ANZ gets approved for 330 minute ETOPS

[Niner Lima Charlie]

The US FAA and New Zealand CAA have approved Air New Zealand to operate their B-777-200ER with RR Trent 800 engines, for for 330 minute ETOPS. Now permits flights from Auckland to Buenos Aires route.

[racedo]

Good for All Black v Pumas matches then,

[Flightmech]

5 1/2 hour ETOPS. Getting too big for minutes. That's impressive:D

[Capot]

And all founded on the blind faith that if one engine on a twin-engine aircraft fails, the probability of the second failing during the remainder of the flight is totally unaffected by that event. Leaving aside fuel-related loss of power on both sides, I wonder how justified that faith really is?

Are we so absolutely certain that double engine failures can never be inter-dependent? That if one fails, a failure of the other can only be a completely random, chance event, that would have happened whether or not the first one failed? That's the fundamental assumption of ETOPS, and of the calculation of the probability of a second failure in the same flight.

Beyond that, from the Airworthiness angle the only difference is that ETOPS aircraft are slightly more carefully looked after than non-ETOPS, aimed at reducing the probability of the first failure and, of course, of the second failure to an even lower number.

330 minutes/5.5 hours is a long time to fly on one engine with, say, 350 passengers and crew on board, hoping like hell that the other one will operate normally until you can land, and that the Statisticians have finally beaten the Gremlins.


PS Maybe the word "monitored" should be substituted for "looked after"; the reality is probably that both are correct, if over-simplified.

[1201alarm]

Do you think a 747 will fly better in case of a fuel problem?

Although I must admit that 330 min ETOPS sounds extremely impressive.

[JanetFlight]

Sorry....now i got a bit confused after reading this OP thread mixing with this one here?
http://www.pprune.org/tech-log/528992-edto-vs-etops.html

[PDR1]

Beyond that, from the Airworthiness angle the only difference is that ETOPS aircraft are slightly more carefully looked after than non-ETOPS, aimed at reducing the probability of the first failure and, of course, of the second failure to an even lower number.

I've always had a concern that one day a lawyer will latch onto this when a non-ETOPS aeroplane of a type which can also be ETOPS-certified crashes. The argument will be that the operator is under a duty of care to make the flight as safe as practicable, and the fact that the ETOPS aircraft are "more carefully looked after" shows that there is a higher level of care which can practicably be applied to the non-ETOPS aeroplane. It rather counters any ALARP claims in the safety case!

PDR

[Ex Cargo Clown]

I've always had a concern that one day a lawyer will latch onto this when a non-ETOPS aeroplane of a type which can also be ETOPS-certified crashes. The argument will be that the operator is under a duty of care to make the flight as safe as practicable, and the fact that the ETOPS aircraft are "more carefully looked after" shows that there is a higher level of care which can practicably be applied to the non-ETOPS aeroplane. It rather counters any ALARP claims in the safety case!

PDR

It is a concern. I understand ETOPS engineering protocol, but any decent lawyer will tear strips out of this.

[Capot]

I used the phrase "probability of the second failing during the remainder of the flight is totally unaffected by that event."

EASA says the same thing, more or less, but differently;

"...objective that the catastrophic loss of thrust from independent causes is no worse than extremely improbable."

There's another problem; ETOPS planning uses the notion that the risk of the second failure - "catastrophic loss of thrust" - increases as time goes on after the first failure. That's why the longer the diversion flight time allowed for an aircraft , the lower its in-flight shut down rate has to be.

But if the second failure is entirely independent of the first, it is a random event, and as such the probability of it happening is exactly the same at any point on the time line of the diversion flight, or indeed at any time, period. The length of the diversion flight makes no difference.

There's a lack of consistency here. I have always suspected that ETOPS was driven by manufacturers wanting to build and sell big twins, and their engines, and airlines wanting to use them economically, ie long flights over water, and that this imperative has created some spurious statistical justification to allow that to happen.

But we have to remember that regardless of all that, the risks of the first failure, followed by a second one, are so low that the "catastrophic loss of thrust" will probably never kill people. None-the-less, I will continue to avoid twins on long over-water or polar flights, although I would take my chances with a survivable forced landing on the tundra or desert.

[kcockayne]

Well, all I know is that I would not want to be sitting for five & a half hours on one engine ! Although I appreciate that the failure won't occur at exactly five & a half hours from alternate, if it happens. It stands a much greater chance of happening at a much later time but, sooner or later it WILL happen.

[Enos]

180 minutes ETOPs for older RR powered 777, (777-200ER 777-300) these aircraft have 5 fire bottles for the cargo holds fire suppression, probably airlines specs.

