That paint scrape looks more like a kink line where the paint popped off. You see that in buckled skin after impact deformation.

I agree with Sir Richard thats seaweed not scrapes..

http://www.3ch.co.uk/grow-wiki/wp-co...pg-194x300.jpg

@Australopithecus
 

you are 100% correct, paint went off due mechanical force (xtreme bending)...seaweeds?? at 30 mtrs or so??

ADS-B data carries the time at which the aircraft generated that GPS position. So it does not matter when that was received as each ADS-B report is perfectly valid. This is to ensure that delays in transmission do not cause the errors you describe.

The problem the receiving system has is that these reports do not come in with the same delay each time, especially if the receiving system is using several remote antennae or even several different receiving stations. This can result in position reports coming in at random intervals and in extreme cases out of order. This is why it is important to use the original data from the aircraft which will carry the timestamp of the GPS position. It is not clear that FR24 and other services do this.

If you click onto the posted link and not look at the posted pictures, its a lot clearer to see that its missing paint.


http://www.news.com.au/travel/travel...-1227177443383

RNP and all trajectory based systems are based on ground speed. The calculations from ADS-B position report time of generation (in each ADS-B position report) can be used to create ground speed. If you want airspeed that is also within the body of the ADS-B report.

Problem is FR24 does not give access to the actual ADS-B reports.

Flightradar24 data is from plane
 

The data provided by Flightradar24 here is the actual ADS-B data sent by the plane

https://twitter.com/flightradar24/st...69337023840256

The timestamps are from the aircraft. It does not matter how long it took to be received, or by whom, or in what order.

Secondary radar is not normally attenuated by rain but primary radar is always attenuated by rain. The shorter the wavelength the more attenuation. An ATC radar of the order of 10cm can be close on completely useless in heavy rain despite technical mitigations.

There is some interesting data in the report at http://www.bea.aero/en/enquetes/flig...nal.report.pdf where on pages 12 and 13 it would seem that locating and recovering the CVR and FDR within a few days is the exception rather than the norm. So recovery of these items for the current accident flight in the next few days would be within the normal time range.

ADS-B from the SSR Transponder is not time stamped by the aircraft. The receiving station adds the time stamp. There is a mechanism for allowing the receiving station to compensate for various latencies in the aircraft system (known as the T-bit). However this is seldom implemented in current installations. Consequently velocity calculations from the ADS-B position reports alone should not be considered reliable. HOWEVER ADS-B does transmit the aircraft's own calculated velocity (usually ground speed) at the same rate that it transmits position (twice per second). This velocity should be considered perfectly reliable but I am not sure if Flight Radar carries the velocity component.

Hopefully the data recorders are preserved in the tail.

Can anyone advise the origin of the altitude recorded on the FDR. Pressure only? Or GPS also?

Maybe I am missing something, but it all seems a bit unsatisfactory. We measure a pressure using ports that are subject to problems such as icing. We then take this pressure and derive a flight level based on 1013. However if ambient temp or pressure was to change as you enter a cell (and the chaotic winds within a cell are due to pressure differentials), this would distort any change in FL that was being measured.

I never quite understood this when we got the data for AF447. Obviously there were significant altitude excursions during the upset. But to what extent were there measured excursions corrupted by sudden pressure (or temp) changes.I recall AF447 pilots noted a dramatic increase in OAT shortly before it all went wrong.

Furthermore, could a perceived change in FL cause the automatics to respond so as to correct this, and could this compound the problems due to pitot tube freezing and loss of valid airspeed.

There seem to be a lot of links in the chain between what we measure and what we derive from it.

ADS-B messages, for reasons I have never understood, do not carry a timestamp, nor any other unique identifier apart from the sender airframe hex code.

FR24, openatc, or any other ADS-B receiving network therefore does not possess any reliable way to discount duplicated messages received from their remote feeders.

If what they've found is upside down, does this mean that the main part of the fin has knifed itself into the mud? Could this make it even harder to retrieve?

Can anyone identify which parts we're looking at in the photo of what looks to be internal workings of the tail?

Timing of ADS-B messages
 

Physicus

Yes, you are correct and I was wrong. ADS-B messages do not have to contain timestamps and mostly do not. However, it is possible to include them along with any other extra pieces of information in optional parts of broadcasts.

The timestamps are added by the (very accurately timed) receiving stations for FR24 usually.

