From the BEA report on AF 447:

"When there are no protections left, the aeroplane no longer possesses positive longitudinal static stability even on approach to stall. This absence specifically results in the fact that it is not necessary to make or increase a nose-up input to compensate for a loss of speed while maintaining aeroplane altitude. This behaviour, even if it may appear contrary to some provisions in the basic regulations, was judged to be acceptable by the certification authorities by taking into account special conditions and interpretation material. Indeed, the presence of flight envelope protections makes neutral longitudinal static stability acceptable.
However, positive longitudinal static stability on an aeroplane can be useful since it allows the pilot to have a sensory return (via the position of the stick) on the situation of his aeroplane in terms of speed in relation to its point of equilibrium (trim) at constant thrust. Specifically, the approach to stall on a classic aeroplane is always associated with a more or less pronounced nose-up input. This is not the case on the A330 in alternate law. The specific consequence is that in this control law the aeroplane, placed in a configuration where the thrust is not sufficient to maintain speed on the flight path, would end up by stalling without any inputs on the sidestick. It appears that this absence of positive static stability could have contributed to the PF not identifying the approach to stall."

Work together
 

Sorry but even as a non pilot, all this talk about 'push the stick forward and you're saved' is bit insensitive on this thread without knowing what happened.

It certainly didn't help 2 very respectable pilots on D-AXLA A320-232 over Perpignan when THS stayed nose up, with the combination of the AOA sensors freezing and normal law dropping out they were unable to save it with the above aforementioned method. After reading the report, i was worried by the lack of notification to the pilots, in that moment id expect 'USE MAN PITCH TRIM' to be slapping me round the face.
Or a clear indication:

Warning - Normal law FAIL STATUS NOW MANUAL
Cause - AOA/ADIR mismatch(or the like)
Result - USE MAN PITCH TRIM(?(perhaps added flashing if stick forward/backward exceeds Xseconds)) or AUTO PITCH TRIM DISABLED!

Would of been even nicer. (In this instance above i believe the PITCH TRIM warning dropped off the display shortly after ie changing flight law.) i stand to be corrected.

Then again what if the warning is wrong and all of it is sending you up the garden path?

If something similar had happened here im not sure id want to be on-board with ANY pilot at FL25(risky i know) or FL370, in that moment attempting to recover a stall. IMHO the transition from 'automated' to 'manual' and not in 'neutral trim' in the wrong moment without any clear reason is a worry, using any automated transportation.
As we have learnt even the most simple things in that moment to react can go undetected (flaps not extended on takeoff due to FB pulled on warning circuit muting the reminder to pilots they're not extended). Whilst not automated, had there been a clear warning, reaction should/could of saved the day.

I'm also shocked to read about lack of stall training due to lack of capability to do so for some aircraft. And still we have not put more pressure on all airlines to enforce real time streaming on capable aircraft with the rest to follow. MH370 whilst is rare, it needs to be answered it cannot be swiped aside as a statistic as some have mentioned here.

On the plus, I salute the many informative posters on here who clearly are outstanding professionals in their field and appreciate their fascinating analysis and input. I hope all of this debate can be focused on making our airways safer, negating the swiss cheese effect ever happening. Hoping no more families suffer this loss of professionals doing their job and PAX in this way, once we have the ACTUAL cause from the experts.

Anyway what do i know, i can barely fly a quadcopter!

Are they cutting the wreckage up so it can be transported by road? Wouldn't it have been better to sail it, intact, to Jakarta?

No disagreement at all. An interesting discussion would be how deep into the stall one ends up during power on, 3kts/per second, approaches.

capt log

NB for Perpignan, the BEA said:In short, any pilot, with full power, full forward stick yet nose high and getting higher should not need (and will not notice) a small "Use Man Pitch Trim" message. They should be trained to know that Pitch Trim may be needed, but in both cases, IIRC, the Pitch Trim was not the whole issue, but the high power as well?

We do need to remember they ignored numerous signs that the AoAs were incorrect, they failed to follow every safety procedure in the test they were doing. I am afraid there gets a point when the crew have to be "accountable" (even if it their training or management the ultimate cause), rather than just blaming the systems / manufacturers because their aircraft are not "uncrashable" :ugh:

@zzuf


OK, I guess I misread your intent. You obviously meant others than Gysbreght!. I spent some time with Nick also.

Nigel, that flight amongst other incidents and accidents (the upset to G-EZJK comes to mind) was why the procedures, discipline and training requirements for post-maintenance check flights have been substantially changed.

