AF 447 Search to resume
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LN-PAA again
Try this link to get the report; 1993/03 | sht
My previous post apparently disappeared somehow.
My previous post apparently disappeared somehow.
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PJ2
I think a picture is worth at least a thousand words. Given that the shackles and pins look as they do, reasonably untouched, and the hoops have broken away, burned, and exposed the Hardy mounting bed, I can't understand why these metallic beds are "Battleship engineered" bomb proof, and the Stabiliser is "frangible". Composites and two phase materials are ill equipped for concentrated bearing points, especially when considering there is a metallic and polymer join to fail. One or the other, but merging them is something that may never be mastered.
bear
I think a picture is worth at least a thousand words. Given that the shackles and pins look as they do, reasonably untouched, and the hoops have broken away, burned, and exposed the Hardy mounting bed, I can't understand why these metallic beds are "Battleship engineered" bomb proof, and the Stabiliser is "frangible". Composites and two phase materials are ill equipped for concentrated bearing points, especially when considering there is a metallic and polymer join to fail. One or the other, but merging them is something that may never be mastered.
bear
Last edited by bearfoil; 5th Mar 2010 at 19:29.
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I think a picture is worth at least a thousand words. Given that the shackles and pins look as they do, reasonably untouched, and the hoops have broken away, burned, and exposed the Hardy mounting bed, I can't understand why these metallic beds are "Battleship engineered" bomb proof, and the Stabiliser is "frangible".
I agree on the rudder attachment vs. VS attachment as well - seems like a good fail-safe has been missed there in favour of "strong enough" (and probably right across the industry - a few 737s would have been better off without the rudder). I do wonder why this is, since the extra strength (of the rudder hinge) implies extra weight which is rarely there without reason. Is it possible that as a moving part the rudder hinge has a cycles-to-failure requirement that leads to it being stronger in static load than the VS attachment ?
Now those VS attachments - again are they much stronger and hence heavier than required ? Maybe they were originally designed to hold a heavier metal VS - possible I suppose. Or maybe they aren't so much different in strength to the composite VS (after all, the overloaded joint always has to fail one side first) ?
A couple more thousand words:
First one is those same attachment lugs (I believe) from AF447. This time the composite didn't break, and the mountings were ripped out of the fuselage - by the VS. If the composite strength was a lot lower than the mounting, then we'd expect the same failure mode under the same loading.
Second image is the VS from the NZ airbus at Perpignan. It looks as though, again, the VS took attachment & some fuselage with it (I admit there isn't enough detail in the image to be sure - best image I could find). Now, in this case we know that the VS was from a high speed water impact and an intact aircraft that disintegrated on impact.
Conclusions:
- It is definitely possible for the VS to float away in one piece and good condition from a high speed water impact of an intact a/c
- The failure mode was different to 587 (different model, but I believe the attachment design is the same)
- If (and this may be your bias and mine) the metal attachment points are stronger than the composite VS, then the forces leading to VS failure must have been significantly different in 587 and 447.
Flying Without a VS
...indeed, no aircraft will fly without vertical stabilizer.
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SmilinEd
I've seen the pic, but can't find it at the moment. I recall seeing some residual structure on the Dorsal spine of the Fuselage, very scant, but not flush, I think it also had the old turret, good for a little Longitudinal stability, still an impressive RTB.
bear
I've seen the pic, but can't find it at the moment. I recall seeing some residual structure on the Dorsal spine of the Fuselage, very scant, but not flush, I think it also had the old turret, good for a little Longitudinal stability, still an impressive RTB.
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I saw the B-52 pic only recently. Yes, it had a small bit of VS sticking up, but more importantly, #1 and #8 engines were well outboard and could be modulated for yaw stability much better than a twin.
GB
Fun: A fighter called for priority landing due to bingo fuel. ATC told him to hold, as they had a B-52 coming in with an engine out.
"Ah, the dreaded seven engine approach.."
GB
Fun: A fighter called for priority landing due to bingo fuel. ATC told him to hold, as they had a B-52 coming in with an engine out.
