Here's an interview with the chief of the KNKT (NTSC) after downloading data from the FDR. He's not revealing too much at this stage which is understandable. It's interesting that he has aircraft models of recent aircraft fatal accidents behind him in his office (Sukoi SJ 100 and Merpati's MA60).

FDR and CVR status - till end of January 16th
 

As far as I know:

There is an unofficial piece of tape - claimed to be from 8501 - containing pre-takeoff comms with the control tower in Surabaya. I ve been listening to that and the quality is not that good. Tried to make a transcript ( because I could not find one ), but hard to confirm what has been claimed, based on that. Could just have been another flight.

Both recorders have been delivered to KNKT/NTSC HQ and Lab in Jakarta. The FDR on Jan.12th, and CVR on the night of Jan. 13th or in the early morning thereafter.

First reported results:

"Safety committee-head Tatang Kurniadi said that 174 hrs of data had been downloaded from the FDR, and 2 hrs and 4 min from the CVR. The data must be converted into a usable format before the lengthy analysis process can begin.- AFP".

Timeframes for download and first analysis given during the last few weeks by KNKT ran from 2 days to 2 weeks. It depends on the quality of what is retrieved. The recorders looked good, so most expect a quick retrieval. But you never know.

A prelim report is often set at 1 month after the accident. But with this open water search and the relatively later finds, it would not suprise me if they would set that at 1 month after the FDR find. So somewhere mid February. All parties involved will want to make sure that what will be reported does not have to be retracted later. Saves us all from all kinds of conspiracy theories.

Expect the worst, but (we all) hope for the best.

Quick and dirty transcript of the interview with the head of the KNKT
 

@ training wheels video

CCTV INTERVIEW WITH HEAD OF KNKT/NTSC

[ a quick and dirty transcript by A0283,which means it is not meant to be 100% correct, my additions are put between [ ] ...
[ Also, the Q's start the questions by the journalist, the A's start the answers by the Head of the NTSC ]
[And, I left the english as it was spoken]

Q ...[illegible]...[Tatang?]..

Q thank you so much for your time, You must be very busy,

Q how is your investigation going, were are you right now,

I think from the [find] of the flightrecorders...

Information has been download,

About 1200 parameters... and then frame hours download for 174 hrs...

Then from CVR... we download the length of 2hr and 4min...of the information [from] the CVR.

Q and did you find any red flags....like anything that caused for an alarm, that immediately stands out,

A ... there are around, just little more... when the accident happened to the aircraft,

A but the content is undisclose methodology...cannot be published,

Q so, to know cause of this crash, do you need all the wreckages, or is it...

A NO,

Q enough for the black boxes,

A [but] it is very good to lift it, makea mock up, and then to show it to the public, as lessons learned,

Q ...you will leave in your hands... you have the key to the cause of the crash,

A we have the key,

Q is it weather, is it because of the clouds,the weather,

A I cannot say like that, [clouds] that is only one aspect, [just] one factor, ...accident always happen because of too many factors ... clouds,

Q so we can you already found other factors,

A yes... also [found] other factors,[confirms and nods],

Q the Indonesian safety record is not very good, compared to other countries, what are some of the most pressing concern[s] that you have, as head of the NTSB [NTSC],

A I think our improvement started in2007, our rate of accident [was] dramatically reduced, from [then] 4.12 to 1.53[per ... ] in 2013, .. [dropped], assisted by the rate increase operational [flying]hrs...

A rate of

A to maintain [improve] our safetyculture, ... and then to enforce safety recommendations,...operators and also the regulators,

Q there is a lot of international attention on this crash, because of the two major crash that happened during[in] 2014, MH370 and MH17,

Q a lot of talks been going on, that [there] should be a better way for the black boxes to be found, for finding the black boxes ... to be found,

Q that this is something crucial for the aerospace industry

A sometimes we find difficulty to find the black box, where are they, especially when they happen at sea, and costly to find,

A I think in the future ... it should be new technology to transfer the FDR and CVR.. [data/information] to another system,

END OF INTERVIEW

No, "required" should be "provided".

