BA B777 Incident @ Heathrow (merged)
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Given the speculation on jet fuel quality at BJS, my personal theory is that on attitude change on finals (aircraft nose up with flaps extended/gear down) a volume of free water moved in both of the wing tanks to the boost pump inlets and sent a slug of water down both engine feed lines.
Free water would have remained frozen to the bottom of the tank for most of the flight, but defrosted on descent. The water scavenge system is quite good on a B777 though...
It's a tribute to modern aircraft crashworthiness that there have been 3 recent landing incidents resulting in aircraft off runways (AFR A343 Montreal, IBE A346 Quito, BAW B772 LHR) without a single serious injury.
Free water would have remained frozen to the bottom of the tank for most of the flight, but defrosted on descent. The water scavenge system is quite good on a B777 though...
It's a tribute to modern aircraft crashworthiness that there have been 3 recent landing incidents resulting in aircraft off runways (AFR A343 Montreal, IBE A346 Quito, BAW B772 LHR) without a single serious injury.
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Intruder - No we do know it for a fact. The AAIB don't make statements that are not grounded in hard fact and the aircrafts Quick Access Recorder has already been analysed which will have all the data on thrust lever angle and engine response. If I balls up in BA I can go into the office and ask for replay of my flight. On the PC they will show me a full run down of the incident, with a visual flight sim style picture of the aircraft path along with full representation of the instruments, FMAs and control positions. That data was all available to the AAIB. Are you suggesting they ignored that and issued a statement based solely on crew reports that they might later have to retract? You really think they are that dumb?
I am also aware that a simple preliminary statement or "Initial Report" like the one they released cannot include all the details known only collectively by a relatively large number of people.
Since an initial report is necessarily based on VERY little hard information, compared to that which will become available later, there is no real risk in making a minor misstatement (e.g., "engines" vs engine) or failing to include other modifiers (e.g., "respond" [as expected])...
I don't know why you feel it necessary to hang your hat on a single statement taken solely from "Initial indications"...
Sevenstroke - C'mon, do you really think that level of detail is going to be in the public domain 2 days after the incident. What is it with you and Intruder's head in the sand attitude to a highly regarded accident investigation body? They've already said the engines (plural) failed to respond, you're still trying to nail it on the crew?
What YOU seem to fail to realize is that if the engines were at a nominal approach power setting at 600', then even if they failed to respond at all until touchdown they would still have been at that same power setting, and the approach would have been nominal at least until the [attempted] power reduction before/in the flare!
I'm not trying to nail anything on anyone (except maybe the rulemakers that seem to think 160 kt to 4 NM on approach is a "good thing" that doesn't adversely impact safety). From all I can see, the Pilots handled a critical situation extremely well! Now we have to wait to find out ALL the reasons they got into that situation in the first place!
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..... is that if the engines were at a nominal approach power setting at 600', then even if they failed to respond at all until touchdown they would still have been at that same power setting, and the approach would have been nominal at least until the [attempted] power reduction before/in the flare!
That is the sort of thing I am trying to get at too - hence the interest in how short the aircraft touched down.
It mayeven have dropped a wing at some point, and in the long run we may find that the 777 responded incredibly well to large control inputs, effectively at or below Vmc..
As FO Coward has said, he feared for everyone's lives at one point, so I fear there was a point he felt they wouldn't get over the fence at all..
Having been around and seen the appalling results of the BEA Trident deep-stall out of Heathrow over 30 years ago now, and despite this accident's implications, I can really see BA's and perhaps Boeings phenomenal relief and need to applaud at an outcome almost beyond belief... all the work that's been put in to Pilot training - indeed their whole staffing philosophy and then the massive leap forward in aircraft design; crashworthiness, safety systems, general handling tolerance and robustness ... unexpected things will happen, but the outcomes have been mitigated this time.
That said, we do need a new International airport - in East London, Thames Estuary - well overdue IMHO.
