BREAKING NEWS: airliner missing within Egyptian FIR
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1) It is foolish to rely on FR24, the sytem works by collecting data over the internet from amatuer ADSB receivers owned by enthusiasts and joining the dots. There are plenty of these stations in well populated areas but the chances of any reliable receiver data in the middle of an enormous desert are a tad slim. In these circumstances FR24 extrapolates (guesses) by extending the last known trajectory until it recieves a valid report or times out.
That's particularly apparent in this instance, where the published data comes from 3 separate receivers, presumably in 3 different locations (see column 13 in the CSV file). Those clearly aren't time-synchronised, which is why we see wild variations of parameter values within the same second.
In other words, trying to construct a time-series with the data is fraught with problems. I'm very disappointed that ASN appears to have fallen into that trap with their dodgy graph.
The data just looks weird. How do you want to get from -7000fpm to +8000fpm at a GS of between 132 and 93kts (means roughly between 60 and 85kts IAS) ?
The data does not seem plausible at all.
Horizontal deceleration is also excessively high. From 400kts to 60kts in 22s.
Especially the initial deceleration from 400 to 340kts in just about two seconds without a clear trend in altitude change does not make much sense. At FL300 this is pretty surely still far above the stall (bar insane tailwind which I wouldn't expect in that area and flight direction).
From my armchair I have difficulties to fathom a force that would decelerate an airliner at that rate while matching the presented data.
Looking at this altogether I would consider the data spurious for whatever reason and don't think any conclusion can be really drawn from it.
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Its now reported that the Egyption Aviation Minister has said that the crew did not report any technical issues despite earlier reports and nor did he request help or declare an emergency.
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For what its worth , data from the Planeplotter network shows slightly different information than the web based plotters , however in situations such as this we never publish it , but always secure the data and submit it directly to the AAIB to pass on to the relevant country's investigators.
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PP support , formerly uksatcomuk
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henra;
Agreed.
I would be examining the pressure bulkhead, first.
Looking at this altogether I would consider the data spurious for whatever reason and don't think any conclusion can be really drawn from it.
I would be examining the pressure bulkhead, first.
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Mention has been made of a previous tail strike.
This is the wiki report of the mid-air break-up of a China Airlines 747 in 2002. Described as the deadliest air disaster in Taiwanese history, the cause of which was metal fatigue consequent upon an inadequate repair following tailstrike damage which occurred 22 years earlier. The repair was not carried out in accordance with the Boeing Structural Repair Manual.
The break-up of the Boeing occurred some 20 minutes after take off whilst the aircraft was believed to be climbing to FL350.
https://en.wikipedia.org/wiki/China_Airlines_Flight_611
This is the wiki report of the mid-air break-up of a China Airlines 747 in 2002. Described as the deadliest air disaster in Taiwanese history, the cause of which was metal fatigue consequent upon an inadequate repair following tailstrike damage which occurred 22 years earlier. The repair was not carried out in accordance with the Boeing Structural Repair Manual.
The break-up of the Boeing occurred some 20 minutes after take off whilst the aircraft was believed to be climbing to FL350.
https://en.wikipedia.org/wiki/China_Airlines_Flight_611
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henra: Regarding Ground Speed, imagine a full loop; your ground speed will approach zero as your angle of travel with respect to the ground approaches vertical.
But as has been pointed out, there are many flaws in this data.
But as has been pointed out, there are many flaws in this data.
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Originally Posted by The Ancient Geek
1) It is foolish to rely on FR24, the sytem works by collecting data over the internet from amatuer ADSB receivers owned by enthusiasts and joining the dots. There are plenty of these stations in well populated areas but the chances of any reliable receiver data in the middle of an enormous desert are a tad slim. In these circumstances FR24 extrapolates (guesses) by extending the last known trajectory until it recieves a valid report or times out.
It is therefore not possible to derive a rate of decent from the last guessed postion and a single and possibly unreliable following report.
It is therefore not possible to derive a rate of decent from the last guessed postion and a single and possibly unreliable following report.
The only instance where FR24 extrapolates the data is if you have the option active in your browser, it will do so for you, but that's it.