Not revealing much but the message is that he clearly knows what happened.
Which is not specially surprising. They've heard recordings from the deck, they got radar data, they got large part of the wreck and (probably) autopsies.

And I suppose the moment when his knowledge will see the light of the day will be earlier then the publication of the preliminary report. Officially or not.

Memory Module Cylinders?????
 

RE AO283's post
"Memory module cylinders" on the CVR , FDR boxes?
I always thought those were the "pingers" and that all data was contained within the CVR FDR boxes themselves.

cylinders on cylinders
 

Nope.

Different brand, but with reference to this picture:
https://commerce.honeywell.com/wcsst...light_rcdr.jpg
The small shiny cylinders are the pingers, which are attached to bigger red cylinders which contain the actual data memory--and some appreciable shock mounting and armoring. The main electronics are in the L-shaped rectangular boxes, which don't actually need to survive, as they are finished with their function by the time serious disruptive forces arrive.

Disclosure: I'm not a pilot. I am an electrical engineer, with a few degrees from MIT.

actual CVR blackbox from QZ8501

http://i.imgur.com/OBmj6wt.jpg


AirAsia flight QZ8501: Recovery crews suspect they have found crashed jet?s cockpit, engine

It's concerning if the Indonesian authorities have control of the recovered data, and they have a history of denying an issue if it is something they feel embarrassed about (like a suicide).

There are reports coming through now that BASARNAS has now located the cockpit about 500 metres from the main fuselage. The pic below is just an artist graphic, but the news report is here.

https://pbs.twimg.com/media/B7h8itYCIAAk_b-.jpg

p.j.m (and others freaking out about Indonesia's capacity to respond)

So far there has been a very transparent and I think successful response (aside the issue about routes, which was not atypical of bureaucratic responses in more developed countries).

Interestingly when the NTSB gave early briefings on information during the Aseana investigation they were criticised on this forum for too much too soon.

So far the Indonesians have found the wreckage, located and recovered the FDR and CVR in very challenging and risky conditions, have recovered bodies with dignity and respect, are recovering the fuselage, and are providing clear updates on the state of the recovery and investigation. It's an error to use isolated past experiences as predictors of present and future events.

While the families of 9/11 victims still demand to see the redacted 28 pages, and Australia now has a range of new laws which substantially inhibit transparency, I'd say don't throw too many stones.

these planes are sort of constructed in three big pieces...the front part, the middle part and the tail part


so, it seems we have found the big parts and they sort of break up that way.

bud leon is correct - and the Indonesian divers merit special acknowledgment for their outstanding recovery efforts in conditions that are dangerous in the extreme.
Western divers would be looking for bravery awards under the conditions that the Indonesian divers are working in.

These divers have not only been battling strong and reversing currents - they have been travelling out to the wreckage sites in 2M to 4M waves and enduring violent seasickness as well.
They have been diving to extreme depths, at their diving limit. Then they have had to deal with low levels of visibility, as well as the potential finding of human remains staring back at them. It's not a job I'd volunteer for.

They have not had the luxury of ROV's or mini-subs or other exotic equipment, as many Western nations would produce and use.
They have done an admirable job of finding the wreckage and recovering some of it, in surface weather that has been less than favourable, more often than it has been favourable.

Cut the Indonesians some slack, I'm sure they are just as interested in improving their SAR skills, and finding the real reasons behind the crash, as any of us are.

The fact that a few of the middle-management Indonesians got a little excited and made pronouncements that were guesses, more than actual knowledge, is no reason to write off the whole exercise as one of total incompetence.

@ albatross on ‘cylinders’, naming conventions and configuration management
 

My intent was to give a general visual description. It would have been more complete if I had written: “The actual recorders have large diameter, orange coloured, vertically mounted, memory module containing cylinders. With the ‘pinger’ being the small diameter, silver coloured cylinder, mounted horizontally with two black brackets onto two orange brackets on the vertical cylinders.

Note - on quite a few recorders these two black brackets are connected directly to the memory module cylinders. Both actual 8501 recorders have a kind of ‘rather fat’ intermediate orange brackets on which these black brackets are mounted.

