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almost half of missing rear right side fuselage
In the Life News video that Kulvertukas posted, there was also a large part of missing fuselage visible. On the video a cargo bay under floor structure is visible and more than half of ceiling of the right side. It is unclear if there is one more piece between tail section missing or not. Probably there is.
On the roof it seems to be a aluminium skin ripping pattern to be visible. No soot or fire damage visible. So, what happened first? tail was broken off or something happened to the fuselage between wings and tail? http://www.keri.ee/crash/siinai4.jpg |
How about the supposed violent ups and down from FR24 data, are they spurious or real? Could the jack screw fail and the HS go uncontrolled? Now the damage to the VS looks like happened in flight and not at the ground impact... Also no wonder the APU/tail cone separated...
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Metrojet 9268 Extended Mode-S Data Decoded - 03/11/15 - FR24
In addition to our initial data, we have decoded Extended Mode-S data from a single receiver with the best reception in the area of Metrojet flight 9268. This is additional data sent from the aircraft when requested by air traffic control. This data is raw data from the aircraft that has been decoded, but not processed, by Flightradar24. Our previously released data set was synthesized data from multiple receivers processed normally through Flightradar24 servers and did not include Extended Mode-S data. Upon request, we have supplied this data to the French Bureau d’Enquêtes et d’Analyses (BEA) as well as the Egyptian investigative authorities. Important Notes About Data Validity We supply this data set with important notes about the validity of certain data within the set. At this point, from 04:13:13.872 to 04:13:30.653 we consider the altitude values to be unreliable. The altitude value is derived via a pressure sensor, which can be affected by changes in pressure outside the aircraft. In this case, what we’re learning about the state of the airframe calls into question the validity of the altitude readings during this time period. From 04:13:31.143 until our last received signal from the aircraft at 04:13:39.384 we received GPS altitude data from the aircraft. While GPS altitude data is not itself unusual, our receipt of it from this flight is. In normal cases, GPS altitude data must be requested from Air Traffic Control, but in this instance, we only see it in the data set after the flight has experienced a significant event and begun to descend rapidly. Similarly, True Airspeed (TAS) is a pressure-derived value and may be unreliable after 04:13:13.872. In this data set, Vertical Speed (Vspeed) is provided from the aircraft via GPS data, not pressure data. Our initial data set provided Vspeed values derived from pressure data, which, like altitude and TAS, we consider unreliable after 04:13:13.872. |
How realistic might the FR24 height variations be?
It would seem to be one hell of a ride. Which part of the airframe constitutes the FR24 altitude trace? Would a detached section register? |
"How about the supposed violent ups and down from FR24 data, are they spurious or real? Could the jack screw fail and the HS go uncontrolled? Now the damage to the VS looks like happened in flight and not at the ground impact... Also no wonder the APU/tail cone separated..."
Once the plane was no longer in normal flight, the FR24 data is useless for anything other than indicating the equipment still had power, IMO. The sensors only read correctly when operated as intended. |
Originally Posted by Mauersegler
(Post 9168052)
Could the jack screw fail and the HS go uncontrolled?
Looking at the damage on the central box/spar structure of the HS it seems conceivable that a huge and sudden excursion of the HS (hit by RPB?) could have been the event initiating the failure of the fuselage structure aft of the CWB. |
FR24 Data
How about the supposed violent ups and down from FR24 data, are they spurious or real? Could the jack screw fail and the HS go uncontrolled? Now the damage to the VS looks like happened in flight and not at the ground impact... Also no wonder the APU/tail cone separated... These are actual sensor readings in FR24. But the question is what caused sensors to give such readings. One explanation could be, that sensor ports were over or under pressurized due to abnormal flight attitude and air flow direction. Plane was not flying anymore. It might have rotated somehow for example. |
The apparent force applied to the tailplane would be consistent with the jackscrew or mounts letting go. But the fuselage would likely have to have still been attached to produce those forces, even though it would be quickly overstressed.
