BA038 (B777) Thread
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We are barking up the wrong tree here.
The water in aircraft fuel tanks is not introduced by refuelling. It is normal when refuelling to take a sample from the bowser/dispenser. The apparatus to do this is built into the truck. This sample is then tested for density and water. This is normal, and done all the time by refuellers. A small sample of the supplied fuel is drawn through a Shell water detector capsule by a syringe. In all my years refuelling aircraft, I have never seen any water detected.
The water in fuel tanks comes from the air in the tank. If the empty tank is full of humid air, the water will settle into the fuel on refuelling. Some aircraft have complicated systems to remove this water. The best I have seen was on the Tristar. A system of jet pumps and small bore pipes sucked up all the water from the bottom corners of the tanks and sent it into the engine feed system. I spent many happy hours cleaning these jet pumps as they became clogged, usually with bits of sealant from the tanks. Even the B777 has a much simpler system of water scavenge to accomplish this. Obviously on this occasion it didn't work.
Also the tanks are sumped by technicians about every day by draining liquid from the bottom sumps of the tanks. This is difficult in the winter as the water will freeze, but is done when practical. I have done this many times, and rarely seen more than a few cc's of water in the drain bottle.
The water in aircraft fuel tanks is not introduced by refuelling. It is normal when refuelling to take a sample from the bowser/dispenser. The apparatus to do this is built into the truck. This sample is then tested for density and water. This is normal, and done all the time by refuellers. A small sample of the supplied fuel is drawn through a Shell water detector capsule by a syringe. In all my years refuelling aircraft, I have never seen any water detected.
The water in fuel tanks comes from the air in the tank. If the empty tank is full of humid air, the water will settle into the fuel on refuelling. Some aircraft have complicated systems to remove this water. The best I have seen was on the Tristar. A system of jet pumps and small bore pipes sucked up all the water from the bottom corners of the tanks and sent it into the engine feed system. I spent many happy hours cleaning these jet pumps as they became clogged, usually with bits of sealant from the tanks. Even the B777 has a much simpler system of water scavenge to accomplish this. Obviously on this occasion it didn't work.
Also the tanks are sumped by technicians about every day by draining liquid from the bottom sumps of the tanks. This is difficult in the winter as the water will freeze, but is done when practical. I have done this many times, and rarely seen more than a few cc's of water in the drain bottle.
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As many Japanese car owners will have noted, there is a relatively cheap and simple way to eliminate atmospheric pollution.
Automotive Brake Fluid is extremely hygroscopic, a feature which dramatically lowers it's boiling -point and helps the system rust from the inside.
The wiley orientals put an inverted soft rubber "top-hat" under the filler-cap....as the fluid level drops, so does the membrane (retaining -cap is vented, as normal.
Now, Concorde's tanks were lined with a flexible-rubber in it's latter days , so it's not an insurmountable problem materials-wise.
I appreciate there are srructural members, baffles and the like to contend with which may necessitate separate "compartment" bags which could be pinked by a standardised coupling. A metal outer-tank would still be required for mechanical strength and containment of the "bladders".....as fuel is removed, the bladder collapses...any water condensatewould collect on the OUTSIDE of the fuel-bladder and inside the structural retaining tank which would need draining, of course.
This doesn't come without a weight penalty, but IMHO there's a major safety benefit (as anyone who'se experienced brake-failure will testify
)
Going back to the fuel spill-return /heat-exchanger idea,- coaxial pipework with the warmed return on the outside would also insulate the supply from ambient temperature. any failure of the inner-pipe would merely "short-circuit" the rerturn /flow path A leak in the return would be no different to what would obtain in the present layout. again, a safety benefit at minimal penalty.
Appreciated that I may well be talking poppycock,but just sometimes, the bystander sees something the participants miss.
Automotive Brake Fluid is extremely hygroscopic, a feature which dramatically lowers it's boiling -point and helps the system rust from the inside.
The wiley orientals put an inverted soft rubber "top-hat" under the filler-cap....as the fluid level drops, so does the membrane (retaining -cap is vented, as normal.
Now, Concorde's tanks were lined with a flexible-rubber in it's latter days , so it's not an insurmountable problem materials-wise.