However, for the purposes of the last minute of the (recorded) broadcasts from QR8051, there are no repeat positions (except for the last two which we are ignoring). Thus it is safe to assume that there is just one ground station responsible for the timestamps.

Given the speed of light (meaning that time received is less than one millisecond from time broadcast), we can use the timestamps given as being perfectly accurate, even down to the millisecond. That is as far as calculating positions is concerned.

@AirScotia "Can anyone identify which parts we're looking at in the photo of what looks to be internal workings of the tail?"

Does this image help: http://www.flightglobal.com/airspace...il-cutaway.jpg

'Black box must be read in Indonesia,' says Minister for Maritime Affairs.

QZ8501: Blackbox Must Be Read In Indonesia, Says Minister

Does Indonesia have the technical resources to deal with the FDR/ CVR? I assumed they'd send them to Australia.

That statement makes me feel uneasy...

Gen question - What band radar / freq / prf are onboard weather radars using?
Can they be switched from hi to lo gain for eg?

Here is another link to a larger sized photo: http://media1.s-nbcnews.com/i/newscm...7106c6972c.JPG

http://i2.photobucket.com/albums/y17...to15/tail2.jpg

Channel News Asia live blog reporting that authorities say tail section identified is 10 metres in length and relatively intact. They are therefore hopeful of the possibility of recovering "black box". Earlier "a signal" had been detected from tail section but could not be re detected later.

SAR efforts continuing as of 2043 (GMT + 7).

Air Scotia

For what it's worth, Channel News Asia also stated that "authorities" believe that the aircraft hit the water in a left hand roll, and the tail section identified (which represents a reasonable percentage of the hull length) does appear to be upside down. There is a good deal of mud so possible parts are submerged.

I have no SAR expertise however so others may comment.

You are being a little pedantic :) To save space as they are trying to crunch a lot of information into a very small space, a 'time of applicability' is sent that refers to even and odd numbered periods (called epochs) of 0.2secs within a longer time frame. This encoding of the UTC time allows the ground station to recreate the 'time of applicability' of the geographic (surface) position data - the latitude and longitude. This is possibly not a worthwhile exercise for FR24 and others but the information is there in the ADS-B message. (See RTCA DO-260B Appendix A A.1.4.2.3.1)

The Strait Times reports:
 

SURABAYA - AirAsia will offer compensation of about US$100,000 (S$133,000) for each passenger of the ill-fated Flight QZ8501, in addition to the initial payment of US$24,000 that was offered earlier to family members, CNN has reported.

Earlier, The Wall Street Journal reported that the airline was conferring with families individually on the initial compensation, meant to help them with their immediate financial hardship.

The Indonesia AirAsia flight went down in bad weather in the Java Sea with 162 people on board, including 155 passengers. No survivors have been found so far.

Some families had declined the initial offer without further information about compensation, citing confusion over the wording of the letter and reservations about the airline's practice of approaching families individually, the Wall Street Journal report said.

Quote: @AirScotia "Can anyone identify which parts we're looking at in the photo of what looks to be internal workings of the tail?"

As former A-320 rated maintenance engineer (few years experience on the type) and seasoned scuba diver maybe I can help:

The photo of registration marks shows bent metal skin, that shed (I assume thick layer of) paint along the bend, exposing primer coating. The fact it looks like upside down is, by my opinion, irrelevant as we do not know the orientation of camera-could be very difficult to take if reported currents are truly in the area of 4-5 kts. Movement of water is witnessed by short lines on photo, created by fast moving particles, suspended in the water.

The photo of red painted part with letters Ai... (Air Asia) shows probably left side of vertical stabiliser. (entire stabiliser is of composite structure)

The photo of inside : It seems it was taken inside the tail end and considering that light comes from the top of photo, I believe camera was held reasonably level. Therefore, this part of tail section probably rests leaning on vertical stabiliser with its right side on the bottom. Right half of horizontal stabiliser pushed into the mud or is (partially) broken away-fuselage rests half inverted to the right side-approx. 130 deg. from normal. Interior shows (deleted) parts of THS mechanism structure, that moves-trims horizontal stabiliser via jackscrew. (deleted). Am surprised that CVR / DFDR were not found, as they are installed very close to position, from where the photo was taken. I assume that part of the fuselage is not in the same piece with the structure photographed or is buried in mud.

