BA038 (B777) Thread
'FAT' with Fuel...
Congratulations to our two ramp men - Green-dot and Swedish Steve - and CONF iture, for finally kicking the OUTAGAS theory into touch. [If the crew or anyone connected with the AAIB ever reads this stuff, no doubt they will have cracked a wry smile.]
Dozy Wanabee,
It's easy to dismiss other people's areas of enquiry as "nonsense". But in the absence of alternatives, was this accident purely an act of God? How about reminding us all of your more sensible theory?
Dozy Wanabee,
It's easy to dismiss other people's areas of enquiry as "nonsense". But in the absence of alternatives, was this accident purely an act of God? How about reminding us all of your more sensible theory?
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This is an accident with very rare circumstances, likely never encountered before. In the order of 10 to minus 9 power: extremely improbable but with catastrophic consequences.
Chances are that the combinations making this happen are conditions that have never made it to the list of required DFDR parameters.
My guess is that if they find the cause to be a unique set of circumstances, the list of recorded parameters will possibly once again be extended.
As an example, such was the case when the B737 rudder PCU servo-valve had been identified as the cause of several accidents.
In case of the 737 rudder problem the conception was also that all swans were white, until presence of a black swan (the PCU) was identified.
Green-dot
Chances are that the combinations making this happen are conditions that have never made it to the list of required DFDR parameters.
My guess is that if they find the cause to be a unique set of circumstances, the list of recorded parameters will possibly once again be extended.
As an example, such was the case when the B737 rudder PCU servo-valve had been identified as the cause of several accidents.
In case of the 737 rudder problem the conception was also that all swans were white, until presence of a black swan (the PCU) was identified.
Green-dot
Last edited by Green-dot; 19th Apr 2008 at 07:15.
Do you mean something like this?
I wouldn't take silence on the part of the AAIB/Boeing/RR/BA to mean that investigative work has slowed down; just that there is nothing more to report that impacts current operations. I'm sure if they turn up something safety critical, there will be an AD or special bulletin out PDQ.
Maybe the mods are just tired of the same old speculation? This second hand account actually ties in very well with the current AAIB report, given that the person relating it wasn't a pilot so could easily confuse loss of all engine power with loss of control of the engines... Who knows?
To focus on these _spontaneous words_ (http://news.bbc.co.uk/player/nol/new...news=1&bbcws=1) would have been very premature before the 30 days period.
But 2 months after the “*no anomalies in the major aircraft systems + fuel conforms to Jet A-1 specifications with no signs of contamination or unusual levels of water content*” Bulletin release and ensuing constructive but unofficial talking, with occasional but repetitive (?) deletion … these *spontaneous* words may fully sound …
But 2 months after the “*no anomalies in the major aircraft systems + fuel conforms to Jet A-1 specifications with no signs of contamination or unusual levels of water content*” Bulletin release and ensuing constructive but unofficial talking, with occasional but repetitive (?) deletion … these *spontaneous* words may fully sound …
Maybe the mods are just tired of the same old speculation? This second hand account actually ties in very well with the current AAIB report, given that the person relating it wasn't a pilot so could easily confuse loss of all engine power with loss of control of the engines... Who knows?
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I think the investigation in that case included a lot of serious test rig kit with rudder assemblies in cold boxes etc. - for G-YMMM you might want most of a wing (+engine) in a cold box. Yikes.
Comet hulls in swimming pools also come to mind.
I wonder if there will be that level of resource put into this incident at this point - at some point, I guess, they decide not to spend any more on investigating what is clearly a very very rare event.
That B737 rudder issue, and the Comet, weren't investigated in the level of detail required until after multiple hull losses - I wonder if we'll ever get the answer on G-YMMM...
The presence of fuel in the tank does not completely rule out mismanaged fuel. What happens between the tank and the engine, and if selectable might not be apparent to the investigators, i.e. not on the FDR.
There is evidence (or inference) that with the fuel metering valve open there was insufficient fuel flow to accelerate the engines; thus whatever is in between, could be mismanaged either manually, automatically, by design, or unintentionally.
There is evidence (or inference) that with the fuel metering valve open there was insufficient fuel flow to accelerate the engines; thus whatever is in between, could be mismanaged either manually, automatically, by design, or unintentionally.
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This is what ruins PPRuNe and threads such as this. Anoraks and their ridiculous theories on subjects they know nothing about. I'm glad those posts were removed. 'Sunspots caused the crash' my @rse.
