MERGED: Air Asia Turnback Perth 25 Jun 17
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I have been to the airport there a few times, I guess I was just playing a bit of "what if" as well.
Living in the NW I have a fair idea of the resources available and I just suspect it wouldn't be as straightforward as some people seem to think if it did all go pear shaped I guess was more my point. Sure if you have no options I'd be headed there but I can only presume at the time with the information they had they decided PH or somewhere further south was a better option was all.
An extra 359 in a town of about 2500 is a fair impost even with an airline potentially throwing money around.
Living in the NW I have a fair idea of the resources available and I just suspect it wouldn't be as straightforward as some people seem to think if it did all go pear shaped I guess was more my point. Sure if you have no options I'd be headed there but I can only presume at the time with the information they had they decided PH or somewhere further south was a better option was all.
An extra 359 in a town of about 2500 is a fair impost even with an airline potentially throwing money around.
Here's an aviation truth - being on the ground is better than wishing you were on the ground.
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This Captain decided Perth was the best option. You might have made a different decision, I might have made a different decision, doesn't mean he's wrong.
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We won't know who's right or who's wrong until the pylons, engine mounts, wing, etc are inspected.
That's the point - if you don't know the answer/outcome why continue for 300 nm?
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We won't know who's right or who's wrong until the pylons, engine mounts, wing, etc are inspected.
That's the point - if you don't know the answer/outcome why continue for 300 nm?
How long is the good engine certified to operate when exposed to level X vibration? What level are they tested to, especially for 90+ minutes.
This thread is about an engine already shutdown for cause (fan rotor wobble) and it's vibration level is at a very low frequency not likely to cause the loss of another critical system including another engine position (lots of damping through all the joints between isolated systems)
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Passenger cooperation
What's with the warning from the Captain, " Our survival depends on your cooperation", what can pax do apart from sitting down and belting up, and it appears the capt put maint support ahead of the safety of the pax with his decision to return to Perth, a 90 min flight on one good engine , with the other vibrating madly, the stress on everything from the turbine shafts, pylons, wing structure and fuselage must have been considerable.
People are different. Some passengers probably found some comfort in the captain's announcement. Please submit a good statement to make during this incident...or suggest silence on the subject of the shaking.
This particular aircraft would now make a good test subject. Put it on a shake table, or maybe hang it from cable(s), and make the bad engine spin to quantify what the aircraft saw during the flight. Then put on some more time to see how much margin there was. Then vary speed and/or eccentric mass until something fails.
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Out of interest what is the paperwork required for a foreign registered aircraft to pick up stranded passengers and drop them domestically - e.g. KUL - Learmonth - Perth (or vice versa)
So many posters absolutely sure their opinion is correct and the Captain's was wrong
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SORRY, not necessarily. Right/wrong surely depends on more than "did some thing break eventually". Because people Have to take the correct decision, before having that inspection done.
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Are they? Do you have a statistical source for this? The central assumption behind ETOPS is that cruise engine failures are independent of one another with one engine operating at Max Continuous Thrust for the maximum ETOPS time limit.
If there is a dependant relationship between the two engines (common fuel source or an engine failure damages another engine) then this assumption is no longer valid, and getting on the ground ASAP is a must.
If there is a dependant relationship between the two engines (common fuel source or an engine failure damages another engine) then this assumption is no longer valid, and getting on the ground ASAP is a must.
And Captains don't go on statistics and all that other waffle you put up. They think of the worst case scenario and plan for it. No Captain I know would have flown past a suitable runway on one engine with hundreds of kms to go to destination.
I have yet to see anything definitive say that the vibration we saw in 2 short videos was that severe and continuous for the other 89 odd minutes to return to PH.
For the time being, I am going with the crew made what they thought was the best decision at the time.
But I'll recap with a small part of that post anyway.
2. The gentleman on the left at about 25 sec mark says "about half an hour to go" leading me to suspect that it may well have been shaking for > 1 hour at that time.
Are you suggesting that we should presume that the vibration only started 1:10 after the failure, because there is nothing definitive to show otherwise?
And also, with regard possibility of a water landing:
3. Reported that "marine emergency services north of Perth were put on standby to prepare for a possible water landing" so you would have to presume that some level of emergency had been called.
Last edited by WingNut60; 28th Jun 2017 at 01:09.
To back you up wingnut, I read somewhere that the vibration levels were uncomfortable until Flap 2, that's the whole flight in my book. I'll put my house on the fact that Air Asia use Learmonth as a planning alternate for wx etc when it suits them.
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How many suitable airports are you allowed to fly by, with any ETOPS aircraft, after losing an engine?
Some airlines use Forrest as an adequate so that they can fly to Perth non-etops. There is no way anyone is going to land at Forrest single engine even if over the Bight. It will be ADL KGL or PTH.
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I was a passenger on this plane
I have not read all posts on this thread but I was a passenger on the plane and can clarify a few things first hand.
First, there was an initial loud bang followed quickly by the vibration. I imagined that a cargo door had blown off. The vibration did last the entire return flight except for the approach to landing when it all but stopped. Presumably lower airspeed reduced the windmilling force.
The vibration was fairly constant and low frequency - maybe 5 to 8 Hz I am guessing. It did seem so wane and surge. During the surging it was extremely unnerving. The toilet block behind me was wobbling so much that the noise prevented me from always hearing properly whatever was being said. In fact, during the emergency briefings from the crew they had to deliver it in person to a couple of rows at a time so we could hear them.
At times the vibration of my seat back was too much to be able to rest against. I had to sit forward in the seat.
