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BREAKING NEWS: airliner missing within Egyptian FIR

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BREAKING NEWS: airliner missing within Egyptian FIR

Old 4th Nov 2015, 08:38
  #801 (permalink)  
 
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However there is one aspect of the FR24 data which is intriguing. By now it is increasingly clear that an in-flight breakup occurred, with complete loss of control the moment the tail section broke off early in the sequence. Data continued to be received from the aircraft for 25 seconds after the start of the upset, which at least indicates that the relevant systems were powered and transmitting (never mind the data). Can someone with knowledge of the bus power/avionics systems provide a plausible scenario for this ? Is this indicative of the engine generators continuing to supply power until loss of signal, or would there be some automatic reversion to battery power (which would remain available as it is in the front bay) after the engines would have shorn off ? Given the G forces involved it is unlikely the crew would/could do anything.
The Transponder (source of FR24 data) may still operate on DC battery, loss of data could be due to equipment feeding transponder going invalid which may also stop the ADS-B transmissions, also as altitude reduces the FR24 ground RX could loose signal due to normal radar range issues.

What would be more interesting was if any ground ATC tracked the Mode A/C/S from this aircraft?
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Old 4th Nov 2015, 08:52
  #802 (permalink)  
 
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any ground ATC tracked the Mode A/C/S from this aircraft?
Yes. This can easily be deduced from position of last radar contact, which is very close to the main wreckage and well beyond the ground location of the tail and other rear fuselage debris along the flight path. Given the heavy military presence in the area, I'm sure there was primary radar tracking as well, from both sides on the nearby border.
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Old 4th Nov 2015, 08:56
  #803 (permalink)  
 
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In the immediate aftermath of Flash Airlines 604 it was thought to be terrorist related but this was very quickly dismissed, even though retrieval was more difficult. I note the accident happened on 03/01/2004 and the final report came out on 25/03/2006, so all things considered, pretty quick.


If security in Sharam el-Sheikh airport wasn't up to scratch wouldn't you imagine some of the 900,000 British who visit each year and can compare it to UK airport security would have drawn attention to any perceived shortcomings?
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Old 4th Nov 2015, 08:59
  #804 (permalink)  
 
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Physical investigation - where?

Having followed this thread since the accident was first reported I don't recall hearing how the investigation is likely to deal with the material remains of the aircraft. From the information available to date it's beginning to look as though examination of the wreckage for evidence of failure is going to be a critical component of the investigation. Would this material be moved or would the investigating team travel to Egypt? - I'd assume the latter.

Also, assuming that the absence of explosive residues on the passengers is being reported correctly (a big "if") would this eliminate the possibility of the event being caused by an explosive device?
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Old 4th Nov 2015, 09:13
  #805 (permalink)  
 
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reading tea leaves

Folks, here's the rules:
1. At the moment, there's a lot of pressure on the press to report _anything_ that can conceivably be associated with this accident. As a result individual "unconfirmed sources", especially from the Tabloids, cannot be used for anything.

2. The FR24 data: They've now come out and given all the information you need: after the first moment, their data is unreliable. Altitude is given by GPS. GPS is not designed to give altitude; if you doubt me, download an app that spits out the raw data from your phone's GPS unit. Lat and Longitude will be precise, but altitude will be all over the place. To get precise information, most terrestrial navigation systems use something else, like looking up Lat. and Longitude on a Digital Elevation Module database.
Certainly, with enough time and controlling for enough factors, you *might* be able to fit that GPS data into a model of the aircraft's altitude. But spikes and other garbage are just not going to work. So, at the moment, the FR24 data are useless.

3. Rear Pressure Bulkhead. Yes, this was is what failed in JAL 123, and in whatever that Viscount crash in Belgium was. I haven't seen it credited with China Airlines 611, however. That was simply structural failure from an improper tailstrike repair. There seems to be a mindset: "Tailstrike = RPB failure", and that's dangerous.

4. A321 and tailstrikes. A321s have the longest bodies of the A320 family, and tailstrike with some frequency. When they do, they don't strike back at the RPB, but further forward. For example, someone scraped this a321 pretty bad, with the center of damage just below the Bulk Cargo Door. This means that, even if the 2001 repair were done perfectly, some other tailstrike might have doomed this aircraft. We've seen here the reports of pilots "not hearing" a tailstrike.

Now, to the tea leaves:

What we do have from the FR24 and the debris field is an aircraft that broke apart while climbing through 30,000 feet. From the photographs, the tail section separated from the rest of the aircraft, and the tail section itself seems to have broken into two parts: one part with the APU and tail cone neatly sheared, the other with half the VS, neatly sheared from the windows to the top along FR65, and, on the bottom, tearing down and forward of FR65 through the rearmost two windows and down to the Bulk Cargo Door (which isn't attached). This tail section is laterally symmetrical: left and right show more or less the same tearing. The horizontal stabilizers have been sheared clean, suggesting that they suffered excessive aerodynamic pressure.