I appreciate there are srructural members, baffles and the like to contend with which may necessitate separate "compartment" bags which could be pinked by a standardised coupling. A metal outer-tank would still be required for mechanical strength and containment of the "bladders".....as fuel is removed, the bladder collapses...any water condensatewould collect on the OUTSIDE of the fuel-bladder and inside the structural retaining tank which would need draining, of course.
This doesn't come without a weight penalty, but IMHO there's a major safety benefit (as anyone who'se experienced brake-failure will testify
)Going back to the fuel spill-return /heat-exchanger idea,- coaxial pipework with the warmed return on the outside would also insulate the supply from ambient temperature. any failure of the inner-pipe would merely "short-circuit" the rerturn /flow path A leak in the return would be no different to what would obtain in the present layout. again, a safety benefit at minimal penalty.
Appreciated that I may well be talking poppycock,but just sometimes, the bystander sees something the participants miss.
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Originally Posted by Swedish Steve
The water in aircraft fuel tanks is not introduced by refuelling. It is normal when refuelling to take a sample from the bowser/dispenser. The apparatus to do this is built into the truck. This sample is then tested for density and water. This is normal, and done all the time by refuellers. A small sample of the supplied fuel is drawn through a Shell water detector capsule by a syringe. In all my years refuelling aircraft, I have never seen any water detected.
Originally Posted by Lemain
Looking at the condensate due to humid air, let us consider the worst case of an empty tank full of saturated air at 30C. The mass of water could be up to 30g per cubic metre (i.e. 30cc water or six teaspoons-full per cubic metre). I am not surprised that you seldom find much water in the sumps.
Originally Posted by Rightbase
IIRC BA038 was pretty well water and ice free before starting the 2-way trip to Beijing and back.
At the risk of stating the obvious, either
1) There was water in the uploaded fuel, or
2) The amount of water condensed from the incoming air was much greater than calculated, or
3) The aircraft hadn't been sumped adequately before the flight, or
4) It wasn't ice in the fuel system which brought down BA038.
Sooty
Sorry, Sooty
It isn't a case of either-or. It is and-and-and.
My (amateur) analysis of water source candidates based on information available is:
3Kg Max dissolved moisture at Beijing uplift (AIB all tanks)
2Kg Max entrained moisture at Beijing uplift (AIB all tanks)
Max adiabatic ingestion into centre tank (single air mass assumed):
0.4Kg descent to Beijing 0 degrees @ surface = 4.8 mg/litre
1.2Kg descent to LHR 15 degrees @ surface = 12.8mg/litre
Max adiabatic ingestion into main tanks (total for both tanks)
0.2Kg Beijing
0.7Kg LHR
Plus an unknown amount caused by centre tank fuel purge jet pumps sucking air for two and a bit hours after the tank is emptied (this may be the AIB's 0.14ltr (=0.14Kg) drawn in through the fuel tank vent system)
Plus any remnants of dissolved and entrained LHR uplift
Plus trapped water that cannot get to the sumps (0.35 litres total found in the main tanks at the earlier inspection - AIB) which is almost certainly totally innocuous.
The total is something like 8 litres max.
About a quarter of the uplift would start in the centre tank, so the centre tank could contribute some 2 litres or more. The centre tank is IMHO significant because instead of sucking air the fuel purge pumps will inject its water into the cold main tanks once the centre tank warms up above freezing.
My (amateur) analysis of water source candidates based on information available is:
3Kg Max dissolved moisture at Beijing uplift (AIB all tanks)
2Kg Max entrained moisture at Beijing uplift (AIB all tanks)
Max adiabatic ingestion into centre tank (single air mass assumed):
0.4Kg descent to Beijing 0 degrees @ surface = 4.8 mg/litre
1.2Kg descent to LHR 15 degrees @ surface = 12.8mg/litre
Max adiabatic ingestion into main tanks (total for both tanks)
0.2Kg Beijing
0.7Kg LHR
Plus an unknown amount caused by centre tank fuel purge jet pumps sucking air for two and a bit hours after the tank is emptied (this may be the AIB's 0.14ltr (=0.14Kg) drawn in through the fuel tank vent system)
Plus any remnants of dissolved and entrained LHR uplift
Plus trapped water that cannot get to the sumps (0.35 litres total found in the main tanks at the earlier inspection - AIB) which is almost certainly totally innocuous.