207 minutes ETOPS for GE powered 777-200LR and 777-300ER 6 fire bottles for cargo hold fire suppression.

How many fire bottles will be required for ANZ 777-200ERs?

[WillowRun 6-3]

But if the second failure is entirely independent of the first, it is a random event, and as such the probability of it happening is exactly the same at any point on the time line of the diversion flight, or indeed at any time, period. The length of the diversion flight makes no difference.


But Capot, is it really accurate to characterize the probabilistic assessment of a second engine failure as such failure being an utterly random event? Even for ETOPS-approved engines, does not the measurement of Mean-Time-Between-Failures (MTBF) still apply? And even if MTBF is an obsolete statistical measurement for this purpose (which I do not claim to know), still, is it not the case that the more hours an engine has been operated in total, the probability of a failure increases?

(I'm not saying your analysis is incorrect - what little knowledge of Statistics I might once have had, I had only for a social science degree, not as Mathematics.)

[Capot]

is it really accurate to characterize the probabilistic assessment of a second engine failure as such failure being an utterly random event? No, I don't think so; that's my point.

But the fundamental notion upon which the whole ETOPS rule is based is that if one engine fails, the probability of the second failing before the aircraft can land is no greater than it would have been without the failure of the first engine to fail.

In other words; if it does fail, it can only do so for a reason unconnected with the failure of the first engine to fail, so that such an event is entirely random. I don't buy this, and nor, I suspect, do you.

[c100driver]

180 minutes ETOPs for older RR powered 777, (777-200ER 777-300) these aircraft
have 5 fire bottles for the cargo holds fire suppression, probably airlines
specs.

207 minutes ETOPS for GE powered 777-200LR and 777-300ER 6 fire
bottles for cargo hold fire suppression.

How many fire bottles will be
required for ANZ 777-200ERs?

A few corrections here. The Air NZ T7 300's are all 240 EDTO and have been for almost three years, as have half the T7 200's. Currently only 4 of the T7 200's will have 330 the remainder will have 240 plus a bit.

207 minutes was always a bit of a boge job to fly transpacific from the westcoast USA to Japan.

There are a number Boeing mods required to extend EDTO, one is increased cargo fire protection. So yes the Aircraft have had extra bottles fitted.

The US FAA and New Zealand CAA have approved Air New Zealand to operate their
B-777-200ER with RR Trent 800 engines, for for 330 minute ETOPS. Now permits
flights from Auckland to Buenos Aires route.

If Easter Island is available then 240 EDTO should cover the flight.

[Two's in]

ETOPS is not exactly a new concept - there must be statistics that demonstrate the safety (or otherwise) of the thousands of ETOPS hours that must have been flown to date.

[ETOPS]

330 minute ETOPS:eek:

Well - if I was a bit younger :ok:

[Offchocks]

It would seem that most here are discussing the loss of a second engine and yes they are important, but don't forget there are other ETOPS considerations than just the engines.
For myself I would not have a problem with operating such equipment, but that is never going to happen now! :{

[Chu Chu]

It seems to me that a second engine failure is unrelated to the first or it isn't. ETOPS is based on the low statistical possibility of a second unrelated failure occurring.

A second related failure seems likely (not certain, but likely) to occur within a short time of the first. If so, a suitable airport 30 minutes away may be as useless as one 330 minutes away. (And, of course, something like a fuel problem could affect 3 or 4 engines as easily as 2).

[Sqwak7700]

And all founded on the blind faith that if one engine on a twin-engine aircraft fails, the probability of the second failing during the remainder of the flight is totally unaffected by that event. Leaving aside fuel-related loss of power on both sides, I wonder how justified that faith really is?

Are we so absolutely certain that double engine failures can never be inter-dependent? That if one fails, a failure of the other can only be a completely random, chance event, that would have happened whether or not the first one failed? That's the fundamental assumption of ETOPS, and of the calculation of the probability of a second failure in the same flight.

Capot, not sure what you are suggesting. According to your logic, then all twin jets could only operate on routes that keep them within gliding distance of a suitable airport.

Why is two hours ok but 5.5 not? If both aircraft that far from a suitable airport loose the remaining donkey they will both be crashing.

:hmm:

[India Four Two]

A few years ago, I landed in Auckland and saw an Aerolineas Argentina A340 at the next gate, which prompted me to look up the great circle route to Buenos Aires:

http://i30.photobucket.com/albums/c309/india42/Screen%20Shot%202015-12-04%20at%2012.55.32%20_zpsphdjsbjq.png

That certainly is a remote part of the world to be flying in ANY aircraft, never mind a twin.

