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zeke
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NZ8 Returns Back To AKL

Mon Jun 25, 2007 7:07 am

Almost the longest overwater flight by a single engine 777......

from http://www.newswire.co.nz/main/viewstory.aspx?storyid=379468&catid=0

"The choice was made to return to New Zealand because that is where the airline's engineering base is."

hmmmmmmmmmm........"engineering base" twin, etops....."turned back after about five hours".....AKL-SFO
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Viscount724
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RE: NZ8 Returns Back To AKL

Mon Jun 25, 2007 7:13 am

The news article does not say that the engine was actually shut down. If it was, I assume they would have been required to divert to a closer alternate airport under ETOPS rules which do not permit flying for 5 hours on one engine.
 
jbernie
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RE: NZ8 Returns Back To AKL

Mon Jun 25, 2007 7:21 am

5 hours out, and possibly more than 5 hours back as i would expect them to be flying at a slower pace.

10 hours flying at least. Looks like it is a 12hr flight normally.

Does QF or UA have engine maintenance in LAX for a diversion there?

Or is it simply a case of it was more efficent to return to AKL and restart from there than to head anywhere else?
 
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zeke
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RE: NZ8 Returns Back To AKL

Mon Jun 25, 2007 7:34 am

Quoting Jbernie (Reply 2):
Or is it simply a case of it was more efficent to return to AKL and restart from there than to head anywhere else?

Don't know, but HNL would have been about 3 hrs away from the diversion point, 2 hrs closer.
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VHVXB
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RE: NZ8 Returns Back To AKL

Mon Jun 25, 2007 1:03 pm

Already posted in the NZ thread New Zealand Aviation Thread #7 (by Zkpilot Jun 20 2007 in Civil Aviation)
 
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zeke
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RE: NZ8 Returns Back To AKL

Mon Jun 25, 2007 2:02 pm

Quoting VHVXB (Reply 4):
Already posted in the NZ thread
New Zealand Aviation Thread #7 (by Zkpilot Jun 20 2007 in Civil Aviation)

Think they are different incidents, the one you posted was a bird strike shortly after takeoff, this one is 5 hrs after takeoff. The post by SunriseValley was 3 hrs after this thread was started.
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NZ1
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RE: NZ8 Returns Back To AKL

Mon Jun 25, 2007 5:58 pm

It wasn't diverted elsewhere due to limited engineering resource on the ground. We have more capability with the aircraft in AKL, and the right decision was made.

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NZ107
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RE: NZ8 Returns Back To AKL

Mon Jun 25, 2007 8:21 pm

Quoting Zeke (Reply 5):
Think they are different incidents, the one you posted was a bird strike shortly after takeoff,

The bird strike happened on the same day as the Beech incident, which was last week. There is one post at the very bottom of the thread, but not in depth.

[Edited 2007-06-25 13:23:55]
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dutchjet
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RE: NZ8 Returns Back To AKL

Mon Jun 25, 2007 8:50 pm

A ten hour flight to nowhere (5hours outbound, problem, 5 hours return)....that sucks for the passengers. The flight was likely almost half-way to SFO and then turned back to AKL.....seems very odd to me. If there was a true need to divert, there were places to land the airplane without flying 5 hours back to AKL (think ETOPS rules) and if it was nothing more than a minor problem, why didnt the flight continue to SFO?

I, for one, hope to hear more about this story......ANZ is a good carrier, one of my favorites and an expert in longroutes accross the Pacific, I would like to hear their reasoning concerning sending the flight on a 10 hour flight to nowhere.

Thank goodness it wasnt a US carrier, this thread would have 900 posts and class action law suits would be planned (think CO's trouble on the AMS-EWR flight a few week ago and the reaction that brought).

Regards.
 
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zeke
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RE: NZ8 Returns Back To AKL

Thu Jun 28, 2007 2:14 pm

Quoting NZ1 (Reply 6):
It wasn't diverted elsewhere due to limited engineering resource on the ground. We have more capability with the aircraft in AKL, and the right decision was made.

Maybe NZ does not have engineering capabilities is HNL, but other airlines have, they have more engineering experience with 777s there at HNL than NZ ever had.