"Ah, the dreaded seven engine approach.."
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Fuel calculations
There is one thing I really would like to understand.. Der Spiegel, as known, says:
A loophole allows him to enter Bordeaux -- which lies several hundred kilometers closer than Paris -- as the fictitious destination for his fuel calculations. "Major deviation would therefore no longer have been possible anymore," says Gerhard Hüttig
What are your comments, as professionals, about the idea that the plane entered an area of severe turbulence because of the above?
A loophole allows him to enter Bordeaux -- which lies several hundred kilometers closer than Paris -- as the fictitious destination for his fuel calculations. "Major deviation would therefore no longer have been possible anymore," says Gerhard Hüttig
What are your comments, as professionals, about the idea that the plane entered an area of severe turbulence because of the above?
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That's what Der Spiegel says ("strong turbulence" thick ice crystals etc..). You imply we (still?) can't know, I assume.
And anyhow I do remember having seen this (recontruction of flight path)
Air France 447 - AFR447 - A detailed meteorological analysis - Satellite and weather data
And anyhow I do remember having seen this (recontruction of flight path)
Air France 447 - AFR447 - A detailed meteorological analysis - Satellite and weather data
Last edited by wizele; 6th Mar 2010 at 15:49. Reason: link added
Lomapaseo, PMFJI...
wizele;
Please take the time to read through this thread for some information on your point.
The "shortage of fuel" and inability to execute a diversion around weather due to a shortage of fuel is nonsense and has been dealt with by those who do airline flying for a living.
Characterizing standard flight planning techniques as a "loophole" is incorrect and misleads readers who may not know any better. It is a statement made in ignorance of how airline flight planning is done.
There are those in the world who make money by sensationalizing accidents at the expense of the victims and their families. They do not appear to be interested in finding out what happened or telling readers something new about the accident.
In my view, Der Spiegel is the last source of information someone should read to get accurate, reliable information on aviation accidents.
We cannot know, in a way that explains the accident, what happened because the flight data recorders have not been located. The data recorders are the best source of information which can tell us what happened and even then we may not know all the details.
All else is pure speculation; anything offered by public media cannot be taken seriously.
wizele;
A loophole allows him to enter Bordeaux -- which lies several hundred kilometers closer than Paris -- as the fictitious destination for his fuel calculations. "Major deviation would therefore no longer have been possible anymore," says Gerhard Hüttig
The "shortage of fuel" and inability to execute a diversion around weather due to a shortage of fuel is nonsense and has been dealt with by those who do airline flying for a living.
Characterizing standard flight planning techniques as a "loophole" is incorrect and misleads readers who may not know any better. It is a statement made in ignorance of how airline flight planning is done.
There are those in the world who make money by sensationalizing accidents at the expense of the victims and their families. They do not appear to be interested in finding out what happened or telling readers something new about the accident.
That's what Der Spiegel says ("strong turbulence" thick ice crystals etc..). You imply we (still?) can't know, I assume.
We cannot know, in a way that explains the accident, what happened because the flight data recorders have not been located. The data recorders are the best source of information which can tell us what happened and even then we may not know all the details.
All else is pure speculation; anything offered by public media cannot be taken seriously.
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Originally Posted by wizele
A loophole allows him to enter Bordeaux -- which lies several hundred kilometers closer than Paris -- as the fictitious destination for his fuel calculations. "Major deviation would therefore no longer have been possible anymore," says Gerhard Hüttig
a) It is not a 'loophole' but common practice and an approved procedure on long-range flights
b) WX avoidance is not normally a MAJOR diversion and would almost certainly have been considered.
BOAC;
To put a bit of flesh to your comment, for an A330 on such a flight, a 30nm to 50nm lateral diversion (to the left or right of course, for others), around enroute weather would burn between 200 and 500kg of fuel. In effect, (it can be worked out mathematically, and some here have done so), such diversions add perhaps 40nm or about 5 minutes to the flight plan distance/time. The A330 burns about 100kg per minute in cruise.
