B777 over the atlantic

[purple haze]

dear all

now heres the scenario, your a pilot of a B777 and your half way over the atlantic, or basically beyond the point of return.

Theres an engine failure, what would be the procedure and would u be able to continue on one engine and for how long?

as with the B747/A340 or any other 4 engine a/c u could continue as u have three engines to rely on in an event of engine failure so surely on that principle atlantic flights should be 4 engined a/c.

i know that 777 engines produce more thrust then 747s being 100,000lbs and 60,000lbs respectively but crossing terrain where there is little chance of making an emergency landing warrants 4 engines if the above principle is correct.


any answers would be welecome.

[Lu Zuckerman]

To: purple haze

If I understand it correctly the aircraft must be within X minutes of an alternate in the event of a single engine failure. As a part of the certification the 777 had to demonstrate this capability and the capability of operating on one engine for an extended period of time. Also, the engines had to demonstrate a certain level of reliability. It was my understanding that the 777 was granted ETOPS right out of the box because of how it was designed. The probability of losing a second engine is quite small unless the first engine failed due to a fuel problem, which can also effect the second engine.

Several years ago the president of Airbus Industries was giving a speech in the US in order to promote ETOPS for the A310. He too reflected on the probability of losing two engines on a two engine aircraft were highly remote or in probability language 1 10-9 or one time in a billion.

Within a very short time a Canadian 767 almost crashed when both engines flamed out due to fuel starvation. The same thing happened to two DC-9s and a DC-10. Shortly after that an L-1011 almost crashed due to oil starvation in all three engines due to a maintenance error. And, how about the 747 that lost all four engines when the plane flew through a cloud of volcanic ash.

I would dammed well imagine that even though the 777 is certified ETOPS the pilots pucker factor will go up by several orders of magnitude when his first engine fails.


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The Cat

[JuniorJetClubber]

Cat

1 in a billion is a patently absurd estimation, the guy deserves to be ridiculed. It is exactly this type of estimating that was so criticised in the Challenger Inquiry. It in fact means you could fly a flight a day and not have a failure in nearly 3 million years. Not very likely. People really ought to chalenge these estimates moer often.

[Lu Zuckerman]

To: Junior Jet Clubber

Contact me via email and i will provide you with information relative to your comments.

What you described is exactly how they prove the certification of commercial aircraft. They manipulate meaningless numbers until it can be proven that the aircraft systems meet the specified JAR and FAA requirements for safety. The 1 10-9 figure was established by the FAA and has been adopted by the CAA, LBA,DGCA and are incorporated in the JARs.

Regarding the Challenger, on the 604 they proved that some of the systems had a safety number of in excess of 1 10-12

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The Cat

[RATBOY]

Purple Haze:

One of the problems you run into here is that each of the system components (engine, fuel system, etc) is so highly reliable that when you put them together the mathmatics used in the usual reliability calculations of mean time between failure and such become meaningless because (among other reasons) the numbers plugged into the equations are all estimates. This is because it takes so long (calendar time) to develop a data set.

If you are not comfortable with the "9 nines" reliability of the engine reflect on the fact that the navigation system (GPS) has "7 nines" as a design goal (to be demonstrated..it will take a couple more years to collect enough data) so your engine may work but you won't know where you are unless you take along your boy scout compass.

[Streamline]

Whatever calculations you make, they can only be based on factors you can think of that have a significant impact in the process.

It takes only a flock of birds or a uncontained engine failure with the pieces all over the place to have significant damage on both engines.

Fly the B 777 or any twin for that matter into some african destinations and you will see that the nine number figure does not stand up anymore.

Good Luck

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Smooth Trimmer

[This message has been edited by Streamline (edited 05 January 2001).]

[This message has been edited by Streamline (edited 05 January 2001).]

[purple haze]

i would say remember Murphys Law.

and knowing my luck, on my first flight there would probably be uncontained engine failure.

[BIK_116.80]

Lu Zuckerman, do you think it might be possible that JuniorJetClubber might have been referring to the space shuttle, "Challenger"?

[Lu Zuckerman]

To: Streamline

The initial numbers to establish reliability are taken from the failure rate databases of the company making the component or the aircraft. In many cases even the largest of aircraft manufacturers don’t have a failure rate database. In cases like that the reliability engineers will get failure rates from other sources. Many reliability engineers (like myself) will accumulate their own failure rates from various jobs they have worked. The US Air Force has an extensive data base for electronic equipment that is based on the projected and demonstrated failure histories of thousands of commonly used electronic parts ranging from a diode to the most complex LSI chip.

Failure rates for mechanical equipment and piece parts are another story. That data that is available does not reflect the specific usage for the piece parts in that data base. In cases like that the analyst must provide some K factor that will allow him/her to calculate the failure rate by multiplying the failure rate by the K factor. It is far from accurate but that is how they arrive at the part predicted rate of failure (MTBF).

The analyst creates a block diagram replicating the piece part relationship within the item under analysis. The failure rate numbers are plugged into the individual blocks and the reliability and unreliability numbers are factored from the failure rates of each piece part and that number is also plugged into the respective blocks. Assuming the unit under analysis would fail its’ function if any of the blocks failed it is considered to be a series block diagram. To get the reliability number for the unit the individual numbers in the series are multiplied. The reliability numbers are a decimal point followed by a series of 9s. The numbers are plugged into calculator or a computer and then chain multiplied. The answer is a series of 9s followed by other numbers that are less than 9.