I see that this was a commercial decision to protect the passengers onto the next NZ service to SFO. If they had diverted to the closer HNL, the aircraft would have to fly empty back to AKL/SFO, and the passengers placed on other carriers flights from HNL.

To me the decision making seems operationally flawed.
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NASBWI
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RE: NZ8 Returns Back To AKL

Thu Jun 28, 2007 11:52 pm

Unless AKL-SFO is operated exclusively by a 777, I don't see anywhere in that article that the flight was operated by one. Supposing a 744 was dispatched? The auther said a problem in "one of the engines", not "one of its two engines".
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sunrisevalley
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RE: NZ8 Returns Back To AKL

Fri Jun 29, 2007 1:17 am

Quoting Zeke (Reply 9):
To me the decision making seems operationally flawed.

No where has it been suggested that the engine was shut down . No doubt the possibility of an engine removal was a possibility when the in-flight condition was being considered by the people on the ground. Given that the engine was still operating it was a reasonable decision to return the aircraft to AKL where the spare engines are located.
 
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zeke
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RE: NZ8 Returns Back To AKL

Fri Jun 29, 2007 1:29 am

Quoting NASBWI (Reply 10):
Unless AKL-SFO is operated exclusively by a 777

NZ8 is a daily 777, except for the day after this event I am told they operated a 744 for the load.

Quoting SunriseValley (Reply 11):
No doubt the possibility of an engine removal was a possibility when the in-flight condition was being considered by the people on the ground. Given that the engine was still operating it was a reasonable decision to return the aircraft to AKL where the spare engines are located.

Do you see the irony in the two sentences....what would cause high vibration levels that one needs to remove an engine from an aircraft ?
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sunrisevalley
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RE: NZ8 Returns Back To AKL

Fri Jun 29, 2007 5:29 am

Quoting Zeke (Reply 12):
Do you see the irony in the two sentences

Zeke; I assume the definition that you are using of irony in this instance is something like the following....
"incongruity between what might be expected and what actually occurs".
If so, so be it. I find it more interesting that of the 16 Trents in service on NZ's 772's two have been removed in what I would consider early in their lifespan, one from -OKA at about 3-months and one from -OKH at about 6-months. Is this statistically about normal?
 
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RE: NZ8 Returns Back To AKL

Fri Jun 29, 2007 9:53 am

Quoting Zeke (Reply 12):

NZ8 is a daily 777, except for the day after this event I am told they operated a 744 for the load.

Monday's return NZ7 flight which i was on left at 2:45am instead of instead of 9:15pm as it arrived late and the crew needed rest and it was a 777
Flown on 727,747-200,747-400,757,777,A320,DC10,DC9.MD-80,SB340,CRJ-200,A380
 
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zeke
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RE: NZ8 Returns Back To AKL

Fri Jun 29, 2007 10:01 am

Quoting SunriseValley (Reply 13):
Is this statistically about normal?

It is with the number of birds they are ingesting ...
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jbernie
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RE: NZ8 Returns Back To AKL

Fri Jun 29, 2007 10:21 am

Question: Is there any way to transport a 777 engine on another aircraft type, some of the 747 series have a way to attach a 5th engine on the inside of the #2 engine? or is the 777 engine too large for that to work? Can another 777 do this?

I fully understand that ANZ will have its main tech base in AKL, but doing a what if scenario.... if the flight that this happened to was say Hong Kong to LHR the option of returning to AKL isn't there, what would they do in that scenario? How would it have been handled if this flight was say 2 hours from SFO in which case a turn around wasn't a choice.

Just looking for a better understanding on how these decisions are made.
 
sunrisevalley
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RE: NZ8 Returns Back To AKL

Fri Jun 29, 2007 11:00 am

Quoting Zeke (Reply 15):
It is with the number of birds they are ingesting ...

This could be so if in the case of -OKA it results in metal in the oil and in the case of -OKH , bearing problems.  scratchchin 
 
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zeke
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RE: NZ8 Returns Back To AKL

Fri Jun 29, 2007 11:40 am

Quoting SunriseValley (Reply 17):

This could be so if in the case of -OKA it results in metal in the oil and in the case of -OKH , bearing problems.