Last edited by HarryMann; 20th Jan 2008 at 00:29.
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Cheers Mike Jenvey
.......I wonder if our Tels guys came up with that pic.
Listened to both the R/T and my phone calls on the tapes today.....very odd, got the adrenaline going again!
.......I wonder if our Tels guys came up with that pic. Listened to both the R/T and my phone calls on the tapes today.....very odd, got the adrenaline going again!
Free water at the bottom of the tanks......nah dont think so......jet pumps in most tanks keep the fuel and water mixed......if I remember water comes out of fuel at 1 ft per hour when the fuel is not being mixed by the jet pumps ie when the aircraft is on the ground which is why we do water drain checks after the aircraft has been on the ground for a considerable amount of time.
Below the Glidepath - not correcting
This is an extract from a 1990 paper (publicly available) regarding scientific analysis methods as employed by the AAIB. It helps demonstrate why the answers will be ready when they are ready, and not because the Editor of a tabloid has a deadline...
Deficiencies in reports matter, because the real aim of investigations is to reduce accident
rates by making effective safety recommendations. If we don't solve the accident properly, our recommendations are likely to be ineffective. But even if we are satisfied that our investigation is sound, it will still be a failure if the recommendations are not adopted. Recommendations involve change: they are disruptive, make work, and cost money. Those with the power to implement them will therefore seek ways to avoid doing so. If the report is open to challenge on any ground - not all the data was gathered, the logic is defective, alternative propositions were not canvassed - then it will be unpersuasive, and inaction is likely to prevail…
…We start with the on-site investigation. We make an initial survey and photograph the scene. The wreckage trail is plotted, and ground scars documented. Then we examine the wreckage in greater detail – are the extremities present? Can control system continuity be established? Were other systems apparently normal? If possible, we document the cockpit control positions, and the positions of control surfaces at impact, and so on. In the case of an accident to a large airliner, the protocols to be followed are detailed in the Manual of Accident Investigation (ICAO, 1970). Witness interviewing, document retrieval and detailed examination of the wreckage follow. In all of this phase, the work can be characterised as data gathering and documentation. There are protocols for each part: how to plot the wreckage trail, witness interviewing techniques and so on. While this phase is in progress, the news media will be demanding to know what caused the
accident, and whom to blame. Of course, we tell them that the analysis cannot be started until all the data have been gathered. Of course this is untrue, but it serves to get them off our backs. In the first place, it is untrue because that is not the way the human mind works. The mind seeks to join bits of information together to make sense of them. At quite an early stage, some parts of the puzzle will become clear. It will be possible to characterise the impact as steep or shallow angle, and high or low energy. If the aircraft started to break up before impact, this will soon be known. The answers to these and other questions will give rise to possible sequences of events, and so guide the search for supporting or rebutting information. At the same time, we must be aware of the danger of the 'glimpse of the blindingly obvious'. The thing that 'obviously' caused the accident may, in reality, have had nothing to do with it. Basic data should still continue to be gathered, and alternative explanations sought. Another reason that analysis starts before all the data is available is that an unguided search of the mass of documentation associated with an aircraft and its crew is likely to be fruitless. We need to be guided by some positive line of inquiry. If a mechanical problem seems likely, the airframe logbooks may have useful information. If the pilot may have been fatigued, crew
flight and duty time records are likely to be relevant. In other words, the search for data is guided by some theoretical propositions, which the data may support or rebut. (There is a distinction between hypotheses and propositions. Hypotheses will be tested statistically, by examining a sufficient number of samples to support or reject the hypothesis with given confidence. A proposition, on the other hand, is a possibility arising from some theory, which we may or may not find that our data fits).
