MERGED: Air Asia Turnback Perth 25 Jun 17
Interesting.
But it all still seems very subjective to me. I would hope that there is further advice that better defines the circumstances that they are describing.
Was the vibration level observed in the passenger's video "high", as envisaged by the advice from Boeing?
Or was it "extreme"and way beyond anything they ever considered? ((Not saying it was. Just asking)
And how long did they anticipate that the vibration would last or be tolerated for?
Quote:
Certain engine failures, such as fan blade separation can cause high levels of airframe vibration. Although the airframe vibration may seem severe to the Flight Crew, it is extremely unlikely that the vibration will damage the airplane structure or critical systems.
Certain engine failures, such as fan blade separation can cause high levels of airframe vibration. Although the airframe vibration may seem severe to the Flight Crew, it is extremely unlikely that the vibration will damage the airplane structure or critical systems.
Was the vibration level observed in the passenger's video "high", as envisaged by the advice from Boeing?
Or was it "extreme"and way beyond anything they ever considered? ((Not saying it was. Just asking)
And how long did they anticipate that the vibration would last or be tolerated for?
And how long did they anticipate that the vibration would last or be tolerated for?
morno
Interesting.
But it all still seems very subjective to me. I would hope that there is further advice that better defines the circumstances that they are describing.
Was the vibration level observed in the passenger's video "high", as envisaged by the advice from Boeing?
Or was it "extreme"and way beyond anything they ever considered? ((Not saying it was. Just asking)
And how long did they anticipate that the vibration would last or be tolerated for?
But it all still seems very subjective to me. I would hope that there is further advice that better defines the circumstances that they are describing.
Was the vibration level observed in the passenger's video "high", as envisaged by the advice from Boeing?
Or was it "extreme"and way beyond anything they ever considered? ((Not saying it was. Just asking)
And how long did they anticipate that the vibration would last or be tolerated for?
Mind you, there may be a difference in the levels of vibration experienced by a Boeing compared to an Airbus in the same scenario but I can't imagine an Airbus would be much more likely to self destruct.
But it all still seems very subjective to me. I would hope that there is further advice that better defines the circumstances that they are describing.
Was the vibration level observed in the passenger's video "high", as envisaged by the advice from Boeing?
Or was it "extreme"and way beyond anything they ever considered? ((Not saying it was. Just asking)
And how long did they anticipate that the vibration would last or be tolerated for?
Was the vibration level observed in the passenger's video "high", as envisaged by the advice from Boeing?
Or was it "extreme"and way beyond anything they ever considered? ((Not saying it was. Just asking)
And how long did they anticipate that the vibration would last or be tolerated for?
As stated much earlier it is way below the expectations for continued flight in turbulence and gusting levels.
Of course some local parts (tubing, brackets, etc.) associated with the failed engine pylon need be inspected before flight.
I expect that the Australian ATSB will later report on findings.
I'm still awaiting any glimpse of overall photos of the fan as I can't see any great fan damage including the cowl
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If you think the vibration was bad enough to require an inspection AFTER the fact why would you continue to fly 300 nm farther PRAYING that the engine pylon won't fail?
No maintenance? Who cares, the plane is grounded for days?
No customs? Does not matter in an emergency. And they were returning to the country of departure so there's no need for customs if you insist in being ridiculously pedantic.
Limited medical? No one is injured.
Limited ARFF? They're not burning, they're trying to land before possible structural damage.
No maintenance? Who cares, the plane is grounded for days?
No customs? Does not matter in an emergency. And they were returning to the country of departure so there's no need for customs if you insist in being ridiculously pedantic.
Limited medical? No one is injured.
Limited ARFF? They're not burning, they're trying to land before possible structural damage.
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https://thewest.com.au/news/wa/airas...-ng-b88518000z
ref above: in the article it states "a source said the pilots were alerted to the problem by a monitoring system and then heard and felt the vibration from the stricken engine, they shut the engine down, did a 180-degree turn and returned to Perth".