Mix engine oils you can get that ..... it only takes one tin by accident.
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airbear
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RE: NZ8 Returns Back To AKL

Fri Jun 29, 2007 12:10 pm

Hi Dutchjet ... "a 10 hour flight to nowhere ... that sucks for the pax" .... you need to remember what ETOPS really stands for , and that is : Engines Turn Or People Swim.

IMHO, a 5 hour return to AKL followed by a complementary night in a hotel bed, sucks far less than (maybe, if they're lucky) sitting in a life raft mid-Pacific waiting to be rescued by someone's Navy. I know that would be my preference!

Cheers, Airbear
 
sunrisevalley
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RE: NZ8 Returns Back To AKL

Fri Jun 29, 2007 8:28 pm

Quoting Zeke (Reply 18):
Mix engine oils you can get that ..... it only takes one tin by accident.

Doesn't surprise me. I remember back in NZ's DC6B days, a change in brand of engine oil resulted in a number of premature engine removals.
 
dutchjet
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RE: NZ8 Returns Back To AKL

Sat Jun 30, 2007 1:48 am

Quoting Airbear (Reply 19):
Hi Dutchjet ... "a 10 hour flight to nowhere ... that sucks for the pax" .... you need to remember what ETOPS really stands for , and that is : Engines Turn Or People Swim.

IMHO, a 5 hour return to AKL followed by a complementary night in a hotel bed, sucks far less than (maybe, if they're lucky) sitting in a life raft mid-Pacific waiting to be rescued by someone's Navy. I know that would be my preference!

Cheers, Airbear

They flew 5 hours over the pacific to a certain point and then turned back to fly another 5 hours over the pacific back to Auckland......does that make a lot of sense to you? After the engine issue was reported, the ""lucky"" pax had a 5 hour flight OVER WATER back to their point of origin. If there was really a problem, get the airplane on the ground as soon as possible, as required by ETOPS, and if there was not a critical issue (which I assume that there was not) get the passengers to the destination or make arrangments for them to get to their destination quickly. And, a 5 hour diversion back to AKL over water indicates that there was no engine shutdown.

If there was really a chance of the airplane making a water landing......why did they fly back to AKL? Please dont overdramaztize this. And, I am sure that the pax wanted to get to SFO, not enjoy a complementery bednight at AKL.

The subject engine needed some servicing....and NZ brought the airplane back to AKL instead of having to deal with it (and the expense of dealing with it) at SFO....thats what really happened here I suspect.
 
sunrisevalley
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RE: NZ8 Returns Back To AKL

Sat Jun 30, 2007 3:45 am

Quoting Dutchjet (Reply 21):
And, a 5 hour diversion back to AKL over water indicates that there was no engine shutdown.

You make it sound much worse than it was in reality. The return route flies right over Samoa and not too far from Raratonga either of which could have been used had the engine needed to be shut down. From an ETOPS view point both were probably closer than HNL. at the point of turn around.
 
dutchjet
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RE: NZ8 Returns Back To AKL

Sat Jun 30, 2007 3:56 am

Quoting Airbear (Reply 19):
Hi Dutchjet ... "a 10 hour flight to nowhere ... that sucks for the pax" .... you need to remember what ETOPS really stands for , and that is : Engines Turn Or People Swim



Quoting SunriseValley (Reply 22):
You make it sound much worse than it was in reality.

Not me........I dont think that the situation was bad at all, how bad could it have been if the airplane (with whatever problem it had) could remain in the air for 5 hours and go all the way back to AKL?

Cheers....dont get me wrong, ANZ is one of my favorite carriers (I have always found their service superb) and that is why I dont really understand the subject situation.
 
airbear
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RE: NZ8 Returns Back To AKL

Sat Jun 30, 2007 5:38 pm

Hi again, Dutchjet. Your comments noted. Given that the incident was obviously not an immediate emergency situation, I am sure - and believe it is perfectly valid - that NZ would seek a commercially "best solution".

