BA038 (B777) Thread
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a) you've got the wrong aircraft (your boeing quote is about 777-200LR and 777-300ER, G-YMMM was 777-200ER)
b) we already know BA38 didn't land with a large amount of unused fuel in CT (which is clearly not the same scenario as the reports you are quoting)
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Vapour lock= cavitation?
Tree,
You seem to have a closer understanding than I do.
...Ive seen fire prorection tables that seem to show that aviation kerosenes with lower freeze points have lower flash points ; and elsewhere that tied to a fall in flash point is a fall in boiling point , at a roughly equivalent rate.
...Im getting at this -57c freeze point fuel being able to start bubbling with demand suction at an oat of 8-11 as it wamed up on final approach.
...Can you determine what the boiling point at MSL might be , and what would the inlet suction pressure have to fall to , to cause a further drop in boiling point (and gassing aeriation).?
You seem to have a closer understanding than I do.
...Ive seen fire prorection tables that seem to show that aviation kerosenes with lower freeze points have lower flash points ; and elsewhere that tied to a fall in flash point is a fall in boiling point , at a roughly equivalent rate.
...Im getting at this -57c freeze point fuel being able to start bubbling with demand suction at an oat of 8-11 as it wamed up on final approach.
...Can you determine what the boiling point at MSL might be , and what would the inlet suction pressure have to fall to , to cause a further drop in boiling point (and gassing aeriation).?
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Originally Posted by Skipness One Echo
Unusual that the airframe still carries full British Airways colours and titles.
Michael
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Overview
This is basically what I see.
1. Given the examination of EEC, FADEC, and appurtenant equipment,
Lack of quantity or quality of Fuel is expected to have caused this
incident.
2. A second Trent Balk at throttle was found to be not pertinent to BA38.
3. Cavitation, though found, has not been identified as Causative.
4. Everything AAIB have supplied has resulted in continuing operation of the Fleet.
5. Two major carriers have modified their fueling procedures (AA, UA).
From this a reasonable set of conclusions can be advanced.
1. Nothing AAIB have released has caused a system wide recommendation.
2. Nothing AAIB have released has caused an Airline recommendation.
3. Several reasonable theories remain which may infer other than the
resultant lack of action.
4. A responsible body as AAIB, not finding any cause to recommend
changes in equipment or procedures, has left open the door to very few
alternate albeit certainly not unobserved causative scenarios.
5. These few alternates are perforce limited to very unique and incident related possibilities. (Not generally assumed to happen again).
6. Microwave sensitive equipment could be adversely affected by tramp signal, returning to 100% post incident functionality, without record of anomaly.
7. Destruction of the Center Tank in the Landing phase may rule out an implication of tank issues.
8. There is probably good reason to withold investigative communication from the public.
1. Given the examination of EEC, FADEC, and appurtenant equipment,
Lack of quantity or quality of Fuel is expected to have caused this
incident.
2. A second Trent Balk at throttle was found to be not pertinent to BA38.
3. Cavitation, though found, has not been identified as Causative.
4. Everything AAIB have supplied has resulted in continuing operation of the Fleet.
5. Two major carriers have modified their fueling procedures (AA, UA).
From this a reasonable set of conclusions can be advanced.
1. Nothing AAIB have released has caused a system wide recommendation.
2. Nothing AAIB have released has caused an Airline recommendation.
3. Several reasonable theories remain which may infer other than the
resultant lack of action.
4. A responsible body as AAIB, not finding any cause to recommend
changes in equipment or procedures, has left open the door to very few
alternate albeit certainly not unobserved causative scenarios.
5. These few alternates are perforce limited to very unique and incident related possibilities. (Not generally assumed to happen again).
6. Microwave sensitive equipment could be adversely affected by tramp signal, returning to 100% post incident functionality, without record of anomaly.
7. Destruction of the Center Tank in the Landing phase may rule out an implication of tank issues.
8. There is probably good reason to withold investigative communication from the public.
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airfoilmod
This is basically what I see.
1. Given the examination of EEC, FADEC, and appurtenant equipment,
Lack of quantity or quality of Fuel is expected to have caused this
incident.
This is basically what I see.
1. Given the examination of EEC, FADEC, and appurtenant equipment,
Lack of quantity or quality of Fuel is expected to have caused this
incident.
The fuel has also AFAIK been tested for quality and found to be just fine.
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Soundman
With all due respect, if a powerplant is not supplied with fuel, it will not run. No matter the location of ample fuel elsewhere. Take a breath, and make the attempt to see the possibilities in what you read. Starvation or exhaustion are not parsed by inanimate objects. Starvation and exhaustion are two iterations of fuel "availability".
Last edited by airfoilmod; 30th Mar 2008 at 02:18.
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Not generally assumed to happen again.
Quoting Airfoilmod:
Perhaps this is why several posts have been removed from this thread (some of mine amongst others)? Maybe some theories approximate the true cause of this incident. If so, this thread is biassed but my theory still stands:
1. A unique set of circumstances causing disruption of a subsystem.
2. Disruption resulting in a reverse logic electrical failure downstream of ELMS. Why downstream of ELMS? Because relays within ELMS provided correct signals to the engine controls according to the AAIB.
3. Spar valve control may have been affected.
4. Provided the fuel synoptic page was not selected at the time of the system disruption (I don't think so in the approach phase), no visible or aural alerts to the flight crew were presented because this may be inherent to the subsystem design (not going into details here because it is proprietary information).
5. Disruption was of a temporary nature and reset itself.
6. Impossible to prove without testing, which is a task for the AAIB, Boeing and RR to do so and find the facts.
Regards,
Green-dot
4. A responsible body as AAIB, not finding any cause to recommend changes in equipment or procedures, has left open the door to very few alternate albeit certainly not unobserved causative scenarios.