[wanabee777]

How many fire bottles will be required for ANZ 777-200ERs?

Good question.

On a triple 7, even after an actual cargo bin fire extinguished, because of the optical smoke detectors, every time the fire suppression system meters a dose of Halon into the compartment, the flight deck will receive a another cargo fire warning until the halon dissipates. The metering will continue until touchdown at which time the entire remainder of the halon bottles will then fully discharge.

Imagine having to put up with that for 5 hrs.

[B-HKD]

As mentioned previously, 4 of the 8 -200ERs were modified and certified to ETOPS/EDTO 330 (additional cargo hold fire suppression bottle and $$$ maintenance and monitoring program).

Although they will be maintained and dispatched under ETOPS/EDTO 330 rules, the furthest they will be planned from the nearest suitable alternate on AKL-EZE-AKL is 300 minutes. The extra 30 minutes are not needed on this particular rotation.

[Capot]

According to your logic, then all twin jets could only operate on routes that keep them within gliding distance of a suitable airport.Yes, I know, and I'm not really suggesting that we should do that. But I do think that we have gone a little too far to the opposite extreme, with 5.5 hour diversions on one engine being allowed.

And I also think that we should stop using slightly spurious statistics to kid ourselves about the risks involved in allowing ever-increasing one-engine diversion times, simply to please the industry's accountants.

[Heathrow Harry]

the real question is how many people will want to fly the route? Argentina is hardly an economic powerhouse and New Zealand is .... small economically speaking.......................

Santiago I could just about see but BA????

[stilton]

Not crazy about being five and a half hours from land on one engine either.


Correct me if i'm wrong though, I can't think of ONE incident / accident since ETOPS began that has been attributed to only having two engines.


In other words a three or four engine aircraft would have been equally affected.

[meekmok]

ETOPS is not exactly a new concept - there must be statistics that demonstrate the safety (or otherwise) of the thousands of ETOPS hours that must have been flown to date.

Surely millions of flight hours now. The original ETOPS certification back in the 80's was based on a world fleet in-service experience of 250,000 hours...

[wanabee777]

As long as the engine out twin is not exposed to excessive or prolonged icing conditions at the lower altitudes, I suppose there's nothing else that could go wrong.

Right??:rolleyes:

[Capot]

Pretty much every double-engine failure in a CAT aircraft I have known about, including two that concerned me directly, was caused by ummm.... finger trouble with the operating crew, exacerbated by the law that says that trouble comes in threes.

So the answer to the question I suppose there's nothing else that could go wrong.

Right??is "Wrong. Something else probably will. Some-one, or something, somewhere, will screw up or fail unexpectedly, in a way that would be harmless if you were not already on the margin with an inop engine and 3 hours from a runway, but now puts you in real danger. And then, what shall we guess at? Diversion closure, say?"

I know, it's a prophecy of doom. But it's the unforeseen or unforeseeable that gets you, every time, and you prepare for that by having plenty in reserve to deal with it. An engine failure depletes that reserve badly, and the way to manage that is not to plan to continue operating for up to 330 minutes if it happens, but to carry that less safe condition for a much shorter time.

I do understand that this is unquantifiable, and that therefore rules cannot be written around it, but it's the reality. Extra fire bottles is not a complete answer, but the requirement is a sort of recognition of what I'm saying.

[GlobalNav]

While there have been many ETOPS approvals over the years, I know they are never a trivial consideration during a new aircraft, or new engine certification. The process is more streamlined now, better focused on the risks and mitigations than ever, but no short cuts. The regulators, FAA and EASA anyway, have been very rigorous.

I suppose there will always be what we call "unknown unknowns", Murphy's Law and all that. It is important that the community maintains the integrity of the mitigations - available diversion airfields, emergency power after engine shutdown, for example - and a careful assessment of new failure modes introduced by new technology designs.

[tdracer]

Imagine having to put up with that for 5 hrs. And that would be different on a quad how?

I'm sure Capot and others will dismiss this as statistical hogwash, but back in the early days of ETOPS, there was an analysis done that showed the more engines a multi engine aircraft had, the more likely it was to crash due to an engine failure. The rational was pretty simple - while the vast majority of engine failures are benign, a very small percentage are not - e.g. uncontained rotor failures and engine fires - and those failures can be catastrophic. The more engines, the greater the likelihood of a catastrophic engine failure.