If you want to spout rubbish do it in Jet Blast or, better still, on another site and leave the grown up subjects to those of us with a vested interest.
Back on topic now please.
If you want to spout rubbish do it in Jet Blast or, better still, on another site and leave the grown up subjects to those of us with a vested interest.
Back on topic now please.
There is evidence (or inference) that with the fuel metering valve open there was insufficient fuel flow to accelerate the engines
...thus whatever is in between, could be mismanaged either manually, automatically, by design, or unintentionally.
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Can someone please close this thread?
It looks like it is going into a dead end street (if it ever ends?) where they will give you a free pukie bag to get rid off all the theories and thesis gathered by mostly "experienced" and qualified researchers along the way.I think CAA will have the final word on it after all,right?
The only other thing I can match with this is a thread started by a BA union rep when it comes down to strike or something similar...100.000 views and all that, almost like a soap opera or a set at Beverly hills 90210 on the end.
Boring and mundane or just superficial who knows.
It looks like it is going into a dead end street (if it ever ends?) where they will give you a free pukie bag to get rid off all the theories and thesis gathered by mostly "experienced" and qualified researchers along the way.I think CAA will have the final word on it after all,right?
The only other thing I can match with this is a thread started by a BA union rep when it comes down to strike or something similar...100.000 views and all that, almost like a soap opera or a set at Beverly hills 90210 on the end.
Boring and mundane or just superficial who knows.
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Quoting safetypee:
Or uncommanded . . . .
Quoting Flintstone:
Sadly, what is worse, are biassed threads . . .
Biassed:
1. A statistical sampling or testing error caused by systematically favoring some outcomes over others.
2. To influence in a particular, typically unfair direction; prejudice.
Time for me to study a bit more about some specific issues in the T7 AMM, WDM, SSM and FIM regarding ATA 28-22-15. Understanding you are a professional, i will skip the details . . . . .
Just for the record, this post originally contained 3 replies to 3 different posters. Somehow 1 reply was removed/deleted minutes after i submitted this post on the 17th of april.
Regards,
Green-dot
There is evidence (or inference) that with the fuel metering valve open there was insufficient fuel flow to accelerate the engines; thus whatever is in between, could be mismanaged either manually, automatically, by design, or unintentionally.
Quoting Flintstone:
This is what ruins PPRuNe and threads such as this. Anoraks and their ridiculous theories on subjects they know nothing about.
Biassed:
1. A statistical sampling or testing error caused by systematically favoring some outcomes over others.
2. To influence in a particular, typically unfair direction; prejudice.
Time for me to study a bit more about some specific issues in the T7 AMM, WDM, SSM and FIM regarding ATA 28-22-15. Understanding you are a professional, i will skip the details . . . . .
Just for the record, this post originally contained 3 replies to 3 different posters. Somehow 1 reply was removed/deleted minutes after i submitted this post on the 17th of april.
Regards,
Green-dot
Last edited by Green-dot; 19th Apr 2008 at 07:34. Reason: Addressing an alteration to this post without my permission.
I wish this thread could be locked and removed. In an effort to correct the record regarding the Comet, if my memory serves me correctly, it was a design defect, not a construction defect, that caused the in flight break-up. To whit, "square" windows in a pressurised hull, leading to stress concentrations at the window corners. It had nothing to do with the redox bonding process.
Quote from Flintstone:
If you want to spout rubbish do it in Jet Blast or, better still, on another site and leave the grown up subjects to those of us with a vested interest.
Back on topic now please
[Unquote]
Quite. And your theory is...?
Skydrol Leak,
The most ludicrous posts on this thread are those asserting which topics are kosher; and which taboo. Thank you for your gratuitous rant. The solution is simply this: if you object to informed professionals (and even me, given the chance
) discussing the merits and weaknesses of hypotheses that you find counterintuitive, or unpalatable; don’t click on this thread, it’s not obligatory. And beware of Skydrol; it can blur vision.
Chris
If you want to spout rubbish do it in Jet Blast or, better still, on another site and leave the grown up subjects to those of us with a vested interest.
Back on topic now please
[Unquote]
Quite. And your theory is...?
Skydrol Leak,
The most ludicrous posts on this thread are those asserting which topics are kosher; and which taboo. Thank you for your gratuitous rant. The solution is simply this: if you object to informed professionals (and even me, given the chance
) discussing the merits and weaknesses of hypotheses that you find counterintuitive, or unpalatable; don’t click on this thread, it’s not obligatory. And beware of Skydrol; it can blur vision.Chris
Better ideas, anyone?