rates by making effective safety recommendations. If we don't solve the accident properly, our recommendations are likely to be ineffective. But even if we are satisfied that our investigation is sound, it will still be a failure if the recommendations are not adopted. Recommendations involve change: they are disruptive, make work, and cost money. Those with the power to implement them will therefore seek ways to avoid doing so. If the report is open to challenge on any ground - not all the data was gathered, the logic is defective, alternative propositions were not canvassed - then it will be unpersuasive, and inaction is likely to prevail…
…We start with the on-site investigation. We make an initial survey and photograph the scene. The wreckage trail is plotted, and ground scars documented. Then we examine the wreckage in greater detail – are the extremities present? Can control system continuity be established? Were other systems apparently normal? If possible, we document the cockpit control positions, and the positions of control surfaces at impact, and so on. In the case of an accident to a large airliner, the protocols to be followed are detailed in the Manual of Accident Investigation (ICAO, 1970). Witness interviewing, document retrieval and detailed examination of the wreckage follow. In all of this phase, the work can be characterised as data gathering and documentation. There are protocols for each part: how to plot the wreckage trail, witness interviewing techniques and so on. While this phase is in progress, the news media will be demanding to know what caused the
accident, and whom to blame. Of course, we tell them that the analysis cannot be started until all the data have been gathered. Of course this is untrue, but it serves to get them off our backs. In the first place, it is untrue because that is not the way the human mind works. The mind seeks to join bits of information together to make sense of them. At quite an early stage, some parts of the puzzle will become clear. It will be possible to characterise the impact as steep or shallow angle, and high or low energy. If the aircraft started to break up before impact, this will soon be known. The answers to these and other questions will give rise to possible sequences of events, and so guide the search for supporting or rebutting information. At the same time, we must be aware of the danger of the 'glimpse of the blindingly obvious'. The thing that 'obviously' caused the accident may, in reality, have had nothing to do with it. Basic data should still continue to be gathered, and alternative explanations sought. Another reason that analysis starts before all the data is available is that an unguided search of the mass of documentation associated with an aircraft and its crew is likely to be fruitless. We need to be guided by some positive line of inquiry. If a mechanical problem seems likely, the airframe logbooks may have useful information. If the pilot may have been fatigued, crew
flight and duty time records are likely to be relevant. In other words, the search for data is guided by some theoretical propositions, which the data may support or rebut. (There is a distinction between hypotheses and propositions. Hypotheses will be tested statistically, by examining a sufficient number of samples to support or reject the hypothesis with given confidence. A proposition, on the other hand, is a possibility arising from some theory, which we may or may not find that our data fits).
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pasoundman, and the concept of fuel exhaustion in a two crew, state of the art airliner is equally entenable, but it has happened, and will continue to, happen. Unfortunately!!
And I am not stating that this is the case here, merely putting it forth as a possible theory, and this is, after all, Professional Pilots Rumour Network.
What I do contend though is that nobody can say with any degree of authority, or even any authority at all, with the exception, perhaps, of the two crew members, what actually happened, and whilst they can relate what happened, they may not be aware of the cause.........or they may be.
The rest of us are reading the newspapers, reading PPRuNe, and listening to hearsay, so hypothesize all you wish, but please don't put anything forward as fact until the accidnet investigation team have done their work.
The one thing I would be prepared to guarantee though is that BA management is in ar$e covering mode.
Whatever the cause, the crew did a great job over the last 500-600?? feet, and whatever the outcome, I wish the two crew well in what will undoubtedly be the most difficult time of their professional flying careers, or probably their entire lives.
And I am not stating that this is the case here, merely putting it forth as a possible theory, and this is, after all, Professional Pilots Rumour Network.
What I do contend though is that nobody can say with any degree of authority, or even any authority at all, with the exception, perhaps, of the two crew members, what actually happened, and whilst they can relate what happened, they may not be aware of the cause.........or they may be.
The rest of us are reading the newspapers, reading PPRuNe, and listening to hearsay, so hypothesize all you wish, but please don't put anything forward as fact until the accidnet investigation team have done their work.
The one thing I would be prepared to guarantee though is that BA management is in ar$e covering mode.