Now, the problems begin. First of all, how accurate are the numbers and do the numbers really represent the inherent failure rates for the parts? When the concept of reliability was first started by the USAF it was to establish the reliability of electronic black boxes. The function of the block diagram was to provide a performance number. By calculating the basic reliability of the black box they could then plug in numbers representing a different part or parts and run the calculation again to determine the effects of the parts change on the predicted reliability of the black box.

There were other types of block diagrams representing very complex and multiple redundancies. If you had a complex or parallel circuit a calculation was performed to establish the reliability of that circuit. That calculation provided a decimal point followed by as many a 12 9s and it was given a reliability of 1 so that in a chain calculation it would have no effect on the ultimate number.

I previously stated that the block diagram concept was to provide comparative performance numbers. Not now. Now they are used to calculate the reliability of the black box and compare it to the required MTBF established by the customer. By selecting the right numbers the reliability requirements were always met. When they applied this concept to mechanical systems the whole thing fell apart due to the lack of reliable failure rate data. I have been doing this since 1968 and it still hasn’t changed.

Now it gets worse. To certify an aircraft it must be proven that the systems meet the probabilities of failure as established by the certification authorities. To do this a fault tree or Systems Safety Analysis must be performed. This is usually in the form of a series of gates arranged to reflect the inter relationship of the components in the system. There are usually AND gates and OR gates. The gates can be visualized like a door with many locks or a door with only one lock. An AND gate has many locks and an OR gate has only one lock. Once the diagram is established it is then determined what must fail in order to lose a function and possibly have an adverse effect on the next higher level.

Lines representing an individual failure that can effect another part of the system connect the various gates. Assume that you have an OR gate with five lines connected to it. Any one of those failures has a key that will open the lock and allow the door to be opened thus passing the failure to the next higher level. Now, assume that the AND gate has five lines connected to it. In order to open the door, all five keys must be used in order for those collective failures to be manifested at a higher level. This combination of AND / OR gates goes upward and terminates at an AND gate which is the highest level in the system. The closer to the top the more AND gate and fewer OR gates.

After constructing the diagram the analyst must determine the probability of total failure of the system. To do this he uses Boolean Algebra to make the calculations. Assuming an OR gate with five inputs the analyst will add the failure rates that were derived from the block diagram to calculate the total failure rate for that gate. One line passes from that gate to the next higher level and the calculated failure rate for that gate is assigned to the line and it in turn passes to the next level and hits another gate. If that gate is an OR gate with several lines connected to it the same calculation is performed and so on. If the bottom gate is an AND gate with five inputs the individual failure rates are multiplied in the same manner as the chain calculations in the reliability block diagram. The line passing out of that gate is assigned the probability of failure for the gate and passes upward just like the OR gate described previously. When all of the lines terminate at the top AND gate a calculation is made and the product of that calculation for the failure probability for that system. It must be 1 10-9 or better. In most cases it is proved to be even better.

Now, ask yourself how reliable is this number if it is based on meaningless numbers that are not representative of the parts that are reflected by those numbers. But that isn’t all. The top numbers that represent the probability of failure represent the systems on the aircraft and not the aircraft. In order to determine the probability of the loss of the aircraft it would be necessary to take the individual top gates and connect them into an OR gate which represents the aircraft. If you would perform the same calculation for an OR gate the aircraft would have a probability of loss well below 1 10-9. The FAA does not require this last calculation because it will prove that the aircraft does not meet the requirements set up for the systems. Even if the numbers that went into the various calculations were true representations of the parts failure rates the answer to the final calculation would be the same. The aircraft cannot meet the FAA, CAA, LBA, DGCA and JAR requirements and it doesn’t make any difference who makes the plane.


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The Cat

[Lu Zuckerman]

To: BIK_116.80

You may be totally correct. When I read his post I was thinking about the Challenger that crashed in the states a month or so ago.

Now, if you want to know what I think really happened on the NASA Challenger just post your approval and I'll let you in on a technical matter that was never brought up in the investigation and if it was, it was hushed up.

Of course it will take the thread in another direction.

Incidently, one of the Women killed in the explosion was my nieces best girl friend and they were room mates in college.



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The Cat

[Dr. Red]

Streamline,

It would take a goddamn catastrophic "uncontained engine failure" to take out the engine on the other wing!


Red

[gaunty]

Lu and Bik

I'm particularly interested in BOTH "Challenger" accidents?? Has anything come out of the Canadair one and I for one would be fascinated to hear about the NASA vehicle.

[Lu Zuckerman]

To: gaunty

To:

Regarding the Challenger explosion this is what the public was told. An “O” ring failed and allowed hot gasses and eventually a high velocity flame jet to escape past the defective “O” ring and impinge on the composite fuel and oxidizer tank resulting in a massive explosion. In addition the public was told that a contract engineer working for Thiokol prepared a Failure Mode Effects Analysis (FMEA) stating that if the “O” ring were exposed to very low temperatures it would most likely fail. He presented the FMEA to his company and they in turn sent it to the NASA Manager of the solid rocket booster branch at MSFC in Huntsville, Alabama for his vetting and final approval. He in fact did sign off on everything in the FMEA including the dire prediction about the failure of the “O” ring.