My opinion is such: Vibration meters alerted the crew, get a high vibe level - perform a precautionary shut-down, return to Perth. Engine gets changed and the people don't get freeked out along with what now is obviously a difficult procedure to determine "what inspections are necessary"?
In a perfect world this is what "should have happened" but probably did not. The crew got alerted and before you knew it (check-list out and performing it) the Fan blade separated. Large fans require maintenance every so often for lubrication, inspection, balancing, overhaul.
I suspect this is a maintenance related issue.
As far as landing at the nearest suitable airport vs what probably was a coaxing of the operator for the FLIGHT CREW TO RETURN to Perth where the company handed out bottle water and $20. vouchers to a group of emotionally changed passengers in need of Post Traumatic Stress Syndrome DEBRIEFING WITH QUALIFIED EMOTIONAL SUPPORT PERSONNEL. (dramatic changes in life experience often occurs to individuals with PTSD in short time. Marriages, relationships, addiction, phobia's etc etc).
ref above: in the article it states "a source said the pilots were alerted to the problem by a monitoring system and then heard and felt the vibration from the stricken engine, they shut the engine down, did a 180-degree turn and returned to Perth".
My opinion is such: Vibration meters alerted the crew, get a high vibe level - perform a precautionary shut-down, return to Perth. Engine gets changed and the people don't get freeked out along with what now is obviously a difficult procedure to determine "what inspections are necessary"?
In a perfect world this is what "should have happened" but probably did not. The crew got alerted and before you knew it (check-list out and performing it) the Fan blade separated. Large fans require maintenance every so often for lubrication, inspection, balancing, overhaul.
I suspect this is a maintenance related issue.
As far as landing at the nearest suitable airport vs what probably was a coaxing of the operator for the FLIGHT CREW TO RETURN to Perth where the company handed out bottle water and $20. vouchers to a group of emotionally changed passengers in need of Post Traumatic Stress Syndrome DEBRIEFING WITH QUALIFIED EMOTIONAL SUPPORT PERSONNEL. (dramatic changes in life experience often occurs to individuals with PTSD in short time. Marriages, relationships, addiction, phobia's etc etc).
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It appears in the Boeing 777 FCTM, Chapter 8, Non-Normal Operations, Landing at the Nearest Suitable Airport; I suspect that most Boeing FCTMs contain a similar passage.
In some FCTMs there is a cross-reference to Supplemental Information along the lines of;
My bolding.
Learmonth does not meet ICAO Rescue and Fire Fighting Services Category 9 standards (as required for airplanes 61 m ≤ length < 76 m) and therefore fails the "adequate facilities" test as a suitable airport for an A330-300.
In some FCTMs there is a cross-reference to Supplemental Information along the lines of;
My bolding.
Learmonth does not meet ICAO Rescue and Fire Fighting Services Category 9 standards (as required for airplanes 61 m ≤ length < 76 m) and therefore fails the "adequate facilities" test as a suitable airport for an A330-300.
I would suggest to you that Learmonth is approved by many large carriers as a full alternate, Suitable alternate or whatever title each airline uses, for a very long time. For example, it has been the No 1 Alternate for Perth for QF Boeing 747s since the 1970 s. If they can't use Learmonth (1.30 away) they have to use Adelaide(2.30+ away) with consquential penalties.
If each airline allows each individual pilot to determine what constitutes "suitable" then that is a very variable standard in my view.
I don't know, but my guess is that Learmonth is used by a number of A380 airlines as a full Alternate for Perth and ergo, if that particular airline considers it safe and appropriate for an A380 that just needs to fuel up, it would be considered safe and appropriate for an A330-300 with an engine shutdown and vibrating, lack of RFF notwithstanding.
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Fair enough.