The arrival fuel was, if I recall either from a comment here or from the BEA report, about 6.5T which is pretty standard for an A330. Even a major diversion costing 1000kg would not compromise arrival fuel seriously. Minimum fuel for the A330 (the point at which the "low fuel caution" comes on) is about 2.7T depending upon a/c pitch attitude.
b) WX avoidance is not normally a MAJOR diversion and would almost certainly have been considered.
The arrival fuel was, if I recall either from a comment here or from the BEA report, about 6.5T which is pretty standard for an A330. Even a major diversion costing 1000kg would not compromise arrival fuel seriously. Minimum fuel for the A330 (the point at which the "low fuel caution" comes on) is about 2.7T depending upon a/c pitch attitude.
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I bow to your 330 experience, PJ, but I'm surprised it is even that much if an early turn and a slow return to track is made? Anyhow, we are agreed it is certainly not 'major'.
BOAC - Yes it's small; - the original argument, (that the crew may not have felt that there was sufficient fuel, due to filing short of destination and later dropping "the alternate", such that diverting around weather was not possible and therefore did not), is moot; there is no basis for the argument, or the point, whatsoever.
A large deviation that would add perhaps 40nm/5minutes/500kg to the flight plan is a lot, given the "geometry" of such diversions done early, as you say. (Sometimes, (obviously), it is best to wait until closer in to ensure clear down-stream pathways and avoid cells attenuated/blanked by closer, larger cells). But the figures are indeed in the ballpark for the A330. For a ten hour flight it would not be unusual to board 1T of Wx Fuel for pos. diversion, on top of contingency, alternate and min.fuel.
I obviously can't comment on theoretical diversion-planning around the weather that AF447 and seven or eight other flights faced but a "larger slice" at a diversion, (longer distance) may have been considered given the relative proximity of cells and the length of the line.
But the evidence that the line was successfully negotiated, as are such ITCZ lines negotiated every day by many airliners, is evidence for the fact that it is done successfully all the time and fuel "emergencies" remain rare and therefore flight planning techniques are working as intended. Even at a full 1T of fuel, there was plenty of reserve fuel left to complete the flight to CDG without concern.
While not intending to draw any more attention to the Der Spiegel op-ed, one point is important to clarify regarding the captain. Der Spiegel states:
suggesting that there was a question as to "who was controlling the plane", and that "not wearing a seatbelt" somehow "contributed". Again, ignorance and sensationalism at its worst. Stating that "in emergencies it [placing 'inexperienced First Officers in the left seat - as if there was some 'magic' associated with that position!] can increase the likelihood of a crash." is just plain stupidity and irresponsible writing.
My earlier response to bearfoil deals with this point and also deals with how crew breaks are usually decided. But it is worth repeating, that because the accident occurred just over 3hrs into the flight which is very close to when crew change would be occuring, we do not know whether the captain was just leaving the flight deck or returning. Arguments can be made for both scenarios. Though I think we can be certain that the captain was not in his seat, we can draw absolutely no conclusions or posit any speculations from this; there are just too many if's.
PJ2
A large deviation that would add perhaps 40nm/5minutes/500kg to the flight plan is a lot, given the "geometry" of such diversions done early, as you say. (Sometimes, (obviously), it is best to wait until closer in to ensure clear down-stream pathways and avoid cells attenuated/blanked by closer, larger cells). But the figures are indeed in the ballpark for the A330. For a ten hour flight it would not be unusual to board 1T of Wx Fuel for pos. diversion, on top of contingency, alternate and min.fuel.
I obviously can't comment on theoretical diversion-planning around the weather that AF447 and seven or eight other flights faced but a "larger slice" at a diversion, (longer distance) may have been considered given the relative proximity of cells and the length of the line.
But the evidence that the line was successfully negotiated, as are such ITCZ lines negotiated every day by many airliners, is evidence for the fact that it is done successfully all the time and fuel "emergencies" remain rare and therefore flight planning techniques are working as intended. Even at a full 1T of fuel, there was plenty of reserve fuel left to complete the flight to CDG without concern.