There is one ‘pinger’ each on the FDR and the CVR. ‘Pingers’ are better called Underwater Locator Beacon’s (ULB's), But in this case labelled “EMERGENCY LOCATING BEACON” by the manufacturer on the one mounted on the actual CVR. Not smart from the manufacturer to label it like this, as the ELB acronym might easily be confused with ELT. The (some are yellow) ELT is the Emergency Locator Transmitter, which should start its work on impact, and works above the water surface (ref its specific ELT higher frequencies). The ULB should start its work when it contacts(sea)water, and works under the water surface (ref its specific ULB lower frequencies). Seems like a small detail. But naming conventions are a sub-category of what is called “configuration management”. And the (most) advanced state of configuration management in aerospace, being both art and science, is (just) one of the reasons why the industry has become, and is, as safe as it is.

@Archae86 - agreed. Note that his image shows horizontally mounted memory module cylinders. So they are not from 8501. Thanks for the nice and shiny image. Better one than you usually find.

@p.j.m. - agreed. @albatross, note that the boss of the KNKT/NTSC pulls the CVR out of the black container by holding onto the ‘pinger’.

@glendalegoon
 

Not always right and not exactly right. But certainly one of the things I look at, from the start of an investigation. In manufacturing they are often called "production breaks". Not always right and not exactly right - and rather simplified - but production break 'lines' are often 'stronger and stiffer' than the areas on either side. So the probability is high that the breaks are on one or either side of these 'lines', and the probability is low that 'through the line itself' is the break. The recovered tail section can be used as a case study. It shows technically important fracturing details.

Note that the production breaks that you mention are on the 'highest level'. Depending on the complexity and design date of the aircraft, there are a number of levels below that. A section break is not the same as the production break/interface of a fuselage panel for instance. This subject is a sub-part of the so-called "interface management". For all kinds of reasons there is a complex relationship between interface management and configuration management. I said something in my previous post about the latter subject.

Let's hope they find the missing passengers and crew in the recently discovered sections.

sunday 12.50 am nz
 

PANGKALAN BUN, Indonesia (AP) " High waves and strong currents in the Java Sea again prevented Indonesian navy divers from accessing the fuselage and what is believed to be the cockpit from the AirAsia plane that crashed three weeks ago, officials said.

A team of 15 navy divers tried to get to the wreckage to examine it and calculate its weight, but failed to reach it due to the unfavorable conditions, said Suryadi Bambang Supriyadi, director of operations for Indonesia's National Search and Rescue Agency.

Indonesian survey ships have located at least nine big objects, including the jet's fuselage, what is believed to be the cockpit and an engine, Supriyadi said. The fuselage is sitting on the seabed at a depth of 28 meters (92 feet).

The 30-meter-long (100-foot-long) fuselage and an attached wing were sighted Wednesday. Divers attempted to reach the wreckage Thursday and Friday, but were turned back because of the rough sea conditions.

Authorities believe many of the bodies are still inside the fuselage. There were 162 people aboard Flight 8501 when it crashed into the sea Dec. 28 en route from Surabaya, Indonesia's second-largest city, to Singapore. Only 51 bodies have been recovered so far.

The head of the search and rescue agency, Henry Bambang Soelistyo, said Friday that the fuselage would have to be lifted because of the divers' inability to reach it. This will be done by either using floating balloons, as the tail section was lifted earlier in the week, or cranes from tugboats. Soelistyo did not say when the operation would start.

Divers, however, still need to reach the wreckage area. The wreckage that appears to be the cockpit was located by sonar imagery about 500 meters (yards) from the fuselage and was partly embedded in the mud.

"What we have so far is only a silhouette of the wreckage," Supriyadi said. "We need to deploy our divers to identify whether it's the jet's cockpit or something else."

He also said the divers have been told to retrieve the bodies of the pilot and the co-pilot if they are able to find them in the cockpit.

CVR & DFR analysis
 

Hi there,
How long does it take to decode, visualize & analyse the DFR data ? (flight parameters, engine performance, structural modes,...). I mean to get the rought lines of the failure scenario ?
I have been working several years on tactical missile design and testing.
Knowing how a missile test had failed (in this case knowing whether it was a stall, a catastrophic descent due to a dual engine failure, or how these engine or other structural element failed, etc...) would have been a matter of several hours (if no data is missing/corrupted).