I don't know, but my guess is that Learmonth is used by a number of A380 airlines as a full Alternate for Perth and ergo, if that particular airline considers it safe and appropriate for an A380 that just needs to fuel up, it would be considered safe and appropriate for an A330-300 with an engine shutdown and vibrating, lack of RFF notwithstanding.
I don't know, but my guess is that Learmonth is used by a number of A380 airlines as a full Alternate for Perth and ergo, if that particular airline considers it safe and appropriate for an A380 that just needs to fuel up, it would be considered safe and appropriate for an A330-300 with an engine shutdown and vibrating, lack of RFF notwithstanding.
The problem with so many of the assumptions in this thread is that the remaining engine WILL get the plane back to Perth. This is a huge assumption on a trip of several hundred kms after an engine failure of unknown cause, when the crew could have landed safely nearby.
That remaining engine is subject to extra stress and higher loads because it's operating for two, at a reduced height, higher drag and higher fuel burn. Life is more important than maintenance facilities and emotional support people at destination. If you lose one engine, the chances of losing the other are a lot higher in this scenario, and then it's the desert and bye bye.
Correction: It's not an official alternate for the A380 as I previously implied, but its a runway an A380 captain would have no hesitation in using if needs must.
Last edited by Spotted Reptile; 27th Jun 2017 at 22:33.
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.
My exact thoughts too, remind me not to fly AirAsia anytime soon, it's a wonder the engine didn't depart the wing.
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.
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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. A blade failure at cruise altitude is likely to be a random event within the ETOPS time limit (ie the second engine suffering a random failure with say a 180 minute ETOPS segment is vanishingly small).
Even if there is a identical common point of failure of engine maintenance for both engines, the chances of the both failures occurring within the one flight is statistically incredibly small. In other words, the engineering is designed to get you home from the the worst case scenario. Sure, it would feel very very uncomfortable, but it will work.
We accept this engineering rational every time we go flying in a twin. Here is a primer from EASA on the IFSD rates and engineering assumptions: Extended Range Operation with Two-Engine Aeroplanes ETOPS Certification and Operation. Have a look at section 3: RISK MANAGEMENT AND RISK MODEL (page 35), see Figure 1 and look at the IFSD rates per 1000 flight hours, and how they derive Figure 2 and the IFSD rate as ETOPS segments goes out towards 10 hours (0.010 failures per 1000 flight hours). If the second engine still works after the first blows up, it will keep working until you land.
Recent incidents that shows that dual engine failures were dependant: US Airways Flight 1549, QF32 and Air Transat 236. In all cases, there was a dependant relationship between the failures (external, birds for Sully, engine disintegration causing a second engine problem for QF32 and the Air Transat crew mishandling a fuel leak causing a common point of failure for the Azores Glider)
Having said all that, in this scenario I would be proceeding to the nearest runway that I believed was safe given my knowledge of the local environment. For me, YPLM is OK, for another pilot who is less familiar with the area that may be YPPH.
This short video shows where a random independent process becomes dependent one. The final simulation appears to defy logic and reason and does not produce the expected normal distribution.
Last edited by CurtainTwitcher; 27th Jun 2017 at 00:00. Reason: added video
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Matt48 - "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"
Exactly. Why subject the operating engine to additional stress? How many hours has the good engine been tested at the vibration level it was experiencing?
Exactly. Why subject the operating engine to additional stress? How many hours has the good engine been tested at the vibration level it was experiencing?
Good one, and perhaps a food truck and chairs.
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Matt48 - "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"
Exactly. Why subject the operating engine to additional stress? How many hours has the good engine been tested at the vibration level it was experiencing?
Exactly. Why subject the operating engine to additional stress? How many hours has the good engine been tested at the vibration level it was experiencing?
My opinion and thinking:
Something goes "bang" and an engine stops. You can't pull over and have an engineer have a look and even if you could, the airplane would be grounded for weeks and maybe months. How do you know what damage has occurred? How do you know the last bolt holding a wing on isn't going to let go?