Oh, and the 777 by itself has 10 of millions of hours of ETOPS experience - if you look at the entire population of twins flying ETOPS (737, 757, 767, 777, 787, plus the Airbus twins) it's certainly at least 100 million hours without an ETOPS related accident.

[27/09]

Heathrow Harry: the real question is how many people will want to fly the route? Argentina is hardly an economic powerhouse and New Zealand is .... small economically speaking.......................

Santiago I could just about see but BA????

I think it's more about New Zealand being geographically a good hub for people want to get to/from South America from Australasia and places west (east to you Europeans). BA is a good hub with the alliances Air NZ has got in South America. I think it makes sense.

[Capot]

there was an analysis done that showed the more engines an aircraft had, the more likely it was to crash due to an engine failure. If I remember rightly, those "statistical analyses" comparing 4-engine to 2-engine aircraft were done as a joke, where the trick was to spot the statistical howler.

I even wrote one myself, as I recall. It started with an assertion that if you have 4 engines, an engine failure is twice as likely as with 2-engines; and so on. Amusing up to a point, but rubbish.

[tdracer]

If I remember rightly, those "statistical analyses" comparing 4-engine to 2-engine aircraft were done as a joke, where the trick was to spot the statistical howler.Well, the analysis I'm referring to was submitted to the FAA as part of Boeing's justification for 120 minute EROPS (as it was then known).
The FAA must have missed the joke :rolleyes:
Oh, and at that time, the requirement for 120 minutes was a shutdown rate of o.o6/1000 hrs., and some engine types were struggling to meet that.
Today most engines are well below o.o1/1000 hrs.

[Landflap]

Quite a long time since I went back-n-forth over the N Atlantic in 757's & maybe the law has changed; but, loss of an engine on a twin engine aeroplane is defined as a 50% power loss and, therefore, a Mayday situation. Next, probability is that the aircraft cannot maintain height and must descend whereafter the single engine is operated at MCT. Now, lower level, MCT and a Mayday...........for 5 1/2 hours......., really ? I mean, honestly ? GOSH !

[Capot]

Well, the analysis I'm referring to was submitted to the FAA as part of Boeing's justification for 120 minute EROPS (as it was then known). With apologies to Boeing and the FAA, I withdraw the word joke" in the case of that analysis.

Others were done as a joke, even, IIRC, in the august pages of PPRuNe.

But it was still a statistical howler; ask yourself, can that statement really be true? Of course not, and when you see an organisation using "statistics" to sell an apparently perverse argument with loads of cash depending on the outcome you have to look more deeply at the statistics used.

[wanabee777]

Imagine having to put up with that for 5 hrs.And that would be different on a quad how?Absolutely nothing.

Obviously, Boeing needs to come up with a better cargo fire detection system for EROPS/ETOPS operations.

[Scuffers]

All this talk of ETOPS is very interesting, but can somebody quantify what the actual impact on a 777 is of loosing an engine?

What I mean is that at cruise altitude, what % of engine power is required to maintain said cruise in normal circumstances?

And following on from that, if your then down to one engine, what other issues are you looking at? I assume asymmetric thrust will have an impact on aero efficiency, ie, drag will be increased? thus range will be reduced? etc etc.

As for likelihood of engine failures, in my totally non representative experience as SLF, I have twice been on 4 engined planes that have had engine shut-downs, never been on a twin with this happen, no idea what this actually means though? (4 engined one were all older?)

[wanabee777]

Loss of an engine on 777 at normal cruise altitude for the current gross weight is going to require a descent to a lower altitude.

What that altitude is, depends on your weight and the airspeed you choose to maintain.

I once had to shut down an inboard engine on a B-707 but with the other three pushed up, we were able to maintain our altitude albeit at a slightly slower airspeed.

Usually, in a 3 or more engine aircraft, loss of an engine is just an abnormal situation.

Loss of an engine on a twin motor airliner is an emergency which requires special procedures for exiting the NAT tracks and proceeding to the ETOPS alternate.

In 2005, a BA 747 lost an engine just after departing LAX and elected to continue to LHR.

http://articles.latimes.com/2005/mar/01/local/me-britair1

[OBOGS]

What is a typical cargo fire suppression capacity on a 744, A340 or A380?

[philbky]

wanabee777, but it didn't make LHR, it had to divert to MAN.

[Speed of Sound]

It started with an assertion that if you have 4 engines, an engine failure is twice as likely as with 2-engines; and so on. Amusing up to a point, but rubbish.

I was boarding a flight from Sydney to Los Angeles a few years ago, when a fellow traveller stowing her overhead luggage, announced to all around that she had once survived a fatal plane crash therefore we were all safe a statistically, it was virtually impossible that she would be involved in another one!