Just prior to the launch an inspection team went out to check the solid motors and the composite fuel tank. The lower part of the tank contained LOX (liquid Oxygen) which is about 260-degrees below zero F. This localized cryogenic temperature and the presence of high humidity caused ice to form around the solid rocket booster. This was noted and the launch crew was notified. Members of the Thiokol management team wanted to scrub the launch in order to wait for the humidity to drop or for better conditions. NASA engineer were reluctant to scrub for two reasons, 1) they didn’t want to miss their launch window and 2)They didn’t want to upset their preplanned successive launches of the other Space Shuttles. It became a pissing contest and NASA won. The person that was most vocal on the NASA launch team was the former manager of the solid motor branch at MSFC who had signed off on the FMEA. He had been promoted and transferred to the Cape.

The rest is history. The “O” ring failed and a jet of hot gasses escaped from the defective seal.

That is what the public was told at least they were told everything except who had signed off on the FMEA and the fact he was the most vocal member of the launch team to order
the launch contrary to what the FMEA had predicted.

Now, I’ll tell you what I think happened but first, I have to talk rocket science. There are several types of solid rocket motors. The most common is that used in small missiles. These are end grain or they burn on the exposed surface. When an end grain rocket burns, it burns like a cigarette. The interior volume of the motor case determines the internal pressure of the combustion. At ignition the interior exposed volume is small so that as the propellant is ignited the pressure is quite high. But, as the propellant burns the interior volume increases and the pressure drops.

On larger solid motors the propellant grain is cast with the center of the grain constructed in a geometric shape. The shape can be in the form of a cross or possibly like a star. In this type of motor the combustion takes place on the surface of the cast in geometric shape. Contrary to the drop in pressure on an end burning propellant grain the pressure remains constant (within design parameters). If you were to measure the perimeter of the cast in geometric shape you would find it equal to the inner circumference of the containing vessel. As the grain burns away the inner exposed surfaces will become less in surface area but it is now getting close to the inner walls of the rocket motor and if all goes well the rockets will be jettisoned just before burnout.

In many large motors such as those used on the shuttle there will be large chunks blown out during the ignition sequence thus increasing the exposed area that burns. This does two things, one, it creates a combustion instability and two, it increases the internal pressure because of the increase of exposed surface available to be burned.

The same thing can happen if there is a crack in the propellant grain. That is why they X-ray the grain prior to assembling the motor. If the grain cracks the surface available to burn is increased and in turn the internal pressure in creases and can be significant enough to blow the rocket motor to hell and back.
Now, a little bit of chemistry. When you were a kid you learned about the fire triangle in that you needed fuel, oxygen and an ignition source to have combustion. Oxygen by itself does not burn and it doesn’t explode. But if you had a combustible dust in the presence of oxygen and you struck a match the explosion would be violent. That’s what happens when a grain elevator explodes.

The solid rocket motor used on the shuttle is made up of segments that are loaded one on top of the other to create the propellant grain. They strap on a pointed end at the top and at the bottom they attach a steerable nozzle. At each segment attach point they install an “O” ring to maintain the internal pressure. I had suggested to NASA that they use non-combustible putty between each segment pair to create a complete seal. As the grain burned the putty close to the burning gasses would be consumed but the primary seal would remain intact. I never heard from them and, as far as I know only the "O" ring seal area has been redesigned and they don’t use the putty.

Now we get back to the Challenger as it reaches altitude. NASA says a jet of flame and hot gasses escaped past the defective seal and impinged on the oxidizer tank causing the explosion.
If the flames hit the Oxidizer tank and caused a rupture there is no combustible material that would burn that fast as to cause the violent explosion.

You also have to ask this question. If the flame got past the seal it had to come from the internal combustion within the motor. In order to get to the seal any propellant in the area would be burning and as a result, increasing the internal pressure high enough to cause the rocket motor to explode. And, that is what I think happened.


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The Cat

[This message has been edited by Lu Zuckerman (edited 06 January 2001).]

[This message has been edited by Lu Zuckerman (edited 06 January 2001).]

[Smoketoomuch]

Purple:
I'm sure Lu can tell you much more than almost anyone here about safety.
One point worth thinking about tho. If an engine fails it might not mean it simply stops developing thrust, depending on *how* it fails it could cause damage to other critical parts, eg the wing. It is arguable therefore that 2 engines are safer than 4 as there is less chance of an engine failure. I believe that Lindbergh had this in mind when he crossed the Atlantic in his *single* engined aircraft.

[3 putt]

Lu:
Excellent technical insight.Any web sites
for more solid state info.

[Lu Zuckerman]

To: 3 putt

You can find all kinds of information on the internet regarding the Challenger explosion but you won't find any thing about the boosters exploding as opposed to the oxidizer tank exploding.

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The Cat

[This message has been edited by Lu Zuckerman (edited 07 January 2001).]