Accidents on initial climb favors pressurization-related events: Fuselage cracks from metal fatigue, improper tailstrike repairs, door failure, and, sure, bombs rigged to cabin altitude. They all occur in this zone.
While any of these are possible, only one is favored by the information we have available.
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Old 4th Nov 2015, 09:15
  #806 (permalink)  
 
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So we are left, probably with a structural failure.

The next step would appear to be to decide if separation of the tail was cause or effect.

Presumably if we do not get an indication from Airbus quite quickly asking for examination of components etc. then we can conclude it is something that concerns only this airframe not a significant number of the Airbus A321 or 3 xx fleet.
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Old 4th Nov 2015, 09:21
  #807 (permalink)  
 
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Thanks. As I assumed the data between 330 and ~343 looks like full Rubbish, after that you can see an increasing barometric Pressure shortly after an increase of Gspd and Vsp. This would fit an Pitotrod thats been used in false direction. (Aerodynamic Drag induced by an Rollover e.g.)
Then the "Airframe" must have entered a more "stable" regime which has been hold until the Generators went out.(If data are correct)

Concluding: Nothing that helps finding the cause.
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Old 4th Nov 2015, 10:03
  #808 (permalink)  
 
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Quote from DingerX " GPS is not designed to give altitude".
GPS is as accurate in altitude as it is in Lat/Long. The accuracy in any dimension is dependent on line of sight to as many satellites as possible in different directions and planes. In the air it is very accurate under most conditions in all dimensions provided it is connected to an external antenna. On the ground in wide open country it is also very accurate, while in towns or very mountainous areas it can become quite inaccurate in any or all dimensions. A phone GPS will not work properly inside a large aircraft as the body is sufficient to block most satellites unless they have line of sight through a window and it needs a minimum of 3 or 4 to obtain a lock with minimal accuracy. I fly gliders and use GPS for height readings and it is extremely accurate, much more so than a barometric altimeter!
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Old 4th Nov 2015, 10:09
  #809 (permalink)  
 
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Why is there a general assumption the fire damage was only caused prior to the aircraft hitting the ground? The photos clearly show that there was an immense fire on the ground. Surely things would have been damaged/scorched/heated/sooted by this fire, not just in the air.
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Old 4th Nov 2015, 10:16
  #810 (permalink)  
 
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I fly gliders and use GPS for height readings and it is extremely accurate, much more so than a barometric altimeter!
That may the case with a glider, but given the context of the tread what about relative accuracy in the case of a RVSM compliant airliner.
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Old 4th Nov 2015, 10:20
  #811 (permalink)  
 
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i have mapped the RF24 data with the location of the pieces of wreckage, I canít attach an image (how can I do this?) but a few findings that may give a bit more context to the crash site

- The south east debris field (containing the tail, but no confirmation of HS here) is located approximately 800m to the east from the flight path (@31k ft), and where the FR24 data starts going strange (04:13:14 onwards), indicating where the Ďeventí might have occurred.
- The north west debris field with the main wreckage is approx. 2km south east of the last FR24 data point, the nose of the aircraft wreckage is pointing south west.
- The main debris field is approx. 2.5km to the north west from the and tail debris field.
- The flight path is straight as an arrow until a time just after the Ďeventí, then drifts to the west, then to the east a bit.
- The points at the end of the FR24 seem to be bunched up spatially, maybe indicating a rapid decent without much vertical travel.

This spatial data seems to me show that whatever the event was it was sudden and the plane became unflyable and came down quickly, the image shows this much clearer than the text.

Does anyone know a spatial location of the HS wreckage?
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Old 4th Nov 2015, 10:34
  #812 (permalink)  
 
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Major components still missing - update nr 3

to the chap who posts these updates ao283

i have seen in photos both winglets - one is fairly intact
(but as the wings are now upside down the 'top part' is bent on impact)

and the other one is very bent and burnt (rhs?) but was recognisable

been looking for the photos but its eluded me
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Old 4th Nov 2015, 10:36
  #813 (permalink)  
 
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Originally Posted by Sober Lark View Post
If security in Sharam el-Sheikh airport wasn't up to scratch wouldn't you imagine some of the 900,000 British who visit each year and can compare it to UK airport security would have drawn attention to any perceived shortcomings?
Passengers wonít really be aware of what goes on behind the scenes, either with checked baggage, cargo or catering / cleaning etc. What they donít see wonít particularly bother them.

