BA747 3 engine LAX-LHR article
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stilton wrote:
Indeed, the levels of redundancy built into modern transports, particularly the 747 allow for continued flight in the event of a loss of significant systems, up to and including powerplants. (That is why they have four!)
They have four because at the time they needed four to get them in the air since more powerfull engines were not available.
Optimum cruise is with four engines. That's a commercial argument and thats the reason of the design. They could easily have build it with less redundancy so it would be even more intersting commercially speaking (lesser weight) but they didn't do that for safety reasons.
That is why the redundancy is build in for safety and not commercial reasons. It's obvious but hard to acept if you do not want to see it that way.
Once one engine is out the remaining redundancy must be used to get the plane on the ground safely and not to continue for commercial arguments only this is the key argument against the continuance of the flight.
That and only that is the main reasoning when one has to answer the question of What is the safest course of action.
Indeed, the levels of redundancy built into modern transports, particularly the 747 allow for continued flight in the event of a loss of significant systems, up to and including powerplants. (That is why they have four!)
They have four because at the time they needed four to get them in the air since more powerfull engines were not available.
Optimum cruise is with four engines. That's a commercial argument and thats the reason of the design. They could easily have build it with less redundancy so it would be even more intersting commercially speaking (lesser weight) but they didn't do that for safety reasons.
That is why the redundancy is build in for safety and not commercial reasons. It's obvious but hard to acept if you do not want to see it that way.
Once one engine is out the remaining redundancy must be used to get the plane on the ground safely and not to continue for commercial arguments only this is the key argument against the continuance of the flight.
That and only that is the main reasoning when one has to answer the question of What is the safest course of action.
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Actually, the customer required four because with the reliability level of 1960's engines, it was deemed unsafe to cross the pond on fewer. Bigger engines could have been built at that time (or shortly after) but no passenger wanted to trust fewer than four donks.
In fact there was something of a tempest over McD-D & Lockheed proposing trijets for overwater flights. Pan Am and BA were especially reluctant - the early sales of trijets were for transcontinental carriers. ETOPS? Don't make me laugh!
What has happened in the three-plus decades since then?
Performance trend monitoring and other on-wing diagnostics can detect an incipient failure well before the donk coughs. Engine time on wing has gone from a thousand hours to ten thousand or more. The statistics are in a new universe. A second unrelated engine failure in one flight happens at a rate measured in decades. In fact the "typical" flight crewperson will probably never experience a true engine failure in a career of professional flying.
To reiterate: an engine failure (sans fire warning) is not an emergency. When it happens, you survey the situation and make a decision. Then you follow through.
In fact there was something of a tempest over McD-D & Lockheed proposing trijets for overwater flights. Pan Am and BA were especially reluctant - the early sales of trijets were for transcontinental carriers. ETOPS? Don't make me laugh!
What has happened in the three-plus decades since then?
Performance trend monitoring and other on-wing diagnostics can detect an incipient failure well before the donk coughs. Engine time on wing has gone from a thousand hours to ten thousand or more. The statistics are in a new universe. A second unrelated engine failure in one flight happens at a rate measured in decades. In fact the "typical" flight crewperson will probably never experience a true engine failure in a career of professional flying.
To reiterate: an engine failure (sans fire warning) is not an emergency. When it happens, you survey the situation and make a decision. Then you follow through.
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Baritone
You raise a point I've wondered about, trend monitoring. Running the remaining 3 at MCT for XX hrs, does this mess up the the benefits, in maintenance terms, which you gained from a trend program?
And can you answer one more thing, at what point in the flight was it apparent that LHR was not an option?
Thanks
You raise a point I've wondered about, trend monitoring. Running the remaining 3 at MCT for XX hrs, does this mess up the the benefits, in maintenance terms, which you gained from a trend program?
And can you answer one more thing, at what point in the flight was it apparent that LHR was not an option?
Thanks
Originally Posted by AIMS by IBM
............
Once one engine is out the remaining redundancy must be used to get the plane on the ground safely and not to continue for commercial arguments only this is the key argument against the continuance of the flight.
That and only that is the main reasoning when one has to answer the question of What is the safest course of action.
Once one engine is out the remaining redundancy must be used to get the plane on the ground safely and not to continue for commercial arguments only this is the key argument against the continuance of the flight.
That and only that is the main reasoning when one has to answer the question of What is the safest course of action.