[Juliet November]

You are probably all correct about the inherent dangers of flying twins on ETOPS rules, but the most commonly used type on cross atlantic flights is the 767, and has been so for quite some time. I belive that upwards of 60 % of all transatlantic flights are performed by 2 engine jets. And even with the latest issue with CF6 engines, I cannot recall an accident with the 767 that has been attributed to ETOPS operations.

Surely, a jet engine is not 100 % failsafe, but it's damn close and that is as good as it's going to get. You are persuing a very interesting intellectual excersise.

I am not defending the calculations which says an engine won't fail for 1 10-9 or whatever, but merely that uncontained engine failures on ETOPS jets is very uncommon.

Purple Haze,
I do not, as the above should indicate, agree that transatlantic flights should be 3 or 4 engined. There are sufficient diversion options to make a 180 minute ETOPS flight perfectly safe. Sure, 3 is better than 2 and 4 is better than 3. But 2 is sufficient, so why the overkill ? It's basically about economics and passengers preferring direct flights on smaller jets over going hub to hub on 747's.

What I'm not so impressed by is Boeings ambition to obtain 207 minute ETOPS, allowing the 772LR to go trans pacific. Not because of the engines, but the lack of suitable diversions. Yes, there are airports with runways in Siberia and other exotic places, but they lack the infrastructure to support a diversion of a 300 pax jet. No shelter, no stairs, no heat, no food, no technical facilities, no nothing. But technically you can land there, and on paper that's supposedly good enough.

Comments anybody ?

[purple haze]

excuse my ignorance but what does ETOPS mean , ive tried looking and cant find it , but i gather its some certificate for an a/c being safe.

can anyone elaborate?

cheers

[Lu Zuckerman]

To: Juliet November

The calculated failure probability of 1 10-9 is for catastrophic failure where the engine sheds some high speed rotating parts and could possibly down the aircraft or cause passenger or crew death. The actual probability of failure or reliability number for the engine is quite a bit lower that 1 10-9 probably around 1 10-6.

These failures are not for a single engine it is for all engines of that type. It doesn’t take a very long time to accumulate 1000,000 hours of total engine operating hours. Let’s say there are 1000 737s that have the same type of engine. If all 1000 aircraft flew for 2000 hours in one year you would accumulate 4,000,000 operating hours and from a statistical standpoint you would expect to have 4 engines fail for any reason that caused loss of the engine function.

The engine on the 737 has already experienced a catastrophic failure at Manchester so, from a statistical point of view you should not experience another catastrophic failure in the life of the 737.


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The Cat

[Roadtrip]

PH - ETOPS stands for "Engines Turn or People Swim." :)

Not actually, it really stand for "Extended Twin Engine Operations"



[This message has been edited by Roadtrip (edited 08 January 2001).]

[lymanm]

I've also heard of another acronym - EROPs, for Extended Range Operations.

Or, similarly mentionned above:

engines running or passengers swimming

har har har

[stagger]

EROPS = Extended-Range Operations

ETOPS = Extended-Range Twin-Engine Operations

But I prefer - opérations de bimoteurs avec distance de vol prolongée.

For some reason it sounds like there's less chance of everyone getting wet if you're flying with "bimoteurs" instead of just two engines.

:)

[This message has been edited by stagger (edited 08 January 2001).]

[Juliet November]

Lu,

Won't start a technical discussion with you, as the outcome would be akin to Burkina Faso going to war against the US. Short and bloody.

However, bringing in the 737 in an ETOPS discussion is pretty far fetched. A more appropriate a/c would be the 767, or which less than 1000 has been built and not all of them ETOPS equipped / certified and with 3 different engine makers and probably several sub-types. So, assuming around 1/2 the 767's are ETOPS and 1/2 of those operate with, say, the PW4000. That'll add up to around 250 of that particular type. Each flying an average of 10 hours pr. day, that's roughly 1 mill. hours/year for the entire fleet. And with an inflight reliability of 1-10 9 a failure will be a most uncommon affair. And losing both engines on the same a/c should be more or less impossible, from a statistical point of view. And finally, the design of any 2 engined ETOPS aircraft has allowed for the aircraft to operate safely on 1 engine for up to 180 minutes.

Please don't kill me over the exact numbers, this should only serve as an example.

In short, I'd feel perfectly safe crossing the pond in any 2-engined ETOPS aeroplane, be it a Boring or A-bus.

Any ETOPS drivers around who's experienced an inflight shutdown and consequently diversion ?

[stagger]

Here's the fundamental problem with ETOPs as I see it...

Say that you'd expect a single engine to fail (not necessarily catastrophically) around once every 30,000 hours of flight. Lets call the probability of single engine failure within an hour of flight Psef

So Psef = 3.33 x 10^-5

Is the probability of double engine failure (Pdef) simply given by…

Pdef = Psef x Psef = 1.11 x 10^-9 (roughly 1 in a billion).

No!

Why not? Because the events are not independent!

Psef can be calculated from the history of a particular engine operating under normal conditions. Sufficient hours of operation have been accumulated under normal operating conditions to indicate that an estimate of Psef = 3.33 x 10^-5 is not unreasonable.

In contrast, comparatively few hours of single engine flight time have been accumulated under the abnormal operating conditions likely to be associated with an ETOPs diversion. Consequently, we simply do not know just how likely it is that the second engine will fail under these conditions.