Thinking about it though, two things come to mind. 1) given that NZ's 772's operate RR Trents, is it possible that there might have been servicing problems or even warranty issues, if they had gone into HNL. After all, UA's 772's are P&W engined, and OK... AA's 772's are RR's, but I don't think AA operate their 772's into HNL, so there may not have been the service facilities. 2) Looking at the logistics of a (non-emergency) diversion to HNL, they would have landed there at some ungodly hour of the early morning. It could have taken a very long time indeed, to get all 200 or so pax through customs, and then either settled into hotels, or an even longer wait to get them all onto flights to SFO or elsewhere. Thinking about it, there may not have been that much of a time difference between such a diversion to HNL, and going back to AKL, staying there, and then flying all the way back. The AKL option in this case seems to me to be far easier.

Airbear
 
buckfifty
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RE: NZ8 Returns Back To AKL

Sat Jun 30, 2007 6:08 pm

The whole point of contention is this: how bad was the situation with the engine? If it was standard twin engine ops, and one engine was inop, the aircraft must fly to the nearest suitable. If the engine was not shut down, legally the engine is not inoperative, but with good airmanship sense, does it make a difference?

Perhaps the engine was still operational, had high vibes, and throttled back to save the engine. If the vibrations were not major (as in, can't see the instruments), the case can be made that the engine could still be used in case the remaining one suffered a failure, and divert to the nearest enroute. But it is still risky, and I would agree with Zeke on this one. Never know what would happen if you spooled down the affected engine, and tried to spool it up again.
 
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RE: NZ8 Returns Back To AKL

Sat Jun 30, 2007 7:38 pm

Quoting Dutchjet (Reply 21):
The subject engine needed some servicing....and NZ brought the airplane back to AKL instead of having to deal with it (and the expense of dealing with it) at SFO....thats what really happened here I suspect.

The engine was actually replaced when it arrived in AKL due to contamination of the oil with bearing material.

Quoting BuckFifty (Reply 25):
If the engine was not shut down, legally the engine is not inoperative, but with good airmanship sense, does it make a difference?

The engine was NOT shut down, but operated at a reduced setting.

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N1120A
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RE: NZ8 Returns Back To AKL

Sat Jun 30, 2007 7:55 pm

Quoting Jbernie (Reply 2):

Does QF or UA have engine maintenance in LAX for a diversion there?

United has a large MX base at LAX and QF a smaller one.
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eta unknown
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RE: NZ8 Returns Back To AKL

Sun Jul 01, 2007 6:46 am

I'm wondering if the AKL-SFO route overflies RAR/PPT rather than HNL (like AKL-LAX). If that's the case. HNL wasn't really an option and PPT/RAR present other difficulties: hotels. In PPT the accommodation costs would be astronomical and RAR has a shortage of hotel rooms, so perhaps return to AKL was the only viable option.
 
XXXX10
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RE: NZ8 Returns Back To AKL

Sun Jul 01, 2007 7:04 am

Although we don't know all the facts I would be concerned if the crew had needed to shut down the 'good' engine-perhaps for a totally unrelated reason.

They would then be flying on one engine which had already had at the very least some abnormalities.

I know that this is unlikely but it is not impossible.
 
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zeke
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RE: NZ8 Returns Back To AKL

Sun Jul 01, 2007 8:02 am

Quoting SunriseValley (Reply 22):
You make it sound much worse than it was in reality. The return route flies right over Samoa and not too far from Raratonga either of which could have been used had the engine needed to be shut down. From an ETOPS view point both were probably closer than HNL. at the point of turn around.

You have actually implied that it flew not to the closest, and also past two suitable aerodromes on the return trip.

You have actually painted a worse picture.
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Viscount724
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RE: NZ8 Returns Back To AKL

Sun Jul 01, 2007 8:17 am

Quoting SunriseValley (Reply 22):
You make it sound much worse than it was in reality. The return route flies right over Samoa and not too far from Raratonga either of which could have been used had the engine needed to be shut down. From an ETOPS view point both were probably closer than HNL. at the point of turn around.

I would feel more comfortable on that NZ 777 for 5 hours with both engines running, even with one at a reducd power setting, and within range of at least two other airports, than I would have felt on the UA 777 that shut an engine down en route from AKL to LAX in 2003 (shortly before they suspended service to AKL) . I think that UA 3-hour plus diversion to Kona, Hawaii still ranks as the longest single engine ETOPS diversion so far.
 
