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BREAKING NEWS: airliner missing within Egyptian FIR

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BREAKING NEWS: airliner missing within Egyptian FIR

Old 5th Nov 2015, 23:26
  #1261 (permalink)  
 
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If it's all fly by wire, I'd think you would want the FDRs as physically close the actual data source as possible, not hanging out there at the end of 100 or more feet of cable. Seems like an architectural anachronism.
Which data is most important in accidents? Command data (from flight deck or autopilot?). Actual control surface data from control surfaces? Engine data? Engine command data? Sensor data (The typical aircraft has sensors basically on every part of the fuselage/wings/tail).

Do you design a recording system that is finer tuned to mechanical failure, control data failure, human failure? Specifically, what do you deem anachronistic?

You can please some of the crash investigators all of the time, and all of the crash investigators some of the time, but...
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Old 5th Nov 2015, 23:29
  #1262 (permalink)  
 
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Alexander Neradko quoted in Kommersant article

Is quoting Alexander Neradko Head of the RussianFederal Air Transport Agency who appears to have said:

- normal cruise,
- instant event ending all FDR registrations,
- lack of FDR data means that it will take months before any conclusions can be drawn,
- during this time work on extracting information from the CVR will continue,
- and a full scale reconstruction with the plane's wreckage will be made,

(we dont have a transcript op Neradko's statements, and the translation is made using software, so be careful before use),

Last edited by A0283; 5th Nov 2015 at 23:53.
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Old 5th Nov 2015, 23:38
  #1263 (permalink)  
 
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CVR/DVR location.

As most aviation folk know flight recorders are located in the tail because of the better ride MOST of the time in MOST accidents.


In THIS case there may have been 26 seconds more data if located in the nose.


Can't win them all.
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Old 5th Nov 2015, 23:40
  #1264 (permalink)  
 
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Grrr Why CVR and FDR are in the tail

If it's all fly by wire, I'd think you would want the FDRs as physically close the actual data source as possible, not hanging out there at the end of 100 or more feet of cable. Seems like an architectural anachronism
Most airplanes crash into things [ CFIT and solid clouds ] nose first. Usually the least damaged parts are in the rear. Thus the recorders are placed as close to the back side as possible.

Note the CVR and FDR were found relatively soon.
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Old 5th Nov 2015, 23:41
  #1265 (permalink)  
 
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@thcrozier - accelerometers

Nothing wrong with your idea from my point of view.

I ran a project at the end of the 1990s trying to use the cheapest INS we could build (and compare it with some aerospace solutions). One of a number of options we tested used the components from the earliest wireless computer mouses. One thing you need to know is if the data runs over any kind of persistent memory. It has long been common 'state of the art technology' practice to use multiple 'inaccurate sources' and run the data through processors which create 'accurate output'.

As i said before, if you dont get it from (the QAR and maintenance computers, you go to) the FDR/CVR, then on to possible other memory, and finally to the more out of the box and innovative solutions.
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Old 5th Nov 2015, 23:48
  #1266 (permalink)  
 
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Is the jackscrew holding leading edge UP?, or DOWN? in 400 knot cruise??
Basic aero: the horizontal stab is an upside down wing, and produces downward force. A lifting body wants to pitch down from its direction of lift. That's why the stab "wing" pushes down on the back, to keep the main wing from pitching down. Since the stab itself is pushing down, it wants to rotate in a direction that would pitch its leading edge up. So the control system must maintain a leading edge down torque on the stab.

In consequence, if the jackscrew failed, the result would be a prompt and very violent nose-down aircraft pitch.

This happened to a Navy A-6 Intruder in 1990 during flight tests; the stab linkage failed at about 400 kt and resulted in an instantaneous -6g pitchover. Capt Hazelrigg was killed in the crash; at 1,500 ft AGL there wasn't time to eject.
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Old 5th Nov 2015, 23:51
  #1267 (permalink)  
 
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NSEU:

Thank you for your reply.

All of the data from all of the sources you mention must be consolidated around hubs or maybe a central processor. I'm suggesting the recorders might be better located as physically close to those locations as possible.

I assume, but don't know, that the recorders are located at the ends of long cables back in the tail because back in the days when they were mechanical, it was assumed that location would suffer the least damage in a crash.

Now that they are solid state, the probability of damage to the memory is rapidly diminishing. The preservation problem is almost solved, so it might be time to focus on data input integrity.
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Old 5th Nov 2015, 23:58
  #1268 (permalink)  
 
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That dailymail article said something to the effect that the toddler was believed to have been found about 21 miles closer to the airport than the cockpit. Well, the tail came down about a mile before the cockpit, so that leaves 20 miles of flying from toddler to tail. That is about 2,5 minutes of flying, during which FR24 data shows not so much as a hint of anything going on, during which nothing was communicated out of the aircraft, and during which nothing out of the normal was recorded by FDR (if we assume it kept recording up until about when the tail was shredded.) Believable?
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Old 5th Nov 2015, 23:58
  #1269 (permalink)  
 
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A horrible and sickening thought, the position of the toddlers body could well be a false trail. The sinai and Egypt in general is home to wild cats, foxes, dogs and wolves, the body may well have been moved from its initial position.
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Old 6th Nov 2015, 00:03
  #1270 (permalink)  
 
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Interesting thought about the videos, OLEOSTRUT. A lot of phones also have accelerometers and gyroscopes in them these days. Not good enough for an INS app yet, but it's in your future. One of the reasons they are inaccurate is because of slow refresh rates, but if you had several of them, maybe the data could be integrated.
Oh, don't count much on phones' accelerometers and gyros, because, first of all, phones don't have gyros. They do have angular rate sensors which are good enough for gaming use (like controlling something by tilting the phone), but next to useless when trying to determine device's true spatial orientation. Typical drift of such "gyro" is in the range of 0.1-1 degree/second in steady conditions, and much larger in the presence of vibration, shocks etc. They also have very limited measurement range, and any significant shock throws the phone's accelerometer off scale, making any future integration attempts worthless.