Given that the first engine has failed it is likely that the probability of the second engine failing is substantially greater than Psef so the probability of dual failure is substantially greater than Psef x Psef.

Note that ETOPs regulations do acknowledge this problem and try to make these events as independent as possible. For each engine - different overhaul times, different mechanics etc. However, these precautions don't deal with the fact that an engine operating alone during an ETOPs diversion is not operating under the same conditions as one of a fully functional pair during normal flight.

[Lu Zuckerman]

To: Stagger

First of all reliability and safety calculations are based on 10-6 so all failure rates must be converted to that value. Your calculations are correct. The probability of losing both engines using your failure rate of 30,000 hours is 1.1109 10-9. However your statement “No” is incorrect because the failure of one engine is independent from the failure of the other. The failure of both engines at the same time can be attributed to an external source (fuel starvation/contamination or, flying through an ash cloud or heavy rain/hail and there fore cannot be quantified in the calculation. It can be considered but the frequency of occurrence is unknown.

In the performance of a Safety Analysis (Fault Tree Analysis) the probability of failure of the two individual engines are joined at an And Gate. That means that to have a total loss of power both engines must fail. The way they arrive at the total figure is to multiply the individual failure rates against each other. Based on your failure rate of 30,000 hours the rate of failure on one engine would be 33.33 10-6 or, 33.33 times in a million hours of operation for that type of engine being used on what ever type of aircraft. By multiplying one failure rate against the other you get 1.1109 10-9.

That is the number that is in the final safety document that is turned over to the certification authorities. However the FAA/CAA may have indicated that the failure of both engines due to independent failure modes might be higher that 1 10-9. If that’s the case the reliability analyst may have to plug in some different numbers when they perform their reliability analysis. The whole thing is based on numbers that may not even have related to the parts being analyzed. Every thing is based on statistical analysis and the numbers in most cases do not reflect the true reliability and safety of the aircraft or its components and appliances. That is why aircraft crash at a frequency higher than that required to gain certification.


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The Cat

[SunSeaSandfly]

Juliet November
Don't diss the 737. There are some that are ETOPs qualified and operated, would you believe.

[GotTheTshirt]

Dr Red,
Yes it is possible for an uncotained failure of a wing engine to disable the engine on the opposite wing. Happened on a DC10-10 wher the No 2 fan let go and debris hit the fuselage and also went under the fuselage to hit No1. The No 2 fan completely distroyed the front of the engine leaving th High Speed gearbox attached by only the electrical cables and Hydro lines.

Secondly throughout the thread, all failure analysis seem to be concerning engine. There are also system failures that could be equally uncomfortable.
Durring B777 test program one air sytem was shut down whereon the main Non Return Valve failed so the aircraft depressurised through the dead system. This happened on 2 separate occasions - first low level - second 40,000 ft. The crew did emergency descent and were taken to hospital.
Imagine complete depressurisation at PON and what the fuel burn would be at 10,000ft !

[TheShadow]

http://fly.to/avia3710

http://www.geocities.com/CapeCanaveral/Galaxy/7728/litrev.html

http://www.pprune.org/ubb/NonCGI/Forum1/HTML/006484.html Similar Singapore Airlines 777 oil loss (Feb 2000) (thread now not retrievable - but reproduced below from archive)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^^^^^
below is from http://www.egroups.com/group/triple7/745.html?

Quote

I'm still catching up with news after the holidays...

AIR TRANSPORT - MAS Admits maintenance lapse after 777 suffers double engine
trouble

Flight International Online News (24Dec99)

Malaysia Airlines (MAS) has admitted that a maintenance lapse was
responsible for the emergency landing of a Boeing 777-200 suffering low oil
pressure on both its Rolls-Royce Trent 800s.

Flight MH137, operating from Kuala Lumpur, Malaysia, to Auckland, New
Zealand, on 4 December, was forced to return to Kuala Lumpur International
Airport after the captain noticed a gradual oil-pressure drop in both
powerplants.

MAS says: "A technical inquiry has established that the engines were losing
oil pressure from a breather vent tube on each engine, which were
disconnected for maintenance. A lapse in hand-over between the shifts had
led to the vent tubes remaining unconnected. An engine test run was
conducted after maintenance. No oil leak was detected until the flight was
despatched."

Full story at http://www.flightinternational.com/fiwelcfra.html.

This is about as close to a sin-bin offence for a failure to meet ETOPS
standards that an airline can approach without heavy fines and a loss of
certification. If either engine had failed due to this problem I daresay
we'd be talking about how Malaysia lost the right to fly 180 minutes
ETOPS....

Russ.
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> A recent B777 in flight shutdown was filed by SIA management as "pre-cautionary" Investigations revealed that there was little oil left in the engine, as most had been ejected over the Bay of Bengal. Non compliance by the crew to shut the offending engine down, would have resulted in a severe case of the shakes!
If it had been correctly filed as an required in flight shutdown,then SQ may have had problems with its 207 mins ETOPS over the pacific.Urm, would you fly here?? Do pax care? Does anybody?

