I stand to be corrected, EEngr, but I think you're referring to the ‘enhanced airborne flight recorder’ (EAFR). As I noted in the 787 thread (#2161, 3 Dec), according to the NTSB report on the Boston battery fire, the 787 is the only aircraft so far thatAs it happens, the 787 EAFR seems to be problematic, but that's for another thread.

The upshot is that I'm assuming we're talking separate FDR and CVR in PK-AXC.

This appears to be where the search is currently at:-

http://i59.tinypic.com/xmiu8k.jpg

Any chance you could authenticate those height, heading etc readings or do we just dismiss them?

sopwithnz
Not true, but this is not the place to discuss it.

Just wondering how many more AoA probes have been pressure washed since that 888 accident...

Did anyone check out the highres picture I linked to here: http://www.pprune.org/rumours-news/5...ml#post8814964 ?

To the right in that picture, looks like it took a hit by a small round thing? OR am I just imagining things? Anyways, it could have happened when the part hit the water!

Just thought about this when I read the post by VR-HFX here http://www.pprune.org/rumours-news/5...ml#post8817418 .

I agree they didn't have a lot of time to react but this statement is not strictly true. As an aircrafter tester, the captain should've been aware of how to react in case the aircraft was not responding correctly. He was, after all, well used to pushing the A320 to it's limits (under Normal Law).

Replying to the post saying "An updraft will not in itself reduce airspeed. Updrafts add energy, not reduce it. The first reaction by the autopilot (or PF) would be to try to maintain altitude by putting forward pressure on the stick. This will in effect increase the speed because of the updraft wind vector":

There is something simple that can be calculated for the angle of attack instantaneous change due to hitting a sudden upcurrent such as in an active Cb. If the current airspeed is say 500kt and the aircraft is flying horizontally, then if a 50kt updraft is suddenly encountered then there will be an instantaneous change of AoA by an angle equal to arctan(50/500) which is about 5.7 degrees. It the aircraft was flying within a couple of degrees of the stalling angle of attack and encounters a transient strong upcurrent then there is a good chance of reaching the stalling AoA very rapidly. What the aircraft control response to that is will depend on how the fly-by-wire system has been coded to react, or how the pilot will respond if he/she recognises what has happened is not clear despite the various postulated scenarios already discussed. Equally there will be a reverse change to the AoA on exit from the same updraft so the net result will depend on how long the aircraft flies within updraft conditions and the velocity of the air within it. Is that not basic physics?

The Straits Times reports:
 

JAKARTA - Indonesia has suspended 61 flights from five airlines who have been found to have no valid permits to fly from the country, its transport minister Ignasius Jonan said on Friday.

The decision to review flight permits comes in the wake of the tragedy involving AirAsia flight QZ8501 which crashed into the sea while on its way from Surabaya to Singapore.

AirAsia was later found in violation of running the flight on a Sunday without valid permit from Indonesia.

Mr Jonan also said that the ministry has suspended 11 officials for negligence and have audited 5 airports in the country since the ill-fated crash.

How hard would it to be to have a basic AOA indicator installed in every commercial jet ? Then a basic training package to be included in every endorsement that trains to react in a situation when all hell brakes lose ? Consider it a last resort recall ? They seem to be taking care of passengers with new lounges , upgraded on board entertainment and meals , but in the end passengers may go without if they knew money went to a instrument that could make a difference ? Just a thought .

In modern systems the controller sees a 'track plot' that is made up from multiple surveillance inputs. Way back in the thread it was reported that secondary radar responses were lost first followed by ADS-B responses later. So the system was receiving both.

The speed displayed can be:
* Generated by the ATC system from the distance between successive track positions and the time. Most systems smooth this by taking the distance between for example the latest report and the one 5 reports ago. This is normal with SSR
* Replicated from the ground speed field of the ADS-B report
* Multi-Sensor Comparison with the speed from one source used but validated/corrected by the other source(s)

What will not happen is that the speed will be invented.

The problem with a snapshot is that you do not know the history of the ground speed displayed. Even if the previous update was 450 followed by 353 then that may not be a significant slow down, it may be an effect of going outside the bounds of the smoothing Kalman filter. What is needed is the raw SSR and ADS-B data received (and required to be retained for 28 days by ICAO). What you may be seeing is a replay of the time the incident involved using standard replay tools that are used for local investigations and training it may even be a replay of the data sent to the controller's display rather than reprocessing the input data.