Then, to conserve power, these sensors are powered down most of the time, and even when they aren't, their readings aren't typically logged. A phone ain't an FDR, and chances of recovering something of value from it is close to nil, unfortunately.
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Old 6th Nov 2015, 00:07
  #1271 (permalink)  
 
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Exclamation Puhhlease

What if a fairly small explosive device took out the cables to the recorder and blew a relatively small hole in the skin of the aircraft. Child is sucked through hole.
Unless the explosive device cut a major structural member- or control cables, etc, a ' small hole " for example the size of a window or two is not likely to 1) suck out a child ( unless he/she was next to it

2) and is NOT likely to result in a rapid disintegration of the airplane.

In fact air systems for pressurization are designed to accomodate a ' window" blowout, requiring as descent to 10 k ASAP, along with dropping of O2 masks.

Explosive decompression myths re a hole sucking out a person seem to be based on a) plane is like a ballon, it pops b) A james Bond movie where gert frobe ? was sucked out... Neither is true ..

Yes an hawian airline had an explosive decompression in which a whole panel blew out due to corrosion and a flight attendant was sucked out and killed . But even then the plane landed as a ' convertable "
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Old 6th Nov 2015, 00:08
  #1272 (permalink)  
 
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Re: Micro gyroscope, accelerometer, gravity sensor, and compass integration

Well Iceheart, you are getting into all the reasons they currently don't work very well, but those will be solved.

Recent cell phones do indeed have gyroscopes. https://en.m.wikipedia.org/wiki/Vibr...ture_gyroscope

As far as the power problem, my iPhone 6 records every movement I make whenever it's in my pocket. In fact I wish I could figure out how to stop it!

Did you read the article I attached to my post?

Last edited by thcrozier; 6th Nov 2015 at 00:21.
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Old 6th Nov 2015, 00:18
  #1273 (permalink)  
 
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FR24 data

A0283,
Prada is it possible to post the FR24 data or statements that you are referring to?
I was going through FR24 data once again. Look here:
Crash of Metrojet Flight 7K9268 | Flightradar24 Blog

It looks like after initial event plane lost yaw control. - tail fin was lost or gaping hole created in fuselage creating non symmetric drag, or both
with plane loosing yaw control, static ports might become not as static as required for correct flight level indication. Due to abnormal attitude against airflow.

I wonder which ADIRU data was fed to ADS-B? Captain side? Then we can tell yaw attitude via abrupt flightlevel changes. Compared to GPS data.

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Old 6th Nov 2015, 00:22
  #1274 (permalink)  
 
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Falling aircraft---

Originally Posted by cookie65 View Post
A horrible and sickening thought, the position of the toddlers body could well be a false trail. The sinai and Egypt in general is home to wild cats, foxes, dogs and wolves, the body may well have been moved from its initial position.
This is about distance travelled after event .Variously reported as 15km/25miles.
Tracking data unreliable but included 80 knots G.Spd
at that speed vertically perhaps several minutes to reach ground.
horizontal speed decaying from 400knots .
Lockerbie 747 covered 40 plus miles
We really want to see the distance last smooth tracking ground position from final ground position, and search that far back
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Old 6th Nov 2015, 00:27
  #1275 (permalink)  
 
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"A horrible and sickening thought, the position of the toddlers body could well be a false trail. The sinai and Egypt in general is home to wild cats, foxes, dogs and wolves, the body may well have been moved from its initial position."

A mile, maybe. 20 miles? I do not think this is a consideration.
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Old 6th Nov 2015, 00:27
  #1276 (permalink)  
 
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There is enough data from ADS-B to calculate backwards from the crash sight.
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Old 6th Nov 2015, 00:28
  #1277 (permalink)  
 
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Isn't the obvious solution to the problem of recorder survival installing redundant recorders in different locations? The things can't be that expensive. What am I missing here?
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Old 6th Nov 2015, 00:28
  #1278 (permalink)  
 
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Originally Posted by RYFQB View Post
That dailymail article said something to the effect that the toddler was believed to have been found about 21 miles closer to the airport than the cockpit. Well, the tail came down about a mile before the cockpit, so that leaves 20 miles of flying from toddler to tail. That is about 2,5 minutes of flying, during which FR24 data shows not so much as a hint of anything going on, during which nothing was communicated out of the aircraft, and during which nothing out of the normal was recorded by FDR (if we assume it kept recording up until about when the tail was shredded.) Believable?
I imagine whatever caused a hole large enough to eject a passenger, was violent enough to sever the cables to this FDR/CVR at the same time.

There is an elephant in the room though - the grainy video purporting to show a bombing. The video appears to show an explosion at the rear of the a/c, trails thick black smoke, but continues to fly. If the toddler was ejected at that point 20 miles seems about right.
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Old 6th Nov 2015, 00:33
  #1279 (permalink)  
 
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Well I am puzzled. All the talk of a violent sudden event but the debris field is very large. The fwd part of the structure came down intact at zero forward speed. If a sudden manoeuvre caused high drag to bleed off the speed, why did it happen so long after the first event (judged by the position of the first debris on the ground along the flight path) ?
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Old 6th Nov 2015, 00:34
  #1280 (permalink)  
 
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E-Jets have two. One on the front and one in the back.
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