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).