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zeke
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RE: NZ8 Returns Back To AKL

Sun Jul 01, 2007 8:22 am

Quoting Viscount724 (Reply 31):
I would feel more comfortable on that NZ 777 for 5 hours with both engines running,

You would feel less comfortable on an engine that was shut down that was making metal, over an engine that was shut down because it making metal ?

In both cases they were not operating as designed, and were not guaranteed to operate if the other was to fail.

Sorry I don’t see the difference.
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jbernie
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RE: NZ8 Returns Back To AKL

Sun Jul 01, 2007 12:42 pm

Quoting Jbernie (Reply 16):
Question: Is there any way to transport a 777 engine on another aircraft type, some of the 747 series have a way to attach a 5th engine on the inside of the #2 engine? or is the 777 engine too large for that to work? Can another 777 do this?

anyone? Bueller? Bueller?

If the only way is to do it via Cargo jet then I can very easily understand the decision, it would make for a logistics nightmare. But as i asked before, how would ANZ handle this event when a return to AKL wasn't possible and they did have to divert to an airport that isnt necessarily ready to replace an RR engine?
 
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RE: NZ8 Returns Back To AKL

Sun Jul 01, 2007 12:57 pm

Quoting Jbernie (Reply 33):
anyone? Bueller? Bueller?

If the only way is to do it via Cargo jet then I can very easily understand the decision, it would make for a logistics nightmare. But as i asked before, how would ANZ handle this event when a return to AKL wasn't possible and they did have to divert to an airport that isnt necessarily ready to replace an RR engine?

Yes the only way to transport a 777 engine is by Freighter.

In an emergency NZ would have diverted to the nearest airport.
 
nzrich
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RE: NZ8 Returns Back To AKL

Mon Jul 02, 2007 7:11 am

Quoting N1120A (Reply 27):
United has a large MX base at LAX and QF a smaller one.

AKL would of been closer than LAX ..
.. AKL-LAX being 12hr 10 min in a 744 thats over 7 hours flying to go ..
Also for the 5 hour journey back to AKL there are lots of diversion airports if required passengers would never of been put in harm in any way .. The first priority for the flight deck would of been safety for some people on this website to suggest otherwise is ludicrous as none of us have the facts the flight deck had .. When travelling over the pacific there are limited stops and all those factors would of been put into the equation ETOPS etc..
Also PPT would of been the closest airport as its about 5 hours out of AKL NOT HNL .. HNL is nearly a 9 hour journey from AKL so really its not that much further to go to AKL then divert to HNL also many diversion airports en route if required on way back to AKL PPT RAR NAN APW TBU IUE NOU .. So its probably nearly safer going back to AKL with all those airport than flying to HNL considering the flight time will not be too much less and that there are many operational airports to divert to if required..
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buckfifty
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RE: NZ8 Returns Back To AKL

Mon Jul 02, 2007 1:38 pm

Quoting Nzrich (Reply 35):
The first priority for the flight deck would of been safety for some people on this website to suggest otherwise is ludicrous as none of us have the facts the flight deck had .. When travelling over the pacific there are limited stops and all those factors would of been put into the equation ETOPS etc..
Also PPT would of been the closest airport as its about 5 hours out of AKL NOT HNL .. HNL is nearly a 9 hour journey from AKL so really its not that much further to go to AKL then divert to HNL also many diversion airports en route if required on way back to AKL PPT RAR NAN APW TBU IUE NOU .. So its probably nearly safer going back to AKL with all those airport than flying to HNL considering the flight time will not be too much less and that there are many operational airports to divert to if required..

The whole point is this. In terms of absolute safety, anytime a twin with one engine inop, you must fly to the nearest suitable airfield. But because it was high vibrations that did not exist at lower thrust levels, instead of shutting the engine down, they retarded the thrust on one of them so that they can continue.

But what if you tried to increase thrust on the damaged engine, in case the other one failed? Will it burst into little pieces also? That is a big risk to take. It's hard to guess what can cause the vibrations to occur inflight, and the state that the engine is in.

And I suppose you know how far those alternates are from each other. That's why it is an ETOPS route.