If there are no problems with the decoding and timing of the data, the first may take one or two days. The second will take longer. In terms of causes and effects I expect the accident scenario to be quite complex, and the investigators would be well advised not to publish any data before they have at least a rough idea of the causal chain of events.

If they have a good idea of the cause but do not feel it urgent to release any information about it, can it be considered that the likely cause is something that does not pose an immediate risk to the operation of other aircraft of the type?

AFR447 fell from 38,000ft and the aircraft broke into similar parts as the Air Asia aircraft. The A330 was dropping at around 11,000fpm (125mph) with very little forward speed. The aircraft debris field was more compact as the underwater currents were not as strong, unlike the stormy sea and strong currents in the latest crash.

As A0283 posted earlier these breaks tend to occur close to the strengthened interfaces - production breaks - between major components. This explains the similarity in components of the debris after very different accidents.

Megathron
 

"If they have a good idea of the cause but do not feel it urgent to release any information about it, can it be considered that the likely cause is something that does not pose an immediate risk to the operation of other aircraft of the type?"

Yes it often can, because otherwise Airbus would issue an All Operators Telex (or whatever it's called these days) which without accepting blame (lawyers!) says "be careful about this".

One more time: ULBs work with SONIC waves and ELTs with RADIO waves. Two different worlds...

@Shadoko - specific frequencies
 

Yes I know. I tried to cover that with the word "specific". I should have written that explicitely as "specific to the use and medium". Your statement is clear and welcome.

@IAN W – on production breaks and AF447
 

As I mentioned in my post ... my statement is a simplification ... even with that in mind, I would personally like to adapt your lines a little to something like: “... A0283 post ... these breaks have a higher probability to occur close to the ‘stronger and stiffer’ interfaces, like the so-called production breaks between major components. This may explain similarities in aircraft break-up and components/debris distribution. Even after quite different accidents.” Or perhaps we should say “accidents with different causes”.

In that respect, depending on the type of accident, it could be well advisable to add a manufacturing engineer (which is a special job function, each Tier 1 aircraft manufacturer has a a few) to an investigation team. Their view can add to the views that people with a pilot, design engineer, and maintenance background may not immediately have. Would be interesting to know if anyone has any knowledge of, or experience with this in practice.

Your remark about AF447 made me think back to that accident. The main debris field was only 600x200m, and that at a depth of 3,900 m if I am not mistaken. That ‘compact’ distribution (its an ocean !, and it was in the ITCZ! at that time, and...) still amazes me ... for that depth. Compared to that, relatively speaking, the QZ8501 sections are (figuratively) ‘miles apart’. More knowledge about this might help (even if we do everything to prevent crashes from happening) future searches.

That is a reasonable inference.

Warning reference to QZ 8501 autopsies below.





It has been reported today that autopsies have QZ 8501 passengers revealed impact injuries such as broken legs, but no burns. Source:

Divers sent to investigate pings from crashed AirAsia flight QZ8501 (apologies for mobile link).

I recall that AF447 pax also suffered broken legs from the upward impact of their seats.

Unlike the AF crash i suspect this airbus hit the sea with some forward speed, cartwheeled and came apart.

I further suspect that this was a weather induced loss of control and at some stage an attempt at recovery was made, but the vertical rate of descent and space between cloud base and hard deck was insufficient

I very much doubt the weather was directly responsible the break up, but if they ended up in a viscous updraft and pitched down and cut the thrust it would be very easy to loose it and recovery in cloud with no visual reference, much turbulence and all manner of warnings going off......there but for the grace of god

Vertical speed of about 10,000fpm is about 100kts straight down so coupled with 100kts forward it will not be pretty on hitting the ocean!

Future search scenario's
 

The majority of posters appear to 'vote' for most likely scenario(s) (and versions of those) going like: ‘... an event or upset, leading to a (low speed) stall, no recognition of that stall, or impossible or too late to recover from that stall, and finally the plane hitting the water at an almost even ‘keel’ ...’

I have read interesting comments on other scenario’s though. So I hope those interested in other scenario’s will share comments or suggestions on the following ‘theoretical scenario’.