IP: Logged

venom
Experienced PPRuner
Posts: 20
Registered: Oct 98
posted 17 February 2000 18:06
---------------------------------------------
Oil does seem to be rather a worrisome problem with SIA. After all the expat engineers left a few years ago, management decided to employ main-land Chinese engineers to make up the numbers. During routine maintance of one of their A310 one of these new boys did an oil change and filled the engine up with hydraulic fluid. The aircraft subsequently had an engine failure after take off.
Lucky the same guy didn't do the other engine. ETOPS policy I hope?

Amazing stuff, but it happened.

[DoctorA300]

In answer to the shadow. You don´t have to go to the far east to experience grave maintenance errors, we can do just as well here in europe. A few years ago a British Midland B737 takeing off from East Midlands
had to shut down 1 engine due to dropping oil qty, the crew elected to divert to Luton, and during approach the other engine started loosing oil aswell, the landing was uneventful, but during the subsequent investigation it was found that both engines hand crancking pad covers had not been installed after a boroscope inspection.

[TheShadow]

http://www.open.gov.uk/aaib/gobmm.htm

(is the Boeing twin engine semi-fail case).

http://www.geocities.com/Heartland/Oaks/8553/circuloB.jpg

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Who knows what evil lurks in the hearts of men?

[Juliet November]

SunSea etc.

I'm aware of that. There's also a few A320's operating under ETOPS. However, my point was that the 737 doesn't operate very often under ETOPS, whereas the 767 (or A330 for that matter) does so far more regularly. And I chose the 767 simply because it's by far the most widely used a/c type fra transatlantic flights. Indeed, the 747 is seeing decreasing usage over the atlantic, in favour of more direct point'to'point routes flown by smaller twins such as the 767, 777 and 330. To my knowledge only a few airlines operate the 747 from Europe to the US east coast, AF and BA being some of them. But they are serving huge hubs FROM huge hubs, and are heavily dependent on lower deck freight to make the crossings profitable (or so I've been told anyway)

[GotTheTshirt]

Re the MAS and BMA incident there is some protection as you are not supposed to carry out routine maintence on BOTH engines of a twin prior to an ETOPS flight!

[Dr. Red]

GotTheTshirt -

The incident you refer to (unless I'm mistaken) was United Airlines 232 in 1989. The DC10's number 2 engine did fail explosively after the six-foot fan blew apart.

The hydraulic lines were severed, rendering flight controls basically useless, but the other engines were not directly damaged, and the pilots managed to ditch at an airport, saving many lives.

Following the incident, hydraulic systems were overhauled with fuses, etc, so the chance of this happening again is greatly reduced.

I would like to point out that the engine that failed was NOT on the "other wing" but centrally mounted, and that this failure was UNIQUE to such a configuration.

I concur there are other factors that can affect the airworthiness situation after engine failure, but still assert that in today's aircraft, the chance of one' engine's failure affecting the other engines directly is infinitely remote (excepting fuel exhaustion, and other no-brainer occurrances).

I would actually be far more concerned about engine schrapnel puncturing the fuel tanks, control surfaces, cabin space, stewardesses, and so on.

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There's nothing like an airport for bringing you down to earth.

[TheShadow]

Dr Red
Got the TShirt was possibly referring to:

NTSB Identification: NYC00FA122 Scheduled 14 CFR 121 operation of CONTINENTAL AIRLINES, INC.
Accident occurred APR-25-00 at NEWARK, NJ Aircraft: McDonnell Douglas DC10-30, registration: N39081 Injuries: 234 Uninjured.

This is preliminary information, subject to change, and may contain errors.
Any errors in this report will be corrected when the final report has been completed.