Later comment: rewiving larger photos I had to edit (delete some parts) of my above post - what I thought was part of stabiliser and jackscrew, actually it is not-therefore nothing can be said about THS position (ANU/AND) and location from this photo, as it shows fuselage structure-frame with part of THS mechanism (drive motor, that is installed on top of structure and is partially visible on the photo and probably some part of THS in the background. Amount of light suggests that THS is not in reasonably one piece.
Am trying to add photos of that area, taken inside of an A-320.
Considering the damage and the fact that CVR DFDR are installed on a rack, fitted to the RH side of fuselage behind pressure bulkead, it seems that part is torn off, so black boxes are probably not attached to photographed structure.

Well no it wasn't. It was a phone call with my cousin who has spent the last 25+ years on/off ships deploying and repairing electronic equipment on certain vessels that "have certain capabilities to do very specific jobs" as he puts it.

His ship is in SEA now and is on standby to help with this search.

AirAsia Airlines press release Jan7, 2015
 

AirAsia Indonesia Flight QZ8501 UPDATE (as of 7th January 2015 8:00 PM (GMT+7)
SURABAYA, 7 JANUARY 2015 – The National Search and Rescue Agency (BASARNAS) Republic of Indonesia today confirmed that the SAR team retrieved a visual confirmation of the tail part of QZ 8501’s aircraft. The visual confirmation was made following underwater documentation of the aircraft’s tail and small wreckage, which showed the plane’s registration number (PK-AXC), captured by the SAR team’s sea divers.

The tail part was found in the additional focus search area (approx. 30 kms from the primary focus area). The SAR operation is still underway as the weather is reported to be clear with good underwater visibility for the divers to continue observation.

Sunu Widyatmoko, Chief Executive Officer AirAsia Indonesia commented, “We would like to extend our appreciation to all authorities and personnel that has been involved in the SAR operation. Today is the eleventh day and the latest finding is indeed an breakthrough for all of us who have been anxiously waiting for further development on the SAR operation.” Following the latest finding, BASARNAS confirmed that the later SAR operation will be focused in this area to see if there are any trapped remains that must be recovered as well as the continued search for the black box.

Earlier today, Indonesian Navy Commander of the KRI Bung Tomo-357, Lieutenant Colonel Ashari Alamsyah officially handed over the debris and passengers belongings of QZ 8501’s flight that were found in the search area to the Deputy Commander of Indonesian Naval Aviation Unit, Colonel Yuwono at SAR Operation center in Juanda International Airport. As for the next phase, debris will be transferred to Indonesia’s National Transportation Safety Committee (KNKT) for further investigation.

This morning, BASARNAS also confirmed to have recovered one more remain from the search area. The remain is still in Pangkalan Bun, waiting to be transported to Surabaya for further identification process. Meanwhile, the Disaster Victim Identification Police Department Republic of Indonesia (DVI POLRI) today announced that they have identified 8 more remains of QZ 8501 passengers as: Ratri Sri Andriani (female),Rudy Soetjipto (male), Jou Christine Yuanita (female), Soetikno Sia (male), Ruth Natalia Made Puspita Sari (female), Nico Giovani (male), Indahju Liangsih (female), Stephanie Yulianto (female). AirAsia Indonesia officially handed over the remains to the respective families at Bhayangkara Hospital, Surabaya this afternoon.

To date, BASARNAS confirmed to have recovered a total of 40 remains of which 24 remains have been identified by DVI POLRI and 16 remains are still being identified.

AirAsia would like to take this opportunity to urge the public seeking progress on the search and evacuation and identification process of QZ 8501 passengers to refer solely to official information from BASARNAS and DVI POLRI.

Our thoughts and prayers remain with the families and friends of our passengers and colleagues on board QZ 8501.

Ian W

Modern phased array radars such as the types used by the Indonesian military are not significantly affected by weather. But you are right I should have said: "I don't believe it possible for even heavy rain to attenuate the return from either passive or primary radar to a significant degree."

Ministry of Defense Will Add Air Force Radar

There is a major difference in this wreckage and that from AF447 and the Perpignan A-320 accidents. The vertical stabilizer was not thrown forward by the impact! This implies that forward speed is much less than those two accidents. Low forward speed is a characteristic of spin in accidents. Rotation is another characteristic of spin in accidents-not enough information yet to make a determination on that point.

If the horizontal stabiliser is indeed run into the full nose up trim range I think I will have some bad things to say about the flight control laws.

We will find out soon.

QZ8501
 

I think a large number of folk will share this view.

"If the horizontal stabiliser is indeed run into the full nose up trim range I think I will have some bad things to say about the flight control laws."