The captain did suggest we pray on two occasions. I was not upset that he said that except that I hoped it did not mean that he was substituting reliance on a higher being over his own effort. He did sound emotional on one of his announcements when he appeared to have to stop mid sentence and then compose himself to continue. Then again it could have been something else that diverted his attention.
He did initially describe the number 1 engine as having siezed. Although I could not see it - I was sitting in the middle, intuitively I imagined that it was still spinning asymmetrically and that must be causing the vibration. I did not know why it could not be stopped but presumed the captain could not contain it.
The passengers around me were discussing why we were not landing at a closer airport. We though we must be close to Learmonth.
The cabin crew did an excellent job. You could tell they were worried but they performed well.
My gut feeling was that we had a 50:50 chance but really I had no idea. I knew the captain was in control but with all the wobbling and vibration I was worried something would break and he would lose control.
Landing was sweet. The captain stood at the door and shook the hands of every single passenger. The crew got hi 5s and the passengers were giving hugs all round.
It's good to be alive!
First, there was an initial loud bang followed quickly by the vibration. I imagined that a cargo door had blown off. The vibration did last the entire return flight except for the approach to landing when it all but stopped. Presumably lower airspeed reduced the windmilling force.
The vibration was fairly constant and low frequency - maybe 5 to 8 Hz I am guessing. It did seem so wane and surge. During the surging it was extremely unnerving. The toilet block behind me was wobbling so much that the noise prevented me from always hearing properly whatever was being said. In fact, during the emergency briefings from the crew they had to deliver it in person to a couple of rows at a time so we could hear them.
At times the vibration of my seat back was too much to be able to rest against. I had to sit forward in the seat.
The captain did suggest we pray on two occasions. I was not upset that he said that except that I hoped it did not mean that he was substituting reliance on a higher being over his own effort. He did sound emotional on one of his announcements when he appeared to have to stop mid sentence and then compose himself to continue. Then again it could have been something else that diverted his attention.
He did initially describe the number 1 engine as having siezed. Although I could not see it - I was sitting in the middle, intuitively I imagined that it was still spinning asymmetrically and that must be causing the vibration. I did not know why it could not be stopped but presumed the captain could not contain it.
The passengers around me were discussing why we were not landing at a closer airport. We though we must be close to Learmonth.
The cabin crew did an excellent job. You could tell they were worried but they performed well.
My gut feeling was that we had a 50:50 chance but really I had no idea. I knew the captain was in control but with all the wobbling and vibration I was worried something would break and he would lose control.
Landing was sweet. The captain stood at the door and shook the hands of every single passenger. The crew got hi 5s and the passengers were giving hugs all round.
It's good to be alive!
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ETOPs/EDTO training around the world is based on ICAO annex 6 part II and compliance guidelines by EASA AMC 20-6 and (the far clearer)FAA AC120-42B.
The confusion around diversion airport selection is largely caused by the ICAO and EASA EDTO documents. This document is misleading when interpreted without context. They appear to suggest En-route alternates to be used are pre-determined by the dispatcher and that flight crews are expected to use the ones on the filed flight plan in the event of an engine failure. The glaring point easily missed is that it is written purely in the context of providing a legal minimum standard for dispatching a flight.
In practice dispatchers tend to reduce the number of nominated ERAs to the minimum required in order to reduce flight plan clutter. Often the NOTAM and weather package do not include non-nominated ERAs.
Many asian airlines training departments actually train their pilots based on this misconception. Compounding this is an institutional deferral to their 'OC' for diversion decisions.
In this case the crew may not have had the information at hand to properly evaluate Learmonth, especially under the physiological circumstances. It may well have been safer from a human factors perspective to follow the simpler option of returning to Perth.
The confusion around diversion airport selection is largely caused by the ICAO and EASA EDTO documents. This document is misleading when interpreted without context. They appear to suggest En-route alternates to be used are pre-determined by the dispatcher and that flight crews are expected to use the ones on the filed flight plan in the event of an engine failure. The glaring point easily missed is that it is written purely in the context of providing a legal minimum standard for dispatching a flight.
In practice dispatchers tend to reduce the number of nominated ERAs to the minimum required in order to reduce flight plan clutter. Often the NOTAM and weather package do not include non-nominated ERAs.
Many asian airlines training departments actually train their pilots based on this misconception. Compounding this is an institutional deferral to their 'OC' for diversion decisions.
In this case the crew may not have had the information at hand to properly evaluate Learmonth, especially under the physiological circumstances. It may well have been safer from a human factors perspective to follow the simpler option of returning to Perth.
Last edited by HPSOV L; 1st Jul 2017 at 16:54.
Out of interest what is the paperwork required for a foreign registered aircraft to pick up stranded passengers and drop them domestically - e.g. KUL - Learmonth - Perth (or vice versa)
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Some airlines use Forrest as an adequate so that they can fly to Perth non-etops. There is no way anyone is going to land at Forrest single engine even if over the Bight. It will be ADL KGL or PTH.
Obviously if there wasn't much in it then ADL or KGI is the better option but if the engine fails in the worst possible position then it will be tough to justify pressing on. The other consideration is if you press on then something else goes wrong that leads to an accident you are going to get smashed in an inquiry or court case.
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The "aviation expert" Neil Hansford at it again. ABC lowering its standards to news.com
AirAsia engine malfunction prompts expert warning on booking budget air travel - ABC News (Australian Broadcasting Corporation)
AirAsia engine malfunction prompts expert warning on booking budget air travel - ABC News (Australian Broadcasting Corporation)