While not intending to draw any more attention to the Der Spiegel op-ed, one point is important to clarify regarding the captain. Der Spiegel states:
So far, it's unclear who was controlling the Air France plane in its final minutes. Was it the experienced flight captain, Dubois, or one of his two first officers? Typically, a captain retreats to his cabin to rest a while after takeoff. Indeed, there's corroborative evidence to suggest that the captain was not sitting in the cockpit at the time of the crash: His body was recovered from the Atlantic, whereas those of his two copilots sank to the bottom of the ocean still attached to their seats. This would suggest that Dubois was not wearing a seatbelt.
In contrast to many other airlines, it is standard practice at Air France for the less experienced of the two copilots to take the captain's seat when the latter is not there. The experienced copilot remains in his seat on the right-hand side of the cockpit. Under normal circumstances, that is not a problem, but in emergencies it can increase the likelihood of a crash.
In contrast to many other airlines, it is standard practice at Air France for the less experienced of the two copilots to take the captain's seat when the latter is not there. The experienced copilot remains in his seat on the right-hand side of the cockpit. Under normal circumstances, that is not a problem, but in emergencies it can increase the likelihood of a crash.
My earlier response to bearfoil deals with this point and also deals with how crew breaks are usually decided. But it is worth repeating, that because the accident occurred just over 3hrs into the flight which is very close to when crew change would be occuring, we do not know whether the captain was just leaving the flight deck or returning. Arguments can be made for both scenarios. Though I think we can be certain that the captain was not in his seat, we can draw absolutely no conclusions or posit any speculations from this; there are just too many if's.
PJ2
Last edited by PJ2; 6th Mar 2010 at 20:00. Reason: correct PPRuNe member referenced
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The crew rest capsule the same. This is difficult, for we assume it was holding the Captain, and perhaps one or two rest FA's. How did it come to be found?
The structure found is the Cabin Crew Rest Module. It is in the belly of the a/c, mid-section and sleeps about six if I recall depending upon the installation.
The cockpit crew rest module, depending again upon installation, (how the airline ordered it), is either behind the cockpit on the starboard side just in front of the Business Class Galley, with two bunks laterally mounted and about 18" width between the bunks and the cockpit wall to stand and change in, or the crew member takes a business-class seat reserved for the purpose, usually a single window seat, puts up a velcroe-mounted tent which fastens around the seat and from the overhead bin structure, (and tries to sleep through the flourescent overhead lights which aren't blocked, and/or the cabin service. Best break time is the middle one when no service is being done).
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Arm 36 g
I have been looking a lot at the right photo in IRep-2 of arm 32 g and manipulated the photo in various ways. The washer under the bolt-head seems browned by corrosion. None of the other similar bolts/nuts have any visible discoloration of their washers in any of the photos I have seen. Also the metal piece to which arm 36 is attached seems like it was corroded. Finally, I can't make up my mind if the break on the arm which is visible is showing signs of fatique or not. The photographic quality is simply not good enough. Has anybody else seen and thought about this?
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But it is worth repeating, that because the accident occurred just over 3hrs into the flight which is very close to when crew change would be occurring, we do not know whether the captain was just leaving the flight deck or returning. Arguments can be made for both scenarios.
So it is possible that the Captain set the course and left the cockpit for his break. And that the 1st officer remained on that course, not deviating to avoid the cells.
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Arm 36 g
Bearfoil; Diversification; BOAC; et al
Well, having made a fool of myself in misinterpreting the BEA's statement - see AF 447 Search to resume - Page 21 - PPRuNe Forums, I decided to go and get an independent translation by a person born in the UK, educated both there and in France, and who has lived in France for over 40 years. Their translation of the offending sentence. i.e.
finishes up using succinct English words in place of the arrays often used in French, and the result is:-
The ambiguity has been nicely removed. 
mm43
Well, having made a fool of myself in misinterpreting the BEA's statement - see AF 447 Search to resume - Page 21 - PPRuNe Forums, I decided to go and get an independent translation by a person born in the UK, educated both there and in France, and who has lived in France for over 40 years. Their translation of the offending sentence. i.e.