What would the damage look like, if an almost intact A320 would dive almost straight in?

Keeping in mind the special circumstance in the 8501 case, being that the water is only 28-30m deep. If you take the fuselage length of 37.50 m and subtract the waterdepth of say 29.00 m you get 8.5 m. Now assume that the nose reaches the seafloor. The tail part that ‘sticks out’ is about 8 m. That would roughly be around frame 68-70. Ergo, around the aft strong frame of the aft passenger door?

The exact angle of entry into the water will then determine how the tail section breaks off. Following the earlier ‘production break’ discussion, that could be either just in front, or just behind the aft passenger door. It could also provide a (the section moving ...forward, backward or sideways) break-up scenario for the components of the tail section.

It is possible to think of a path now, that leaves the vertical tail rather undamaged( we can try to match that with the visible fractures – of course trying to exclude damage caused by pulling the tail on board Crest Onyx). And losing the APU and the THS. Where perhaps (see earlier posted scenario’s) the tail section with tail floated before it became water logged, anchored, and overturned. But now the THS also floated before becoming water logged. And therefore it is possible it will be found a bit further away.

I did some tower diving in the past from 10-12 m. When you get in under even a small angle with the vertical, your spine is bent, quite a force, so would fuselage show a kind of water dampened whip 'reflex'. Always very complex to make dynamic stress calculations ... but ...

Answers to these questions might be of some assistence in future searches. Till this accident it seemed most likely, if anything was found on the surface, find vertical tail or rudder first. Would it help to give SAR crews a description of most probably objects to look for. Also helping to separate ocean garbage from aircraft components and fragments.

@ A0283...
 

Not an expert but if as you suggest the aircraft "went straight in" then one would have to assume it is not in a "stalled" condition, thus probably hitting/entering the water at a substantial speed.

In this case it would most likely break apart in many small pieces upon hitting the water almost like hitting solid ground.

@A0283
A vertical or close to dive into water would cause considerable damage to the nose of the aircraft and stresses would show that the aircraft hit something nose first.
Passenger injuries would show severe seatbelt injuries and seats would be broken away from the floor and compressed toward the front of the fuselage. I am not sure that pax would show the same broken legs that appear to be apparent in this case. There would also be more detritus from inside the fuselage.

[Theoretical Scenario]

The concertinering of the fuselage seems to show that the aircraft hit the sea surface belly first perhaps with a slight nose down to provide the hydraulic disconnection of the empenage at the pressure bulkhead. As pointed out several times the break line of the tail is not consistent so there may have been a one wing low and turning vector.
So as a theoretical scenario, loss of control, stall into a relatively flat spin. This would also fit with the descent rate, a dive would have been considerably faster more than 30,000 fpm.
From Stall/Spin " if the impact occurs nose down, at a high rate of descent which is typical of stall/spin scenarios, the G forces tend to be much higher, the aircraft does not slide much and there are resulting fatalities."

[/Theoretical Scenario]

Millions of tiny bits'n pieces....

Whatever remained would show orthogonal/circumferantial crumple lines instead of longitudinal.

This one here pretty surely hit flat (with maybe a touch of bank angle). If anything rather a tad Nose Up rather than Nose Down. Especially the seat structures showed signs of vertical and pratically no visible longitudinal bending. The same with the folds in the fuselage/tail skin

An interesting news article:

AirAsia flight QZ8501: Crash highlights perils of South-east Asia's crowded skies - South-east Asia News & Top Stories - The Straits Times

Ask for a higher level on the Atlantic you will get a similar 'UNABLE DUE TRAFFIC' response. Then the article segways from that into apparently trying to blame ATC for the incident. Looking at the surveillance pictures showing the amount of traffic around 8501 - it takes a fair amount of hyperbole to call the airspace 'busy'.

As pointed out multiple times ATC has to meet separation standards that are enforced (often by automation 'snitch'ing to supervisors) Unless the flight crew states this is an urgent request to avoid weather, then the request will be treated as routine, so you will need to standby while the controller coordinates the level change with other sectors and the next air traffic unit. As I have said before 'communicate' in time can reduce pressure on 'aviate' later. If concerned take the weather avoidance then tell ATC what you are doing. Ideally do it into a space in the TCAS traffic picture :ok:. You have to balance the risk of the weather against the risk of loss of separation.

