BA038 (B777) Thread
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I don't suppose anyone has the additives that the Chinese add to the fuel to drop the freezing point ???
I have a feeling there is something there that shouldn't be there.
Failing that, anyone who comes ex-PEK, can you get a cupful of fuel and I will do a decent NMR on it, I have a suspicious feeling about all of this.
I have a feeling there is something there that shouldn't be there.
Failing that, anyone who comes ex-PEK, can you get a cupful of fuel and I will do a decent NMR on it, I have a suspicious feeling about all of this.
Perhaps there is a specific molecule in the fuel that acts as a nucleus that collects several water molecules about it. This wax/water blob would then freeze to cold surfaces and subsequently collect its fellows.
The Reverend
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GE matters aside, it is interesting that both roll back aircraft (Delta and British Airways) were uplifted in China.
Why can't people accept the Boeing and RR findings and recommendations?
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Airfoilmod :
.............. What I think would be fascinating is a hard copy made available of this thread. Warts and All. Informal Hangar Talk with the odd expert poking in now and again, a year long exercise in the new format of the "Pilot Lounge"
Remember this is the second thread on the accident, the first one was pretty huge as well.
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.............. What I think would be fascinating is a hard copy made available of this thread. Warts and All. Informal Hangar Talk with the odd expert poking in now and again, a year long exercise in the new format of the "Pilot Lounge"
Remember this is the second thread on the accident, the first one was pretty huge as well.
.
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Why can't people accept the Boeing and RR findings and recommendations?
They are no more than interim.
They used non-representative fuel, and unless they are being very odd haven't managed to recreate the problem using representative fuel (anyone know ?)
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In addition, the new fuel/ice behaviour needs examination and new rules written - AND all engine/fuel installations need to be examined against the [future] new rules. There may be more aircraft at risk than we know.
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They are no more than interim.
They used non-representative fuel, and unless they are being very odd haven't managed to recreate the problem using representative fuel (anyone know ?)
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In addition, the new fuel/ice behaviour needs examination and new rules written - AND all engine/fuel installations need to be examined against the [future] new rules. There may be more aircraft at risk than we know.
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The Reverend
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Phil,
Low freezing point Chinese or Russian fuel has been in use since Adam was a little boy. I am talking about exposure of this fuel for some 30 odd years before my retirement. Can you tell me why this problem has only affected the Trent800.
They are no more than interim.
Additives (again)
Several of us discussed this matter waaay back. I brought up some issues -- as did airfoilmod and several others -- related to FSII. As was mentioned a few posts previously, these additives work by attracting water molecules to attach themselves to the additive molecules. It may well be that the properties of the resultant "stuff" are just not well known in long lasting low temp conditions.
Excerpt from a post from last June (18th):
“I am certainly no subject matter expert when it comes to fuels and fuel properties but several previous incidents (and a couple of accidents) keep worming their way into my thoughts when I think of this occurrence. The cases I’m talking about have this in common: Unpredicted or unexpected changes to the behaviour, consistency, lubricity, viscosity or dispersal characteristics of fuel – caused by FSII. (Contrary to what some have written FSII is not one specific chemical formulation but can be one of several compositions, including dipropylene glycol, glycerol formal, and DiEGME.) As many of you know, the amount (if any) of FSII in the fuel loaded in China could fall into a fairly wide spectrum and still be within specs. In serving this ball into the PPRuNe court, I expect (and would appreciate) comments and critique on the possibility of FSII being a factor.”
Grizz
Excerpt from a post from last June (18th):
“I am certainly no subject matter expert when it comes to fuels and fuel properties but several previous incidents (and a couple of accidents) keep worming their way into my thoughts when I think of this occurrence. The cases I’m talking about have this in common: Unpredicted or unexpected changes to the behaviour, consistency, lubricity, viscosity or dispersal characteristics of fuel – caused by FSII. (Contrary to what some have written FSII is not one specific chemical formulation but can be one of several compositions, including dipropylene glycol, glycerol formal, and DiEGME.) As many of you know, the amount (if any) of FSII in the fuel loaded in China could fall into a fairly wide spectrum and still be within specs. In serving this ball into the PPRuNe court, I expect (and would appreciate) comments and critique on the possibility of FSII being a factor.”
