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.

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.

Can't all be right, guys. :confused:

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.

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,

Smilin_Ed

Phil Gollin's post effectively answers your question - I would have basically said the same.

Pinkman

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

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 :O
Pity they couldn't find a library pic of a 777.

On fire? Just for clarity.

Basil, you're mistaken, this does happen, I've witnessed it a few times.... how can you make such statements without knowledge of the facts...

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.

Not unprofessional but totally naff in my book.

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.

This thread originally was all about an aircraft incident not about retiring captains?

:ugh:

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.

Basil,

It's a common send off in the U.S.

Anothet 'touch' in the U.S. is to get a transponder code that has a special significance to the retiring pilot.

misd-agin,
Thank you for the info re the US.
This was, of course, at a UK airport and is not at all a common sight here.

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

Hi,

dont know Peter but would like to wish him well in the future, wherever that may take him.

Rgds.

It hasn't yet occured to anyone to ask why someone would take redundancy from a well paid job at age 45, a year after being involved in a major incident, with causes as yet unreported. I haven't read much of the thread, so I'm assuming the causes are unknown.

Must also have a severe effect on pension, so why do it?

Other forces at work?

I'll let you all get back to discussing more important stuff, like firemen spraying aeroplanes with water.

Bizzare old place, pprune, unless it's me.

Stansted 13 June 2008

A manager kindly arranged this for me on my last flight - it was a complete surprise.

http://steemrok.com/other/Water%20arch%20sm.jpg

There is no truth in the rumour that the RFF was called out in case I messed up my last landing.

Congratulations, Captain. Is that the bird that took a bird in #2?

Our ship was GBYAL, but I don't recall the reggie of the 757 that gave that bird a very severe headache.

It was quite an emotional moment - and strange too. Under the arch it was like taxying through a waterfall & we lost sight of the centreline for a few seconds, prompting the thought: 'Great, my last flight & I'll probably end on the grass!'

No it hasn't, because everyone else has read the thread and thus knows the causes.

capt.peter burkill
 

having just read the article referrinng too capt.burkills last flight before taking voluntary redundancy at the age of just 44, i was wondering would he have a problem getting a captains role in another carrier.?best of luck too him:ok:

Captain
 

Relative to the Captain's personal decisions, I suggest it is private, and in a civil forum would remain so. Sullenberger has wandered the public domain, so an easy answer would be any carrier would be only too happy to hire Sully, bridge his seniority, and amplify his take home remuneration.

Just wanted to add a comment that (in my opinion) the test procedure for icing that was set up to replicate in some way the combination of limiting permissible conditions was the best way to go. It may be true that it went a little beyond the actual conditions (as they are thought to be known). But it is well to consider what can happen.

I read the test reports carefully; they seemed well thought out. The only thing which caught my eye was that it had never occurred to me that the fuel piping and heat exchanger could be such an efficient scavenger of small amounts of water from the fuel.

One thing I saw way back was a Boeing memo concerning the use of the 3-degree Centigrade safety margin in using the stagnation* temperature of the outside air as the limiting low temperature of the wing interior.

*A term from thermodynamics; yes, I know a different term is usually used here. (a senior moment that I cannot recall it).

Anyway, 3C margin is a round number: 5 degrees in Fahrenheit as we mostly used to use. That margin goes back a long way-- at least to before the mid-60's and the days of the first commercial jet-- I researched that at the time. Interestingly, in the Boeing memo the justification for its continued use was that it had been used for a long time without any problems (or words to that effect). The memo was a quite frank, thorough and informed discussion of the issues surrounding fuel temperature, written before this incident. It was an informative memo of the sort that is so seldom seen in engineering any more. I was going to mention it and post a link to it, but when I did so, it had been removed (or moved).

The moral of this is, I think, that there are things in engineering that we do not fully understand (or lack the capability to deal with using practical mathematics), and so need now to increase our margins in this area.

OE

I fully accept that if there are suspicions raised of peculiar behaviour in the icing behaviour of fuel it should be investigated, and not for just one engine/aircraft set-up, but for all.

However, the present information is based on an unrepresentative fuel/water mix and hence can only be indicative of a possible problem. Only when either the icing problem is found to occur with a properly representative set-up OR when a suitable explanation for a different fuel/water mixture is found can any reliance be placed on thetest results.

The false start given by various non-AAIB press releases is irresponsible.

.

I haven't been following the thread but have just been forwarded this:
 

OFTEN WHEN TRYING TO DETERMINE WHY SOMETHING WENT WRONG . . . . I try to see what Civil Air Regulations said about it. In this case it is CAR 4b - section 435(b) . . . I was trying to figure out why the fuel filter iced-up on the BA 777 Glider at Heathrow. I found it. this subparagraph said . . . . [(d) Provision shall be made to maintain automatically the fuel flow when ice-clogging of the filter occurs, unless means are incorporated in the fuel system to prevent the accumulation of ice particles on the filter.]

This Standard missed the transition from CAR 4b to FAR Part 25 or Part 33 - Engines. The B-777 has a fuel heater but it merely requires a certain temperature. Too bad we didn't stay with the automatic Bypass feature!

JIM

Too bad you haven't been reading the thread. :*

If you had, you would realise the problem wasn't in the filter. :ugh:

Sooty

I am basically a lurker, but I've read the thread fully, and see a loophole for stoic. The FOHE is not labelled as a filter, filtering is simply not its intended function. Nominally, its blockage was caused by trapping ice at the tube sheet. There is even a bypass, but for the oil, not the fuel, and that through an air cooled matrix.

Technically, it did 'filter' the fuel. Additionally, it is not intended as a fuel heater, but does that as well, though 'poorly'.

with respect,
bear

Basic Physics
 

Ok I have read thru most of this thread and I find it very disturbing why the reason for this failure cannot be found. In this year of 2009 I would expect the science community to have some ability to determine when a liquid will become a solid.

Have I missed something really simple here? Could it be that some players involved do not want to find the truth?

Now I have to admit that I am well known social dyslexic who often cannot see the motives that confound the human race to self destruct....

But hell...I just cannot see why this big modern airplane suffered from something as simple as fuel coagulation on descent. Did we not all learn to apply CARB HEAT....jeez!

DERG

If you had really read this thread as you claim, and taken on board some very erudite input from fuel chemists and engine system engineers, then you would have realised that the "simple" issue is extremely complex.

MBA vs MSc!
 

This is not a difficult problem to solve and I am sure that many realize this.

The complexity is in the mind and is more to do with social science than hard science.

DERG


I assure you personally your cryptic reference has been broached, ad nauseum. If not, surprise us all, as commercial interests versus safety and technological considerations are well covered.

In a way, I'm with DERG on this. Time to call in ye old pump engineer. Tell to bring his cavitation check list. Go down it item by item. One of them hasn't been looked at hard.

Generally speaking, if you have something to add, add it. Hide and seek is for children.

For me?
 

bearfoil said:
Generally speaking, if you have something to add, add it. Hide and seek is for children.

I did. Over a year ago. In detail.