I agree that this is the issue and that decision has been placed in the captains hands. To me it is not black and white whether the decision making process was right or wrong. As has been mentioned before there is demonstrated historical risk to divert or turnback, while there is only implied risk to continued with some loss of redundancy.
I don't see that any lessons learned from a safety standpoint can be gleened from second guessing another choice. I'm quite satisfied that the captain did not make his decision hastily and did consult with others. To me the long and short of it, is that it's the captainjs decision and it should remain that way. There is no need to go to a rule book to sort this out.
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Originally Posted by issi noho
Baritone
You raise a point I've wondered about, trend monitoring. Running the remaining 3 at MCT for XX hrs, does this mess up the the benefits, in maintenance terms, which you gained from a trend program?
You raise a point I've wondered about, trend monitoring. Running the remaining 3 at MCT for XX hrs, does this mess up the the benefits, in maintenance terms, which you gained from a trend program?
And can you answer one more thing, at what point in the flight was it apparent that LHR was not an option?
Thanks
Thanks
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Before someone from the "old school" jumps on me, let me point out that while the technology has played a great part in improving safety, there is a well-documented side effect, namely:
It's possible to Murphy-proof the daylights out a system, to the point that a minimally-trained operator (pilot???) can make it work pretty well 99.9% of the time. But if this becomes a way of life, then safety starts sliding downhill again - we see this in the third world.
Put in other terms, we start raising a new-and-improved generation of "Murphies".
(My corollary proposition: One pilot should always be over age 60!)
It's possible to Murphy-proof the daylights out a system, to the point that a minimally-trained operator (pilot???) can make it work pretty well 99.9% of the time. But if this becomes a way of life, then safety starts sliding downhill again - we see this in the third world.
Put in other terms, we start raising a new-and-improved generation of "Murphies".
(My corollary proposition: One pilot should always be over age 60!)
Well 'AIMS', those are just your personal opinions and have no basis in the rules under which the aircraft was certified.
These same rules state that continued flight is an option as long as it is considered 'as safe'
I contend that it certainly was, all performance parameters were met, and, as stated earlier the remaining redundancy was superior to the majority of modern jet transports (certified by the same FAA)
It seems quite the Irony that this only has become an issue in the US. If the flight had originated elsewhere the continuation would not have been an issue.
Indeed the same aircraft had an engine problem with a consequent shutdown a short time later on a SIN-LHR flight and continued, landing on three with no objection by any of the relevant civil aviation authorities.
We didn't always live in the world of twins and ETOPS, the redundancy enjoyed by 3 and 4 engine transports has been used in such a manner ever since they started service, and continued flight with one shutdown was never questioned, (unless there was good reason) there was not in this case.
Certainly, when the 747 first flew it needed 4 engines, and they were at the limits of their capability.
That is what makes the 744 such a superb and capable design, in that it combines the tremendous redundancy of Boeings conservative design with modern powerplants that provide a quantum leap in performance.
These same rules state that continued flight is an option as long as it is considered 'as safe'
I contend that it certainly was, all performance parameters were met, and, as stated earlier the remaining redundancy was superior to the majority of modern jet transports (certified by the same FAA)
It seems quite the Irony that this only has become an issue in the US. If the flight had originated elsewhere the continuation would not have been an issue.
Indeed the same aircraft had an engine problem with a consequent shutdown a short time later on a SIN-LHR flight and continued, landing on three with no objection by any of the relevant civil aviation authorities.
We didn't always live in the world of twins and ETOPS, the redundancy enjoyed by 3 and 4 engine transports has been used in such a manner ever since they started service, and continued flight with one shutdown was never questioned, (unless there was good reason) there was not in this case.
Certainly, when the 747 first flew it needed 4 engines, and they were at the limits of their capability.
That is what makes the 744 such a superb and capable design, in that it combines the tremendous redundancy of Boeings conservative design with modern powerplants that provide a quantum leap in performance.
Last edited by stilton; 17th Apr 2006 at 02:51.
A Solution!
Barit 1, you've got the answer.
In fact, the over-60 doesn't even need to fly, he'll be far too decrepid for that.
He (or she, sorry Ma'am) just needs to be tied to the jump seat to mutter "Don't forget Murphy" every 15 minutes between start-up and shut down.
This is only temporary. In around 2020 he'll be replaced by the dog put on the flight deck to bite the systems monitor (ex-Pilot, perhaps? Reborn Flight Engineer?) if he/she tries to take control from the automatics.