Perhaps that stress would be enough to detach the APU housing before the section [once] holding the tailplane parted with the rear fuselage. The jackscrew and its connections could become a major focus. |
FR24 Sensors
Where, on the A321, are the sensors that feed the ADS-B transmissions?
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Shadow detail adjusted
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Data Source(s) for FR24
How it works - Flightradar24.com - Live flight tracker!
"The primary technology that Flightradar24 use to receive flight information is called automatic dependent surveillance-broadcast (ADS-B). Aircraft gets its location from a GPS navigation source (satellite). The ADS-B transponder on aircraft transmits signal containing the location (and much more)." Implication is that the altitude and groundspeed are from GPS. No air data. Next question is the location of the GPS antenna, ADS-B antenna, GPS and ADS-B avionics on this airframe. |
GPS reading will be wildly inaccurate on an inverted, gyrating, tumbling and spinning metal structure. Unless the receiver is at dead center of gyration, it will give unusable measurements, not to mention the time the antenna is shielded from satellite view.
Operated as intended, it does well. |
Flightradar24 has released a revised data set:
Metrojet 9268 Extended Mode-S Data Decoded | Flightradar24 Blog Most important additions are GPS-derived groundspeed & vspeed. As before, there's rather sudden transition from business-as-normal at 04:13:14 to a 8000 fpm descent at 04:13:18, followed by a couple of phugoid oscillations (though still continuing to descend), and recording stops at 04:13:39 with vspeed of -26000 fpm and groundspeed of 47 knots. For some reason, all timestamps have been shifted, so 04:13:18 in the new spreadsheet corresponds to 04:13:01 in the original spreadsheet. Barometric altitude exhibits a small anomaly (a blast wave?) at 04:13:13.7 and then goes wild. Even with the abnormal descent rate, the aircraft has not been overspeed at any time (combined horizontal+vertical speed never exceeded 410 knots). |
Those were frightenly high frequency phugoids, on the order of 8 seconds bottom to top. What's the expected frequency for an intact A321?
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air data on ADS-B
Implication is that the altitude and groundspeed are from GPS. No air data. Next question is the location of the GPS antenna, ADS-B antenna, GPS and ADS-B avionics on this airframe. There are two antennas. one is on the roof and other is on the belly. GPS antenna, obviously is on the roof. |
Would initial loss of HS/rudder - but not yet full tail structure - cause a phugoid cycle?
Followed by full tail empennage loss and ensuing tumble/disintegration? Just trying to figure sequence of breakup.... |
Originally Posted by Vinnie Boombatz
(Post 9168085)
Implication is that the altitude and groundspeed are from GPS. No air data.
Groundspeed is, of course, GPS-derived, as is true track. FR24 appear to use the terms "track" and "heading" interchangeably, though if they are decoding EHS data they ought to have access to both (and IAS, too). |
Originally Posted by cats_five
(Post 9167748)
No, it's missing the part BEHIND the red line in the photo.
the part aft of the red line is also aft of the grill in the skin and the drawing below shows that is just the muffler which I suspect is squashed into the cone http://i68.tinypic.com/152hjy1.jpg |
Captain Chelsey (Sully) Sullenberger of US Airways Flight 1549 that water landed in the Hudson, said in a Google talk that the automatic protection from phugoid mode implemented in the Airbus A320, prevented him from manually getting all possible lift from the wings at four seconds before water impact, causing the crash to be more violent.
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https://img-fotki.yandex.ru/get/9059..._c9c8f095_orig
looking at this image and the drawing above the cone has broken at frame 78, so where is the heavy duty frame supporting all the HS operating parts. BTW what are those rod two of which appear to be able to move in the vertical plane and two in the horizontal plane, are they part of this screw jack ppl refer to, and where is the heavy frame , is it at the back of the main tail plane section or in the desert? thanks to A0283 for the image it shows the parts I was asking about at the rear of the tail section http://i64.tinypic.com/2rmqjac.jpg |
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