Corps joined AI in 1982 as an engineering test pilot, with special responsibility for flying qualities. No doubt he would have expressed an opinion on all these matters, but presumably his remit would have extended only as far as advising the handling properties, and the requirements for type certification. Subject to that, major decisions on systems design would rest with the engineers, IMHO.
You say that, contrary to my post, "BZ would not have been responsible for implementation details such as whether to interconnect controls or not - that would have fallen to the aeronautical and pilot engineering teams to hash out."
To indulge in thread drift: whom do you have in mind?
Around 1986, when we were discussing the feature in study groups, we were told informally that it had been insisted on by BZ. After all, he was the senior vice-president for engineering around that time, and we understood he was in charge of the FBW project. He was himself an experienced test pilot, and former chief test pilot of Airbus.
Gordon Corps joined AI in 1982 as an engineering test pilot, with special responsibility for flying qualities. No doubt he would have expressed an opinion on all these matters, but presumably his remit would have extended only as far as advising the handling properties, and the requirements for type certification. Subject to that, major decisions on systems design would rest with the engineers, IMHO.
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from TP:
For my part definitely anti-lack of connection. A sidestick is the modern way of guiding an airliner, permitting a table! But it needs to have a backdrive.
from CS:
Is a visual “on instrument” procurement of your fellow’s input, as propagated and necessary on the Bus, accurate and quick enough?? This extensively used argument is futile, don’t you see? I have always said that I don’t ask for a precisely duplicated input, I simply need the tactile presence and direction. Any rumble-stick of the next door game shop does the job, and with almost no weight and cost penalty.
So you call 1000 T7s a minuscule fleet, statistically not worthy of standing up to the Bus FBW fleet? Who has a jaundiced view of how statistics work?
from CG:
Would be great, wouldn’t it? 
Out of interest are you anti side-stick or just anti-the lack of interconnection?
from CS:
Could a sidestick system work in both directions, and would it be accurate enough and quick enough?
but the Boeing FBW fleet is still miniscule in comparison with Airbus’s
from CG:
The 1 or 2 people polarising this debate are non pilots who do have parochial views and I think most people would prefer if they were given minimal time and the professional pilots here continue with their interesting and informative discussions.
Last edited by Gretchenfrage; 3rd Jan 2013 at 04:08.
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@Gretchenfrage:
1000 T7s is not a minuscule fleet but only 12,6% of total boeing FWB and airbii FBW combined.
A350 will have a 'rumble-stick' in case of dual input.
Any rumble-stick of the next door game shop does the job
Last edited by A33Zab; 3rd Jan 2013 at 09:37.
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1000 T7s is not a minuscule fleet but only 12,6% of total boeing FWB and airbii FBW combined.
When it concerns losing life, the percentages no longer matter, at least to me. Such numbers are certainly NOT minuscule in terms of casualties.
Concerning the rumble stick, it's not exactly what i'd like, but i have to admit it's a start! But only a very, very small step. It needs more.
Last edited by Gretchenfrage; 3rd Jan 2013 at 13:35.
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Bet it cost more to implement and certify for civil aviation use than a trip to the Toulouse branch of "Game" though! 
GF - you seem puzzled as to why they're not doing everything you ask. Last I heard you didn't work for Airbus engineering, so I'm at a loss as to understanding why. Interconnection is not objectively better no matter how much you and others claim it to be so.
Statistical comparisons of the sort you're making are fairly meaningless - the only way to make it so would be to build exactly the same number of T7s as A330s, have them flown by the same airlines on the same routes, with the same pilots trained to the same standards and have the flying conditions be exactly the same for each of the flights. If you wanted to be really accurate you'd also need a control group of the same number of, say, 767s and A300s (non-FBW types) flown in the same manner. Real-world conditions however would make such experiments practically impossible.
GF - you seem puzzled as to why they're not doing everything you ask. Last I heard you didn't work for Airbus engineering, so I'm at a loss as to understanding why. Interconnection is not objectively better no matter how much you and others claim it to be so.
Statistical comparisons of the sort you're making are fairly meaningless - the only way to make it so would be to build exactly the same number of T7s as A330s, have them flown by the same airlines on the same routes, with the same pilots trained to the same standards and have the flying conditions be exactly the same for each of the flights. If you wanted to be really accurate you'd also need a control group of the same number of, say, 767s and A300s (non-FBW types) flown in the same manner. Real-world conditions however would make such experiments practically impossible.