Whatever the cause, the crew did a great job over the last 500-600?? feet, and whatever the outcome, I wish the two crew well in what will undoubtedly be the most difficult time of their professional flying careers, or probably their entire lives.
Last edited by KaptinZZ; 20th Jan 2008 at 01:33.
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interesting article
This is an article from 2006. It relates to a GE90 and not an RR but it's interesting.
"The Unthrustworthy 777
Air Safety Week, Oct 9, 2006
Emergency Airworthiness Directive Issued For The 777's GE90 Thrust Rollbacks
An emergency Airworthiness Directive (AD) issued September 30 stems from two occurrences of engine thrust rollback during takeoff on Boeing 777-300ERs, which are powered by General Electric GE90-115B engines. The concern is that the GE90 engines powering Boeing 777-200LRs and 300ERs could suffer dual thrust reductions on take-off, with potentially catastrophic consequences.
In the two instances cited, just the one engine was affected but because it's software-related, the FAA cites the possibility that "a dual-engine thrust rollback could occur just after V1 (takeoff decision speed after which takeoff is to proceed even after an engine failure). This would result in the airplane not having adequate thrust to complete the takeoff. A dual-engine thrust rollback, if not corrected, could result in the airplane failing to lift off before reaching the end of the runway or failing to clear obstacles below the takeoff flight path."
Trouble-shooting technicians have found that the two cases in which there were single-engine thrust reductions during takeoff were the result of a flawed software algorithm in the Full Authority Digital Engine Control (FADEC). The emergency AD requires operators of GE90-115Bs powering 777-300ERs as well as GE90-110Bs powering 777-200LRs to amend their procedures to prohibit takeoffs at anything less than full-rated thrust. This is being stipulated because the rollbacks are only likely to occur at reduced powers, during the so-called "balanced field" takeoffs. When the power levers are set to maximum, the predictive software is out of the picture. For the foreseeable future, passengers on lightly loaded 777's are liable to think that they're on a shuttle launch."
"The Unthrustworthy 777
Air Safety Week, Oct 9, 2006
Emergency Airworthiness Directive Issued For The 777's GE90 Thrust Rollbacks
An emergency Airworthiness Directive (AD) issued September 30 stems from two occurrences of engine thrust rollback during takeoff on Boeing 777-300ERs, which are powered by General Electric GE90-115B engines. The concern is that the GE90 engines powering Boeing 777-200LRs and 300ERs could suffer dual thrust reductions on take-off, with potentially catastrophic consequences.
In the two instances cited, just the one engine was affected but because it's software-related, the FAA cites the possibility that "a dual-engine thrust rollback could occur just after V1 (takeoff decision speed after which takeoff is to proceed even after an engine failure). This would result in the airplane not having adequate thrust to complete the takeoff. A dual-engine thrust rollback, if not corrected, could result in the airplane failing to lift off before reaching the end of the runway or failing to clear obstacles below the takeoff flight path."
Trouble-shooting technicians have found that the two cases in which there were single-engine thrust reductions during takeoff were the result of a flawed software algorithm in the Full Authority Digital Engine Control (FADEC). The emergency AD requires operators of GE90-115Bs powering 777-300ERs as well as GE90-110Bs powering 777-200LRs to amend their procedures to prohibit takeoffs at anything less than full-rated thrust. This is being stipulated because the rollbacks are only likely to occur at reduced powers, during the so-called "balanced field" takeoffs. When the power levers are set to maximum, the predictive software is out of the picture. For the foreseeable future, passengers on lightly loaded 777's are liable to think that they're on a shuttle launch."
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Intruder, having dealt with the AAIB in the past they are not concerned with publicity or politics in the way the NTSB is; they will refrain from commenting until they have assessed the available evidence. I believe this is because they are a purely investigative agency, whereas the NTSB has a much wider remit.
As for some of the less informed posters, I found this thread easier to follow when the servers were jammed solid. Danny, can we slow them down again please?