Scorch marks ...
 

After the fuselage was lifted from Crest Onyx to shore, at some stage, there was a guy using a torch. He was cutting at at least two places.

Have not seen that before. Will be clear though during reassembly that it was not from the crash.



Picture 1 -Torch is handled by a man with a medium dark blue shirt with logo “ST” on it. He is closely observed by another man in civvies (@ I found later that this man is from KNKT). Cutting is vertical on the side of the first frame between the last window and the lavatory section, on the'inside' of the lavatory section.

Picture 2 –Cutting itself not observed. But ashore, 10 guys putting the structure up, you can see a very long horizontal scorch mark. Running from the door to the fuselage painted word “Fly”. Part that was cut away was a strip with 5 windows and PK-AXC registration letters. That part was still there in daylight when Crest Onyx was already in Kumai port in daylight. That same (lefthand aft part of fuselage – watch out, it is lying upside down) strip was hinged about 135 degrees outside when still on deck.

Picture 3 –The man with the long crowbar. You can see torch marks on the longitudinal stiffener just below his torso.

Picture 4 –The man making the vertical cut, view from outside, ... have seen the picture.. (@ later -same torch operator as in Picture 1)

CVR type
 

I found one good picture of the QZ8501 CVR after recovery.

Cockpit Voice Recorder = Model FA2100, L3communications
CVR carried Emergency Locating Beacon = TELEDYNE BENTHOS

Other CVR configuration information like serial, manufacturing number, and HW and SW config nrs were clear for parts. I wait till I get a better picture before posting that.

Appreciated, but I do not understand the point?

Any pilot conducting any test flight should be aware of some basic principles, well documented well before this accident, and probably before WW2. There is no point in testing something if you are betting your life on the test succeeding? Surely you test "High AoA protection" on the assumption it might not work?

As the BEA report stated, another crew had done a similar profile and: and next flight:Somewhat nearer ideal :ok:

Funny my recollection was, despite the time stamps, Gysbreght's post was not on my browser when I selected reply. So, yes, lots of others!

Nigel, sorry, the point I was trying to make as simply that those undertaking that type of flight were not properly prepared, briefed or understanding the consequences of what they were doing, which is something for which I agree they must bear responsibility.

That will definitively be individual for every aircraft, and even depending on actual weight (the lighter you are, the steeper you climb and the longer the nose needs to come down). It also depends on how quickly you reduce thrust, which may significantly help to get the nose down quickly.
It also very much depends on how and when you would define the airplane to be stalled.

Dismantling techniques
 

I presume that the investigators have authorised the somewhat barbarous dismantling that is shown in the pictures.

The assumption must be that they do not expect to learn a great deal from the wreckage. ie they already have a pretty clear idea of the cause of the incident.

A more apt user name there isn't. Ian W's response hopefully shed some light. In a competitive industry, and an industry wherein to remain in service one must earn revenue in excess of expenses or not exist, the cost of everything matters. Therefore, the bean counters are directed to analyze cost. The problem is for beancounters, not everthing pertaining to safe and effective ops can be numerically quantified to three decimal places. Sadly, between management and number crunches, that leaves Safety Critical issues like training underfunded and under-resourced. Politics have nothing to do with it. Your point on regulation being lax also is a matter of cost, in terms of how many tax dollars are allocated to that function. That's another group of bean counters at work, right?

I'm surprised to see this dismembering too. It looks more like disposal than careful dismantling.

A previous poster mentioned that Airbus had advised on the breaking up of the tail section, and I believe this was before the DFDR was found. So I think they decided on the sawing-up before they had any other evidence. Why would this be?

they decided on the sawing-up before they had any other evidence. Why would this be?
 

It could be that Airbus has been passed information that has not yet been (and may never be) released to the media. That's not a conspiracy, that's normal.

Chains?
 

Look further on the tail pic to the left of the guy with no crowbar is - looks like a chain in that crease from the "balloon" that raised the tail - if you zoom/enhance?

After MH370 I think everyone is looking for a mystery... This looks to be straightforward with little room for conspiracy theories.

This Getty Images photo shows a torch being used... An Indonesian worker cuts the tail of the AirAsia flight QZ8501 in... News Photo 461419122 | Getty Images

Thanks
 

Ok, thanks. - missed that.

Bit worrying having some guy using a cutting torch to chop it up without - from the pics apparently - nobody in authority guiding/controlling him.

Anyway, fuselage found so hopefully some closure for the relatives on the way.