“… also for turning up something that hasn’t been properly understood before …”
Like the Lightning gear collapse during landing attributed to a structural vibration (resonant frequency) which momentarily moved the mechanical portion of the electo-mechanical valve? This, IIRC, involved a very few events on one variant type, but was a rarity without logical explanation.
Are there any interesting vibrations, system selections, or characteristics which could contribute to such a theory during an approach in a 777?
If so then presumably with structural considerations, there might be an enormous combination of weight, cg, configuration, speed, turbulence, control input, intersystem activity, etc that might account for the apparent rarity of this event.
Like the Lightning gear collapse during landing attributed to a structural vibration (resonant frequency) which momentarily moved the mechanical portion of the electo-mechanical valve? This, IIRC, involved a very few events on one variant type, but was a rarity without logical explanation.
Are there any interesting vibrations, system selections, or characteristics which could contribute to such a theory during an approach in a 777?
If so then presumably with structural considerations, there might be an enormous combination of weight, cg, configuration, speed, turbulence, control input, intersystem activity, etc that might account for the apparent rarity of this event.
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Mystified
I don't spend much time worrying about it, but note how baffling it is that there are those who post how irritated they are by other's posts. If one is annoyed, and insists on shutting a thread or that other's simply shut up, wouldn't it be easier for them to move along? Why would one wish to be irritated by other people? Seems somewhat immature.
Which brings me to this moment. I do not believe Websites have ANY obligation to allow full and free access to those they wish to exclude. This isn't a "Free Speech" environment; that would be the Public Square, which this venue is NOT. This is Private Property, and as such requires deference to, and respect for, the OWNER(S). I have believed that since the beginning of the Ether.
BA38. In 1988 (roughly) our company, with its progenitor, Boeing Aircraft, was looking at ETOPS. There were essentially two camps, as there are re: mandatory 60 year old retirement. Two crew Twin engine A/C were an assault on all who held dear the concept of "Four's enough, but not too many". Loss of the Flight Engineer was difficult as well. Many were very sceptical of two engines more than gliding distance from an Aerodrome.
As the BA38 issue unfolds, I continue to fully believe in ETOPS, though initially my faith was shaken. I continue to be confident because I think the incident was unrelated to ETOPS. A combination of reading, sifting through admittedly sparse Data, and Intuition tells me that. I am fascinated by the posts here, by those far smarter and more experienced than I, and I think to squelch vigorous and respectful debate would be a great Loss. As I have said, this post is now the property of the owner of this website, to do with or not whatever he/they may wish.
AFM
Which brings me to this moment. I do not believe Websites have ANY obligation to allow full and free access to those they wish to exclude. This isn't a "Free Speech" environment; that would be the Public Square, which this venue is NOT. This is Private Property, and as such requires deference to, and respect for, the OWNER(S). I have believed that since the beginning of the Ether.
BA38. In 1988 (roughly) our company, with its progenitor, Boeing Aircraft, was looking at ETOPS. There were essentially two camps, as there are re: mandatory 60 year old retirement. Two crew Twin engine A/C were an assault on all who held dear the concept of "Four's enough, but not too many". Loss of the Flight Engineer was difficult as well. Many were very sceptical of two engines more than gliding distance from an Aerodrome.
As the BA38 issue unfolds, I continue to fully believe in ETOPS, though initially my faith was shaken. I continue to be confident because I think the incident was unrelated to ETOPS. A combination of reading, sifting through admittedly sparse Data, and Intuition tells me that. I am fascinated by the posts here, by those far smarter and more experienced than I, and I think to squelch vigorous and respectful debate would be a great Loss. As I have said, this post is now the property of the owner of this website, to do with or not whatever he/they may wish.
AFM
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This is only my second post, so forgive me if I appear to go over old ground.
I fly for fun, but my real business is power.
I know elsewhere, that wax has been targeted as the culprit, and in my view, this is partially correct.
When wax forms in fuel, it is also the fraction of the fuel with the most heat, that has been effectively removed, and the heat left in the remaining liquid will be at a lower heat value, and this could be further aggravated if the remaining fuel has in fact separated into its other fractions, with the worst fuel( lowest amaount of energy) being at the bottom of the tank.
The result, in my viiew is that the FADEC worked fine, but the amount of fuel pumped into the engine lacked the required energy (kJ) to meet the power demanded.
Just my 2 cents worth from a dreaded PP.
Cheers
I fly for fun, but my real business is power.
