BA B777 Incident @ Heathrow (merged)
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Taking a different angle on this, I was pleased to see that the FO has now been given credit. The public seem to think that an aircraft is operated by a 'man and a boy', rather than a team. I hope Joe Public (AND the press) take this lesson. It's teamwork.
Flying to the 'angels wings' on the 777 (the maximum pitch attitude) is very difficult, and one relies on one's colleague to advise on RoD, altitude, and lateral position in relation to the runway. This was a great team job. Having flown with Pete, it doesn't surprise me that he and his colleague did so well.
Flying to the 'angels wings' on the 777 (the maximum pitch attitude) is very difficult, and one relies on one's colleague to advise on RoD, altitude, and lateral position in relation to the runway. This was a great team job. Having flown with Pete, it doesn't surprise me that he and his colleague did so well.
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the two engines
OK, we know the 2 engines failed to respond simultaneously.
This is very strange, they are totally independent: only a couple of bits are shared, either fuel or throttle.
It has happened ok, we all know, but why it happened just on short final and not during the previous 12 hours of perfect functioning. The fact that this fault developed just a few seconds before touch down could mean this is more likely fuel related. Otherwise it must be something else, but what?
...fuel related?
If it was fuel related this was totally unexpected and all indicators were showing perfect values so it is possibly going to be some sort of sensors fault or fuel contamination, but if it is contamination why this became a problem only in the last 30-60 secs of a 12hr + flight?...
Excellent job done by all crew.
If you read this message please note I think you are heros.
This is very strange, they are totally independent: only a couple of bits are shared, either fuel or throttle.
It has happened ok, we all know, but why it happened just on short final and not during the previous 12 hours of perfect functioning. The fact that this fault developed just a few seconds before touch down could mean this is more likely fuel related. Otherwise it must be something else, but what?
...fuel related?
If it was fuel related this was totally unexpected and all indicators were showing perfect values so it is possibly going to be some sort of sensors fault or fuel contamination, but if it is contamination why this became a problem only in the last 30-60 secs of a 12hr + flight?...
Excellent job done by all crew.
If you read this message please note I think you are heros.
aka Capt PPRuNe
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Just a quick note to the detractors... you should see some of the stuff we have been deleting from this thread. If you think some of the speculation from some of the contributors is bad, you should read what we have had to go through and delete.
PPRuNe is not a definitive site and whilst the moderators are actively trying to keep some semblance of coherence and prevent the hoards of "experts" who post some astoundingly stupid theories, what remains is, hopefully, a reasonable selection of questions and suppositions that make the thread entertaining AND informative. I would really like to write a book with the content of what we have in fact deleted from threads like this. It would be a best seller in the comedy section of most bookstores.
We try to keep the posts tracking along the lines of the subject matter. There will always be some deviation. Questions that are just so banal (in our humble opinion) or blatantly conjured up by someone with the IQ of a dipstick, together with responses equally as uneducated, are removed in order to keep things sane.
If you think the detractors are having a coronary over what they've read so far, they'd have been eviscerated if they'd have had to read the stuff we've deleted. There is a balance to be had and some very basic questions are allowed as they help to enlighten those who are not so sure of all the terminology to understand better what is being debated.
So, thanks to everyone who has contributed and "yah boo" to those who'se whose literary attempts have been removed for the sake of sanity and preservation of IQ and normal blood pressure. No need to respond to this post as it will also probably be deleted if it isn't relevant to the thread topic.
Please leave the rest of this debate to the issues and not the emotions of the Mr Angry's of Bournemouth.
PPRuNe is not a definitive site and whilst the moderators are actively trying to keep some semblance of coherence and prevent the hoards of "experts" who post some astoundingly stupid theories, what remains is, hopefully, a reasonable selection of questions and suppositions that make the thread entertaining AND informative. I would really like to write a book with the content of what we have in fact deleted from threads like this. It would be a best seller in the comedy section of most bookstores.
We try to keep the posts tracking along the lines of the subject matter. There will always be some deviation. Questions that are just so banal (in our humble opinion) or blatantly conjured up by someone with the IQ of a dipstick, together with responses equally as uneducated, are removed in order to keep things sane.
If you think the detractors are having a coronary over what they've read so far, they'd have been eviscerated if they'd have had to read the stuff we've deleted. There is a balance to be had and some very basic questions are allowed as they help to enlighten those who are not so sure of all the terminology to understand better what is being debated.
So, thanks to everyone who has contributed and "yah boo" to those who'se whose literary attempts have been removed for the sake of sanity and preservation of IQ and normal blood pressure. No need to respond to this post as it will also probably be deleted if it isn't relevant to the thread topic.
Please leave the rest of this debate to the issues and not the emotions of the Mr Angry's of Bournemouth.