On April 25, 2000, at 1942 Eastern Daylight Time, a McDonnell-Douglas DC10-30, N39081, operating as Continental Airlines flight 60, was substantially damaged when an uncontained engine event occurred during takeoff from Newark International Airport (EWR), Newark, New Jersey. The 3-man cockpit crew,
11-person cabin crew, and 220 passengers were not injured. Visual meteorological conditions prevailed at the time of the accident. An instrument flight rules flight plan had been filed for the flight, between Newark and Brussels Airport (BRU), Brussels, Belgium. The scheduled passenger flight was conducted under 14 CFR Part 121. The captain stated that he conducted a crew briefing prior to boarding the airplane. Startup and taxi were normal, and during the taxi, the captain again briefed the cockpit crew, and included engine failures and non-reject situations. The airplane lined up on Runway 04L, and the captain applied takeoff power slowly and smoothly. At takeoff decision speed (V1), there was a loud explosion. A white "engine fail" light illuminated in front of the captain, and the number 1 engine N1 decreased by 30 percent. Number 2 and number 3 engines appeared normal. The captain continued the takeoff, and the landing gear was raised. A red, left main landing gear warning light illuminated on the front panel. The airplane turned to a heading of 010, and slowly climbed to 3,000 feet. During the climb, an airframe vibration developed. After level-off, the crew began to troubleshoot the emergency, and found that when the number 3 engine N1 was reduced to about 25 percent, the vibration disappeared. Both the number 1 and the number 3 engines remained at approximately 25 percent N1 for the rest of the flight. Air traffic control provided vectors for a return to Newark. During the return, the crew dumped about 90,000 pounds of fuel. The crew also ran both 1-engine, and 2-engine inoperative checklists, and prepared data cards for both scenarios. The captain flew the ILS glideslope down to a full-stop landing, on Runway 04R. The ACARS recorded the landing at 2016. After the initial stop, the brakes would not release, so the crew shut down the engines on the runway, and the passengers and crew disembarked through the normal deplaning doors. The airplane was later towed to a ramp. According to the captain, the use of crew resource management (CRM)
by both the cockpit and cabin crews was a major factor in the successful handling of the emergency. Examination of the airplane revealed that all three General Electric CF6-50C2 engines were damaged. The number 1 (left) engine "low pressure turbine" case was breached in the vicinity of the second stage nozzles, from approximately the 3 o'clock, to the 9 o'clock position. The breach was about the width of the second stage nozzle segments, and all of the segments were missing from the engine. Each segment consisted of six nozzle blades. Nine of the 16 nozzle segments were recovered intact, and additional portions of segments were found, for a total recovery of about 85 percent of the nozzle blades. The majority of nozzle material was found on the departure runway; however, one nozzle segment was found in the left main landing gear wheel well. One of the eight anti-rotation nozzle locks was recovered. The threaded stud from that lock had been sheared from the plate, and the engagement tangs exhibited wear and damage. The first stage low pressure turbine blades had minor trailing edge airfoil damage, and the second stage low pressure turbine blades exhibited circumferential rub marks on the inner platform leading edge, and on the airfoils near the blade root. The number 2 (center) engine exhibited leading edge damage to two fan blades. The number 3 (right) engine had leading edge damage to all fan blades, consisting of tears, rips and material loss. Pieces of fan blade, and material similar to that of the second stage nozzles from the number 1 engine, were found embedded in the engine inlet acoustic panels. The left main landing gear, front inboard tire, was ruptured, and the front outboard tire exhibited tread separation, but remained inflated.
Impact marks were noted on the outboard side of the left engine pylon, the left wing outboard flap, the underside of the fuselage, the left main landing gear access door, the left side of the fuselage aft of the left wing, and a right wing panel outboard of the flap actuator housing. The installation of upgraded nozzle locks, per Service Bulletin 721082, was accomplished in 1997.

or maybe

http://www.ntsb.gov/NTSB/brief.asp?ev_id=20001212X22049&key=1

Related to: a long history of slag inclusions in milled titanium billets used in GE CF-6 (ask the FAA's Jay Pardee about that)

NTSB Identification: NYC00IA250

Scheduled 14 CFRPart 121 operation of Air Carrier CONTINENTAL AIRLINES
Incident occurred Tuesday, September 05, 2000 at NEWARK, NJ
Aircraft:McDonnell Douglas DC-10-30, registration: N14090
Injuries: 244 Uninjured.

This is preliminary information, subject to change, and may contain errors. Any errors in this report will be corrected when the final report has been completed.

On September 5, 2000, at 1919 Eastern Daylight Time, a McDonnell-Douglas, DC-10-30, N14090, operated by Continental Airlines as flight 60 received minor damage when the number two engine experienced an uncontained engine failure during the takeoff roll at Newark International Airport (EWR), Newark, New Jersey. There were no injuries to the 3-man cockpit crew, 11 flight attendants, or 230 passengers. Visual meteorological conditions prevailed for the international flight destined for Brussels, Belgium. Flight 60 was on an instrument flight rules flight plan conducted under 14 CFR Part 121.

According to Continental Airlines, the captain initiated a takeoff on runway 4L. When the airplane's speed was about 80 knots, the N1 fan speed on the number 2 (center) engine declined from 104 percent to 78 percent, and the engine fail light illuminated. The captain then initiated a rejected takeoff. After clearing the runway, the airplane was stopped on the taxiway. Emergency personnel reported damage on the number 2 engine. The remaining engines were shut down, and the airplane was towed to the gate where the passengers deplanned through the jetway.

The engine was a General Electric CF6-50C2. Examination of the engine revealed the low pressure turbine case was separated around its circumference, at the back side of the second stage vanes. In addition, from the 9 o'clock position to the 2 o'clock position, a 2 1/4 inch wide strip of the metal case was missing from over the top of 2nd stage vanes. A visual examination through the opened engine case revealed no 2nd stage vanes present in the engine.

The 2nd stage low pressure vanes consisted of 15 segments held in place by locks. Twelve segments were recovered, either on the runway or adjacent areas. One additional piece was jammed into the aerodynamic boat-tail located above the engine. Several pieces of engine cowling and assorted hardware were also recovered. Rubbing damage was visible on the trailing edge of the 1st stage turbine blades and the leading edge 2nd stage turbine blades.

Damage was confined to the engine, engine cowling, and aerodynamic boat-tail above the engine.

The engine was retained for further investigation.

or maybe this one two days later: http://www.ntsb.gov/NTSB/brief.asp?ev_id=20001212X22067&key=1

and there's lots of other DC-10 similar

[TheShadow]

DC-10 uncontained engine incidents article:

http://www.GeoCities.com/Eureka/Concourse/7349/regulatorsfret.html

[Dr. Red]

I stand corrected... :)

[GotTheTshirt]

Dr Red, The Shadow,

Showing my age ! but no the incident was in 1970-72. The aircraft was a DC10-10. I have some photos in the archives but the No 3 fan let go and debris went under the fuse to hit No 1. Debris also hit the fuse and tail and just missed ingesting into No 3 ( Hows that for a bad hair day !) One passenger was killed being sucked out of a RHS seat through the demolished window ! ( apparently no truth to the rumour he hadnt paid for his drink)
This was around the same time that TWA lost a fan on an L1011 going into NY.
The big Fan engines were big problems i the early 70's!
I seem to think Continental and Denver but not certain - will check the attic !