I've had the opportunity to investigate a military accident (dive into water @550 knots 50 degrees ND, and to see the wreckage first hand of a 250 knot fly into the water in (near) level flight. In addition, I had the opportunity to participate in almost the entire AF447 thread. QZ8501 was not a dive into the water. A high speed dive would shatter the aircraft into its component bits & pieces with the leading component pieces more highly fractured than the trailing components (due to deceleration).

From the damage observed so far, the aircraft entered the water at very low forward speed in a near level, slightly left wing down attitude. The major velocity component was downward. By comparing the damage observed with AF447 and with some of the events of the Perpignan A320 accident, there is one glaring difference. The vertical stabilizer remained attached to the fuselage structure until the tail was crushed from beneath. Instead, the skin forward of the VS shows a small section of fore and aft force induced compressive wrinkling in addition to the vertical compressive force induced folding along the stringers lower down. Below that, the structure was shattered and is missing with damage extending further up the port side than the starboard side.

In other words, it hit the water slightly left wing down, with minimal horizontal velocity, in a flat attitude with relatively high vertical velocity. I'm open to differing opinions, but there is only one way I know of to put an aircraft into the water in this way, and that is a flat spin (as differentiated from a nose down spin).

Transport aircraft are not intentionally deeply stalled during flight testing nor are they spin tested let alone training pilots how to recover from a full stall or a spin. For this reason, if a spin is entered at altitude, it is likely to continue. Often flat spins in jets are not recoverable events and are dependent on the specific aircraft characteristics (mass distribution-types of control surfaces, general planform etc.)

I know some of you fly aerobatics including spins however, flat spins in larger aircraft have an additional hazard in that the crew is located far from the center of rotation, and thus even a modest rate of rotation in a spin creates disabling eyeballs out g effects. For example, in the F-14 front seat, you had to lock your shoulder harness at the beginning of the event or you would be folded over in your seat and unable to eject. I don't think A320 pilots would be particularly effective in recovering from a spin if they found themselves involuntarily staring at their kneecaps:uhoh:.

Assuming that the foregoing analysis is in the ball park, it will be very interesting to learn how this departure from controlled flight developed.

@Machinbird: Your comments on flat spin are interesting, and it is possible to put some figures on the g load that a pilot would encounter using some basic physics. The acceleration during circular motion is 4 Pi squared times the radius for the motion times the square of the number of rotations per second. If the pilots are about 15 metres from the centre of rotation during a flat spin, and the aircraft was rotating about a vertical axis taking 3 seconds per rotation which is not unrealistic in this scenario then this gives a radial acceleration which after normalising to 10 m/s/s for 1G, leads to a g load in a direction facing the front of the aircraft (eyeballs out as you said), of over 6G. Any faster rotation than 3 seconds per turn would give even higher g loads which would likely render the pilot unable to react to the controls as you have detailed in your post. This calculation confirms your analysis if the aircraft did end up in a flat spin, despite this being a significant departure from the normal flight envelope. Nevertheless the FDR data should ultimately provide evidence as to whether the aircraft did end up in a spin following the event sequence at the time of loss of contact.

With a few minutes to spare after an LPC, the instructor demonstrated how easy it was to spin an a320. The spin was totally classic albeit with an astonomic RoD. Recovery was similarly straighforward. I think the loss of altitude was about 6000'.
I am in no way suggesting that in real life things would be so simple, but it was an interesting and reassuring experience.

For those drawn to the fake CVR recording on Youtube that has been linked to at least once, please don't think it's genuine - it's very clearly not from an A320, and is probably a recording from a different incident.


There is no audible Bank Angle warning in an A320 afaik.

Of course that was without the out-of-spin g forces which may have made things a little more interesting. :eek:

As has been pointed out, there has been no spin testing of A320s (!) to provide data on which to base a simulation. The reason the simulation behaved in a "totally classic" manner will have been precisely because that was how it was programmed to behave, similarly the recovery. Any reassurance you gained was based on an educated guess, at best!