Water in Fuel?
Thanks to Noddyscar for this much earlier in response to my question:
"......Noddyscar Fuel Drain check on DY chk
On the 777 daily check for ERs you usually do the Fuel Drain check for water contamination
Drain 1 gallon from center fuel tank sump drain valve as per AMM.
I guess if this was not done in PEK due cold weather, the water content in the tank could have been higher than realised. Would explain both engines flaming out. Crew thinking indication they had fuel........"
Fox Niner wrote: '......The 777 is not prone to fuel icing. the fuel tanks are positioned in the wings in such a way that the OAT can not "reach" the fuel and cool it down as much.
I have not seen a colder fuel temperature than around -30 degrees C on the B777, also overflying siberia. A 747 is much more affected by fuel cooling.
In China we get uplifted with jet A1 or TC1. (russian grade).......'
I can't see how the wing design is going to make much difference to the fuel temperature, except that a thinner wing of larger area may cool the fuel more quickly than a deeper wing. The fuel is sitting on a slap of light alloy (the lower skin) with the ullage (air space) above it. The tanks are vented to atmosphere, so the fuel temperature is going to fairly rapidly cool to outside air temperature, but be warmed a bit by heat loss from the pumps and any pumped, but unused, fuel.
If the water in the fuel above the tank drain was frozen (is that possible?), might this have resulted in a false sample reading, if one was taken at PEK?
Are the jet pumps, to emulsify water in the fuel, in the engine feed tanks(?) running all the time, pilot actuated, or automatic as required?
The question I'm leading to, is whether water content in the fuel could have reached a percentage that it reduced the engine's performance enough to cause what happened?
The 777 uses a different (ultrasonic) fuel gauging system to just about everything else in the air. Could it have lead the pilot to believe he was looking at fuel when it was in fact water; if the water detector was fully submerged in water and not showing a water level? The fuel densitometer should have picked this up, but if it wasn't in the water, perhaps it couldn't indicate this?
Maybe the descent through moisture laden air, causing a lot of water to enter the tank vents, as the outside air entered to maintain pressure equilibrium in the ullage, was 'the straw that broke the camel's back' and the fires went out.
Jumpseat777 was the first to mention that the gauging system is ultrasonic. To clarify his description of the gauging system, the water detector is also an ultrasonic probe, but it points down, to detect a water/fuel interface, whereas the other probes (around 60 of them, all told) look up, to detect the fuel/air interface by measuring the speed of sound in fuel. This gives a fuel height, which if known in three places in a tank, gives a level, and hence a volume. The densitometer reading allows this to be converted into a fuel mass. It is conceivable that the software now allows the fuel probes to detect the false surface of water in them as a secondary return, but I am not aware of this. Can anyone confirm?
Elsewhere on the net, someone has stated that it takes seven gallons of water before the water detector gives a reading. Anyone know how many gallons of water it takes to fully submerge it?
"......Noddyscar Fuel Drain check on DY chk
On the 777 daily check for ERs you usually do the Fuel Drain check for water contamination
Drain 1 gallon from center fuel tank sump drain valve as per AMM.
I guess if this was not done in PEK due cold weather, the water content in the tank could have been higher than realised. Would explain both engines flaming out. Crew thinking indication they had fuel........"
Fox Niner wrote: '......The 777 is not prone to fuel icing. the fuel tanks are positioned in the wings in such a way that the OAT can not "reach" the fuel and cool it down as much.
I have not seen a colder fuel temperature than around -30 degrees C on the B777, also overflying siberia. A 747 is much more affected by fuel cooling.
In China we get uplifted with jet A1 or TC1. (russian grade).......'
I can't see how the wing design is going to make much difference to the fuel temperature, except that a thinner wing of larger area may cool the fuel more quickly than a deeper wing. The fuel is sitting on a slap of light alloy (the lower skin) with the ullage (air space) above it. The tanks are vented to atmosphere, so the fuel temperature is going to fairly rapidly cool to outside air temperature, but be warmed a bit by heat loss from the pumps and any pumped, but unused, fuel.
If the water in the fuel above the tank drain was frozen (is that possible?), might this have resulted in a false sample reading, if one was taken at PEK?
Are the jet pumps, to emulsify water in the fuel, in the engine feed tanks(?) running all the time, pilot actuated, or automatic as required?
The question I'm leading to, is whether water content in the fuel could have reached a percentage that it reduced the engine's performance enough to cause what happened?
The 777 uses a different (ultrasonic) fuel gauging system to just about everything else in the air. Could it have lead the pilot to believe he was looking at fuel when it was in fact water; if the water detector was fully submerged in water and not showing a water level? The fuel densitometer should have picked this up, but if it wasn't in the water, perhaps it couldn't indicate this?