I would not impugn the ATC by claiming they were producing made up 'eye candy'.

Sea State and Pings at Tail Crash site.....


BBC News - AirAsia QZ8501: 'Pings' detected in plane search

Mr Snuggles - thank you for posting link to hi-res pics. From the apparent concave folding of the skin, the pressure hull was probably intact on entering the water (otherwise the water pressure would equalise inside and out). The hull probably broke on contact with the sea floor or perhaps on the way down (if the water was stratified, on encountering layers of different density)?

Triskel
[QUOTE]Mr Snuggles - thank you for posting link to hi-res pics. From the apparent concave folding of the skin, the pressure hull was probably intact on entering the water (otherwise the water pressure would equalise inside and out). The hull probably broke on contact with the sea floor or perhaps on the way down (if the water was stratified, on encountering layers of different density)?/QUOTE]

As we saw in the AF incident and other cases where an intact plane contacts the sea at high vertical speed, the water is about as friendly as concrete. This causes conciderable damage.
I would have thought the main damage would be done on impact with the sea surface and secondary damage as the wreckage was moved by the currents. I doubt there is sufficient depth for density layers to be a factor.
Even the Hudson ditching caused considerable damage with for example a support from the cargo hold being punched up into the cabin injuring a flight attendant.
I would however concur with you opinion that the aircraft wss relatively intact at impact.

Relatively intact at impact is not the impression that these images transmit.
The tail structure is torn off and the various hull pieces are widely separated, in water shallower than the airplane was long. To me that suggests the airplane may have come apart even before it hit the water.

How likely is it for the FDR to have detached from the airframe if the a/c reached the surface intact?

We discussed this at some length during the marathon AF 447 threads. Some professional pilots do not see it as the answer ... the link is to a discussion in PPRuNe Tech Log.

You clearly identified what has to go with an AoA gage in the cockpit: training. When and where it is an aid, and normally an additional scan item, is the key enabler to another instrument being of use in the odd occasions where it would be useful.

The paper linked in that post tells why IFALPA isn't so supportive of it as a solution.
Further that point, and as noted some posts ago: would it have been of use in this incident if the flight deck crew went into a fairly rapid task overload? FDR analysis will clarify, but a small wager is made at this point that the answer is no, not in this case.

Triskel:

Did you look at the right on the highres, just above the hyphen? (It needs to be the picture with the A upside down.) To me it looks like something round hit the airplane - or I need to adjust my medication... *joke* Maybe, just maybe they hit hail of some kind...? Absolutely not explanation in and of itself but might give a hint, possibly?

ANZ Perpignan
 

The crash was caused by pilot error - plain and simple.
The pilot was not a qualified test pilot.
Airbus specify that the AOA functional test MUST be carried out above 10000 ft AGL because if the test fails a lot of altitude will be lost in recovery.
He carried out the test at low level with predictable results.

Gents, best pull in your horns. This aircraft impacted with significantly less velocity than did AF447. Granted that it is a smaller aircraft and thus a bit harder to tear up into little bits, but the degree of deformation and disassembly was much higher in AF447.

This aircraft hit with very low forward velocity, from all appearances. Perhaps a spin or flat spin. Kinetic Energy goes as the square of the velocity. A spinning aircraft should have lower kinetic energy than a deeply stalled one at terminal velocity.

My physics is rusty, but isn't velocity a product of speed plus direction? A spinning aircraft may not have forward speed, but it does have plenty of changing direction, therefore plenty of velocity. So it will hit the ocean with plenty of energy, I assume?

I would think that any breakup could have occurred on impact. The fuselage if the concertina effect is correct would have been crushed from beneath and the hold and passenger cabin filled with water and possibly with engines/wings detached could have sunk fairly rapidly but all the parts would be carried and rolled along by the 4 to 5 knot currents until they embedded sufficiently in the seabed mud in a position that the current no longer moved them that could take from minutes to hours. So parts being miles apart would not be at all surprising. If the entire tail empennage complete with pressure bulkhead was one of the pieces after hitting the sea surface it may well have floated in severe winds for hours or even a day or so. This would drift the tail in a totally different direction to the rest of the aircraft and it could easily be several miles in a random direction before eventually sinking.

