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Air Asia Indonesia Lost Contact from Surabaya to Singapore

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Air Asia Indonesia Lost Contact from Surabaya to Singapore

Old 4th Jan 2015, 17:27
  #1201 (permalink)  
 
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Ice?

I admit to reading only 66% of this thread so perhaps I might have missed something. Apologies if this is the case.

It is well known that the CFM56 fan is neither capable nor certified to tolerate bird strikes of a size such as occured in the case of US Airways Flight 1549. A little research reveals that earlier CFM56 fan sets suffered from resonance and high-cycle fatigue. And in addition, rain/hail ingestion has also given rise to several incidents with this engine.

Perhaps what is generally less well known is that CFM56 fan blades have been observed to suffer significant damage in the event of ice accretion. When this occurs, high levels of N1 engine tracked order vibration are likely to be observed, along with audible changes in engine 'tone'. The consequences of prolonged engine operation in this condition merit little discussion.

The following report therefore, although not conclusive, contains some degree of credibility:

AirAsia Flight 8501 Crash Possibly Caused by Icing, Indonesian Report Says - WSJ

Are A320 and B737 pilots routinely trained in ice shedding manouvres, and what is the policy for avoidance of potential ice accretion?

By way of explanation, my personal backgound is in aircraft and engine prognostic health monitoring, including engine bird strike detection and fan blade damage detection.

Last edited by BigG22; 4th Jan 2015 at 20:42.
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Old 4th Jan 2015, 17:29
  #1202 (permalink)  
THUNDERTAILED
 
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A thought. Now that accellerometers are so tiny, would it not be possible to mount sets of them at each extremity of the aircraft (nose , tail, wingtips) and then calculate a graphic representation of the aircraft's movements in space? Could be presented to the crew as a 3rd person view perhaps?
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Old 4th Jan 2015, 17:53
  #1203 (permalink)  
 
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Thanks IcePack. It was a simple question - can I set the a/c up at turbulence penetration speed/mach, power and attitude and the a/c will then maintain power and attitude and ignore any other sensor inputs?
I get the impression the answer is 'no', because the various protection systems will kick in.
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Old 4th Jan 2015, 19:41
  #1204 (permalink)  
 
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A question for those who know A 320 cabin sidewall materials.
There was an image earlier in this thread of a damaged sidewall, including the window surround, that was recovered at sea. The sidewall was neatly cut across the top, is though it had been sheared.
Is there anything other than high speed aerodynamic stresses that can shear a composite structure so cleanly?
It seemed to me that this bit of debris was pretty strong evidence that the aircraft had broken up in flight. Is this a mistaken belief?
Certainly the absence of any cockpit communications during a long fall from 30 odd thousand feet is more consistent with a catastrophe than an icing/loss of control scenario.
After all, they were in ongoing ATC communication, unlike AF447.

Last edited by etudiant; 4th Jan 2015 at 19:55.
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Old 4th Jan 2015, 19:59
  #1205 (permalink)  
 
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etudiant.

As I answered to the original poster of that picture, we need to see the adjacent structure to make any claims of any sorts.

This type of damage can occur in many ways. One of the many ways may be that when the plane hit the ocean the forces made the bottom half snap cleanly from the wall structure but the upper part may have been stuck by, well, let's say, an overhead cabin and thus the crumbled upper part. This is just one of MANY explanations for this. Please remember that.
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Old 4th Jan 2015, 20:02
  #1206 (permalink)  
 
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Etudiant

anything 'other' than high speed aerodynamic stresses that could do that,?

Whatever you mean by high speed aerodynamic stresses... lots of things could. A kniife like object striking it maybe...

Water is hard when struck at any speed.
Depending on how an object is supported acceleration or deceleration alone can achieve surprising things. Aerodynamic s doesn't have to come into it, high speed or not
so proof of nothing yet IMHO

NB. Aerodynamic Forces create stresses (and strains) on objects... per se there
is no such thing as an aerodynamic stress, other than maybe between molecules
of air.