In this situation, in addition to the bang and the engine stopping, the entire fuselage engine and wing was shaking. The airplane and its occupants belongs on the ground and YPLM is long enough, wide enough and hard enough to not cause further danger. It was day time the terrain around the airport is forgiving and its hardly Broome in the dry season traffic wise.
Forget the problem with the stairs, hotels and every other thing you can dream up.
https://www.youtube.com/watch?v=6XU0nAGKLYY
Whilst very different the Sioux city crash shows what fragments at high speed can do to an airplane.
How many stuff ups can one have before a spade is called a spade? Are Europe and the US wrong?
Something goes "bang" and an engine stops. You can't pull over and have an engineer have a look and even if you could, the airplane would be grounded for weeks and maybe months. How do you know what damage has occurred? How do you know the last bolt holding a wing on isn't going to let go?
In this situation, in addition to the bang and the engine stopping, the entire fuselage engine and wing was shaking. The airplane and its occupants belongs on the ground and YPLM is long enough, wide enough and hard enough to not cause further danger. It was day time the terrain around the airport is forgiving and its hardly Broome in the dry season traffic wise.
Forget the problem with the stairs, hotels and every other thing you can dream up.
https://www.youtube.com/watch?v=6XU0nAGKLYY
Whilst very different the Sioux city crash shows what fragments at high speed can do to an airplane.
How many stuff ups can one have before a spade is called a spade? Are Europe and the US wrong?
Last edited by Berealgetreal; 27th Jun 2017 at 01:51.
My opinion and thinking:
Something goes "bang" and an engine stops. You can't pull over and have an engineer have a look and even if you could, the airplane would be grounded for weeks and maybe months. How do you know what damage has occurred? How do you know the last bolt holding a wing on isn't going to let go?
In this situation, in addition to the bang and the engine stopping, the entire fuselage engine and wing was shaking. The airplane and its occupants belongs on the ground and YPLM is long enough, wide enough and hard enough to not cause further danger. It was day time the terrain around the airport is forgiving and its hardly Broome in the dry season traffic wise.
Forget the problem with the stairs, hotels and every other thing you can dream up.
https://www.youtube.com/watch?v=6XU0nAGKLYY
Whilst very different the Sioux city crash shows what fragments at high speed can do to an airplane.
How many stuff ups can one have before a spade is called a spade? Are Europe and the US wrong?
Something goes "bang" and an engine stops. You can't pull over and have an engineer have a look and even if you could, the airplane would be grounded for weeks and maybe months. How do you know what damage has occurred? How do you know the last bolt holding a wing on isn't going to let go?
In this situation, in addition to the bang and the engine stopping, the entire fuselage engine and wing was shaking. The airplane and its occupants belongs on the ground and YPLM is long enough, wide enough and hard enough to not cause further danger. It was day time the terrain around the airport is forgiving and its hardly Broome in the dry season traffic wise.
Forget the problem with the stairs, hotels and every other thing you can dream up.
https://www.youtube.com/watch?v=6XU0nAGKLYY
Whilst very different the Sioux city crash shows what fragments at high speed can do to an airplane.
How many stuff ups can one have before a spade is called a spade? Are Europe and the US wrong?
It will be interesting to see what comes out of this. If you consider how much pressure CASA puts on local operators it begs the question what does a foreign operator have to do to get it's AOC revoked or investigated by CASA?
Air Asia have had two very close calls in Australia now they're flying past perfectly acceptable alternates on one engine.
My money is on CASA doing nothing as per usual as they are not interested in upsetting a foreign country, and will just continue hammering the local operators and making what is already an uneven playing field even more uneven.
Air Asia have had two very close calls in Australia now they're flying past perfectly acceptable alternates on one engine.
My money is on CASA doing nothing as per usual as they are not interested in upsetting a foreign country, and will just continue hammering the local operators and making what is already an uneven playing field even more uneven.