Last edited by DozyWannabe; 3rd Jan 2013 at 15:50.
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Agreed, but in what group would you rather be: in the 12% with no casualties or in the rest with more than 200 perished?
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From a previous post, and relative to "statistics".
There are conditions in any complex system that may possess glaringly deficient process, or architecture.
Someone told me once to never believe an engineer who works on his own.
Reason? They work from spec. The format is narrow, and any peripheral vision is considered heresy.
I do not necessarily like working in groups, but I will defer in this thread to the pilot group.
ciao
There are conditions in any complex system that may possess glaringly deficient process, or architecture.
Someone told me once to never believe an engineer who works on his own.
Reason? They work from spec. The format is narrow, and any peripheral vision is considered heresy.
I do not necessarily like working in groups, but I will defer in this thread to the pilot group.
ciao
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What of the pilot engineering group? Also note that there is a distinct difference of opinion within the piloting group itself.
EDIT : And there was never a case in the A320 project, or the experiments that preceded it of an engineer working on his or her own - the teams were large, specialised and picked from the best the European aviation industry had to offer. The information I have suggests that BZ's engineering title was more of an honorific, in the same manner as Bill Gates' was after he stepped down as Microsoft CEO.
EDIT : And there was never a case in the A320 project, or the experiments that preceded it of an engineer working on his or her own - the teams were large, specialised and picked from the best the European aviation industry had to offer. The information I have suggests that BZ's engineering title was more of an honorific, in the same manner as Bill Gates' was after he stepped down as Microsoft CEO.
Last edited by DozyWannabe; 3rd Jan 2013 at 16:34.
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I think isolating sidesticks from view and from feedback, PLUS NO Connectivity, is a terrible idea.
Proposal: Captain, in left seat, operates his SS with right hand. F/O operates his SS with his left hand. The sticks are located on the console, the throttles on the fuselage wall, where the sticks are now.
No connectivity, no Feedback, improved "cooperative visuals" only.
No conclusions. Not yet.
Discuss?
"Climb, then!" ..... "(
), But I have hald aft stick for some time now!"
Woops.......
Proposal: Captain, in left seat, operates his SS with right hand. F/O operates his SS with his left hand. The sticks are located on the console, the throttles on the fuselage wall, where the sticks are now.
No connectivity, no Feedback, improved "cooperative visuals" only.
No conclusions. Not yet.
Discuss?
"Climb, then!" ..... "(
), But I have hald aft stick for some time now!"Woops.......
Last edited by Lyman; 3rd Jan 2013 at 16:39.
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GF - you seem puzzled as to why they're not doing everything you ask.
Last I heard you didn't work for Airbus engineering, so I'm at a loss as to understanding why
So one has to work for Airbus to be allowed to question its design?
By the same reasoning I could say one has to be qualified to operate both systems before being allowed to participate in this discussion, what I never did.
Interconnection is not objectively better no matter how much you and others claim it to be so.
Statistical comparisons of the sort you're making are fairly meaningless.
Some professionals pretend its coincidence, others say its due to better design.
It all runs down to that. Most intelligent professionals do not very much accept coicidence as explanation when it runs down to safety.
Thats more like NG sensational air disaster journalism.
Last edited by Gretchenfrage; 3rd Jan 2013 at 16:39.
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@Lyman - To what benefit? In airliner operation the PNF/PM is supposed to be monitoring the aircraft, not the other pilot.
I want to know why you think such a proposal would be an improvement and to understand your reasoning - a reasonable request, no?
Says who? Certainly not me.
Using the same flawed method to derive conclusions from statistics, one could have argued that the B747 was less safe than the L-1011 and DC-10 by the end of the '70s, yet nobody argued that. Why the rush to do so here?
I want to know why you think such a proposal would be an improvement and to understand your reasoning - a reasonable request, no?
Preposterous! At this very moment, the statistics speak a clear language: system 1 - no victims, system 2 more than 200. Twist it as much as you want, decry the one as much as you can, a zero is a zero.
Last edited by DozyWannabe; 3rd Jan 2013 at 16:43.
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No worse ignorance exists, than rejection prior to investigation...
Perhaps acceptance without question?
Example. A friend was signing off a tail wheel endorsement for her student. She sat in back of the Citabria, the student in front. Citabria has foot operated brakes in front only. Instructor has none. They landed, and the student applied brakes, instructor said "get off the brakes, get off". She had to endure the aircraft rolling over on to its top because she could not prevent her student from screwing things up.....