This seemed to give great comfort to the person sitting next to me, a nervous flyer, and I didn't have the heart to tell him that chances of the plane crashing was exactly the same, whether this woman was on board or not! :*

[peekay4]

Well it's easy to show mathematically that the probability of at least one engine failing is greater when you have 4-engines vs. 2-engines. But it's not double.

[GlobalNav]

"Well it's easy to show mathematically that the probability of at least one engine failing is greater when you have 4-engines vs. 2-engines. But it's not double."

But there is, mathematically at least, a significantly lower probability of a return with only a single engine operating with a 4-engine jet.

[alainthailande]

[Just concerned and a bit more knowledgeable than average SLF here, long time passionate reader, few posts as my profile says, sorry to intrude, kindly bear with me]

The subject of the probability of a second engine failure has been touched at the beginning of this thread, but not discussed much later.
I have a question here: of course the maths say that it's exactly as probable as the first failure, but what do the engineers say? There must be some extra stress put on the remaining engine even if the flight level is decreased, isn't it?
I'd assume that the remaining engine must be running at a higher thrust than usual for up to 5 hours and a half, isn't this changing the odds a little bit? Pushing things even further: what about prolonged asymmetrical thrust? isn't this possibly altering the airflow to the engine and causing some different forces to apply? (if not to the engine, to the pylon?)

Side note: I suffer from mild fear of flying (hence PPrune as my therapy :ok:), and I usually feel a lot safer aboard a quad. The posts above really are food for thought!

[evansb]

Do Lloyd's of London consider ETOPS a higher risk than 3 or 4-engine trans-oceanic ops? If so, by how much?

[c100driver]

Alain, Try not to confuse a piston engine at MCT with a turbine at MCT.

Running a turbine at MCT does not decrease reliability or increase the likely hood of an engine failure. It just increases the cost of overhaul and reduces the time on wing due usually due to reduced EGT margin caused by the higher temp and RPM.

Generally for a given engine, more thrust = reduced life = more cost which is why operators try to keep thrust use to as low as possible.

Engines such as the CF6 (LM2500 for example) run for hundreds of thousands of hours at maximum power in electrical power generations.

[wanabee777]

wanabee777, but it didn't make LHR, it had to divert to MAN

Well...

You gotta give 'em an "A" for effort.:)

[sandos]

"Well it's easy to show mathematically that the probability of at least one engine failing is greater when you have 4-engines vs. 2-engines. But it's not double."

But there is, mathematically at least, a significantly lower probability of a return with only a single engine operating with a 4-engine jet.

Yes, it is, even if one assumes engine failures are "coupled" it probably means that all will fail instead of 3. Either engines never fail together, meaning likely 1 will fail. Or they do fail together meaning 4 will fail. That 2 or 3 would fail seems highly unlikely. Especially 3? 2 is possible if, say, some part that serves one side of the airplane breaks.

Also, external forces of course means more than one engine might fail. Such as ash or birds or (multiple) missiles.

[rob_ginger]

Alain, If you're nervous about flying and you think more engines is safer then DON'T read this:

https://en.wikipedia.org/wiki/Eastern_Air_Lines_Flight_855 (http:// https://en.wikipedia.org/wiki/Eastern_Air_Lines_Flight_855)

..where all three engines failed because of a "common mode" problem, namely a maintenance engineer's mistake.

But the silly thing is most of us drive to and from the airport, and you're MUCH more likely to get killed in a car accident. (Some friends with young children, when traveling without them, used to catch the same taxi to the airport then get on separate flights until they realised how pointless that was.)

[Basil]

chances of the plane crashing was exactly the same, whether this woman was on board or not!
More chance; she sounds unlucky to me ;)

[netstruggler]

rob-ginger said
But the silly thing is most of us drive to and from the airport, and you're MUCH more likely to get killed in a car accident.

Not necessarily. It depends whether you measure risk per kilometer, per hour or per journey.

The reason Air Travel is generally seen as much safer is that most statistics quote deaths per passenger kilometer, which is favourable to large vehicles travelling long distances. Even the space shuttle doesn't do bad on that measure despite two fatal accidents in only a few dozen flights.

...but if you have an average car journey to the airport, followed by an average flight - the riskiest part is the flight.

[peekay4]

..but if you have an average car journey to the airport, followed by an average flight - the riskiest part is the flight.
For General Aviation maybe, but not for commercial airline flights, not by a long shot.