When Murphy once stopped my Prentice engine in cloud over the Italian mountains (Naples - Brindisi) because both mags got damp, in his haste to leave with the only umbrella he dropped a card that said "Sooner or later someone will think that it's possible to Murphy-proof a system. That's the moment, Murph' ole boy, to go for it".
Congratulations on the point you were really making...exactly right!
In fact, the over-60 doesn't even need to fly, he'll be far too decrepid for that.
He (or she, sorry Ma'am) just needs to be tied to the jump seat to mutter "Don't forget Murphy" every 15 minutes between start-up and shut down.
This is only temporary. In around 2020 he'll be replaced by the dog put on the flight deck to bite the systems monitor (ex-Pilot, perhaps? Reborn Flight Engineer?) if he/she tries to take control from the automatics.
When Murphy once stopped my Prentice engine in cloud over the Italian mountains (Naples - Brindisi) because both mags got damp, in his haste to leave with the only umbrella he dropped a card that said "Sooner or later someone will think that it's possible to Murphy-proof a system. That's the moment, Murph' ole boy, to go for it".
Congratulations on the point you were really making...exactly right!
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I can only repeat what I have stated before.
The available redundancy should not be used for commercial reasons.
The simple fact that these failures are very rare, means that it’s commercial impact is very low anyway and reinforces the argument.
I am sure that if you ask any CAA if the redundancy is there for commercial reasons they would say no, they would have no other choice.
There is no reason to start a technical discussion since the aforementioned principle makes it obsolete.
The FAA did what they had to do and as far as other CAA is concerned, they are controlled by politics so their opinion does not matter.
I could go flying half pissed but if nothing happens then I did nothing wrong seems to be the reasoning by those who get away with it. This is not good enough.
The available redundancy should not be used for commercial reasons.
The simple fact that these failures are very rare, means that it’s commercial impact is very low anyway and reinforces the argument.
I am sure that if you ask any CAA if the redundancy is there for commercial reasons they would say no, they would have no other choice.
There is no reason to start a technical discussion since the aforementioned principle makes it obsolete.
The FAA did what they had to do and as far as other CAA is concerned, they are controlled by politics so their opinion does not matter.
I could go flying half pissed but if nothing happens then I did nothing wrong seems to be the reasoning by those who get away with it. This is not good enough.
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I am sure that if you ask any CAA if the redundancy is there for commercial reasons they would say no, they would have no other choice.
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And what sort of expert are you to make the statements you have as fact? And pray tell us how much experience you have in the industry? In other words- what do you know about it, and if you are an expert, why is your profile so bare?
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Aims I was once on a B747 operated by a well known U.S. carrier which, over Greenland, en route to the West Coast had an engine failure. Interestingly, we did not divert to the nearest available airfield. Nor did we continue to the destination. Nope, we went ORD, which happens to be just what the captain told us - a "suitable" maintenance base for the operator in question. (I trust you will concede that this was quite a distance and that many suitable airfields were passed en route).
I did not then, nor do I now consider that the captain or operator did anything strange or unreasonable. However, it seems to me that this falls neatly into the area that you criticise thus:
It seems to me that - apart from the utterly circular nature of the dialogue of the deaf which this particular topic seems to generate - that there is a fundamental and fatal logical flaw at work in this type of argument. This is the one that people try to bring out when they start to talk about ETOPs and loss of an engine on a two engined aircraft - in order to make key points about redundancy and levels of safety.
While redundancy and reliability statistics suggest that flights of some time and distance can be achieved within acceptable safety levels on one engine, it is agreed that getting on the ground ASAP is essential. However, were you to add multiple levels of statistical and practical safety and redundancy as in the B747 some people, such as yourself, seem to think that the additional safety margins in the B747 should be ignored in any decision-making. Some even seem keen to consider the B747 on 3 engines to be equivalent - for decision-making purposes - to being on one engine in a twin-engined aircraft. A typical argument is that both are in a state of greater risk (which is a truism, but tells us nothing about comparative risk).
As many B747 pilots have repeatedly pointed out, those who make such arguments rarely show any grasp of either the decision-making process which this crew followed or the level of redundancy in the B747. To repeat, on three engines the B747 has greater redundancy than a twin jet. Dreaming up complex scenarios in which a second engine is lost, etc. is the next response ... which I will not go into, because it has been done to death already.
I did not then, nor do I now consider that the captain or operator did anything strange or unreasonable. However, it seems to me that this falls neatly into the area that you criticise thus:
The available redundancy should not be used for commercial reasons.