Part of airmanship is to mitigate risk. And in this case, I do question the validity of the decision to continue on one engine (or an engine and a half) for five hours.
 
TG992
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RE: NZ8 Returns Back To AKL

Mon Jul 02, 2007 3:32 pm

BuckFifty - what are your qualifications for questioning the judgement of two pilots with 25 years plus of experience?
And what information are you privy to about the exact performance and behaviour of the contaminated engine?

Just interested..
-
 
dutchjet
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RE: NZ8 Returns Back To AKL

Mon Jul 02, 2007 8:28 pm

Quoting BuckFifty (Reply 36):
The whole point is this. In terms of absolute safety, anytime a twin with one engine inop, you must fly to the nearest suitable airfield. But because it was high vibrations that did not exist at lower thrust levels, instead of shutting the engine down, they retarded the thrust on one of them so that they can continue.

But what if you tried to increase thrust on the damaged engine, in case the other one failed? Will it burst into little pieces also? That is a big risk to take. It's hard to guess what can cause the vibrations to occur inflight, and the state that the engine is in.

And I suppose you know how far those alternates are from each other. That's why it is an ETOPS route.

Part of airmanship is to mitigate risk. And in this case, I do question the validity of the decision to continue on one engine (or an engine and a half) for five hours.

Very well stated summary, thanks.

Quoting TG992 (Reply 37):
BuckFifty - what are your qualifications for questioning the judgement of two pilots with 25 years plus of experience?
And what information are you privy to about the exact performance and behaviour of the contaminated engine?

Just interested..

Why challenge the posters qualifications.....we are questioning the decision...the point is did NZ and its pilots make the correct decision? Once again, should the pilots have kept the airplane in the air for 5 hours 9over water) and flown all the way back to AKL with one of its engines not operating properly?

I understand that going back to AKL was the most efficient and most economical thing to do for NZ.....its always easiest to deal with a broken airplane at an airlines home base where maintenance facilities are located, and its always easier to deal with a planeload of pax needing new-booking at your central hub. This is especially true in the Pacific where maintenance facilities are few and far between and alternative flights and accommodation for the passengers are extremely limited.

But, was NZ 's ""practical"" decision to return to AKL the safest option? I have my doubts.....flying five hours over water in a twin engined airplane with one engine having issues (and how serious those issues were could not,of course, be determined until the airplane was on the ground) does not seem right to me. Did NZ adhere to ETOPS rules? And, how important is it that the engine with the vibration issue was not completely shut down but instead throttled back? Could the airplane have remained in the air for a reasonable amount of time if the ""good"" engine subsequent failed and only the ""damaged"" engine remained?

And, this is not meant to be an attack on NZ.......its an interesting and serious situation that all airlines, the manufacturers, and the governmental agencies can learn from. Long range and ULH twin operations are becoming more and more the norm (think 772LR and the upcoming 787/A350 long range variants). It could very well be that NZ was in total compliance with all ETOPS rules and regs, yet the wrong outcome resulted.
 
TG992
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RE: NZ8 Returns Back To AKL

Mon Jul 02, 2007 10:20 pm

And what makes you think that the pilots would be willing to risk their lives for the company's convenience?

Some posters seem to forget that the pilots are just as stuck up there as the passengers.
-
 
buckfifty
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RE: NZ8 Returns Back To AKL

Mon Jul 02, 2007 11:57 pm

Quoting TG992 (Reply 39):
And what makes you think that the pilots would be willing to risk their lives for the company's convenience?

Some posters seem to forget that the pilots are just as stuck up there as the passengers.

I'm not about to go on a big post trying to justify my qualifications so that you can be satisfied. My opinions I do speak on my own behalf, and in aviation, there are never any absolutes, besides the fact that sooner or later, things do fall to the ground. Were the pilots wrong for flying back to AKL (ostensibly at the behest of the company)? I cannot say that they were, but I do question the circumstances of the decision itself.