Grizz
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Hot Dog...
You are asking the wrong question... the question is not "why only RR" but rather "at what point, as the temperature decreases in a given fuel will it also affect other engine/airframe combinations"?
That is the point inherent in Phil's and Grizz's excellent replies.
That is the point inherent in Phil's and Grizz's excellent replies.
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Read http://www.pristaerospace.co/hi-flas...ils/index.html on how dissolved water comes out of solution as avaition fuel is cooled. This explains where the water came from initially. (AAIB reports 70ppm dissolved water in the fuel) The resultant ice and supercooled water then adheres to pipework in the fuel delivery system, including the small bore tubing in the inlet to the FOHE. (anyone know the ID of these tubes as they appear to be very small bore to me? ) In tests the delta P across the FOHE was observed at levels in excess of 9 barg suggesting tube blockage. (in the NTSB pic of the FOHE tube sheet, after recent testing, many of the tubes are plugged) If the fuel is heated the water remains dissolved and is not problematic in the fuel delivery system.
If you click on "history" on the above website the first instance of this type of failure is reported in a B52 in 1958, where 5 of the eight engines stopped.
Re anti icing additives the Shell Avaition website declares that anti icing additive is mandatory on all military aircraft fuel but is not necessary on commercial aircraft where the fuel is heated.
Was the fuel on the aircraft in question too cold for too long? Does cold unheated fuel on shorter flights deposit ice in the fuel system pipework and is not a problem because not enough of it has formed before the flight ends safely? If the fuel is heated what is the lowest safe temperature before the dissolved water starts to leave the fuel and become an operational problem?
As a retired engineer I am interested in this problem as I flew the same route as a passenger 8 hours behind BA038. I was in a 747 and the OAT west of the Urals was -76 C for hours. My flight was uneventful. I keep asking myself why?
If you click on "history" on the above website the first instance of this type of failure is reported in a B52 in 1958, where 5 of the eight engines stopped.
Re anti icing additives the Shell Avaition website declares that anti icing additive is mandatory on all military aircraft fuel but is not necessary on commercial aircraft where the fuel is heated.
Was the fuel on the aircraft in question too cold for too long? Does cold unheated fuel on shorter flights deposit ice in the fuel system pipework and is not a problem because not enough of it has formed before the flight ends safely? If the fuel is heated what is the lowest safe temperature before the dissolved water starts to leave the fuel and become an operational problem?
As a retired engineer I am interested in this problem as I flew the same route as a passenger 8 hours behind BA038. I was in a 747 and the OAT west of the Urals was -76 C for hours. My flight was uneventful. I keep asking myself why?
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find this slightly concerning:
"Some small items of debris were discovered in the following
locations:
1. Right main tank – a red plastic sealant scraper
approximately 10 cm x 3 cm under the suction
inlet screen.
2. Left main tank, water scavenge inlet - a piece of
black plastic tape, approximately 5 cm square;
a piece of brown paper of the same size and
shape, and a piece of yellow plastic.
3. Right centre tank override pump – a small
piece of fabric or paper found in the guillotine
valve of the pump housing.
4. Left centre tank water scavenge jet pump
– small circular disc, 6 mm in diameter, in the
motive flow chamber."
Especially as it now appears to have been fuel starvation!
"Some small items of debris were discovered in the following
locations:
1. Right main tank – a red plastic sealant scraper
approximately 10 cm x 3 cm under the suction
inlet screen.
2. Left main tank, water scavenge inlet - a piece of
black plastic tape, approximately 5 cm square;
a piece of brown paper of the same size and
shape, and a piece of yellow plastic.
3. Right centre tank override pump – a small
piece of fabric or paper found in the guillotine
valve of the pump housing.
4. Left centre tank water scavenge jet pump
– small circular disc, 6 mm in diameter, in the
motive flow chamber."
Especially as it now appears to have been fuel starvation!
There have been much worse incidents concerning things left in aircraft!
1. Inspection Engineers chair.
2. Flow pack in the tanks discovered on fuelling the aircraft.
I could go on point is to learn by our mistakes and in this case a basic design flaw may have been over looked!
luckily only a dented pride, a rather expensive insurance bill, but no lives lost!