Iím inclined to wonder why, if security is Ė as alleged Ė so lax at Sharm, no one has attempted to smuggle a bomb on board an aircraft previously. If it were that easy, I find it difficult to believe it hasnít been done before now.
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Old 4th Nov 2015, 10:39
  #814 (permalink)  
 
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@Wiggy, provided the GPS is connected to an external antenna then it will work accurately, down to a few feet or less of the location of the antenna. In the air it will be receiving data from perhaps a dozen or so satellites at any one time which gives great accuracy. On the ground much less so as not only will it receive fewer satellites most of the time but it may also receive reflected signals from buildings which could cause spurious readings. Try driving along a motorway with one at a constant speed and and watch the fluctuations as you go under bridges, or the huge spikes if you go through tunnels. Imagine the latter effect on a fixed antenna on a rotating body where it is seeing a different set of satellites as it rotates. Mine will often tell me I reached 600 mph as I exited the tunnel (I had it set to record every second), with no signal in the tunnel it estimates position until you exit and it receives again, if there was a turn in the tunnel you will not be where it expected so it will correct it the next second, similarly if you change speed. This should go some way to explain what happened after the event in respect of GPS readings.
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Old 4th Nov 2015, 10:41
  #815 (permalink)  
 
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How about plotting the GS/VS as x and y. You will get the trajectory with the variations being due to thrust/drag of the tumbeling aircraft.
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Old 4th Nov 2015, 10:48
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Passengers wonít really be aware of what goes on behind the scenes, either with checked baggage, cargo or catering / cleaning etc. What they donít see wonít particularly bother them.

Iím inclined to wonder why, if security is Ė as alleged Ė so lax at Sharm, no one has attempted to smuggle a bomb on board an aircraft previously. If it were that easy, I find it difficult to believe it hasnít been done before now.
Just putting it out there, but it may be, Contrary to what the Governments say in their propaganda, that not everybody is itching to either blow up an aircraft nor Hijack an aircraft.

Let's face it - there's much easier places to bomb.
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Old 4th Nov 2015, 10:59
  #817 (permalink)  
 
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Not sure about exploding poop, but there was an incident in the 80s that involved a guy flushing a live hand grenade in an aircraft lavatory. The explosion punctured the APB and severed two out of three hydraulic lines, but the crew managed to land the aircraft safely.
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Old 4th Nov 2015, 11:01
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From we 'know' I see it like this.

The absence of any distress call would suggest a very rapid event. The size/shape of the debris field clearly indicates that the airframe break-up at altitude. The various tail parts and components/systems are identifiable and show only relatively minor signs of heat damage and at at some distance from the rest of the aircraft remains.

Based on various photographs, because the 'one piece' outlines are clear to see on the desert floor, the front section of the fuselage c/w wings must have remained largely intact until hitting the ground with little or no horizontal airspeed in a sort of upside down belly flop. Since the wings appear to have remained attached to the fuselage, it would seem to suggest that the fuel tanks did not explode until hitting the ground - after all I would expect them to be fairly full so early in the flight and had one or more exploded for whatever reason it would have blown the airframe into far smaller fragments...probably.

A single heat flash was detected by IR satellite at a time and location indicating a mid-air explosion of some sort.

The section of fuselage between the wings and tail disintegrated significantly, indicating that whatever caused the explosive event was in this area. If PAX seated in this area did indeed suffer severe burns (with those forward of this section suffering mostly impact traumas of one sort or another), then this would confirm that the event was centred somewhere aft of the wings.

The cause was either 'accidental' or foul play.

It is difficult to see how a structural failure of any sort would have caused a mid-air explosion - consider JAL123 and BEA706, or indeed AA96/TA981 for example.

Hypothesising for a moment, if the central fuel tank was largely empty, an 'accidental' explosion similar to that of TWA800 might have occurred. An engine failure might have caused debris to puncture the fuel tank.

If it was the result of foul play, there is no evidence of any projectile strike. However, at that altitude even a relatively small explosive device in the rear cargo hold would cause a break up. But would it explain the heat flash? Even if passengers at the rear of the plane do indeed show no signs of explosives on their person, it does not mean there was no bomb. They were severely burned anyway, so such evidence might have been lost.

I'm not convinced that the CVR and FDR will provide a clear answer and suspect that definitive explanation will be some long way off...
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Old 4th Nov 2015, 11:05
  #819 (permalink)  
 
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Ka-2B pilot

GPS is as accurate in altitude as it is in Lat/Long.
No it isn't.

If you fly gliders I can assume you know the difference between height, altitude and pressure altitude.

A GPS altitude is expressed above what datum? Think about it for a minute.

The earth is not round, it is an oblate spheroid. GPS altitude is measured above a geometric model of the earth. In some places the surface of this model is above the "real" sea level surface and in some places below the "real" surface. WGS 84 is one such model etc

I fly gliders and use GPS for height readings and it is extremely accurate, much more so than a barometric altimeter!
Perhaps you do but no it isn't.

Here is a link to a useful article on the subject with good diagrams.

GPS and altitude for hang gliding and paragliding | Cross Country Magazine

Have a read and a think.

As I said earlier, the FR24 data is almost useless.
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Old 4th Nov 2015, 11:13
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Fuel/air explosion in the empty ACT, in the rear hold?
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