Bonin was pulling the whole time, even when Robert says: "you climb, GO DOWN"..... Captain DuBois says: "Eh,CLIMB!!". Bonin says... "I have been..."
Well then. We evolve... Sometimes being stubborn can kill, or trash a Citabria.
Perhaps acceptance without question?
Example. A friend was signing off a tail wheel endorsement for her student. She sat in back of the Citabria, the student in front. Citabria has foot operated brakes in front only. Instructor has none. They landed, and the student applied brakes, instructor said "get off the brakes, get off". She had to endure the aircraft rolling over on to its top because she could not prevent her student from screwing things up.....
Bonin was pulling the whole time, even when Robert says: "you climb, GO DOWN"..... Captain DuBois says: "Eh,CLIMB!!". Bonin says... "I have been..."
Well then. We evolve... Sometimes being stubborn can kill, or trash a Citabria.
Last edited by Lyman; 3rd Jan 2013 at 16:55.
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I'm not rejecting anything, I just want to know why you think such a setup would be better. If you're going to do nothing but put words in my mouth then I have nothing more to say on the matter.
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None of what we're discussing here is going to change anything in terms of how any manufacturer implements their PFCs - but that aside what we're talking about is the relative usefulness of being able to feel precisely what one's opposite number is doing.
In modern airliner operations where there is no direct connection between PFC and flight surface and with technology that is reliable enough to make this possible, and given that only one person is ever supposed to be PF at any given time - what is the benefit?
A "rumble" tactile feedback system to warn of dual input seems a fair compromise to me.
There was plenty of indication of what the PF was up to on the ADI early in the sequence (and plenty of evidence on the CVR to suggest that the PNF wasn't happy about it) - why the PNF hesitated in taking control is a matter for the HF experts.
In modern airliner operations where there is no direct connection between PFC and flight surface and with technology that is reliable enough to make this possible, and given that only one person is ever supposed to be PF at any given time - what is the benefit?
A "rumble" tactile feedback system to warn of dual input seems a fair compromise to me.
There was plenty of indication of what the PF was up to on the ADI early in the sequence (and plenty of evidence on the CVR to suggest that the PNF wasn't happy about it) - why the PNF hesitated in taking control is a matter for the HF experts.
Last edited by DozyWannabe; 3rd Jan 2013 at 17:23.
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Why not, as an interim measure, enable the stick position display in flight (I understand it displays only on the ground)? I wonder if an obvious nose up demand from PF would then have been visible to the Captain when he re-entered the cockpit?
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Again - to what benefit? Adding more data to the visual perception channel risks overloading it. Why the need to know precisely and at all times what your opposite number is doing with the PFC when only one pilot is supposed to be PF?
I swear I'm not being facetious - I really want to know why it's such a big deal for some.
I swear I'm not being facetious - I really want to know why it's such a big deal for some.
Last edited by DozyWannabe; 3rd Jan 2013 at 17:33.
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Is it just possible, Dozy, that it could have be 'big deal' for 200+folk? I repeat
"I wonder if an obvious nose up demand from PF would then have been visible to the Captain when he re-entered the cockpit?"
"I wonder if an obvious nose up demand from PF would then have been visible to the Captain when he re-entered the cockpit?"
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DW
Well, I guess to know the answer to that you would have to be a pilot a be seated next to someone you might not know controlling an aircraft in a way that you are "less able" to monitor. I´m sure you are intelligent enough to imagine it, but then again, I guess you would have to really be there to really know.
(BTW, I fly the Airbus and like it a lot, but IT DOES have some shortcomings, no design is perfect from the start. In the meantime people have to learn to live with it. Users doing that are not the mark of a perfect design, only of human brains working to adapt and do the best with what they have.)
Get a rating, sit in the seat and you will see for yourself I´m sure.
Well, I guess to know the answer to that you would have to be a pilot a be seated next to someone you might not know controlling an aircraft in a way that you are "less able" to monitor. I´m sure you are intelligent enough to imagine it, but then again, I guess you would have to really be there to really know.
(BTW, I fly the Airbus and like it a lot, but IT DOES have some shortcomings, no design is perfect from the start. In the meantime people have to learn to live with it. Users doing that are not the mark of a perfect design, only of human brains working to adapt and do the best with what they have.)
Get a rating, sit in the seat and you will see for yourself I´m sure.