The size of this arm is calculated to withstand a maximum load of 120,000 N,
corresponding to a relative acceleration of 36 g of the rudder in relation to the
vertical stabilizer.
corresponding to a relative acceleration of 36 g of the rudder in relation to the
vertical stabilizer.
Ce bras est dimensionné par calcul pour résister à un effort maximal d’environ 120 000 N, correspondant à une accélération relative de 36 g de la gouverne de direction par rapport à la dérive.
'Arm 36 g' is designed to withstand a maximum load of approximately 120,000 N, corresponding to a relative acceleration of the arm by the rudder in relation to the vertical stabilizer.
'Arm 36 g' is designed to withstand a maximum load of approximately 120,000 N, corresponding to a relative acceleration of the arm by the rudder in relation to the vertical stabilizer.
mm43
Last edited by mm43; 8th Mar 2010 at 03:53.
Razoray;
Of course it is possible.
However, having done this many times before retiring and knowing, with variations on the theme because the problems we are confronting are the same no matter the airline or airplane, that these things have much in common, the captain in his or her changeover briefing would not "set the course" and leave the cockpit expecting blind obedience. Nor does such a notion make sense.
If circumstances were such that this kind of directive were required, the captain would, and should, remain in the cockpit until the anticipated threats were handled and passed.
So while it is possible, it is almost certainly not the case. The flight deck crew must remain free to make operational decisions "in the moment" when/if circumstances require. Part of the briefing would include the requirement to call the captain to the flight deck if any operational matter out of the ordinary which, for example, required a significant change to the flight plan or required an emergency drill.
If the captain is uncomfortable leaving the crew for whatever reasons, he or she remains on the flight deck and assigns breaks as necessary, until such time as conditions permit a break for the captain. Such a situation would be very rare and as such is always complex and difficult to define. It could involve someone not feeling well for example; it happens and crews deal with these matters as they arise.
If you need a metric, I would not leave the flight deck in the hands of a First Officer who was brand new on the airplane, who had never been overseas before, and who had never dealt with complex weather systems in the ITCZ or demonstrated to me his/her ability to read and use radar information to navigate same, while in the company of a new, MCP-licensed Relief Pilot. Others will define their personal judgement of comfort differently. I have never had to alter rest schedules for such reasons.
PJ2
So it is possible that the Captain set the course and left the cockpit for his break. And that the 1st officer remained on that course, not deviating to avoid the cells.
However, having done this many times before retiring and knowing, with variations on the theme because the problems we are confronting are the same no matter the airline or airplane, that these things have much in common, the captain in his or her changeover briefing would not "set the course" and leave the cockpit expecting blind obedience. Nor does such a notion make sense.
If circumstances were such that this kind of directive were required, the captain would, and should, remain in the cockpit until the anticipated threats were handled and passed.
So while it is possible, it is almost certainly not the case. The flight deck crew must remain free to make operational decisions "in the moment" when/if circumstances require. Part of the briefing would include the requirement to call the captain to the flight deck if any operational matter out of the ordinary which, for example, required a significant change to the flight plan or required an emergency drill.
If the captain is uncomfortable leaving the crew for whatever reasons, he or she remains on the flight deck and assigns breaks as necessary, until such time as conditions permit a break for the captain. Such a situation would be very rare and as such is always complex and difficult to define. It could involve someone not feeling well for example; it happens and crews deal with these matters as they arise.
If you need a metric, I would not leave the flight deck in the hands of a First Officer who was brand new on the airplane, who had never been overseas before, and who had never dealt with complex weather systems in the ITCZ or demonstrated to me his/her ability to read and use radar information to navigate same, while in the company of a new, MCP-licensed Relief Pilot. Others will define their personal judgement of comfort differently. I have never had to alter rest schedules for such reasons.
PJ2