Agreed :ok: I had recently done my "CAA Check Pilot" (post-maintenance Test Pilot) on ex-Mil jets, and learned a lot re the approach, attitude and philosophy such testing needed. Perpignan then happened, and everything that (ex-)CAA & RAF TP rang ominously true.

To justforfun, mudman
 

On the previous page, number 101, are posted results of photos I got last night. And can add that there are many more photos today. The mr 1 in my post is the same as mr 4 by the way.

On the first photos that you find (Google) you do not see a supervisor. I had the same question that you had. Later I found the mr 1 photo, which shows a person who appears to be supervising closely. In other photos he may stand behind the wreckage. Hope this helps.

Would be interesting to know why they cut it this way, and why in this manner. Hope to find an answer in the Prelim or Final Report.

Also note that the 'strip with windows' that I mentioned in my post on 101, was mangled further when they pulled the tail wreckage onboard the Crest Onyx. Was searching for photos that show this, and there are a few.

On the structure found ...
 

I twice posted a scenario that could explain a number of questions that I had about the finds and their sequence. Both times they were rejected. So I won't post the sequence again.

Starting point was an earlier post which was accepted though. In which it looks like a 'giant hand' grabbing the horizontal stabilizer and rotating it.

In the scenario referred to, one sequence might lead to opening up the pressure bulkhead. Leading to a sequence of failures, and in line with that a sequence of specific finds.

I have not had time to think about what kind of aerodynamic forces would shape this 'hand'. Perhaps another poster would be able to shed some light on that. If not, then we would have to change over to hydrodynamic forces, and that would steer the scenario in another direction.

And perhaps there is somebody who has an idea about what kind of forces would be required for such an 'opening up', scenario. Is it realistic with a THS span of 12.45m. You can mail that to me if you dont want to post it.

It is not possible to collect and analyze and make aerodyn/hydrodyn and stress/strength calculations at the same time ...

For my money, your second point on "hydrodymanic forces" is a good avenue of inquiry.
Such a twisting might be the result of a rotating body not hitting the water's surface in a more or less "flat" attitude (as did AF 447) but rather in a more or less "tilted" attitude.
It might not need to rotating to get a tear like that if it has sufficient ground speed and tilt, depending on the vertical velocity at impact as compared to lateral / horizontal velocity.

Feedback to Lonewolf
 

Lonewolf, I started out with the aerodynamic. Then considered the hydrodynamic. But today officials stated that tail and FDR/CVR were 800 m apart, and tail and main fuselage plus wings 2,000 m. That increased the probability on the side of the aerodynamic. Also, because the vertical stabilizer still looked pretty smooth.

The damage to the lower side of the rudder area, that looks a bit like that on (high speed) AF447. Which puts another grain of salt on the aerodyn scale. Don't you think?

Surely how it hit the water, and what caused the damage seen is really of little matter.

It may or may not indicate if there was any control at the time it hit the water, but again, that won't help find the cause.

What is needed is the reason that caused the loss of control (not pointing to pilot involvement or not) at some 30k feet above the damage being looked at.

Maybe this is why they are not too worried about the "hacking up" of the wreckage?

Having done a high-altitude stalling module recently, I thought it was of great benefit despite the caveat that the aerodynamic simulation might not be exact.

It showed:

a) You had to agressively reduce the AoA by pitching down to a far greater degree than in any other flight phase.

b) The engines were next to useless, given spool-up times and the thrust generated near the aircraft ceiling, so it was more a glider-style recovery.

c) You were going to lose a LOT of altitude, no matter what.

d) If you tried to level out too early, before getting to c), it was quite possible to stall again.

I would argue that the fidelity of the simulator was unimportant in getting those basic principles across. After all, every LoC / jet upset is different, especially if it has been in part caused by something malfunctioning, be it software, hardware or wetware.

@A0283:
I see your points. Just a thought: once things fell apart, the movement of the water and "how long a given bit floats" may offer sufficient explanation for how the dispersal came about. Or not.
You are more likely right in your estimates, as you've examined it in more detail.

That is a great deal more intact than I thought it would be. I expected component parts.

No sign yet of front part of fuselage, ie cockpit?