Tracking the pieces using winds and currents is possible but all sorts of assumptions have to be made on how long each would float what the sea state, currents and winds were at the time how long to get stuck in the mud etc. The calculation would probably depend more on the assumptions than any data.

Do you arrive at that provisional conclusion based on the condition of the bits so far found, on the track info available, or both?
If true, then should not most of the major parts of the wreckage be near to each other?
EDIT: deleted. Ian W explained how it might come about that way.
Note: I will guess that Airbus did not do spin tests on the A320 family. Maybe computer modeling is sufficient to make an informed estimate of what it will do in such a condition. Absent that info (which some people may have seen, but I have not) how an A320 spins is a bit of a guess.
@thecrozier: The latter, except with slowly changing heading.

FWIW too close a comparisons to AF 447 seems to me premature.

@thcrozier

I recall that it made a slow, smooth turn. No spinning.

re tail detach
 

" susiser said '
IF the aircraft was in a nose up- pitch up attitude when it hit the water, IMO the tail section AFT of the pressure bulkhead would hit first and likely to be torn off- thes has to do with the manufacturing joint/join in this area.

and the FDR/CVR might still be with the fusealege section, or totally separated from both. Add in wind and current and a logical area to look would be between the fuselage and tail debris locations.

I'm sure the experts and pros with details of the exact mounting have done a thourough search - but hampered by waves and weather. I have not yet heard of finding for sure the major fuselage section.

Just have to wait and see . . .:(

AirScotia: Linear velocity has a speed and direction component, but they aren't involved in a product that says something about the energy of the system. That would be speed and mass.

Rotational velocity - the rate at which a body is spinning about an axis through its center of gravity - also needs a mass component and its distance from the spin axis to form "angular momentum", which would indicate how badly impacting a fixed object (e.g. the water surface) would damage the rotating body. The accident-investigation experts can pontificate re any signs that occurred here.

I would suspect that a lot of the direction and loading of the impact is already known by the doctors doing the, albeit brief, autopsy checks on the bodies.

I am certain we will be told when it is thought best to tell us.

Quote:
Originally Posted by Machinbird http://www.pprune.org/images/buttons/viewpost.gif
Gents, best pull in your horns. This aircraft impacted with significantly less velocity than did AF447.

Primarily from some of the relatively undamaged seat structure and by the lesser accordion action visible on the structure.

Ian W sayeth, Not asking argumentatively, and notwithstanding TV shows such as "CIS," would these doctors have any qualifications for judging such things?

Just some physics facts about definitions. Terminal velocity is often loosely used to refer to the speed when the force of gravity balances the drag in the opposite direction in freefall. So strictly terminal velocity is a vector in the direction that gravity is pulling, where the magnitude of that vector is the terminal speed that gives a drag force equal numerically to the downward force due to mass of the object being considered.

If you want to consider energy then you can take the linear kinetic energy (mass times the square of the speed) as a major component, but if there is rotation then there is rotational kinetic energy equal to the moment of inertia of the system times the square of the magnitude of the angular velocity. Clearly the rotation of the entire airframe would contribute but also rotation of say, spinning turbines at high speed could also be a component. Rotation axes in different directions could lead to transfer of rotational energy between different modes. Apart from these contributions to total kinetic energy there is also some energy in vibration of massive components as well but likely to be numerically less significant. Of course there is stored energy in unburned fuel that can be released as well.

The various elements of kinetic as well as potential energy can then be dissipated into destructive rupture, distortion and other failure modes on impact (as well as a small amount to heat and sound). This is a physics perspective as a general consideration applying to any accident in the air.

Daily Mail reports:
 

A director from the Indonesian search-and rescue agency said readings detected on Friday suggest the black box may be outside the tail section of the plane. It comes as footage has emerged showing Indonesian military divers investigating the submerged tail of doomed AirAsia flight 8501, as search and rescue teams are hopeful that the black box from the plane's wreckage has been located. Having located the tail of the plane on Thursday, search teams began pressing ahead with their efforts to find the black box and retrieve bodies from the wreckage, and on Friday afternoon reported detecting 'pings' from the flight data recorder.

