A330/A340 EAD (AoA PROBES)
Join Date: Jan 2008
Location: ...
Posts: 3,753
Likes: 0
Received 0 Likes
on
0 Posts
Dozywannabe what is your response regarding post 63 and Post 68 on http://www.pprune.org/tech-log/50324...ency-ad-4.html
Conic Plates
According to the EASA EAD, these new-fangled "conic" plates could be either factory fitted or retro-fitted to both the Thales and Goodrich AoA probes. Can anyone explain their purpose? To prevent damage to the existing vanes, perhaps? Or to prevent icing?
Presumably they are comparable to the installation on VC10s in the 1960s, but bigger? Any chance someone might have a photo, or be able to take one while going up the front steps?
Thanks in anticipation...
Presumably they are comparable to the installation on VC10s in the 1960s, but bigger? Any chance someone might have a photo, or be able to take one while going up the front steps?
Thanks in anticipation...
Join Date: Aug 2011
Location: Grassy Valley
Posts: 2,074
Likes: 0
Received 0 Likes
on
0 Posts
From the standard install I see on the 330, does the advantage come from a smaller diameter pivot at the vane mount? This would seem to give the vane more mechanical advantage against accretion at the through hole? Less advantage for any ice accretion at the larger diameter pivot on the standard install? also less ice to melt for the heater?
Join Date: Jun 2009
Location: somewhere
Posts: 451
Likes: 0
Received 0 Likes
on
0 Posts
AoA sensor installation.
For the Thales AoA sensor to protect from ice accretion to the protruding (non heated) base.
For the Goodrich AoA sensor to protect from water ingression in outer bearing. (Perpignan accident)
Thales conical plate installation, on top the original flat plate.
below Goodrich AoA sensor (plate not shown) , Conical plate and an image from the Bea final perpignan report.
For the Goodrich AoA sensor to protect from water ingression in outer bearing. (Perpignan accident)
Thales conical plate installation, on top the original flat plate.
below Goodrich AoA sensor (plate not shown) , Conical plate and an image from the Bea final perpignan report.
Join Date: Apr 2002
Location: FUBAR
Posts: 3,348
Likes: 0
Received 0 Likes
on
0 Posts
SLFand Proud,
perhaps better keep it that way
I said tends to , and the day it doesn't, my response to any control malfunctions will be a whole lot more instinctive/rational than having to fumble around on the overhead panel switching sh1t off. But, your understanding of this may not be as highly developed of course, if you have never been handed an out of control aircraft, & been expected to sort it out fairly rapidly, you can be excused for that.
It is not massively advanced, nor modern, to have commercial aircraft , in the year 2012, performing potentially lethal manouveres, requiring that you disconnect most of the "raison d' etre " to control them. . . . do you not see a contradiction here ?
perhaps better keep it that way
I said tends to , and the day it doesn't, my response to any control malfunctions will be a whole lot more instinctive/rational than having to fumble around on the overhead panel switching sh1t off. But, your understanding of this may not be as highly developed of course, if you have never been handed an out of control aircraft, & been expected to sort it out fairly rapidly, you can be excused for that.
It is not massively advanced, nor modern, to have commercial aircraft , in the year 2012, performing potentially lethal manouveres, requiring that you disconnect most of the "raison d' etre " to control them. . . . do you not see a contradiction here ?
Last edited by captplaystation; 31st Dec 2012 at 10:17.
Join Date: Aug 2009
Location: Germany
Age: 67
Posts: 1,777
Likes: 0
Received 0 Likes
on
0 Posts
It is not massively advanced, nor modern, to have commercial aircraft , in the year 2012, performing potentially lethal manouveres, requiring that you disconnect most of the "raison d' etre " to control them. . . . do you not see a contradiction here ?
A hight technology industry laboratory
Incident:
A pipe carrying water is leaking and water drops on a equipment powered by electricity
Solution DGAC
Suspend a tin below the leak and empty it before it overflows
Repeat as many as requested
This is what the DGAC asked the pilots with their procedure
Last edited by jcjeant; 30th Dec 2012 at 20:27.
Join Date: Oct 2012
Location: Bucuresti
Posts: 47
Likes: 0
Received 0 Likes
on
0 Posts
SLFand Proud,
perhaps better keep it that way I said tends to and the day it doesn't, my response to any control malfunctions will be a whole lot more instinctive/rational than having to fumble around on the overhead panel switching sh1t off. But, your understanding of this may not be as highly developed of course, if you have never been handed an out of control aircraft, & been expected to sort it out fairly rapidly, you can be excused for that.
It is not massively advanced, nor modern, to have commercial aircraft , in the year 2012, performing potentially lethal manouveres, requiring that you disconnect most of the "raison d' etre " to control them. . . . do you not see a contradiction here ?
perhaps better keep it that way I said tends to and the day it doesn't, my response to any control malfunctions will be a whole lot more instinctive/rational than having to fumble around on the overhead panel switching sh1t off. But, your understanding of this may not be as highly developed of course, if you have never been handed an out of control aircraft, & been expected to sort it out fairly rapidly, you can be excused for that.
It is not massively advanced, nor modern, to have commercial aircraft , in the year 2012, performing potentially lethal manouveres, requiring that you disconnect most of the "raison d' etre " to control them. . . . do you not see a contradiction here ?
You did indeed say 'tends to'. But this discussion is not about what aircraft - of any type - 'tend' to do; it's a discussion about what a particular type does with multiple equipment failures - 'tendency' is irrelevant. You suggested in your post that should the aircraft you are piloting ever cease to do what it 'tends to' you would be out of your depth.
You rather underline it by claiming in the event it does happen, your response will be both instinctive and rational. Which is pretty much by definition impossible. Either you use your instinct - which in most cases of aircraft upset is likely wrong (see pilots stalling planes passim,) or you rationally evaluate the situation. If you are terrified of having to rationally evaluate a situation - "fumble around on the overhead panel switching sh1t off" suggests someone liable to 'intuitive' panic responses rather than rational action - then you should consider whether a career in the arts may be more suitable.
Join Date: Aug 2011
Location: Grassy Valley
Posts: 2,074
Likes: 0
Received 0 Likes
on
0 Posts
Aircraft most definitely have tendencies. Ignore them at your great risk.
As in "landing light", another thread, or "Twitchy in roll direct", from 447.
Or, "watch it, lest you roll it into a ball." Maybe, instinct and rational will be wrong, but likely not. Sometimes rote is good: "critical thought is not helpful"
(alcorfr, another thread). Sometimes intuition is all you have.
"behind is not good, but don't get ahead of yourself" etc.
"Incoherent"? Maybe an apology?
edit.... Before Feb 2008 (BEA 038) reside the oldtimers. I have yet to see anyone from the pre "ice fuel" thread demonstrate foolishness. I look for join date, and pause, lest my keyboard get me in trouble.
just sayin...
As in "landing light", another thread, or "Twitchy in roll direct", from 447.
Or, "watch it, lest you roll it into a ball." Maybe, instinct and rational will be wrong, but likely not. Sometimes rote is good: "critical thought is not helpful"
(alcorfr, another thread). Sometimes intuition is all you have.
"behind is not good, but don't get ahead of yourself" etc.
"Incoherent"? Maybe an apology?
edit.... Before Feb 2008 (BEA 038) reside the oldtimers. I have yet to see anyone from the pre "ice fuel" thread demonstrate foolishness. I look for join date, and pause, lest my keyboard get me in trouble.
just sayin...
Last edited by Lyman; 30th Dec 2012 at 21:48.
Join Date: Oct 2012
Location: Bucuresti
Posts: 47
Likes: 0
Received 0 Likes
on
0 Posts
Aircraft most definitely have tendencies. Ignore them at your great risk.
As in "landing light", another thread, or "Twitchy in roll direct", from 447.
As in "landing light", another thread, or "Twitchy in roll direct", from 447.
You are paid to know what to do when it does not "go up at the rate I ask, down in a similar fashion ( with Left & Right similarly easily defined.)" I think you'd probably agree, that's what makes skilled pilots relevant - otherwise a very basic computer could do the job.
Join Date: Aug 2011
Location: Grassy Valley
Posts: 2,074
Likes: 0
Received 0 Likes
on
0 Posts
My bad. I agree. Experience is beneficial related to ts breadth.
I do not consider "predictability" a "tendency". I can't source it really, but have always associated a 'tendency' with a bad habit or characteristic, be it mechanical or otherwise.....
I do not consider "predictability" a "tendency". I can't source it really, but have always associated a 'tendency' with a bad habit or characteristic, be it mechanical or otherwise.....
Join Date: Jul 2002
Location: UK
Posts: 3,093
Likes: 0
Received 0 Likes
on
0 Posts
Just popping in to clarify that the "twitchy" comment was not made regarding AF447, it was made by a single poster once on one of the early 447 threads and was neither supported nor refuted by anyone else.
Join Date: Apr 2002
Location: FUBAR
Posts: 3,348
Likes: 0
Received 0 Likes
on
0 Posts
SLF
I will bow to your obviously superior viewpoint (24 posts AND SLF ) as evidently my 18,000hrs flight experience, including 14,000 in Command of B737, makes me wholly unworthy of contradicting your expert opinion of Airbus FBW, and the qualities required of a professional pilot & aircraft Commander.
As you say, perhaps, 35 years later I should consider whether I may indeed have been more suited to a career in the arts.
Oh BTW you are correct, English is not my first language, I am Scottish, but I am endeavouring, with all my best efforts, to master it, along with French & Spanish, as I live my life/work in 2 different countries, excluding the UK.
Being home to many individuals like you, who insist on displaying this particularly British , and not very endearing trait, nominating themselves "armchair experts" on something they in all likelihood have no qualification in, nor usually participated in ,at least in a professional capacity, may have been at least part of the reason I left it behind 20 years ago.
What a blessing that was.
I will bow to your obviously superior viewpoint (24 posts AND SLF ) as evidently my 18,000hrs flight experience, including 14,000 in Command of B737, makes me wholly unworthy of contradicting your expert opinion of Airbus FBW, and the qualities required of a professional pilot & aircraft Commander.
As you say, perhaps, 35 years later I should consider whether I may indeed have been more suited to a career in the arts.
Oh BTW you are correct, English is not my first language, I am Scottish, but I am endeavouring, with all my best efforts, to master it, along with French & Spanish, as I live my life/work in 2 different countries, excluding the UK.
Being home to many individuals like you, who insist on displaying this particularly British , and not very endearing trait, nominating themselves "armchair experts" on something they in all likelihood have no qualification in, nor usually participated in ,at least in a professional capacity, may have been at least part of the reason I left it behind 20 years ago.
What a blessing that was.
Last edited by captplaystation; 31st Dec 2012 at 10:12.
A33Zab,
Thanks for producing, as usual, such superb pictures (and apologies for my late acknowledgement).
This is a much more subtle mod than I had imagined. The 1960s VC10 AoA probes, which were dedicated to its three-stage stall protection system, enclosed the (much smaller) vanes completely. Slots in the cones admitted the airflow. The VC10s smaller sister, the BAC 1-11, employed a similar stall protection system. However, the (larger) vanes of its AoA probes were not enclosed.
Reviewing the big picture, it does seem strange that Airbus aircraft have latterly been experiencing so many problems resulting from icing of pitot probes, and now AoA probes. After all, these aeroplanes are operating in a similar environment to other types, and (presumably) jet airliners generally since even I was wearing short trousers. Granted, these FBW types are much more reliant on the availability and accuracy of the data concerned than previous types, most of which didn't even have AoA probes. If the heated AoA probes on my VC10 had become frozen, I might have been none the wiser unless I was pushing the buffet margins and waiting for the auto-ignition lights to flicker. But I flew the A320 for the first 14 years of its operation, and probe icing didn't seem to be an issue. Were we simply living in blissful ignorance?
Thanks for producing, as usual, such superb pictures (and apologies for my late acknowledgement).
This is a much more subtle mod than I had imagined. The 1960s VC10 AoA probes, which were dedicated to its three-stage stall protection system, enclosed the (much smaller) vanes completely. Slots in the cones admitted the airflow. The VC10s smaller sister, the BAC 1-11, employed a similar stall protection system. However, the (larger) vanes of its AoA probes were not enclosed.
Reviewing the big picture, it does seem strange that Airbus aircraft have latterly been experiencing so many problems resulting from icing of pitot probes, and now AoA probes. After all, these aeroplanes are operating in a similar environment to other types, and (presumably) jet airliners generally since even I was wearing short trousers. Granted, these FBW types are much more reliant on the availability and accuracy of the data concerned than previous types, most of which didn't even have AoA probes. If the heated AoA probes on my VC10 had become frozen, I might have been none the wiser unless I was pushing the buffet margins and waiting for the auto-ignition lights to flicker. But I flew the A320 for the first 14 years of its operation, and probe icing didn't seem to be an issue. Were we simply living in blissful ignorance?
Join Date: Aug 2011
Location: Grassy Valley
Posts: 2,074
Likes: 0
Received 0 Likes
on
0 Posts
It is a puzzle. For sixty years, the USAF had been flying to 50,000 feet, and experienced none of the "hitherto unknown characteristics of fuel icing".
Then BA038. Then Airbus is plagued by ice afflicting its mechanical sensors critical to airspeed data displays. Then Angle of Attack vanes.
It takes a cynic to lay off the issue on heating, metallurgy, and other well developed legacies of our aeronautical technologies.
If it is indeed down to sensor design, then shame on the kit and its sponsors who spec it. I don't believe it. Because if it is, we have some gaping holes in our technologies.
The alternative is to look elsewhere. I take note of Captain Scott's troublefree experience in the gen one 320. I have a friend who flew the 320 for ten years, nary a belch or hiccup. What is new that hasn't to do with sensors and heating?
Processing? Mitigating pathways post fail? Because if it is 'Probes', perhaps a return to yarn on the Radome? A Pendulum on the glareshield?
A33 thank you for the exquisite photography. I think I see the improvement in the AD compliant kit. The "base" cone is proud of the fuselage, where the original appears flush. It also appears the pivot is reduced in diameter, making it less susceptible to ice "sticking" its action.
I wonder if adding small "spades" at the vane trailing edge would increase the vanes ability to remain "in stream". Perhaps even making the vanes into a double, a "bi-vane". Anything that ancient that has problems begs a change of some sort.
Then BA038. Then Airbus is plagued by ice afflicting its mechanical sensors critical to airspeed data displays. Then Angle of Attack vanes.
It takes a cynic to lay off the issue on heating, metallurgy, and other well developed legacies of our aeronautical technologies.
If it is indeed down to sensor design, then shame on the kit and its sponsors who spec it. I don't believe it. Because if it is, we have some gaping holes in our technologies.
The alternative is to look elsewhere. I take note of Captain Scott's troublefree experience in the gen one 320. I have a friend who flew the 320 for ten years, nary a belch or hiccup. What is new that hasn't to do with sensors and heating?
Processing? Mitigating pathways post fail? Because if it is 'Probes', perhaps a return to yarn on the Radome? A Pendulum on the glareshield?
A33 thank you for the exquisite photography. I think I see the improvement in the AD compliant kit. The "base" cone is proud of the fuselage, where the original appears flush. It also appears the pivot is reduced in diameter, making it less susceptible to ice "sticking" its action.
I wonder if adding small "spades" at the vane trailing edge would increase the vanes ability to remain "in stream". Perhaps even making the vanes into a double, a "bi-vane". Anything that ancient that has problems begs a change of some sort.
Last edited by Lyman; 31st Dec 2012 at 13:55.
Join Date: Jul 2002
Location: UK
Posts: 3,093
Likes: 0
Received 0 Likes
on
0 Posts
It appears that the new AoA vane housing (also available from both Thales and Goodrich) is a new design intended to reduce the risk of the kind of blockage that brought down the Perpignan A320 and caused a single vane to freeze in the case of AF447. As yet, we don't know which model was fitted to the aircraft in this incident, but it appears that the EAD is causing a review of this new design and a fix should be in the works.
Last edited by DozyWannabe; 31st Dec 2012 at 14:49.
Join Date: Aug 2011
Location: Grassy Valley
Posts: 2,074
Likes: 0
Received 0 Likes
on
0 Posts
NWA accident you refer to was caused by pitot heat selected OFF prior to take off, and not selected ON thereafter. Perhaps a poor example then, here, since the problematic A330 probes were operating heated when they failed.
Rgds.
Rgds.
Join Date: Aug 2009
Location: Germany
Age: 67
Posts: 1,777
Likes: 0
Received 0 Likes
on
0 Posts
Hi,
DW
Long ago (you made yourself note) probes are prone to icing or blocking by ice particles and since that time there has been no suitable solution found and I think it will not change until prohibit aircraft from flying in icing environments or equip each sensor with a flamethrower
DW
As yet, we don't know which model was fitted to the aircraft in this incident, but it appears that the EAD is causing a review of this new design and a fix should be in the works.
Join Date: Jul 2002
Location: UK
Posts: 3,093
Likes: 0
Received 0 Likes
on
0 Posts
@Lyman - It was a general reference to historical pitot tube blockage-related problems, not a specific comparison to the Thales AA issue.
@jcj - The problems we're talking about are not the traditionally-accepted blockage of one or two sensors, but changes to the design post-certification that raise the risk of a triple failure.
@jcj - The problems we're talking about are not the traditionally-accepted blockage of one or two sensors, but changes to the design post-certification that raise the risk of a triple failure.
Last edited by DozyWannabe; 31st Dec 2012 at 15:13.
Join Date: Aug 2009
Location: Germany
Age: 67
Posts: 1,777
Likes: 0
Received 0 Likes
on
0 Posts
@jcj - The problems we're talking about are not the traditionally-accepted blockage of one or two sensors, but changes to the design post-certification that raise the risk of a triple failure.
So .. 2 probes .. double failure ... 3 probes .. triple failure ....
But if you have 3 probes and one is heated near is melting point .. you will have only a double failure
It's just to find how heat a probe near his melting point .. and able to continue to function normally ...
Last edited by jcjeant; 31st Dec 2012 at 15:25.
Join Date: Aug 2011
Location: Grassy Valley
Posts: 2,074
Likes: 0
Received 0 Likes
on
0 Posts
Dozy
"DozyWannabe @Lyman - It was a general reference to historical pitot tube blockage-related problems, not a specific comparison to the Thales AA issue."
Thanks for the disclaimer, had you included it prior, electrons would be conserved.
And your post would have been unnecessary, being superfluous to the discussion....
"DozyWannabe @Lyman - It was a general reference to historical pitot tube blockage-related problems, not a specific comparison to the Thales AA issue."
Thanks for the disclaimer, had you included it prior, electrons would be conserved.
And your post would have been unnecessary, being superfluous to the discussion....