Maybe the descent through moisture laden air, causing a lot of water to enter the tank vents, as the outside air entered to maintain pressure equilibrium in the ullage, was 'the straw that broke the camel's back' and the fires went out.
Jumpseat777 was the first to mention that the gauging system is ultrasonic. To clarify his description of the gauging system, the water detector is also an ultrasonic probe, but it points down, to detect a water/fuel interface, whereas the other probes (around 60 of them, all told) look up, to detect the fuel/air interface by measuring the speed of sound in fuel. This gives a fuel height, which if known in three places in a tank, gives a level, and hence a volume. The densitometer reading allows this to be converted into a fuel mass. It is conceivable that the software now allows the fuel probes to detect the false surface of water in them as a secondary return, but I am not aware of this. Can anyone confirm?
Elsewhere on the net, someone has stated that it takes seven gallons of water before the water detector gives a reading. Anyone know how many gallons of water it takes to fully submerge it?
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spool up
wondering what the spool up characteristics are on the trent engine.
does anyone know if the plane had an uninterrupted idle descent from cruise?
just wondering...you guys know what I mean.
does anyone know if the plane had an uninterrupted idle descent from cruise?
just wondering...you guys know what I mean.
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RE: FADEF failure?
a common-mode loss of aircraft-supplied power would cause both engines to shut down only if both dedicated generators had also failed
Last edited by Bill.Martin; 18th Jan 2008 at 22:59. Reason: Typo - word missing!
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AirScrew,
I am not worthy! Or deserving. Of your disapproval of the majority of correspondents on this fine site.
In the world outside the aviation industry anything that moves (or doesn't move) is open to scrutiny by would-be "barrack-room lawyers".
I've had a bellyfull over three decades.
The aviation industry is safe because it is supervised to a degree that most souls would find insufferable. None more so than the team on the flight deck.
Nature teaches us how to trust people. Hence, a decision was made to present the Captain, Senior First Officer and Cabin Service Director (apparently with orders not to look the least bit happy) to inspire public confidence.
The facts will out.
In Black Box Veritas.
Mr (Flight Lieutenant) Jonathan Tapper and Mr (Flight Lieutenant) Rick Cook did not have a Black Box. Soon, hopefully, their memories will receive the respect they deserve.
I am not worthy! Or deserving. Of your disapproval of the majority of correspondents on this fine site.
In the world outside the aviation industry anything that moves (or doesn't move) is open to scrutiny by would-be "barrack-room lawyers".
I've had a bellyfull over three decades.
The aviation industry is safe because it is supervised to a degree that most souls would find insufferable. None more so than the team on the flight deck.
Nature teaches us how to trust people. Hence, a decision was made to present the Captain, Senior First Officer and Cabin Service Director (apparently with orders not to look the least bit happy) to inspire public confidence.
The facts will out.
In Black Box Veritas.
Mr (Flight Lieutenant) Jonathan Tapper and Mr (Flight Lieutenant) Rick Cook did not have a Black Box. Soon, hopefully, their memories will receive the respect they deserve.
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Maybe all the cockpit screens went blue with the dreaded message 'Windows fatal error'.
Seriously, at that stage of a long flight, which tanks would be in use? Wing tanks, fuselage tanks or both? Would both engines draw fuel from the same tank at that late stage of the flight? What would make two engines, designed to operate independently, cease functioning together so late in the flight? Cross-feeding contaminated fuel? Well, maybe but surely that would have manifested itself as a problem earlier. I would bet that they didn't run out of fuel - there are reports in this forum of fuel leakage after the event and in an earlier post I mentioned the fire brigade hosing down under the aircraft long after the incident took place. I think the answer to this has to be (somehow) fuel management systems (computer) related so let's see.
Another (late) thought. Avgas floats on top of water (hence drain tests on my C152 for first flight of each day). What happens with Avtur? Is it lighter than water too?
Seriously, at that stage of a long flight, which tanks would be in use? Wing tanks, fuselage tanks or both? Would both engines draw fuel from the same tank at that late stage of the flight? What would make two engines, designed to operate independently, cease functioning together so late in the flight? Cross-feeding contaminated fuel? Well, maybe but surely that would have manifested itself as a problem earlier. I would bet that they didn't run out of fuel - there are reports in this forum of fuel leakage after the event and in an earlier post I mentioned the fire brigade hosing down under the aircraft long after the incident took place. I think the answer to this has to be (somehow) fuel management systems (computer) related so let's see.
Another (late) thought. Avgas floats on top of water (hence drain tests on my C152 for first flight of each day). What happens with Avtur? Is it lighter than water too?
Last edited by Xeque; 18th Jan 2008 at 23:26. Reason: added last bit
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A question for someone with 777 engineering/operations expertise.