E.g., there's been no passenger fatalities due to a US airline accident since Feb, 2009. That's 6+ years of zero fatal accidents.

For comparison, in the same time period about 250,000 (!) people died in US car crashes, an average of 37,000 deaths per year. No matter how you slice it (per trip, per travelled mile, per hour, etc.), the fatal accident rate for cars is going to be > 0.

[slast]

For a bit more background on early ETOPs discussions see the latter part of post #26 in Tech Log (http://www.pprune.org/9180842-post26.html) in the thread on "savings from fewer engines".

I won't repeat it all here but in the 1982 ICAO ETOPS study group, the statistical data put forward by "the industry" (Boeing/Airbus/IATA) was very flaky. They did not want many issues that result in engines and systems not delivering their full performance to be counted. They were strongly opposed by IFALPA and others, which led to their opening position being rejected and the much more detailed rules that today allow very long range diversions.

[stagger]

Well it's easy to show mathematically that the probability of at least one engine failing is greater when you have 4-engines vs. 2-engines.

Indeed - all else being equal (which it never is) if you increase the number of engines you increase the probability of experiencing an engine failure. With a sufficiently large number of engines - the probability of at least one engine failing approaches gets close to 100%. The only way to reduce the probability of an engine failure to zero is to not have any engines :8

[Landflap]

Yes, well, if we are going to be silly ; Boeing were asked why they opted for four, rather than , say, three or even two engines for the 747 design. They replied ; "We couldn't find anywhere to place the fifth !! !

[daved123]

In the seventies, the airline I worked for managed to occasionally install a 5th engine on 747s. OK, it seemed to use a fair bit of cargo-straps round the fan blades but - there it was - 'number 2 and a half'

[cessnapete]

The BA 747 diverted to Man due fuel system mismanagement by crew.
Plenty of fuel left for LHR.

[No Fly Zone]

IMNHO, 330/5.5 hour ETOPS is stretching the otherwise excellent idea a bit too far. Since virtually all ETOPS qualified airplanes and flight plans include a very long over-water segment, with few or no options, I have to believe that a few carriers are pushing the limits a bit too far. Perhaps the principal fault is limited to one engine. perhaps there is collateral damage that the crew does not know about or that in time may affect the other, Only Remaining engine. Some details they know and some they cannot know.
Are the long haul carriers so hungry for cash that they will risk 350 - 600 souls simply to keep the cash flowing. (In a few cases, the weight of the printed currency, alone, carried as 'freight' can impact the airplane's range. A few carry A LOT!!)
In addition, only a fool plays the statistical games; just because that 1:1 Million event has occurred, does NOT mean that another one, similar or different, cannot occur and even on the same flight. In fact, after one even has happened, the odds of a second one actually increase. Reasonable ETOPS times are a good thing, but they have become excessive. Let's curb those profits a bit and focus on safety. Every flight on every route.:ok:

[PAXboy]

No Fly ZoneAre the long haul carriers so hungry for cash that they will risk 350 - 600 souls simply to keep the cash flowing.Yes.

Corporates will always risk their long term reputation for short term gain. Mainly because, when the risk finally bites - the men who thought it up are retired and on the golf course. They can then blame the next generation for having messed up their brilliant work.

This book is often recommended in these forums and it is very good:
The Tombstone Imperative: The Truth about Air Safety
Book by Andrew Weir

For me (paxing for 50 years now) 330 is too long. I agree that the journey to the airport is hazadous but I will not boost their bonus in this way. I am well aware that the 777 has paved the way but (as given by others) it is the unknown, the unexpected that trips you up. It is the increasing complexity of systems and human's understanding and interaction with them. Four donkeys did not help AF 447.

You pays your money and you takes your choice.

[172driver]

Four donkeys did not help AF 447.

It only had two (AB 330).

Other than that, I'm with you on that one. 330 is a tad too long for my taste, even more so given the route they intend to use this on.

[GlobalNav]

"IMNHO, 330/5.5 hour ETOPS is stretching the otherwise excellent idea a bit too far. "

Well, why is 330 minutes too far? Why was 300 minutes not too far? 180?

What would make it too far is neglecting to fully account for the failure modes and probabilities, mitigations, redundancies and so forth. If anything, the manufacturers and regulating authorities now have more certification experience and service history to go on than ever. With a properly computed aircraft performance, fuel load, plus the means to provide adequate electrical power for the required amount of time the airplane should be capable of reaching the planned diversion runway. The availability of the diversion runway, weather conditions and so forth are certainly challenges and the dispatcher must keep a wary and vigilant eye on them.