Last edited by HarryMann; 4th Jan 2015 at 20:17.
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Old 4th Jan 2015, 20:13
  #1207 (permalink)  
 
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The debris found shortly after the AF447 crash showed similar characteristics, and that was high velocity impact with the ocean. The cruise-level destruction of MH17 resulted in much smaller pieces (apart from engines) and fragmented bodies.
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Old 4th Jan 2015, 20:14
  #1208 (permalink)  
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Slats11, your economic model is a little off. It should be Revenue - (Fixed Costs + Product Costs) = Profit. The biggest fixed cost savings which LCC find is in operating from cheaper airfields. They will only operate from expensive airfields when loading is always high (e. g. Hong Kong). Through clever hedging they might save on fuel as well but that can be a double edged sword. Whilst staff costs are cheaper in Asia than in Europe, there is no difference here between legacy and LCC carriers. Both pay peanuts for ground staff and cabin crew but both have to recruit internationally for the flight deck and maintenance. The real savings are in product costs. LCC try to achieve higher turn around times and higher efficiency by removing services which are not required in order to perform the contract of moving the customer from A to B. The inference that LCC are compromising safety is not accurate because if they were, their insurance premiums would move in tandem, killing their profit. Allianz actuaries will be sratching their heads trying to figure out why Malaysian* airlines are now such a big risk. 3 crashes yes, but no obvious link.

*Air Asia Indonesia is controlled by its parent, Air Asia notwithstanding that for political/legal reasons an Indonesian investor appears to own 51%.
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Old 4th Jan 2015, 20:17
  #1209 (permalink)  
 
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Thank you for the considered replies.
I spoke of high speed aerodynamic because in my limited experience, composites rarely snap cleanly as they did here, they usually have bits sticking above the line of separation, unless the break is very forceful and sudden. That plus the abrupt silence of the crew together are pretty significant, imho.
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Old 4th Jan 2015, 20:18
  #1210 (permalink)  
 
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@Machinbird

Here is a KML file which expands on my post 1197.
Plug it into Google Earth and you will find the FR24 data plotted, showing the actual coordinates along with the debris locations etc.



https://www.dropbox.com/s/8j2tl52m5d...08501.kmz?dl=0
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Old 4th Jan 2015, 21:10
  #1211 (permalink)  
 
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Part ID

Clips on this piece have been noted previously. What is top and what is bottom?

I answered my own question: clips are at the panel top as suggested by A320 photos showing a radius on the panel concavity below the window. Panel bottom torn, top undamaged.

Last edited by Leightman 957; 4th Jan 2015 at 21:39. Reason: RE Pics of A320 interior panels
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Old 4th Jan 2015, 21:18
  #1212 (permalink)  
 
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'Crashed AirAsia jet's pilots did not get weather report' according to Jakarta Post

'Crashed AirAsia jet's pilots did not get weather report' - The Economic Times

Sorry if already posted. If true, I'm stunned
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Old 4th Jan 2015, 21:19
  #1213 (permalink)  
 
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The only window I've seen is a plastic panel which is undamaged at one end and torn at the other. The wind probably tore it from its fixings. Would all passengers please replace their tin foil hats.

Given that the fixings in the bottom of the photo have hooks pointing up, I'd imagine that's the top. We can all rest easy knowing if we get bored on our next flight we know how to annoy the cabin crew by dismantling the interior of the aircraft.
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Old 4th Jan 2015, 21:26
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'Crashed AirAsia jet's pilots did not get weather report' according to Jakarta Post 'Crashed AirAsia jet's pilots did not get weather report' - The Economic Times

Sorry if already posted. If true, I'm stunned




Seen that there were other flights shortly ahead of him, behind him and to either side of him, it would be surprising if any weather reports would have changed a thing for the pilot of 8501.
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Old 4th Jan 2015, 21:31
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ettore, I am going to post what I already posted on the 31st December, as I am led to believe, if we apply "normal" European decision making as regards go/no-go, whether to penetrate weather, how much separation to allow, there would be NO air travel in this part of the world.

I therefore humbly submit, that the failure (if there was one ) to get a "weather report" is neither here nor there in the grand scheme of things. Throw your hands up in horror if you wish, but, I am led to believe that, operating in that part of the world, is based very much on firstly going, and sussing it out the best you can once underway.