While redundancy and reliability statistics suggest that flights of some time and distance can be achieved within acceptable safety levels on one engine, it is agreed that getting on the ground ASAP is essential. However, were you to add multiple levels of statistical and practical safety and redundancy as in the B747 some people, such as yourself, seem to think that the additional safety margins in the B747 should be ignored in any decision-making. Some even seem keen to consider the B747 on 3 engines to be equivalent - for decision-making purposes - to being on one engine in a twin-engined aircraft. A typical argument is that both are in a state of greater risk (which is a truism, but tells us nothing about comparative risk).
As many B747 pilots have repeatedly pointed out, those who make such arguments rarely show any grasp of either the decision-making process which this crew followed or the level of redundancy in the B747. To repeat, on three engines the B747 has greater redundancy than a twin jet. Dreaming up complex scenarios in which a second engine is lost, etc. is the next response ... which I will not go into, because it has been done to death already.
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hi
I liked AIM by IBM's idea about NOT using the redundency for commercial purposes.
Have any of you flown a 4 engine jet on 3 engines? I did a "3 engine ferry" of a BAE146 about 17 years ago. My first 3 weeks on the plane.
Taxied out for takeoff with 4 engines, set takeoff power, really odd sound, taxied back to gate, took passengers off, figured out which engine was "bad"...ferried from KSJC to KSAN ( can you guess the airline?).
So, there you go, everyone can be happy. The passengers can get off the plane and wait for a good one. The bean counters can be happy to get the plane to a major MX facility. The pilots can be happy...well maybe not everyone is happy.
I think the best way to fly anywhere is with all engines running "right". If they aren't running right go to some place safe darn soon. Take care of the passengers and then all you brave guys can do a "3 engine ferry" if you like.
While regulations would let you continue to destination...those regs were thought of in one sense...but GOOD sense would say, in this case, LAND AT THE SECOND BIGGEST CITY IN THE USA at a damn good airport and then worry about it, instead of flying for a dozen hours and STILL NOT GETTING to the destination.
all the best
jon
I liked AIM by IBM's idea about NOT using the redundency for commercial purposes.
Have any of you flown a 4 engine jet on 3 engines? I did a "3 engine ferry" of a BAE146 about 17 years ago. My first 3 weeks on the plane.
Taxied out for takeoff with 4 engines, set takeoff power, really odd sound, taxied back to gate, took passengers off, figured out which engine was "bad"...ferried from KSJC to KSAN ( can you guess the airline?).
So, there you go, everyone can be happy. The passengers can get off the plane and wait for a good one. The bean counters can be happy to get the plane to a major MX facility. The pilots can be happy...well maybe not everyone is happy.
I think the best way to fly anywhere is with all engines running "right". If they aren't running right go to some place safe darn soon. Take care of the passengers and then all you brave guys can do a "3 engine ferry" if you like.
While regulations would let you continue to destination...those regs were thought of in one sense...but GOOD sense would say, in this case, LAND AT THE SECOND BIGGEST CITY IN THE USA at a damn good airport and then worry about it, instead of flying for a dozen hours and STILL NOT GETTING to the destination.
all the best
jon
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.... then all you brave guys can do a "3 engine ferry" if you like.
When you say
I liked AIM by IBM's idea about NOT using the redundency for commercial purposes.
The attractive phrase "NOT using the redundancy for commercial purposes" applies to all such examples, but it brings no clarity whatsoever to the different safety issues and the different levels of risk that apply. Which was my point in my earlier post above.
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the concept of the forum lacks the punch of face to face conversation.
when I refer to "brave" I meant those who have never flown a 4 engine plane on 3 engines AND still make posts as if they had.
Was the 3 engine ferry I did unsafe? it was not one bit unsafe for the passengers we left at the gate.
And a lightly loaded BAe146 with just 2 pilots and proper fuel for a flight from KSJC to KSAN flys with complete lack of oomph for just about anything. I think we barely made FL180 and that seemed to take forever.
Read the manual someday and enjoy the special things you have to do.
AS to REGS aforementioned (up a couple of posts)...the regs even say I can loop the Golden Gate Bridge, if it is the only way I can save the plane(ultimate authority of the pilot in command)...( a heck of a lot of explaining if that were the case)
But you might remain correct on one concept...you can't regulate good sense!
end of chat
jon
when I refer to "brave" I meant those who have never flown a 4 engine plane on 3 engines AND still make posts as if they had.
Was the 3 engine ferry I did unsafe? it was not one bit unsafe for the passengers we left at the gate.