Does the 777 have any sort of fuel heaters that heat fuel before the fuel gets to the fuel filters/water seperators?
If so, do these require to be switched off on the approach check list?
Does the 777 have any sort of fuel heaters that heat fuel before the fuel gets to the fuel filters/water seperators?
If so, do these require to be switched off on the approach check list?
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"Danny" & "Doors on Auto"
Have you kept everything that was deleted? It would be great to see a comedy "out-takes" thread of the incident in JB
Think it would be great idea.......... worth considering anyway.
Have you kept everything that was deleted? It would be great to see a comedy "out-takes" thread of the incident in JB
Think it would be great idea.......... worth considering anyway.
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Originally Posted by H.Finn
...
At some point, it was discovered that there was a huge chunk of ice floating in the fuel tank of one of the aircraft, as the condenced water never had time to melt...
...
At some point, it was discovered that there was a huge chunk of ice floating in the fuel tank of one of the aircraft, as the condenced water never had time to melt...
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For the record
Yes not part of the airplane its part of the engine...dual purpose cools the oil heats the fuel... Fuel/Oil heat exchanger..no switches no manual input works as long as fuel flows...
and someone asked about AIMs its dual its actually a cabinet full of IC cards called card files
Yes not part of the airplane its part of the engine...dual purpose cools the oil heats the fuel... Fuel/Oil heat exchanger..no switches no manual input works as long as fuel flows...
and someone asked about AIMs its dual its actually a cabinet full of IC cards called card files
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Danny,
Outstanding work to keep the site going in the face of overwhelming demand.
I find your calm commentary and TightSlot's quiet, but uncompromisingly firm, good humour inspiring.
Even just seeing a contrail makes me happy. Flying should be impossible. Unless you're an angel.
God alone knows what cheers a hack on the rolling tv news. Other peoples' misery, I suspect. A life without romance is not a life IMHO!
Outstanding work to keep the site going in the face of overwhelming demand.
I find your calm commentary and TightSlot's quiet, but uncompromisingly firm, good humour inspiring.
Even just seeing a contrail makes me happy. Flying should be impossible. Unless you're an angel.
God alone knows what cheers a hack on the rolling tv news. Other peoples' misery, I suspect. A life without romance is not a life IMHO!
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The AAIB report implies (to me anyway) that the engines did not "cut out" as is being reported by many, but maybe stayed at the same power setting despite the movements of the power levers.... Obviously not being able to add power as required at that time resulted in a landing short.... if so, the opposite could also happen, the auto-throttle/crew trying to reduce power, and landing long if nothing happened 
Strange goings on onboard G-YMMM!
Strange goings on onboard G-YMMM!
BGQ - re a/t, ok, thank you. Again, I don't think this is an area of high interest in terms of causes, but merely something to understand.
Bill.Martin;
Unquestionably in mission-critical systems, the design goal is for system, control and indicator independance.
The disturbing aspect of this, apropos your remarks simfly, (and I may have missed other comments already made to this effect) is, both engines "failed", (ok Sir Ralph, "failed to respond") at the same time. This was not a single-"engine" failure - this was an "across the beam" failure involving independant systems - far more disturbing I should think.
Since FADECs are truly independant with their own generator (PMA) and electrical backups for FADECs are part of the design, and since documented engine roll-back behaviours almost always involve only one engine*, the need to examine the "corpus collosum" if I may, of the autothrust system , may be more highly indicated than in other areas of investigation, (and the investigators, I realize, will have comprehended this almost immediately after the initial determination of failure mode(s) ).
ILoadMyself; terrific post - very true, and well stated - tip 'o the hat.
*I found a documented case involving a CFM56 which if nothing else, makes interesting reading for further knowledge on such systems. It can be found at, "TSB Report on Cathay Pacific A340"
Bill.Martin;
Unquestionably in mission-critical systems, the design goal is for system, control and indicator independance.
The disturbing aspect of this, apropos your remarks simfly, (and I may have missed other comments already made to this effect) is, both engines "failed", (ok Sir Ralph, "failed to respond") at the same time. This was not a single-"engine" failure - this was an "across the beam" failure involving independant systems - far more disturbing I should think.
Since FADECs are truly independant with their own generator (PMA) and electrical backups for FADECs are part of the design, and since documented engine roll-back behaviours almost always involve only one engine*, the need to examine the "corpus collosum" if I may, of the autothrust system , may be more highly indicated than in other areas of investigation, (and the investigators, I realize, will have comprehended this almost immediately after the initial determination of failure mode(s) ).
ILoadMyself; terrific post - very true, and well stated - tip 'o the hat.
*I found a documented case involving a CFM56 which if nothing else, makes interesting reading for further knowledge on such systems. It can be found at, "TSB Report on Cathay Pacific A340"