No lives lost is the important bit!
Unfortunately as humans we a prone to Human error!
and to poor grammer
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Oilandgasman:
Thanks for the link to Prist Aero (it is missing an M):Cheers, M
Thanks for the link to Prist Aero (it is missing an M):Cheers, M
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With all due respect to Prist
And I've used it, the first paragraph is deceptive. It's claim, The Water cannot be removed......(on production) is false, because it then describes how supercooled water comes out of solution in the Fuel line, to clog filters and bends, (Something I posted at the beginning of this thread).
If, on Board, the water is "removed", it could just as easily be taken out on the ground, after cooling the Fuel.
Without irritating Pinkman too much, it is eminently possible to produce and transport water free Fuel. Expensive? Oh Yeah.
But it isn't necessary.
The 777/Trent, with new architecture and a mod for its FOHE will be most welcome back into the High and Frigid Land of ETOPS. My posit......
AF
If, on Board, the water is "removed", it could just as easily be taken out on the ground, after cooling the Fuel.
Without irritating Pinkman too much, it is eminently possible to produce and transport water free Fuel. Expensive? Oh Yeah.
But it isn't necessary.
The 777/Trent, with new architecture and a mod for its FOHE will be most welcome back into the High and Frigid Land of ETOPS. My posit......
AF
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Low freezing point Chinese or Russian fuel has been in use since Adam was a little boy. I am talking about exposure of this fuel for some 30 odd years before my retirement. Can you tell me why this problem has only affected the Trent800.
Seriously Rev, I think the Trent might be the canary in the coal mine and there are broader issues at work that we've yet to divine.
You ask why only the Roller, I ask how did this get past the design and certification process, and, the entire fleet of airplanes all of these years and flight hours.
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The Rev and vapilot
Peace. It isn't one question or the other, it's both. One is pressing, mitigation of a duplicable Fault in one specific a/c, and the other, prevention of unknown problems possible with other types. Also, what other "discrepancies" does Chinese Fuel exhibit besides low FP, if any.
Could the build up of ice in the line upstream of the FOHE in both GE and Trent meet a different obstacle (resolution) closer in? The HP in GE is "in front" of the FOHE, which also has a two pass profile for the oil, heating the Fuel more than a one pass design (Trent).
Boeing has addressed, and NTSB reviewed, the mechanism thus far. NTSB claims another incident is likely without a change in the 777-200ER. FAA has yet to speak since its AD modification. The language of the resulting Interim has "exonerated" other types, so far. Wiser, and sounder minds than mine are comfortable with the pace, what else to say??
AF
Could the build up of ice in the line upstream of the FOHE in both GE and Trent meet a different obstacle (resolution) closer in? The HP in GE is "in front" of the FOHE, which also has a two pass profile for the oil, heating the Fuel more than a one pass design (Trent).
Boeing has addressed, and NTSB reviewed, the mechanism thus far. NTSB claims another incident is likely without a change in the 777-200ER. FAA has yet to speak since its AD modification. The language of the resulting Interim has "exonerated" other types, so far. Wiser, and sounder minds than mine are comfortable with the pace, what else to say??
AF
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Airfoilmod ;
Boeing has addressed, and NTSB reviewed, the mechanism thus far. NTSB claims another incident is likely without a change in the 777-200ER. FAA has yet to speak since its AD modification. The language of the resulting Interim has "exonerated" other types, so far. Wiser, and sounder minds than mine are comfortable with the pace, what else to say??
NO. The tests, as far as can be ascertained, have been carried out using unrepresentative fuel. The mechanism is indicated, but NOT confirmed, and DEFINATELY NOT understood. The mechanism needs to be explained with representative fuel and a real understanding of the mechanism obtained so that new operating and design rules implemented.
The AD has NOT "exonerated" other types whether "so far" or not - have they managed representative tests on ALL other aircraft and engine installations ?
The pace may be as fast as it is possible, but it is nowhere near complete, and if the fuel/ice behaviour is as odd as the AAIB report indicates it may be many years before the whole problem is sorted out.
Is it time to panic - obviously not.
Is it time to relax - no, there is much work still to be done.
.
Boeing has addressed, and NTSB reviewed, the mechanism thus far. NTSB claims another incident is likely without a change in the 777-200ER. FAA has yet to speak since its AD modification. The language of the resulting Interim has "exonerated" other types, so far. Wiser, and sounder minds than mine are comfortable with the pace, what else to say??
NO. The tests, as far as can be ascertained, have been carried out using unrepresentative fuel. The mechanism is indicated, but NOT confirmed, and DEFINATELY NOT understood. The mechanism needs to be explained with representative fuel and a real understanding of the mechanism obtained so that new operating and design rules implemented.
The AD has NOT "exonerated" other types whether "so far" or not - have they managed representative tests on ALL other aircraft and engine installations ?
The pace may be as fast as it is possible, but it is nowhere near complete, and if the fuel/ice behaviour is as odd as the AAIB report indicates it may be many years before the whole problem is sorted out.
Is it time to panic - obviously not.
Is it time to relax - no, there is much work still to be done.
.
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Whoa
Thus Far, I said. I don't claim the mechanism is understood or that anything is in concrete. I am paraphrasing the results from the report.
Rolls is designing a new FOHE, (For the Trent RB211-800 ONLY). Where have I misinterpreted the report? Who claims this situation is resolved?
No AD "exonerates" any a/c, ever. It is written and enforced to address a specific deficiency. It does not address other a/c but the 777-200ER.
It is the Trent fit 777's that are the focus here, if you want others investigated, well, you are allowed to have input to the Authority, it is encouraged. The reports claim no other type is suspect.
AF
Rolls is designing a new FOHE, (For the Trent RB211-800 ONLY). Where have I misinterpreted the report? Who claims this situation is resolved?
No AD "exonerates" any a/c, ever. It is written and enforced to address a specific deficiency. It does not address other a/c but the 777-200ER.
It is the Trent fit 777's that are the focus here, if you want others investigated, well, you are allowed to have input to the Authority, it is encouraged. The reports claim no other type is suspect.
AF
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I have not read this thread but I wonder if this feedback is interesting for you....
Sir, I am concerned at the decision to allow Boeing 777 aircraft with Rolls-Royce engines to continue flying after the crash landing at Heathrow in January 2008 (report, Mar 14). I cannot help comparing the response to this accident with that after the loss of an Air France Concorde at Paris in 2000. The latter aircraft was brought down after a collision with a metal object on the runway, that should never have been there in the first place. Yet despite the aircraft being relatively blameless, the entire Concorde fleet was grounded within days pending hugely expensive modifications to the fuel tanks.
Within a very short time of the Heathrow crash landing in January 2008 it was apparent that there was a potentially serious design problem affecting this aircraft. The temporary operating procedures for these Boeing 777s, pending modifications, appear to be no more than window dressing to deflect public opinion. I have read internet forums where Boeing 777 pilots have resorted to exchanging informal ideas about what best to do if faced with unresponsive engines at the critical moments on the approach to land. This should not be happening in 21st-century aviation.
It is a letter to your Times newspaper of today. I took the guys name out just in case he-you know-offednded someone?
Sir, I am concerned at the decision to allow Boeing 777 aircraft with Rolls-Royce engines to continue flying after the crash landing at Heathrow in January 2008 (report, Mar 14). I cannot help comparing the response to this accident with that after the loss of an Air France Concorde at Paris in 2000. The latter aircraft was brought down after a collision with a metal object on the runway, that should never have been there in the first place. Yet despite the aircraft being relatively blameless, the entire Concorde fleet was grounded within days pending hugely expensive modifications to the fuel tanks.
Within a very short time of the Heathrow crash landing in January 2008 it was apparent that there was a potentially serious design problem affecting this aircraft. The temporary operating procedures for these Boeing 777s, pending modifications, appear to be no more than window dressing to deflect public opinion. I have read internet forums where Boeing 777 pilots have resorted to exchanging informal ideas about what best to do if faced with unresponsive engines at the critical moments on the approach to land. This should not be happening in 21st-century aviation.
It is a letter to your Times newspaper of today. I took the guys name out just in case he-you know-offednded someone?