So the 7700 Airbus fbw planes must be falling like coconuts.

I'm sure the NTSC has invested in the technical resources required to analyse the black boxes in Indonesia considering the number of accidents the country has had in recent time.

Debris photos
 

Thanks hoistop. Ref
http://www.pprune.org/rumours-news/5...ml#post8814500
I can't dispute your credentials but do admit confusion over dissimilarity between debris pic and purported A320 THS horiz jackscrew at:
https://www.flickr.com/photos/8353822@N02/2108746312/
I can find no others.
Orientation of latter pic apparently is looking upward with light entering via window at lower right.
I'm also uncertain of debris orientation vis your explanation of 130 deg counter clockwise from normal meaning “up” is on left side of pic.

Registration numbers of “EAX” or “FAX” on metal skin (rivets, adjacent panels parted at end), dark characters on white background located on fuselage sides fwd of rear pax door and below windows.
Indonesia AirAsia Airbus A320-200 » Juergen's paint hangar

All three pics at:
AirAsia Flight QZ8501 plane tail confirmed found
suggest tail is separated from main fuselage through or aft of rear pax door, ie at rear pressurization bulkhead which is close to the “Ai” vertical fin script in pic 3.

The apparent rapid descent of QZ8501 raises the question of pressurization effects at impact. I understand there are overpressurization vents; question is their flow capacity and what if any overpressure would remain after a 4 minute descent from FL29, and what additional effects that would have on how the aft airframe might come apart at impact.

I also note BG47's mention a couple posts down that the tail is 30km from what is still the primary search area...and recall that transponder and other data disappeared closer in time to the last pilot transmission than the probable time it would take the AC to descend from FL29, which unfortunately does not decrease the probability of inflight airframe failure.

Other comments regarding fwd component separation of the Vfin a la AF447 of course depend on relative fwd speeds, 447 being faster than AA debris so far suggests. Both may have been fully stalled but AA more horizontal, if intact.

Hoping for observations from others familiar with A320 stabilizer/bulkhead structure.

Ok, I'll stick my neck out.
Wing failure in extreme turbulence caused the large paint removal scrapes just before it took the tail section off.

No matter how fast you descend, there will never be positive pressure at impact, if anything, you would run into negative pressure relief issues.

Here is an imagine that shows how screw jack assembly looks like:
https://www.flickr.com/photos/8353822@N02/2147258443/
For NU the nut goes to the right side of picture

Not "EAX" or "FAX", the character preceding the "A" is a hyphen: (PK)-AX(C).

LapSap

Good try but the letters are very small in comparison to the wing, so the damage is not consistent with a hit from a very large object. Maybe a passing aileron might have made a dent, but that's as far as I would speculate. SPECULATE, please, I am in no position to make definitive statements here...

A picture of the airplane in question, to put things in perspective. Sorry, this was the largest image I found that wouldn't distort the forum layout.

And yes, the registration number is PK-AXC.

http://berita.suaramerdeka.com/konte...AXC-Andika.jpg

If the screw jack is wound all the way to the slow end of its travel, it reminds me of an accident to a light aircraft with a female pilot.
She had engaged the auto-pilot in altitude hold just before take-off. The AP had wound the trim fully UP before she accelerated for take-off, and the AAIB concluded that she would have been incapable of pushing on the stick with sufficient force to avert the disaster that occurred.
They concluded that the force required would have been over 50 pounds, meaning that she would not have been able to take one hand off the column to re-trim the aircraft, and so avoid the stall.

Fuselage "scrape", stab bulkhead, FDR
 

Thanks for the clarifications on registration characters.

I don't seen any clear indication that a dent or scrape occurred. There are no visible longitudinal waves in the metal as in the case of a scrape over length, and a dent requires a striking object which adds another level of conjecture. If anything the upper (in the pic) 'scrape' ridge appears outward from the interior, and the lower appears inward ie an accordion combination. Loss of paint can also be overextension in one direction or sequential bending in opposite directions (because the panel as photographed is close to original curved/planar shape. The axis of the paint loss could also be consistent with a flat landing of high vertical velocity.

Correction: FDR located aft of the pressurization bulkhead and though close in distance to the diver/photographer, not visible by diver. Absence of pings is odd unless no detectors had not yet been in place.. Mud doesn't appear to be a problem.

How tall are the registration characters in real life? They look to be roughly the same height/width as the pax windows, so possibly 60cm x 40cm?