I know elsewhere, that wax has been targeted as the culprit, and in my view, this is partially correct.
When wax forms in fuel, it is also the fraction of the fuel with the most heat, that has been effectively removed, and the heat left in the remaining liquid will be at a lower heat value, and this could be further aggravated if the remaining fuel has in fact separated into its other fractions, with the worst fuel( lowest amaount of energy) being at the bottom of the tank.
The result, in my viiew is that the FADEC worked fine, but the amount of fuel pumped into the engine lacked the required energy (kJ) to meet the power demanded.
Just my 2 cents worth from a dreaded PP.
Cheers
Wing and engine in a cold box
Firelight and Infrequentflyer789
Yes, yikes! I don't think a "cold box" of the necessary size would be too difficult to find. Expensive yes; there are some pretty large reefer warehouses around but renting one out for a few months could put a considerable dent in the distribution of beef or frozen veg. Getting the temperature down to minus 50C would be a challenge (normal working temperature being minus 18-20C) and intake/exhaust another, assuming the engine would have to be working.
If the AAIB were to go the route of testing temperatures it would probably be more expedient to rig up a prefab coldstore around an existing airframe.
oh, and Brian... JS Mills?
Yes, yikes! I don't think a "cold box" of the necessary size would be too difficult to find. Expensive yes; there are some pretty large reefer warehouses around but renting one out for a few months could put a considerable dent in the distribution of beef or frozen veg. Getting the temperature down to minus 50C would be a challenge (normal working temperature being minus 18-20C) and intake/exhaust another, assuming the engine would have to be working.
If the AAIB were to go the route of testing temperatures it would probably be more expedient to rig up a prefab coldstore around an existing airframe.
oh, and Brian... JS Mills?
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AFM:
The reason the EMC zealots get short shrift is that as a rule, they violate the precept that 99% of other proposers of pet-theories manage to follow:
No matter how improbable your theory, please walk through it from cause to effect. Those opining on fuel waxing, FADEC failure, inner engine icing, pilot error, partial spar valve failure, etc all at least provide the courtesy of a scenario and some sort of support chain.
IMHO, only the proponents of mystical EMC feel that a bit of arm waving, appeal to the vagaries of past unexplained accidents, and exasperated frustration that their explanation is not just ratified as-is, can somehow suffice as support for their otherwise unsupportable stance.
This comes to mind:
That is simply not how scientific inquiry and accident investigation in particular is to be approached. Einstein said: "Keep an open mind. But not so open your brain falls out."
The reason the EMC zealots get short shrift is that as a rule, they violate the precept that 99% of other proposers of pet-theories manage to follow:
No matter how improbable your theory, please walk through it from cause to effect. Those opining on fuel waxing, FADEC failure, inner engine icing, pilot error, partial spar valve failure, etc all at least provide the courtesy of a scenario and some sort of support chain.
IMHO, only the proponents of mystical EMC feel that a bit of arm waving, appeal to the vagaries of past unexplained accidents, and exasperated frustration that their explanation is not just ratified as-is, can somehow suffice as support for their otherwise unsupportable stance.
This comes to mind:
That is simply not how scientific inquiry and accident investigation in particular is to be approached. Einstein said: "Keep an open mind. But not so open your brain falls out."
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System characteristics.
Quoting safetypee:
Taking the AAIB reports published into consideration, (perhaps the investigation has progressed beyond what has been published sofar) if no evidence of an anomaly has been found:
Approaching the issue from another angle, i would go for a combination of system selections (including interaction or possible interference with other systems) and characteristics.
A question that comes to mind would then be: which (sub) system components could (due to a yet undefined fault) migrate from commanded position without generating a fault indication to the flight crew but result in reduced fuel flow and cause engine rollback?
A question related to the one above is, why was the APU door open during approach if there was no mention in the AAIB reports of an electrical power failure? Isn't the APU normally an after landing checklist item?
Green-dot
Are there any interesting vibrations, system selections, or characteristics which could contribute to such a theory during an approach in a 777?
Approaching the issue from another angle, i would go for a combination of system selections (including interaction or possible interference with other systems) and characteristics.
A question that comes to mind would then be: which (sub) system components could (due to a yet undefined fault) migrate from commanded position without generating a fault indication to the flight crew but result in reduced fuel flow and cause engine rollback?
A question related to the one above is, why was the APU door open during approach if there was no mention in the AAIB reports of an electrical power failure? Isn't the APU normally an after landing checklist item?
Green-dot