Standing by for corroboration/shooting down as required, but that is how I have been told it is. My (prev) post below.


I have not had the "pleasure" of flying in that part of the world, however, a couple of very experienced colleagues that did, for some time, intimated to me that if you did not accept to routinely fly through weather that you assuredly would avoid in Europe, you wouldn't operate any flights.

I doubt (knowing the individuals & their experience) if this was too much of an exaggeration, I believe it is quite probably the day to day reality of ops in that part of the world.
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Old 4th Jan 2015, 21:34
  #1216 (permalink)  
 
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@etudiant

May be, may be not.

But - and again if this is true - it would be quite dearly telling about poor airmanship, safety culture and it would draw hefty liability consequences.

@captplaystation

May be. But - again, if this is true - it would certainly draw hefty liability consequences.
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Old 4th Jan 2015, 21:37
  #1217 (permalink)  
 
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RE: "pilots did not get weather report"

That article strikes me as pure hyperbole. Does this newspaper expect that Captain Iriyanto was supposed to sit on the runway for an hour and a half waiting for a weather report?

This Captain was local to the area, he knew what the weather was like (all he had to do was look up as he walked to the plane.) There were a half a dozen other planes out in that weather, he could have gotten pireps anytime he was curious. Weather reports can only give generalized reports for an area, they can't pinpoint individual cells anyway. That's what the planes' weather radar is for.

Much ado about nothing.
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Old 4th Jan 2015, 21:49
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Thanks ekw. I doubt there is any significant connection for Allianz to find between this, MH370 and MH17. They appear to be 3 very different incidents.

In some ways I find this the most disconcerting due to possible underlying factors.

I had simplified it a bit. Less popular airports, less popular timeslots, pre-packed food (for sale), reduced baggage etc are among the many ways LCC reduce costs. My point is LCC pay much the same for planes, interest rates, and fuel. So there are only so many places they can reduce costs. And so everything that is discretionary is reviewed to minimise costs.

The inference that LCC are compromising safety is not accurate because if they were, their insurance premiums would move in tandem, killing their profit.
Not so sure about that. The fact is that airline travel is very safe so it is difficult to see any differences that may exist. So people have to make subjective decisions due to insufficient objective data. As others have commented however, most people can't do this and price is paramount.

We are in the midst of widespread and probably unprecedented changes between society and technology. Never before have people been so divorced from the technology they use. This is a general issue that is changing all society. Aviation is but one symptom of this.

I think these changes are a risk for all. Air France is not a LCC. But I do believe LCC are probably more vulnerable to these changes.

Last edited by slats11; 4th Jan 2015 at 22:18.
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Old 4th Jan 2015, 21:57
  #1219 (permalink)  
 
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Captainplaystation, exactly.

If you fly in or near the the ITCZ for long enough, sooner or later you are going to end up, where you shouldn't, or don't want to be. There can be many reasons for this.

The important point being, give yourself plenty of margin for this eventuality.

Culture

Properly trained crews anywhere can be as good or as bad as anywhere else. However if they are allowed to pressurized by corporate greed and face punishment by a culture of fear and intimidation, that is a recipe for disaster. This is especially so for inexperienced pilots who maybe allow themselves to be so pressured influencing incorrect decisions. This is where, a proper regulator (or lack of) that ensures this doesn't occur is the real problem, as I see it.
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Old 4th Jan 2015, 22:04
  #1220 (permalink)  
 
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Properly trained crews anywhere can be as good or as bad as anywhere else. However if they are allowed to pressurized by corporate greed and face punishment by a culture of fear and intimidation, that is a recipe for disaster. This is especially so for inexperienced pilots who maybe allow themselves to be so pressured influencing incorrect decisions. This is where, a proper regulator that ensures this doesn't occur is the real problem, as I see it.




Here we have a very senior captain on a routine flight, which was also routine for the many other airplanes in the same sky at the same time.
It is difficult to extrapolate this accident into an issue centering on 'corporate greed' or ' a culture of fear and intimidation'.
That just seems a cop out to me when we have a very specific accident to evaluate.
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