But Suyadi Bambang Supriyadi, director of operations of Indonesia's search-and-rescue agency, said pings detected about 1km southwest of the wreckage suggest the black box may be located elsewhere, reports Business Spectator. Inside the wreckage: Divers search for AirAsia black box. The underwater searches ended before dusk on Friday, after divers were unable to find the black box Lifting balloons were loaded onto helicopters in preparation of recovery efforts to lift the tail out of the Java Sea, despite worries that the black box may have been separated from the tail during the crash.

Navy ships USS Sampson and USS Fort Worth have deployed helicopters and sonar devices into the Java Sea to aid the recovery operation off the coast of the Indonesian island of Borneo. Only 43 bodies have been retrieved so far, as monsoon rains and winds have caused choppy sea conditions and blinding silt from river run-off, reducing visibility underwater and preventing the removal of large pieces of the wreckage. Many of the other passengers are believed to be inside the wreckage of the plane's main cabin, which has not been located, due to strong currents moving debris around. At two weeks, most corpses will sink, said Anton Castilani, head of Indonesia's disaster identification victim unit, and there are already signs of serious decomposition.

'Divers have reached the tail part but ... the visibility was below one metre so they only managed to retrieve various debris,' said Bambang Soelistyo, chief of Indonesia's search and rescue agency. 'Now we are waiting for the speed of the current to ease. If it gets calmer later, they will go back to do another dive to determine whether the black boxes remained in the tail or were detached,' Mr Soelistyo said on Thursday. Divers travelled by rubber boat from the KRI Banda Aceh warship that was being stationed close to the site of tail wreckage, which Mr Soelistyo said would be lifted off the seabed by retrieval experts on Friday if weather permitted.

Lieutenant. Edy Tirtayasa, commander of Indonesia's navy rescue team, told Channel News Asia they planned to send two contingents to the plane. 'We are going to send down one observation team to take photos. Then two teams will do the recovery process -- to recover bodies if there are any,' he said.
[/B'If not, they will recover the black box for investigation and then other debris from the aircraft, he said.

[B]Coordinating Minister for Maritime Affairs Indroyono Soesilo told reporters the black box would be analysed by experts in Indonesia when it was located.
It will provide essential information about the plane along with final conversations between the captain and co-pilot, despite the Indonesian meteorological agency indicating that weather was the 'triggering factor' of the crash, with ice likely damaging the engines of the Airbus A320-200. Five other big objects have been found on the floor of the ocean, though no visual confirmation has been obtained yet. Smaller pieces of the plane, such as seats and an emergency door, have been collected from the surface.

Is there a reason the hours of darkness are not used to search for the pingers?
It should be less noisy than during daytime and the lack of visibility is not a concern.

For every guy in the water, there are several more topside who need decent visibility to properly support them.

The pieces of the puzzle thus far are:

Convective wx.
Sudden loss of comms.
A number of bodies recovered, of which one of the first two was a flight attendant (possibly rear seat occupant)
Wide dispersed wreckage, of which empennage comprises a large section.
Short rapid climb preceeding loss of comms and ATC SSR/primary radar ident.

Displays hall marks of let`s get out of Dodge fast, in heavy clag and leaving the tail behind. The question is how do you make an A320 go ballistic.

On take off, JATO booster rockets might be of help. :E (Meant as a joke. A320 airworthiness cert probably does not include JATO takeoffs.)

On high, the FDR when found may provide a few clues if that was what happened.

Do we have any indication of the actual duration of the steep climb?
3 seconds vs 30 for example, quite a different kettle of fish.

For every guy in the water, there are several more topside who need decent visibility to properly support them.


Absolutely, so the divers and support people should all be getting rest.
I'm thinking of having some of the ships that drag acoustic arrays work at night, they should be able to triangulate the pingers pretty well, if they are still running.

I haven't read all this thread, but has anyone suggested a jet coming out of a CB's?

Red Sprites and Blue Jets

Afaik, lightening of whatever type is not a significant threat to airplanes. The bolts travel through the outside of the metal body and the charge is leaked off through trailing wicks.


A terrorist device would be a much more likely explanation, imho.

Toruk Macto Airbus has AOA protections so having a dedicated AOA instrument is deemed less important by some people. This is a much argued controversy.
The stall warning is the most basic AOA indicator which is carefully designed to help prioritize attention. This topic was argued in depth on the AF447 thread.

BEA Report extract: