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AAIB BA38 B777 Initial Report Update 23 January 2008

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AAIB BA38 B777 Initial Report Update 23 January 2008

Old 12th Feb 2008, 12:50
  #341 (permalink)  
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davy 123... you're out of order!

Surely if you don't want to read threads and posts you can find something else to do?

What about those who've been away and not been able to log-on for a week or two?

No harm is being done by keeping this post live..... especially since the anoraks and hangar-sweepers continue to keep the rest of us amused with their "expert" opinions and suggestions! Cheers bm
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Old 12th Feb 2008, 13:10
  #342 (permalink)  
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My "non-expert view". Big problem. We were told an answer, originally, was likley within about 3 days of the incident.

It is clear that no one, so far, has that answer. Let people speculate as it provides discussion on this site.

It also proves that the cause is more complicated/obscure than was at first thought.

As long as people debate it gives interesting reading.
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Old 12th Feb 2008, 15:07
  #343 (permalink)  
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For what it's worth (and forgive me if it's already been Posted), Jet A-1/AVTUR has a maximium freezing point specified as -47 deg C http://www.dstan.mod.uk/data/91/091/00000500.pdf DEFSTAN 91-91 Issue 5.
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Old 12th Feb 2008, 19:15
  #344 (permalink)  
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My "non-expert view". ..............................................

It is clear that no one, so far, has that answer. Let people speculate as it provides discussion on this site.

It also proves that the cause is more complicated/obscure than was at first thought.

As long as people debate it gives interesting reading.
1. You don't know that "the answer" hasn't been "found" - in fact your concept of having an "answer" demonstrates that you don't understand that almost all outcomes are multi factorial (ie: "The holes in the cheese lining up")

2. In my opinion Informed speculation on this matter stopped quite a few pages ago.

3. The "cause" may or may not be complicated and obscure - we simply don't know. What we do know is that the aircraft was landed without loss of life - not all the holes in the cheese lined up. We don't know, for example, if the crew contributed to their own predicament (although I hope not).

4. Sorry, but the debate here is no longer interesting. Witness yet more pointless "debate" about contaminated, frozen, fuel. We simply don't know.

5. I don't know anything and have nothing useful to contribute, apart from suggesting that this incident proves the existence of Gremlins.

Could we please put a sock in it? At least read the whole thread before contributing?

P.S. Re insurance: Nothing unusual, Boeing has an entire division dedicated to repairing and/or rebuilding accident damaged aircraft by the side of runways around the world - and they do an excellent job. I would have thought that these Gentlemen would have been on the scene and provided the insurers with a rough quote within a very short time.
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Old 12th Feb 2008, 19:37
  #345 (permalink)  
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Wall Street Journal


United, American Plan Safety Push
After Icing Linked to British Crash

February 12, 2008; Page D6

Prompted by suspected ice accumulation in the fuel system of a British Airways PLC jumbo jet that crash landed near London last month, two major U.S. carriers are stepping up safety initiatives to prevent such problems, according to people familiar with the matter.

The moves come amid growing indications that a buildup of ice crystals or slush simultaneously restricted fuel flow and reduced the thrust of both engines of the Boeing 777 jet moments before the Jan. 17 accident at Heathrow International Airport, these officials said.

UAL Corp.'s United Airlines, and AMR Corp.'s American Airlines are taking precautionary steps to ensure fuel quality and re-evaluate fuel characteristics before investigators release preliminary findings. While it is common for airlines to ramp up safety efforts in the wake of a high-profile crash, they typically wait until the release of such findings or early safety recommendations by regulators or manufacturers.

United is reassessing certain quality-control systems it uses for accepting and testing fuel at airports, according to these people, and is reviewing procedures its mechanics use to drain water from jetliner fuel tanks. American has launched an effort to determine if a different type of jet fuel could better withstand temperature extremes on the longest and coldest polar routes, other officials said.

The moves come as U.S. and British investigators are focusing on whether ice crystals may have clogged the plane's dual oil-cooler systems, according to people familiar with the details. The radiator-like devices use fuel flow from each of the wing tanks to cool engine oil, and fuel then flows from there to the nearby engine during flight.

Investigators also want to determine how mechanics who worked on the aircraft before a pair of earlier flights may have reacted to warnings of potential ice buildup in the fuel. An internal Federal Aviation Administration memo last month said "a maintenance message indicating excessive water in the center tank was set during taxi on the two previous flight legs, although it cleared itself both times."

Water can be drained from Boeing 777 fuel tanks only on the ground, so part of the puzzle is what mechanics did to ensure the fuel system wasn't contaminated. United's routine procedures call for removing excess water after every several hundred flight hours.

United, American and Rolls-Royce Group PLC, which made the engines on the plane that crashed, have declined to comment on the investigation. Boeing Co., which said its 777 aircraft flew for 12 years and about 3.6 million hours world-wide without a major accident, said "it would be inappropriate to comment at this stage." The crash didn't result in fatalities.

The analysis and safety-oversight efforts by the airlines haven't uncovered any significant new icing-related hazards or resulted in operational changes. British regulators are expected to issue an update on the probe within a few days, though they don't appear ready to release new safety mandates or recommendations. The latest moves highlight how closely large segments of the global aviation industry are following the investigation, believed to be the first time ice contamination in fuel brought down a large, state-of-the-art jetliner with no apparent mechanical or computer malfunctions.

The FAA recently asked U.S. carriers that fly Boeing 777 aircraft to comb through their historical safety data to identify instances when engines were slow to rev up in response to pilot commands, or may have reduced thrust on their own, according to one person familiar with the investigation.
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Old 12th Feb 2008, 20:11
  #346 (permalink)  
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Just thinking out loud....

How often has this happened before (momentary fuel starvation due to ice/slush somewhere in the system, with it getting 'washed out' seconds or maybe a minute later)?
It just never happened at 2nm out at 600ft....
Needed only two holes in the cheese to line up.

And as said before, I don't envy the investigators, now that the ice has melted....

Has this reminded anybody else of the classic 'icicle murder' mystery? "No murder weapon was ever found."
Thank goodness everybody walked away from this one.....
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Old 12th Feb 2008, 22:19
  #347 (permalink)  
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We are due the 30 day report from the AAIB by this weekend, methinks the airlines which are now looking at water contamination are reading between the lines like we are all doing and perhaps, realising that they could improve the frequency of their water checks, "checking every several hundred hours", you've got to be joking. I, personally, probably going out on a limb, cannot believe that both engines would be affected within seconds of each other of the same or similar cause of a physical reason for fuel restriction in separate fuel feeds, (if they were separate). I am concerned that in the absence of a confirmed cause for the explananation of the accident that icing is blamed when it cannot be proven, this could possibly happen again without the advantage of the generous grass landing strip and the undoubted skill of the handing pilot. Well done sir. I would not like to see this thread closed until the AAIB report is issued, we are all entitled to our opinion and to offer our possible reasons, especially if someone is away and has missed a lot of posts.
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Old 12th Feb 2008, 22:35
  #348 (permalink)  
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Water drain checks is a normal practice where I work and has to be signed for on the 'Daily'
If this is the case a substantial amount of water in the fuel would also give a false reading in qty.Did the a/c have a fuel qty defect (carried forward) in the T/log?
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Old 12th Feb 2008, 23:21
  #349 (permalink)  
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Water in Fuel Tanks

Are some of those who do regular water drains able to comment on whether they are seeing increasing amounts of water relative to the amount of tank top ups.

There was a time when we were concerned about Cladisporeum (spelling?) which grew in aircraft fuel tanks at the water fuel interface producing a corrosive of integral tanks. Many wing skins had to be replaced. Fuel additives were developed to combat the problem.

Then there was/is the additive called FS11 (I think) which is supposed to lower the temperatures at which icicles form in fuel..

Are we seeing the result of a relaxation of fuel specifications/testing and a growing problem of water content between the refineries and the final deliveries.?
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Old 13th Feb 2008, 00:56
  #350 (permalink)  
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"How often has this happened before (momentary fuel starvation due to ice/slush somewhere in the system, with it getting 'washed out' seconds or maybe a minute later)?
It just never happened at 2nm out at 600ft....
Needed only two holes in the cheese to line up."

Forgive the uninvited views of a piston engine wallah but my understanding is that fuel temperature is kept above a minimum figure due to heat exchange with the hydraulic circuits routed through the tanks. As a consequence, any water present should not freeze but remain in suspension due to pump activity and eventually be injected into the engines. Wrong?

I think the question of quality control from refinery deliveries might be apposite.

And thanks BoeingMEL, I for one have been absent for quite some time so appreciate the chance to catch up with what has become an unusually interesting thread. Speculation often is fun and can be usefully informative; the problem arises with those who are unable distinguish between speculation and demonstrable fact. This is dangerous and tiresome. I'll now get back to pushing my broom . .

Last edited by Gipsy Queen; 13th Feb 2008 at 01:07.
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Old 13th Feb 2008, 02:45
  #351 (permalink)  
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Planning landing at Heathrow with 30 min in the tanks is legal and would justify the official statement adequate fuel.
It would also justify (if officially confirmed in a coming update !?) that crossfeed was open and flaps limited at 20, in order to follow a probable requested low fuel procedure 262 287
An open crossfeed could justify than both engines took fuel from the same wing tank, and therefore, as officially stated, one eng had to wait 8 sec longer than the other one to develop identical symptoms.

A few questions:
1- As I understand it, a low fuel procedure would request a crossfeed to be open and ALL fuel pumps selected ON. So what could justify that the engines were maybe not taking fuel from their own side ?
2- Which fuel quantity does trigger a LOW FUEL EICAS MSG ?
3- Will the AAIB simply publish the actual FOB at the time ???
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Old 13th Feb 2008, 02:56
  #352 (permalink)  
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Gipsy Queen, Jet-A freezing point is -40c, Jet-A1 freezing point is -47c, TS-1 as supplied in Russia and Beijing has a lower freezing point of -50c. If your tank fuel temperature reaches 3 degs. above the freezing point of fuel carried, you have to take steps to avoid a further drop of fuel temp by either increasing your cruise Mach number or descending to a lower flight level with a higher OAT.

Fuel temperature on the 777 is displayed in white on the primary EICAS in the lower right corner. If the fuel temperature reaches the established minimum, the indication turns amber in color and the FUEL TEMP LOW advisory message is displayed. The 777 system automatically defaults to the limit associated with the highest freezing point of fuel approved for use on the 777, which is 37C for Jet A fuel. However, the EICAS message can be set to other values. For example, if Jet A-1 fuel is used, the message can be set to 44C
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Old 13th Feb 2008, 06:32
  #353 (permalink)  
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On the HUGE assumption that the engine problems were caused by icing/slush will a change in testing procedures be sufficient, or will changes to pipe diameters or heating arrangements be required ?

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Old 13th Feb 2008, 09:25
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Given the assumption you make, and given the hard information we have about this accident, and given the information we have about the 777 (a fine machine, far more reliable on a day to day basis than we humans, I would say), I think it more probable that changes would be made to airline SOPs. Some, I suspect, would not need changing The AIIB has sort of here before, not so long ago in fact........
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Old 13th Feb 2008, 09:48
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The pumps stir the fuel and keep water in suspension in flight but what happens at a cold layover? Does it all sink to the bottom and freeze up in one layer? What causes that layer to break up again if temperatures remain below zero? Can it just sit there? If it partly melted on the ground could you drain off the water leaving the ice and convince yourself the water was gone?

Edit: Can the water sensor detect ice in a layer or in suspension in the air?
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Old 13th Feb 2008, 13:59
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Thumbs up

As a Layman, I have found this string an excellent insight into the different aspects and considerations of flying, particularly of a 777 - and behalf of myself I would like to thank everybody for the information posted.
It now seems to me that the authorities are firming up as to the actual causes of this accident.
However, to get the full story - I expect that one must wait for Sky TV 'National Geographical' Channel, Air Crash Investigation to complete their dossier and to which I am looking forward to.

Last edited by spacefella; 13th Feb 2008 at 14:21.
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Old 13th Feb 2008, 15:26
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ref the earlier post about water drains , it is on a DAILY check . BUT , what is the frequency of a DAILY check on a 777 ?? 48 hours !!! Also to get water to 'settle' out of the fuel you need to follow the AMM procedure, which requires a minimum qty of fuel in EACH tank , and left for about 3-4 hours . In todays high utilisation scenario of long haul ops with short turnrounds how often does this happen ?? And for example on a 777 you're not putting fuel in the centre tank except on sectors over 7 hours generally so unless you pre fuel several hours before departure on a flight where you're using it you generally dont get a 'proper' water drain check. Having said that the modern systems with good scavenge and jet pumps does seem to work pretty well as we generally find very minute water quantities on a water drain these days. How many people remember taking a gallon of water out of the left wing tank every morning on a 737 when the -300's were brand new !! and that was european ops where we believe we have high fuel standards !!!! Note that this is clarification for those interested and not related to this incident as i am not upto date on BA's current procedures re fuel and water drains.
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Old 13th Feb 2008, 18:44
  #358 (permalink)  
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Engine Oil Temperature

"The radiator-like devices use fuel flow from each of the wing tanks to cool engine oil, and fuel then flows from there to the nearby engine during flight."

Do engine oil temperature drop when the engines are at idle for a while? Can the problem be low engine oil temperature plus low fuel temperature and excessive water/ice in the tanks?
Old 13th Feb 2008, 19:33
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It will be interesting to know....
1) At what altitude the Boeing low fuel drill was actioned on BA038 and if the flaps were ever retracted to 20degrees.
2) What investigation checks were made of the centre tank contents after two water in centre tank fuel messages were generated.
3) If BA B777 min fuel policy often causes crews to action the Boeing min fuel drill on arrival prior to landing... thus causing all engines to feed initially from
only the fuel/contaminates/dregs remaining in one tank.
4.) Seems you need to save a lot of fuel by your min fuel policy to equal the cost of a total B777 W/O.
5.) Next time over London maybe...would be more costly.
6.) Fuel loads should be increased to totally avoid the SOP use of the low fuel state drill as it has been proven both engines will quit if run off a common contaminated tank.
7) The low fuel state drill should be reclassified as an emergency recall drill
and its use now avoided as a SOP.

Last edited by scanscanscan; 13th Feb 2008 at 19:48.
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Old 13th Feb 2008, 19:39
  #360 (permalink)  
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Low fuel?

What are you talking about?
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