5. These few alternates are perforce limited to very unique and incident related possibilities. (Not generally assumed to happen again).
6. Microwave sensitive equipment could be adversely affected by tramp signal, returning to 100% post incident functionality, without record of anomaly.
7. Destruction of the Center Tank in the Landing phase may rule out an implication of tank issues.
8. There is probably good reason to withold investigative communication from the public.
5. These few alternates are perforce limited to very unique and incident related possibilities. (Not generally assumed to happen again).
6. Microwave sensitive equipment could be adversely affected by tramp signal, returning to 100% post incident functionality, without record of anomaly.
7. Destruction of the Center Tank in the Landing phase may rule out an implication of tank issues.
8. There is probably good reason to withold investigative communication from the public.
1. A unique set of circumstances causing disruption of a subsystem.
2. Disruption resulting in a reverse logic electrical failure downstream of ELMS. Why downstream of ELMS? Because relays within ELMS provided correct signals to the engine controls according to the AAIB.
3. Spar valve control may have been affected.
4. Provided the fuel synoptic page was not selected at the time of the system disruption (I don't think so in the approach phase), no visible or aural alerts to the flight crew were presented because this may be inherent to the subsystem design (not going into details here because it is proprietary information).
5. Disruption was of a temporary nature and reset itself.
6. Impossible to prove without testing, which is a task for the AAIB, Boeing and RR to do so and find the facts.
Regards,
Green-dot
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Agree
I would agree that because of the way the investigation has unfolded, the incident was caused by factors narrowly applicable to BA38. Having released information that isn't considered to threaten continued and consistent operation of the Fleet or the Airport, I would assume AAIB is satisfied; if not, their inquiry obviously doesn't have disquieting implications.
I would agree that because of the way the investigation has unfolded, the incident was caused by factors narrowly applicable to BA38. Having released information that isn't considered to threaten continued and consistent operation of the Fleet or the Airport, I would assume AAIB is satisfied; if not, their inquiry obviously doesn't have disquieting implications.
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Good Grief
What a leap. My post was meant to emphasize the lack of an extrapolative conclusion by AAIB; If there was such a finding, of course broader implications would have been entertained. If AAIB are keeping things close,
that's their prerogative, and no safety questions applicable to the Fleet or
crashsite are appropriate. Am I missing something? If a Jag hits a tree,
do we garage all Jags and cut down big trees? For goodness sake don't assume my metaphor implies Pilot error.
(TWA800, CONCORDE, TENERIFE- all fascinating, but off thread, I think)
that's their prerogative, and no safety questions applicable to the Fleet or
crashsite are appropriate. Am I missing something? If a Jag hits a tree,
do we garage all Jags and cut down big trees? For goodness sake don't assume my metaphor implies Pilot error.
(TWA800, CONCORDE, TENERIFE- all fascinating, but off thread, I think)
Last edited by airfoilmod; 30th Mar 2008 at 19:38.
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Remaining Fuel Quantity
What was the official fuel remaining in the aircraft at time of impact? Does the AAIB actually know this? All I could see was "a significant amount of fuel leaked' Now question was was there sufficient fuel to flow without cavitation in the pumps??
snanceki: re Airfoilmod
There are several I can think of, but the obvious reason is they must be free to speculate about all the possibilities in order to eliminate those they can. Publishing their speculations would lead to the inevitable 'selective emphasis' that sells newspapers by disturbing the public. L-38 has a timely example of this.
re your questions:
Now you are doing it.
The 777 has built up a good safety record. The process leading to this failure has only been seen on this flight. Selective emphasis describes this as unique then suggests complacency within the investigation by asking for evidence of uniqueness.
The investigators will obviously look at what was different about this flight. They will also look into all the history - of this aircraft type and of all past accidents - to see whether anything already known about might have contributed here. As the investigation proceeds factual evidence and careful testing will eliminate some possibilities, and may reveal new factors to be considered and eliminated in turn.
This process has to be undertaken by specialists who understand aircraft, who know how accidents happen, and who are as dispassionate as it is possible to be in sometimes harrowing circumstances.
Air travel is as safe as human endeavour can make it - and that is very safe.
And that doesn't sell newspapers.
There is probably good reason to withold investigative communication from the public.
re your questions:
If they don’t understand the causal reasons how can anybody assume
1. Causal factor(s) was unique to BA038
2. Causal factor(s) won’t happen again.
Should we assume they don’t understand the causal factors?
1. Causal factor(s) was unique to BA038
2. Causal factor(s) won’t happen again.
Should we assume they don’t understand the causal factors?
The 777 has built up a good safety record. The process leading to this failure has only been seen on this flight. Selective emphasis describes this as unique then suggests complacency within the investigation by asking for evidence of uniqueness.
The investigators will obviously look at what was different about this flight. They will also look into all the history - of this aircraft type and of all past accidents - to see whether anything already known about might have contributed here. As the investigation proceeds factual evidence and careful testing will eliminate some possibilities, and may reveal new factors to be considered and eliminated in turn.
This process has to be undertaken by specialists who understand aircraft, who know how accidents happen, and who are as dispassionate as it is possible to be in sometimes harrowing circumstances.
Air travel is as safe as human endeavour can make it - and that is very safe.
And that doesn't sell newspapers.
@Airfoilmod
I find your point 6 rather cryptic (my fault I'm sure).
What is a 'tramp signal'? Do you mean an interfering EM pulse?
How could such a pulse cause fuel control signals to be changed, without the real-time recordings of those same signals also showing the change?
I find your point 6 rather cryptic (my fault I'm sure).
What is a 'tramp signal'? Do you mean an interfering EM pulse?
How could such a pulse cause fuel control signals to be changed, without the real-time recordings of those same signals also showing the change?