In many instances, pilots do go risk their lives just because they are under pressure by the company to minimize the cost of a diversion, offset by a certain degree of risk. In any situations such as these, we call back to the company to ask them for information and solutions, and sometimes, those decisions may or may not be made by a pilot. Most of the time, diverting to a company port would be the first priority, then to one with adequate ground facilities, and then we would just need one with a runway long enough to fit the plane. The ones in the plane do make the last call, but the pressures are sometimes immense as to decide what is 'the right thing' to do. In the middle of the Pacific, these decisions would obviously be a lot harder to make.
 
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zeke
Posts: 9744
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RE: NZ8 Returns Back To AKL

Tue Jul 03, 2007 7:41 pm

Quoting Nzrich (Reply 35):
Also for the 5 hour journey back to AKL there are lots of diversion airports if required passengers would never of been put in harm in any way ..

My calcs make it closer to a 6 hrs for return trip, the ground speed would be in the region of 80-90% of the outbound ground speed due to one engine inop and then tracking into wind.

Quoting Nzrich (Reply 35):
Also PPT would of been the closest airport as its about 5 hours out of AKL NOT HNL ..

Correct, but HNL was by far the closest engineering port that handles 777s, the reason for return to AKL given in the article was for engineering.

Quoting Nzrich (Reply 35):
HNL is nearly a 9 hour journey from AKL so really its not that much further to go to AKL then divert to HNL

The NZ schedule shows a 767 flying AKL-HNL in 8:45, flight time would be around 8:15 in a 767, or close to 8 hrs in a 777.

Quoting Nzrich (Reply 35):
also many diversion airports en route if required on way back to AKL PPT RAR NAN APW TBU IUE NOU ..

The initial part of the route would be something like NZAA->OT->H436->WI->H277->AA->G594->AKLOM->B200->FICKY which would put the event happening around the reporting point PUMIS (S05°00'00.00" W153°03'42.00")
PIMUS-AKL-2605 nm
PIMUS-PPT-777 nm
PIMUS-RAR-1045 nm
PIMUS-NAN- 1894 nm
PIMUS-APW- 1239 nm
PIMUS-TBU- 1612 nm
PIMUS-IUE- 1298 nm
PIMUS-NOU- 2576 nm
PIMUS-HNL- 1598 nm (just within 207 min)

Work out the flight times with a nil wind ground speed of 450 kt (single engine 777 would be around that speed), then work them out for a realistic 420 kt when in a westerly direction....taking into account a 30 kt headwind.

Quoting Nzrich (Reply 35):
So its probably nearly safer going back to AKL with all those airport than flying to HNL considering the flight time will not be too much less and that there are many operational airports to divert to if required..

You have missed the point, as soon as they turned around they are already diverting...you are talking about rediverting... you have missed the fact that every airport you mentioned is into wind, and aircraft fly lower and slower on one engine.

Quoting TG992 (Reply 37):
BuckFifty - what are your qualifications for questioning the judgement of two pilots with 25 years plus of experience?

The pilots would have at best 18 months experience on the 777

Quoting Dutchjet (Reply 38):
Very well stated summary, thanks.

I agree
We are addicted to our thoughts. We cannot change anything if we cannot change our thinking – Santosh Kalwar
 
nzrich
Posts: 1094
Joined: Mon Dec 05, 2005 9:51 pm

RE: NZ8 Returns Back To AKL

Tue Jul 03, 2007 8:22 pm

Quoting BuckFifty (Reply 36):
The whole point is this. In terms of absolute safety, anytime a twin with one engine inop, you must fly to the nearest suitable airfield. But because it was high vibrations that did not exist at lower thrust levels, instead of shutting the engine down, they retarded the thrust on one of them so that they can continue. But what if you tried to increase thrust on the damaged engine, in case the other one failed? Will it burst into little pieces also? That is a big risk to take. It's hard to guess what can cause the vibrations to occur inflight, and the state that the engine is in. And I suppose you know how far those alternates are from each other. That's why it is an ETOPS route. Part of airmanship is to mitigate risk. And in this case, I do question the validity of the decision to continue on one engine (or an engine and a half) for five hours.