As for some of the less informed posters, I found this thread easier to follow when the servers were jammed solid. Danny, can we slow them down again please?
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Buzzbox,
I'll say it again:
TAT Probe Icing.......
..............................
..............................
Even if this was the case, would the FADEC not hold idle above some low set N1/2/3 limit and the undershoot would not have been so large?
I'll say it again:
TAT Probe Icing.......
..............................
..............................
Even if this was the case, would the FADEC not hold idle above some low set N1/2/3 limit and the undershoot would not have been so large?
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WRT the difference between the approach to R27L versus R27R (based solely on Google/Wikimapia, not actual local knowledge) R27L has obvious buildings and a highway as well was a perimeter road on the runway centreline, whereas R27R 'only' has car parks (but are these ground-level or multi storey?).
Landing short (even shorter than BA038 achieved) on either would have been disastrous, but R27L would have involved the Air Canada Cargo Facility buildings and the A30 highway (with occupied vehicles) against 'just' mostly unoccupied vehicles.
http://wikimapia.org/#lat=51.471359&...15&l=0&m=a&v=2
(You can pan and zoom the above view).
An even earlier touchdown approaching R27L might involve a water landing, whilst R27R appears to be domestic housing . . .
(none of the above seem preferable to reaching the RESA)
Landing short (even shorter than BA038 achieved) on either would have been disastrous, but R27L would have involved the Air Canada Cargo Facility buildings and the A30 highway (with occupied vehicles) against 'just' mostly unoccupied vehicles.
http://wikimapia.org/#lat=51.471359&...15&l=0&m=a&v=2
(You can pan and zoom the above view).
An even earlier touchdown approaching R27L might involve a water landing, whilst R27R appears to be domestic housing . . .
(none of the above seem preferable to reaching the RESA)
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Fuel Crossfeeding topic (Please delete if unsuitable)
Various theories abound, and hopefully soon the AAIB will give us the answers, and the speculation will end.
It may have been caused by a whole spectrum of malfunctions.
One thing for sure is that this particular incident was very unusual.
The crew did as well as they could given the bare seconds they had to cope with a highly unusual event.
Although not stating a possible reason for the incident (and hopefully this post will not be seen as imaginative speculation, but leaning more towards disccusion), the topic of fuel crossfeeding on the approach is an interesting one.
The Boeing 777 FCOM (12.20.3) states that "Fuel balancing may be done in any phase of flight".
I do not know if this applies to other Boeing types or indeed Airbus aeroplanes. But I am sure you gurus out there can comment.
Now, if fuel sometimes does get contaminated (with water or detergents etc.), then would it not be prudent NOT to fuel balance close to the ground (approach, landing or go around). Obviously, configuring both engines to one fuel tank exposes one to additional, perhaps unnecessary risks.
Do UK Airlines have a policy on fuel crossfeeding close to the ground?
As, I said earlier, this post in no way implies that this particular 777 was crossfeeding, it is merely to raise the topic, which MAY have some relevance.
(Please feel free to delete the post, if it does to meet the required standard).
It may have been caused by a whole spectrum of malfunctions.
One thing for sure is that this particular incident was very unusual.
The crew did as well as they could given the bare seconds they had to cope with a highly unusual event.
Although not stating a possible reason for the incident (and hopefully this post will not be seen as imaginative speculation, but leaning more towards disccusion), the topic of fuel crossfeeding on the approach is an interesting one.
The Boeing 777 FCOM (12.20.3) states that "Fuel balancing may be done in any phase of flight".
I do not know if this applies to other Boeing types or indeed Airbus aeroplanes. But I am sure you gurus out there can comment.
Now, if fuel sometimes does get contaminated (with water or detergents etc.), then would it not be prudent NOT to fuel balance close to the ground (approach, landing or go around). Obviously, configuring both engines to one fuel tank exposes one to additional, perhaps unnecessary risks.