Let's face it... hydrodynamic forces would be capable of anything
imaginable and unimaginable entering water at speeds from 100 kts
upwards. Including twisting and if the tail struck first, tearing it off.
lets see

To Msunduzi
 

My impression is that 'losing control at high altitude' would happen more often (probability wise and statistically), than things getting 'out of control' ( either by weather events (that's one reason why we have pilots who can put things right), or SA loss leading to a flip like the 747 years ago (where the pilot provided both cause and solution, albeit after a significant drop) ). If that is so, then you would have to divide the flight path in altitude steps, call it a 'ladder'. And ask for each step of the ladder what happens, and what the pilots' options are. Like posters do in the interesting stall discussions here. And that also includes the final splash. The whole plane hitting the water or large separate sections ... that points to different possible causes. Which you test by going up the ladder again. Both top and bottom of the ladder are relevant for 'solving' this accident.

On hacking up. Nobody knows what the cause was. Real hacking up would not start until after reading and analyzing the recorders and the investigation being further along the line. The only reason for hacking up now would be transportation requirements (bridges, roadwidth ..etc ... the diameter of the fuselage is 4.14 m ... one lane on western highways is something like 3 m...isn't it?)

I tend to agree. Before the tail was recovered, there was an official statement that the rescuers first priority was finding the casualties, the second was the black boxes.

The main interest in the wreckage, as reported, was about the position of the control surfaces (or "tail flaps" as it was reported) which could give valuable information about the airplane's last flying moments. Based on that information, the interesting pieces would IMHO be the actuators and the THS jackscrew.

Presumably the rescuers also took enough underwater photos and videos to enable them to establish the pre-recovery condition of the wreckage. I'd assume that to be standard practice in this kind of salvage jobs.

To Lonewolf ...
 

At first thought. There might be two 'theoretical reasons' that could explain the 2,000 m. First floating, and second forward speed. But both start with hitting the water and losing the THS and the bottom of the tail with the APU.

On the first, floating. So you have an open tube ... which if it fills, will fill quickly ... if not, the plane might be weighed nose down and keep the open end up for a while (until the swell flows in) and might float around a bit ... at the 1-2 knots published current that distance would take roughly 30 minutes to 60 minutes.

On the second. The forward speed would combine losing the tail followed by skimming over the surface like a flat stone. At say 60-120 knots that would be roughly 2,000 m in roughly 0.6-1.2 min. The impression is that the plane went up and down quite vertical (not far from LKP) and pretty fast. So, that seems to be less probable.... In spite of the fact that the lower aft section may still have been attached (as mentioned, the aft top panel stayed connected to the tail/rudder section).

What it does not explain is the apparent stripping of most interior components..... Which gives a bit more probability on the side of a higher speed and above break up. Also, skimming has lower probability, when reviewing earlier widebody waterlandings.

Theory and practice can be quite different of course. But it gives some idea I guess. And no more than 'some' idea ... at this stage and with the publicly available information.

the wreckage looks very much less fragmented then i/we were expecting

reminds me of 2 tridents that went down with little or no forward speed

PI and ZT both had wreckage/fuselage compacting that looked somewhat like this with wings attached

BEANCOUNTERS...
 

someone mentioned clearing the BEANCOUNTERS from responsibility, blaming instead a lack of required standards

SO


Back in the beginning, there were no standards and we learned the hard way what had to be done to keep things safe and assure passengers there was as good a chance to get from A to B on an airliner as on a train, ship, car, or horse.

And they did it.

And then the regulators codified many of those same things.

BUT THEN came the cheapos. IF THE FAA or over seas version hasn't mandated it, then WE DON'T HAVE TO DO IT and can save money.

THE OLD GUYS shook their heads...they knew better. We are learning the same things over and over again that we knew 40 years ago.

all at the cost of passengers and crew.


So it is beancounters, because they have an excuse, an ENABLER in local regs that aren't as tight as a drum.

Given the remarkable condition of the fuselage, an attempted but unsuccessful "controlled" ditch in gale conditions?

There has been some discussion on hydrodynamic forces as cause for apparent damage.

By way of a reminder I would say that my understanding of hydrodynamic force is the forces acting in fluids in motion and not objects that impact fluids such as water. Accordingly unless someone pulls a stunt such as flying into Niagara Falls at their full fury then the question of hydrodynamic force does not really come into play.
The damage sustained to an aircraft impacting against any surface is caused by the dynamic force of the travelling aircraft and not by movement of the surface or depth of the water.
In this instance my money is on the in -flight loss of the empennage as a result of aerodynamic forces imposed upon it beyond its structural limititations.

I just would not have expected the remainder of the airframe to survive anything like to the extent it has. It appears borderline surviveable, and the fuselage (what is visible) still looks circular.