[GotTheTshirt]

Dr Red, & The Shadow

Senility has not quite set in !!!
The following from DC 10 Fatal Accidents on the net.
I do have the pictures somwhere ( got them at the same time as the T Shirt) And the other wing engine was damaged !!

3 November 1973; National Airlines DC10; over New Mexico, USA: The aircraft had an uncontained failure of one of the wing mounted engines. A piece of the engine struck the fuselage and broke a passenger window. One of the 116 passengers was sucked out of the aircraft during a rapid decompression. The remains of the passenger were not found.

[SKYDRIFTER]

PRAGMATIST NEEDED -

Just as a single truck took out a barracks of 200 marines and a rubber dinghy nearly sunk the destroyer Cole, Murphy's Laws are waiting for an ETOPS opportunity. The arrogance required for simple oversight or mistake will do the most damage.

The Newark DC-10 accident is sufficient evidence to send the math boys back to 'thinking' school. Beyond what nearly happened (hydraulic leak, as well)is the fact that the event was plagued with a pre-existing and highly ignored history. While the uncontained failures date to the 1970's, the FAA (I believe) only cited a history since 1989.

Pay attention to the fact that the same company suffered two more uncontained engine failures in short order. The aircraft were all based out of the same city; where is the maintenance oversight by the FAA? Add to that the obvious maintenance standard which is alleged to have been the bizarre initiation of the Concorde crash.

I respectfully submit that engineering arrogance has already condemned a planeload of passengers.

[Techman]

It is very interesting to see all these numbers, describing the statistical probability of single and dual engine failures. But I can assure you all, that when you are sitting 180 min from an airfield and one engine suddently becomes very silent, numbers don't mean **** . You are sitting there with one engine left, build by the same manufacturer, at the same plant and maintained by the same people as the one that just stopped working.

Perhaps engines on etops a/c should comply with the same requirements as flight control computers, build at different locations and maintained or at least overhauled by different organizations.

But I guess as always the only numbers that really matters are those followed by a $

[Dr. Red]

Speaking of meaningless probabilities, check out this site:

http://www.amigoingdown.com

Gives you the chances that your flight will "go down" - probably just a random number generator!

------------

On a more serious note, I reverse my previous insinuation that ETOPS is infallible. It's clear that NOTHING can be immune from system failures, etc.

Red

[Jetdriver]

Purple Haze,

Sorry a bit late picking up on this thread. Some mind numbing statistics been given though.

Going back to your question. The procedure is really quite simple.

You would gradually descend to an altitude at which the aircraft could maintain altitude on its one remaining engine. ( A 3 or 4 eng' a/c would do much the same). This process takes a lot longer than most people think.

During the above you would start the process of diverting to a suitable aiport. The decision of airport is subject to continuous assesment during any Etops flight. The airport chosen (in your Scenario) would probably be around 2 hours away maximum at the single engine flying speed.

The remaining engine will probably work fine for years notwithstanding the couple of hours you require. The fact that the first one failed is for most Pilots a once in a lifetime event.( Most, not all!) If it really isn't your day and the other engine fails, then your choices are really made for you.

It is interesting that there are more critical scenarios from a fuel point of view. For example a depressurization ( regardless of how many engines you have) will in all cases require a descent to around 10,000 ft. At this altitude those engines burn a lot of fuel. The weather is often quiet unpleasant as well. There is a certain irony that if the engine also fails in this scenario you would be better off from a fuel standpoint than if they both kept running.

As others have said the rules concerning twin engine operations over extended distances, limit the allowable distance from a suitable diversionary airport. These rules also take into account terrain factors where they may be applicable.

There is a lot of opinion on the rules concerning ETOPS however the point I am trying to make is that there are far more difficult scenarios to contend with than a twin engine aircraft having a single engine failure in flight wherever in the world it happens to be.

[purple haze]

thank u for the mind boggling yet interesting answers.

lu z. just out of curosity, whats ur background, u gave some very through answers.

[lamer]

tried the amigoeingdown website...

1/200000 for korean from afghanistan to angola

1/46000000 for ba from kjfk to egll

looks about right ! :)

[Speedbird48]

Ask the crew of the United 777 that departed Dulles for Frankfurt with the oil filler caps lose after a maintenance screw-up. They called back to ask about fluctuating oil pressure but were told to continue. It had very little oil at Frankfurt.
This is the sort of thing that will get us not the mechanical side of things.

[Pilot1113]

This is in reference to the "Challenger" explosion in 1986.

My, oversimplifed, view is that I understood that when the SRB 'exploded' it detached from the assembly, swung around and slammed in to the main vehicle. This caused the Orbiter to be pushed outside it's flight envelope and explode because of the stresses on the aircraft.

Then again, what the heck do I know... I'm only a pilot.

Neil Harrison
AOPA Member
Purdue University Student