ANZ gets approved for 330 minute ETOPS

[wanabee777]

Originally Posted by Enos

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??

[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
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]

Originally Posted by wanabee777

Imagine having to put up with that for 5 hrs.

Originally Posted by tdracer

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...al/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.