Ok actually i have flown this route many times from 99 till 2004 i do know how far these islands are apart .. I can tell you if safety was a priority all Air NZ Flight deck would land any aircraft they operate at the nearest available airport thats my experience with working with the flight deck .. Between AKL and PPT which is about 5 hours out and roughly where the plane would of been there are many airports to choose from .. From PPT RAR is about 2 hours away from there you have APW TBU NAN VLI NOU NLK AKL so a plane could easily be within etops all the way back to NZ ..Now there is not a lot of islands and airports between PPT and HNL and mainland USA with facilities .. At least most of the aiports from PPt to AKL exc some have some kind of maintenance facilities and are capable of dealing with a emergency ie hospital fire facilities runway etc etc etc ..

As for mitigate risk .. Do you know all the facts ??? Im sure you dont so your really just guessing ..Those flight deck on that flight had more information than you or I ,they would of made the best decision possible with help from Air NZ maintenace and boeing etc etc .. They would know the alternatives and if required would of diverted if the safety of the aircraft was in any doubt .. Air NZ planes have diverted to the nearest airfields before and have been stranded till engineers and parts have been flown in and the company would rather that than lose a aircraft , crew and passengers .. In a statement to TV3 news in NZ it was stated the situation was not serious but it did require the plane to return to AKL.. If it had been serious you can guarrantee that aircraft would of been put down at the closest airport available ...
"Pride of the pacific"
 
buckfifty
Posts: 1278
Joined: Tue Oct 16, 2001 4:05 pm

RE: NZ8 Returns Back To AKL

Tue Jul 03, 2007 9:23 pm

Quoting Nzrich (Reply 42):
As for mitigate risk .. Do you know all the facts ??? Im sure you dont so your really just guessing ..Those flight deck on that flight had more information than you or I ,they would of made the best decision possible with help from Air NZ maintenace and boeing etc etc ..

When you have high vibrations, my guess right now is as good as the guess that they have on the flight deck at the time. The FADEC can tell you that you have high vibes on that engine, but it cannot tell you why. Unless if there were other warning messages that popped up, really, everybody's guessing. Even the engineers on the ground. If the vibrations are serious enough that they have to reduce the thrust on that engine, then there is a serious operational issue here.

Quoting Nzrich (Reply 42):
From PPT RAR is about 2 hours away from there you have APW TBU NAN VLI NOU NLK AKL so a plane could easily be within etops all the way back to NZ ..Now there is not a lot of islands and airports between PPT and HNL and mainland USA with facilities ..

So let's say the remaining engine does need to be used. Push it up, and boom, engine surge. Now you're up crap creek. ETOPS caters for aircraft flying on one engine, not gliding distance.
 
nzrich
Posts: 1094
Joined: Mon Dec 05, 2005 9:51 pm

RE: NZ8 Returns Back To AKL

Wed Jul 04, 2007 7:05 am

Quoting BuckFifty (Reply 43):
When you have high vibrations, my guess right now is as good as the guess that they have on the flight deck at the time. The FADEC can tell you that you have high vibes on that engine, but it cannot tell you why. Unless if there were other warning messages that popped up, really, everybody's guessing. Even the engineers on the ground. If the vibrations are serious enough that they have to reduce the thrust on that engine, then there is a serious operational issue here.

All i can say is i trust all the Air NZ pilots with my life and i do that every day i go to work .. Why because i know the guys there will always make sure the safety of the aircraft ,crew and passengers comes first , i have seen it with my eyes where thay have not been happy so flights have been cancelled suspended etc etc .. We have some of the most experienced flight deck in the world and i trust their skills and experience ..

Quoting BuckFifty (Reply 43):
So let's say the remaining engine does need to be used. Push it up, and boom, engine surge. Now you're up crap creek. ETOPS caters for aircraft flying on one engine, not gliding distance.

Yes i understand about Etops what i was trying to convey is that all the way from PPT to AKL you can fly back passing close to airports and never be more than basically an hour away from a airport ..

Anyway this incident will all be audited by the Cival Aviation Authority CAA in NZ im sure so if it was a major safety breach it will come out ..
"Pride of the pacific"
 
cchan
Posts: 951
Joined: Sat May 17, 2003 8:54 pm

RE: NZ8 Returns Back To AKL

Wed Jul 04, 2007 10:55 am

It looks like this argument is based on some proposed scenarios with no facts about what the problem really was  Yeah sure

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