[Basil]

Four donkeys did not help AF 447.
It only had two (AB 330).
I didn't think PAXboy was referring to the engines :E

[Rwy in Sight]

When the 777, back in 2007, began to push the envelop of the ETOPS, I read somewhere (I don't want to to misquote) that executives of compagnies and regulating authorities need to consider how would they feel if in a flight, going single engine beyond 180 minutes, are members of their families flown by an average agency pilot in night and bad weather. I tried to quote as close as I remember it.

One can argue that such a personalization is not a good decision making tool but I think it has some merit.

[pax britanica]

The bit I dont get is-longer ETOPS=more fire bottles.

Surley the two are completely unrelatede and their should be the same number of fire bottles on any aircraft flying an ETOPS critical track like Nz-Arnetina which is 90 plus percent over nothing . Does losing an engine increase the risk of fire does havign two engines not four and flying exactly the same tracks-the 4 engine plane in theory can fly on an even more remote track and therefore is more vulnerbale toa fire on board but no where to land situation.

Sure aircraft engines are incredibly reliable even compared with early generations of fan jets BUT 330 mins is too far for me I am afraid and will one day end in a lot of tears but for the airline execs the sums are
-lots of other airlines do it so its unlikely to be mind that crashes
-I wont be here very long so will have likely moved on if there is a crash

- As we have all heard many times there are lies damn lies and statistics and,
As we have all heard on here many times 'its when the holes in the cheese line up'

To my mind we are pushing things a bit too far with this one , putting too much faith in statistics and allowing too much tolerance to a critical component failure scenario creating a pretty big hole in the cheese and making alignment of others that bit easier.

PB

[wanabee777]

Cargo or cabin fire notwithstanding, I was never keen on the idea of having to descend into icing conditions for any length of time due to the loss of pressurization and/or an engine.

[PAXboy]

PAXboyFour donkeys did not help AF 447.172driver
It only had two (AB 330).Ooops. Too hasty research on my part.

How many minutes ETOPS for me? Good question. As I travel less these days, I've not had to consider it directly but, I'd be thinking 120.

Which raises the key question: How do I find out how many minutes it will be? Coz the carrier sure as heck ain't gonna say!

[c100driver]

Almost all the operators use the least EDTO that the sector requires. Most Transpacific flights can be flown at 180 minutes. There are some areas that 180 minutes doesn't fit so some will be 207 minutes (old approval but still valid) or 240 minutes.

The Atlantic would be 120 minutes minimum, but can change to 180 minutes if, for example BIKF weather is below minimums and another pairing is required.

The EDTO maximums are just that, most flights will have ETP's that are less than 180/240/330 etc

I recently had a flight where our EDTO was planned at 180 minutes but due to the times in the alternate forecasts the flight 1 hour behind is had to operate a 240 EDTO flight. So there is not much point in asking about a flights "EDTO minutes" because they change and then the only ones that will know are the pilots and the dispatcher.

[India Four Two]

PAXboy,

Go to gcmap.com and enter your route like this: LAX-SYD and click Map.

Go to the bottom of the page and click on the ETOPS tab. Choose an ETOPS time and an aircraft type. Click Draw Map.

The no-go areas will be shown as dark blue. Here's the 180 min map:

http://i30.photobucket.com/albums/c309/india42/Screen%20Shot%202015-12-16%20at%2020.38.03%20_zpsjycyprz6.png

and here is the 120 min map:
http://i30.photobucket.com/albums/c309/india42/Screen%20Shot%202015-12-16%20at%2020.41.27%20_zpsh435akat.png

[ExSp33db1rd]

..............that she had once survived a fatal plane crash therefore we were all safe a statistically, it was virtually impossible that she would be involved in another one!

Which is why one should get on board with ones' own bomb - there is no evidence of their ever being two bombs found aboard an aircraft.

Then there was the story of the Rabbi refusing to climb the aircraft boarding steps ( long time ago ) Eventually the Captain left the flight deck to talk to him, and said " Father, there is no reason not to fly, you of all people must know that when your number is up, your number is up, and there is nothing you can do about it " The Rabbi replied " My son, I'm not worried about my number coming up, I'm worried about YOUR number coming up".

330 mins ETOPS ? Never say Never, Murphy is always with us.

[hitchens97]

330 mins ETOPS ? Never say Never, Murphy is always with us.

You joke, but people have been jailed because professionals (in this case judges) don't understand probability theory and the difference between independent random variables and dependent random variables.

Which as SLF brings me on to a question? Do you get any sort of training in statistics or probability theory as a pilot?

[NWA SLF]

I have a problem with saying its the bean counters who dictate the lengthy ETOPS as in several cases it has taken one high fatality crash to take down an airline (TWA, Pan Am for example). What are the 4 engine options? A380 which has had its very near major fatal crash due to one engine failing and the B748. For my millions of miles of trans-Atlantic and trans-Pacific flights, I never felt less secure when the airlines I flew switched from 4 or 3 engine airlines to twins. But then again I am an engineer with a great deal of statistical experience. Today I would have more concern flying a B707 or DC-8 on any of those routes despite having half the engines. That is thanks to brilliant engineering advances.

[ExSp33db1rd]

Which as SLF brings me on to a question? Do you get any sort of training in statistics or probability theory as a pilot?

I certainly didn't, but I was taught that there were lies, damned lies and Statistics, and that 4 engines were better than 2, and that no airline Captain would be happy until the flight engineer could say " we've lost number 8, Sir " and the reply would be " which side ?"

[No Fly Zone]

@PaxBoy, @172Driver, @GlobalNav, @India 4-2, et al.
Thanks for sharing your thoughts guys (gals?). If I may, I do believe that for a properly qualified and equipped airplane, some ETOPS time is appropriate. I am not smart enough to know the magic number, but I suggest that 60 minutes is not enough and that 330 minutes is far too high. Of this I am quite sure: when a high time ETOPS flight converts 450+ living souls into 450+ dead bodies, the ETOPS times are too high and they will come down. IIRC, @India 4-2 is the fellow that posted the great maps; (Thank you!!) I'm going back there for a more detailed look.
As wonderful as today's airplanes truly are, they are not perfect. Once in a while one of them will fall from the sky, not through pilot error - which can also happen, but due to some mechanical fault. If that airplane was sixty minutes closer to the 'nearest suitable runway,' would the crew and SLC survive? I do not know the correct answer. Do you?
The only item about which I am absolutely certain is that when a Big One falls while under ETOPS conditions, the allowed ETOPS times will come down.
Thanks for reading; more importantly, thank you for thinking!:ok:

[Heathrow Harry]

we'll know when an ETOPS goes wrong - maybe 2-3 hours of communication with an aircraft that isn't going to make it

the media will go mad....................

[GlobalNav]

As a former air force transport crew member (C-141A) I share the emotional preference for four engines over two. Compared to WWII vintage transports, the C-141A had superb engines - power and reliability. I don't need five fingers to count the engine shutdowns I have experienced with thousands of flight hours in 22 years.

As an engineer, but not a propulsion expert, I know there is a large body of mandatory standards, measurement criteria and demonstrations required to determine ETOPS approval. Every time a new airplane or a new engine fit is evaluated on transport airplanes, the ETOPS process receives a great deal of attention, as it should. This system has proven itself I believe, and to the degree that it is faithfully followed, with the integrity and professionalism expected of test pilots and engineers, we can trust it for ETOPS 180 and even for ETOPS 330.

Human nature, being what we know it to be, can lead to shortcuts, deviations from process, pencil-whipping and the like. Just as hazardous for ETOPS 180, though, as it would be for ETOPS 330.

Once the airplane is certified and delivered, the operator (airline), its management, flight operations, maintenance, and so forth take on the responsibility for following a very strict set of mandated requirements. to the degree that those charged with these responsibilities carry them out responsibly, we can trust ETOPS, whether for 180 minutes for 330.

We know HOW, we know the technology and the engineering. It only remains to DO the job responsibly.

[SeenItAll]

Among the many things that the worriers miss is that the amount of time an ETOPS 330 plane is likely to be in an area beyond ETOPS 240 or 207 is small. Further, propulsion difficulties that are not common to all engines (e.g., running out of fuel) generally appear when engines are at high or changing loads (e.g., on takeoff or in climb, not in cruise).

Thus, the situation one must be worrying about for ETOPS 330 is one in which the plane has taken off and cruised for at least 4 hours (i.e., to get beyond ETOPS 240 range) -- and then has a problem.

While anything is, of course, possible, the statistics show this situation to be highly unlikely. And note further, you are still not in the soup. You have one remaining good engine that must also go bad before the sh__ really hits the fan.

In my younger years I flew B707s, DC8s, B747s, DC10s, L1011s and A340s all of the time. But the safety record of B757s, B767s, A330s and B777s trumps them all. I, for one, am a statistician and decision analyst, and have no concerns about ETOPS. I do have great concerns about the driving safety of cabby who picks me up at the airport, though. Those guys really are dangerous.