And a lightly loaded BAe146 with just 2 pilots and proper fuel for a flight from KSJC to KSAN flys with complete lack of oomph for just about anything. I think we barely made FL180 and that seemed to take forever.
Read the manual someday and enjoy the special things you have to do.
AS to REGS aforementioned (up a couple of posts)...the regs even say I can loop the Golden Gate Bridge, if it is the only way I can save the plane(ultimate authority of the pilot in command)...( a heck of a lot of explaining if that were the case)
But you might remain correct on one concept...you can't regulate good sense!
end of chat
jon
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Jon - my only question is - current practice is to have a ferry crew with current simulator trng for the 3-engine ferry. Sounds to me like that your experience was as a line crew. Isn't there a special AFM chapter for this?
(Special preflight inspections, restrictions, etc.)
(Mind you - I'm well aware that ferrying has NOTHING to do with this thread!)
(Special preflight inspections, restrictions, etc.)
(Mind you - I'm well aware that ferrying has NOTHING to do with this thread!)
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barit1:
you raise an excellent point...at that time ( mind you it was 17 years ago) pretty much everyone had been sim trained in 3 engine ferry on this type of plane...the ALF engine was not the most robust. (ALF= avco lycoming fan?)
Lots of special things to do, even drawing with a pencil certain power settings ON THE THROTTLE quadrant.
I recall the sim training and really flying it on 3 wasn't all that bad...losing another one especially on takeoff would have required considerable skill I think.
if you put the passengers safety and comfort first you probably won't do too badly.
all the best
jon
you raise an excellent point...at that time ( mind you it was 17 years ago) pretty much everyone had been sim trained in 3 engine ferry on this type of plane...the ALF engine was not the most robust. (ALF= avco lycoming fan?)
Lots of special things to do, even drawing with a pencil certain power settings ON THE THROTTLE quadrant.
I recall the sim training and really flying it on 3 wasn't all that bad...losing another one especially on takeoff would have required considerable skill I think.
if you put the passengers safety and comfort first you probably won't do too badly.
all the best
jon
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Safer than sailing across!
Leaving the pax behind for a 3 engine ferry means zero risk to the pax from that operation.
Flying over populated areas on 3 rather than 4 increases the risk to people on the ground. The risk is miniscule, but it exists.
The ferry is done to get the aeroplane fixed more cheaply than if everything had to be taken to the aircraft for it to be fixed on site. The risk is accepted for a commercial reason.
Risk is balanced against cost, and this happens every day, on every flight. It would be safer for all pax if they were given high energy 'space' food in little bags, rather than have the danger of trolleys, bottles, cutlery etc loose in turbulence. It would be far safer if all seats (OK, except flight crew!) faced backwards, but pax don't like it, so commercial pressure reduces safety. How about replacing the weight of on-board entertainment systems with airbags? I could go on.
Aviation is probably the most risk-assessed and regulated human activity, and if all this assessment and regulation means that it is deemed to be permissible for a particular 4 engined aircraft to proceed on 3 with an acceptable degree of safety, and if the bloke at the sharp end agrees with that, then what is the problem?
The flight is obviously not as 'safe' on 3 as on 4, but it is a minor and acceptable risk.
IMHO, the interesting topic to discuss is not the safety of this flight, it is why the FAA reacted the way it did.
Flying over populated areas on 3 rather than 4 increases the risk to people on the ground. The risk is miniscule, but it exists.
The ferry is done to get the aeroplane fixed more cheaply than if everything had to be taken to the aircraft for it to be fixed on site. The risk is accepted for a commercial reason.
Risk is balanced against cost, and this happens every day, on every flight. It would be safer for all pax if they were given high energy 'space' food in little bags, rather than have the danger of trolleys, bottles, cutlery etc loose in turbulence. It would be far safer if all seats (OK, except flight crew!) faced backwards, but pax don't like it, so commercial pressure reduces safety. How about replacing the weight of on-board entertainment systems with airbags? I could go on.
Aviation is probably the most risk-assessed and regulated human activity, and if all this assessment and regulation means that it is deemed to be permissible for a particular 4 engined aircraft to proceed on 3 with an acceptable degree of safety, and if the bloke at the sharp end agrees with that, then what is the problem?
The flight is obviously not as 'safe' on 3 as on 4, but it is a minor and acceptable risk.
IMHO, the interesting topic to discuss is not the safety of this flight, it is why the FAA reacted the way it did.