Do UK Airlines have a policy on fuel crossfeeding close to the ground?
As, I said earlier, this post in no way implies that this particular 777 was crossfeeding, it is merely to raise the topic, which MAY have some relevance.
(Please feel free to delete the post, if it does to meet the required standard).
Seeking some perspective
Just seeking some perspective on the timing of the events, all values approximate with many assumptions.
Standard approach at 200 ft/sec (120 kts average GS), ROD 600ft/min; time to threshold from 2nm (12000 ft) ~ 60 sec, flare 10 sec from 50 ft.
Flare time 10 sec from 100ft (assume 100 ft flare commencement height in a reduced power condition – reducing to Vs), thus 500ft altitude loss in 44 sec gives an average descent rate of ~ 11 ft/sec. This ‘modest’ value might be due to initially trading airspeed for descent rate (height).
N.B. this does not equate to, determine, or otherwise infer the touchdown ROD.
The perspective:- Many viewers will take 44 secs to read this post, some will take longer particularly if they attempt to understand ‘the situation’ (calculations), which involves higher mental workload.
Whatever the cause of the problem, this perspective indicates why the crew did such a good job.
Standard approach at 200 ft/sec (120 kts average GS), ROD 600ft/min; time to threshold from 2nm (12000 ft) ~ 60 sec, flare 10 sec from 50 ft.
- With unresponsive engines at 600 ft:- worse case (no thrust) in this class of aircraft, might (IMHO) result in 9 deg glide path (1800 ft/ min 30 ft/sec), but this is not achieved instantaneously and probably not achievable at all before a flare would have to be commenced at a much earlier height than normal (20 sec or less to ground contact) – not the case.
- With reduced thrust (flt idle), a 6 deg glide path (1200 ft/min, 20 ft sec) might be expected, but again not instantaneously (30 sec to ground contact) - unlikely.
- A more reasonable scenario is a slightly reduced thrust setting, that used for deceleration from 160kt to stabilize at Vref, thus a thrust increase would be required before 500ft, but the thrust change was not obtained (engines unresponsive).
Flare time 10 sec from 100ft (assume 100 ft flare commencement height in a reduced power condition – reducing to Vs), thus 500ft altitude loss in 44 sec gives an average descent rate of ~ 11 ft/sec. This ‘modest’ value might be due to initially trading airspeed for descent rate (height).
N.B. this does not equate to, determine, or otherwise infer the touchdown ROD.
The perspective:- Many viewers will take 44 secs to read this post, some will take longer particularly if they attempt to understand ‘the situation’ (calculations), which involves higher mental workload.
Whatever the cause of the problem, this perspective indicates why the crew did such a good job.
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Well done..
Fantastic job by all.Both Flight Crew and Cabin Crew.
I'm not qualfied in flying a plane but seems like a professional job boys.
I am qualifed in the cabin and can only hope I will react as well as my colleagues,if the need arises.
WTDWL.
''Ladies and gentlemen,your flight today will be 12 hours and 10 minutes.The safety video will take 5 minutes.By putting your newspapers down now,you'll have a better chance of reading them tomorrow''!.
I'm not qualfied in flying a plane but seems like a professional job boys.
I am qualifed in the cabin and can only hope I will react as well as my colleagues,if the need arises.
WTDWL.
''Ladies and gentlemen,your flight today will be 12 hours and 10 minutes.The safety video will take 5 minutes.By putting your newspapers down now,you'll have a better chance of reading them tomorrow''!.
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I personally think it was down to spark plug failure probably bpr6 when we all know it should have bpr9s. well it makes as much sense as some of the other cr*p posted on here. whilst i understand that you real pilots out there need to make sense of this as quickly as you can, this thread has been hijacked by ifs, whatifs, buts and maybees . The only facts at the moment are THAT THE PLANE CAME UP SHORT AND THE CREW SAVED THE DAY.