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ANZ gets approved for 330 minute ETOPS

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ANZ gets approved for 330 minute ETOPS

Old 3rd Dec 2015, 13:33
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ANZ gets approved for 330 minute ETOPS

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.
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Old 3rd Dec 2015, 14:53
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Good for All Black v Pumas matches then,
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Old 3rd Dec 2015, 15:25
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5 1/2 hour ETOPS. Getting too big for minutes. That's impressive
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Old 3rd Dec 2015, 16:20
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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.

Last edited by Capot; 3rd Dec 2015 at 17:35.
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Old 3rd Dec 2015, 16:34
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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.
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Old 3rd Dec 2015, 16:41
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Sorry....now i got a bit confused after reading this OP thread mixing with this one here?
http://www.pprune.org/tech-log/52899...-vs-etops.html
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Old 3rd Dec 2015, 16:59
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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!

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Old 3rd Dec 2015, 17:26
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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!

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It is a concern. I understand ETOPS engineering protocol, but any decent lawyer will tear strips out of this.
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Old 3rd Dec 2015, 18:03
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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.
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Old 3rd Dec 2015, 18:19
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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.
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Old 3rd Dec 2015, 18:42
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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?
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Old 3rd Dec 2015, 18:42
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Pr(of an event)

Originally Posted by Capot View Post
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.)
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Old 3rd Dec 2015, 18:52
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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.
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Old 3rd Dec 2015, 19:07
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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.
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Old 3rd Dec 2015, 21:36
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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.
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Old 3rd Dec 2015, 21:45
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330 minute ETOPS


Well - if I was a bit younger
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Old 3rd Dec 2015, 22:36
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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!
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Old 3rd Dec 2015, 23:41
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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).
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Old 3rd Dec 2015, 23:56
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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.

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Old 4th Dec 2015, 05:02
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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:



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