The data they posted is the data one or more of their receivers received. It's the RAW data, as broadcasted by the airplane.
If there is an error in the data, it's because the airplane was broadcasting erroneous data, not because FR24 extrapolated anything.
Last edited by Standard Toaster; 31st Oct 2015 at 20:23.
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The "initial data" in this report reminded me of last year's crash of the A320 AirAsia flight in Indonesia, in which the "initial data" suggested 6,000 fpm, sudden climb, sudden descent, etc… although weather was a big factor in the case of AirAsia. But the two seem eerily similar in that they were fairly soon after reaching cruise or near-cruise altitude, then sudden high rates of descent, etc.., then uncontrolled descent and impact without explanation.
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something in the pitch control system of that airplane broke and rendered it uncontrollable...THS jackscrew maybe? Tail strike repair?..
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I have a FR24 supplied receiver and a program to see the raw data it receives.
AFAIK, The aircraft transmits GPS position, groundspeed, heading, bank angle and an altitude, every second. Software calculates VS. FR receive all this data but only plot every 30sec or minute on the webpage.
Obviously bank angle isn't shown on FR24 but I can clearly see it on raw data analysis.
AFAIK, The aircraft transmits GPS position, groundspeed, heading, bank angle and an altitude, every second. Software calculates VS. FR receive all this data but only plot every 30sec or minute on the webpage.
Obviously bank angle isn't shown on FR24 but I can clearly see it on raw data analysis.
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The wreckage looks to be consistent with a flat stall/spin scenario.
This is consistent with the failure of some- or all flight control surfaces during cruise flight, including failure of the hydraulics. This has occurred in the past as a result of bulkhead failures /depressurization.
This is consistent with the failure of some- or all flight control surfaces during cruise flight, including failure of the hydraulics. This has occurred in the past as a result of bulkhead failures /depressurization.
The data just looks weird. How do you want to get from -7000fpm to +8000fpm at a GS of between 132 and 93kts (means roughly between 60 and 85kts IAS) ?
The data does not seem plausible at all.
Horizontal deceleration is also excessively high. From 400kts to 60kts in 22s.
Especially the initial deceleration from 400 to 340kts in just about two seconds without a clear trend in altitude change does not make much sense. At FL300 this is pretty surely still far above the stall (bar insane tailwind which I wouldn't expect in that area and flight direction).
From my armchair I have difficulties to fathom a force that would decelerate an airliner at that rate while matching the presented data.
The data does not seem plausible at all.
Horizontal deceleration is also excessively high. From 400kts to 60kts in 22s.
Especially the initial deceleration from 400 to 340kts in just about two seconds without a clear trend in altitude change does not make much sense. At FL300 this is pretty surely still far above the stall (bar insane tailwind which I wouldn't expect in that area and flight direction).
From my armchair I have difficulties to fathom a force that would decelerate an airliner at that rate while matching the presented data.
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Moreover, FR24 data is not synchronous, it's subject to whatever latency exists in the Internet connection between the enthusiast's receiver and the server.
That's particularly apparent in this instance, where the published data comes from 3 separate receivers, presumably in 3 different locations (see column 13 in the CSV file). Those clearly aren't time-synchronised, which is why we see wild variations of parameter values within the same second.
In other words, trying to construct a time-series with the data is fraught with problems. I'm very disappointed that ASN appears to have fallen into that trap with their dodgy graph.
That's particularly apparent in this instance, where the published data comes from 3 separate receivers, presumably in 3 different locations (see column 13 in the CSV file). Those clearly aren't time-synchronised, which is why we see wild variations of parameter values within the same second.
In other words, trying to construct a time-series with the data is fraught with problems. I'm very disappointed that ASN appears to have fallen into that trap with their dodgy graph.
COAA also calculate position by triangulation when they do have the positionless data fromby the aircraft but I am fairly sure it is still timecoded. People using that method have to have their computers synchronised to a time standard and it is rejected if their PC clock is not correct.
I have supplied ship's AIS data to the authorities a few times, it has similarities to that from aircraft and can be used by them to reconstruct what happened.