The total is something like 8 litres max.
About a quarter of the uplift would start in the centre tank, so the centre tank could contribute some 2 litres or more. The centre tank is IMHO significant because instead of sucking air the fuel purge pumps will inject its water into the cold main tanks once the centre tank warms up above freezing.
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Re. water amounts/tests
IF you had bothered to look at the thread, and the second interim report you will see that the tests are on "out of spec" fuel (90 ppm ????) and were still faked/forced to get some sort of problem.
The fuel in China has been stated to have been in spec (or "exceeded" spec) (70 ppm).
The second interim report goes into the samples taken in remaining tank (40 ppm ???????) and likely fuel conditions.
It is no good setting new hares running if they have already been shot.
See, for instance, post 2476,
IF you had bothered to look at the thread, and the second interim report you will see that the tests are on "out of spec" fuel (90 ppm ????) and were still faked/forced to get some sort of problem.
The fuel in China has been stated to have been in spec (or "exceeded" spec) (70 ppm).
The second interim report goes into the samples taken in remaining tank (40 ppm ???????) and likely fuel conditions.
It is no good setting new hares running if they have already been shot.
See, for instance, post 2476,
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We're now at 130 pages with really nothing new on the subject.
I'm "unsubscribing".... keeps down my incoming e-mail.
Maybe when there's something really new, there will be another thread.
CJ
I'm "unsubscribing".... keeps down my incoming e-mail.
Maybe when there's something really new, there will be another thread.
CJ
Captain Peter Burkill
made his final flight for BA yesterday.
BA hero Peter Burkill takes off - mirror.co.uk
I don't think so - unless they're on fire.
Apologies for the source
Pity they couldn't find a library pic of a 777.
BA hero Peter Burkill takes off - mirror.co.uk
fire trucks sprayed it with water - a traditional send-off for retiring pilots.
Apologies for the source
Pity they couldn't find a library pic of a 777.
Last edited by Basil; 30th Aug 2009 at 16:16.
"The INTRODUCER"
But not always...
I landed at Singapore in a BA 744 and on shutdown the FO came on the PA and announced that the captain had just that minute told him that it was his (the captain's) final flight as he was retiring and would be returning to London as pax. Perhaps we'd like to congratulate him. Which we did.
I supose there's an argument that that's the professional, albeit boring, way to do it. A bit like the RAF not allowing studes to make their final sortie on a course solo.
I supose there's an argument that that's the professional, albeit boring, way to do it. A bit like the RAF not allowing studes to make their final sortie on a course solo.
Controversial, moi?
Were talking about two fire trucks forming an arch of water that falls just like rain. Aircraft fly in rain all the time, it's not unprofessional.
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Send Off
I was a passenger on a United B777 flight from LHR to Chicago a couple of years ago when, on landing at Chicago, the Captain came on the PA to advise passengers not to be alarmed at the sight of fire tenders spraying an arc over the aircraft as it passed - we were not on fire! It was a 'traditional' send off for the Captains last flight. A nice touch I thought.
They tried to do this to me on my last commercial flight but the OAT was well below zero and the aircraft was on a quick turnround! Fortunately the firemen were persuaded to desist and common sense prevailed.
It is NOT a traditional send off.
It MAY be done but I know many retired pilots who were not washed out, most because they didn't make a big deal of their retirement.
overstress,
Quite.
manrow,
this refers to the pilot commanding the 777 on the day of the accident.
Edited to add: and probably more interesting than some of the rubbish spouted on this thread.
It MAY be done but I know many retired pilots who were not washed out, most because they didn't make a big deal of their retirement.
overstress,
I've witnessed it a few times
manrow,
this refers to the pilot commanding the 777 on the day of the accident.
Edited to add: and probably more interesting than some of the rubbish spouted on this thread.
Last edited by Basil; 1st Sep 2009 at 21:04.
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Normally I wouldn't post here, but just wanted to make you all aware that the "send off" had nothing to do with Captain Pete. He knew nothing about it until it happened.
I'll run back to where I belong now...
Gg
I'll run back to where I belong now...
Gg