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EgyptAir 804 disappears from radar Paris-Cairo

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EgyptAir 804 disappears from radar Paris-Cairo

Old 1st Jun 2016, 20:51
  #941 (permalink)  
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@notapilot: the wreckage is lying at a depth of around 3,000 meters; It wasn't a fix for the lack of other means, this system is supposed to be more efficient (like 20 times faster) than classical towed pinger locators. Egyptians already used Alseamar services for Sharm-El-Sheikh crash and the Russians at Sotchi.

@Coagie: detection range is said "typically 4-5 km", which doesn't mean it's under near perfect conditions but rather an operational range. But you are right, this system doesn't need either a dedicated ship to operate and can be deployed fast enough and at long distance from whatever asset available on the spot. H/V Laplace was close enough to be send there though.

DETECTOR-1000/6000: the latest acoustic detection system

DETECTOR-1000/6000 is a very efficient, long range acoustic detection system for locating acoustic pingers. It can cover very large areas in a small amount of time speeding up search operations.

Key features

Extremely long detection range (typically 4 to 5 km for black boxes)
Simple and robust
Easy to use, even in poor weather
Immediate deployment from various platforms: vessel of opportunity, helicopter, submarine, inflatable boat etc.
Equally suitable for deep water and shallow water
Intuitive and user friendly interface
Increased coverage speed (by a factor of 20)
Dramatically reduced Search and Recovery costs
Recorded signals can be made available for Post Processing and use by Investigators (optional)
Isolates natural sounds such as whale song to accurately locate a beacon


Search and Recovery operations : Underwater Locator Beacons (ULBs), NATO aircraft pingers and distressed submarine signal
Drug enforcement: detection and localization of underwater drugs canisters
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Old 1st Jun 2016, 21:54
  #942 (permalink)  
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ELB Run Time

The usual ULBs have a run time of 30 days. Certainly in the case of AF447 that run time was not adequate. In the case of MH370 there was probably no satisfactory search area to even begin looking for an ULB.

While ULB technology may seem archaic - how often does the 30 day run time and short detection range really make any difference?

After AF447 there were proposals to require 90 days of run time instead of 30. Would that have helped find any aircraft lost at sea in the last 10 years?


With the searches of recent years I would have tried for the following modest improvements in ULBs:

Very accurately controlled frequency: Not 36.5-38.5 KHz but something more like 37.5 +/- 3 Hz. Easy to attain with current technology. And this would allow use of serious digital signal processing methods to extend the range by a factor of 5 to 10 (a guess without serious calculations)

Reduced on-time after the battery gets below something like 40% capacity
Further reduction at 20% with a goal of 6 months run time.

Frequency shift modulation might be nice - encoding the aircraft ID.
Easy to do with a very slow rate and very small deviation.

Dukane has been offering a 3 month run time ULB for quite awhile.

As a design engineer I could list 5 or 10 more wonderful features... but my view is that what we have now is very nearly adequate - if not satisfying all of our wishes for easy recover of the FDR and CVR.

We have come a long way from the FAA proposed specs of 1968 - which was when I was working on avionics! Among other things: 200 foot depth range


edited ELB/ULB error, hat tip to Coagie!
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Old 1st Jun 2016, 22:38
  #943 (permalink)  
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How deep is the seabed there anyway?
The locus of "French Warship" (LaPLace?) at 19:49:56z was 33° 25'N 29° 14'E. The water depth at that point is 3,024m (9,921').

Call it 10,000' in old money.

Think in terms of flying at FL100 and trying to find a sound, somewhere in a hundred square mile search zone below you, which to the human ear in air is pretty much like the sound volume and pitch of clacking of the backs of two teaspoons together.
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Old 1st Jun 2016, 22:54
  #944 (permalink)  
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As an ancient mariner, I spent some brief time standing sonar watches in a destroyer. It was important to know the sea's thermal profile vs. depth, which affects the transmission and refraction of sound through the sea. For that, a bathythermograph device was lowered into the sea. Technology has undoubtedly changed, but I wonder what devices can measure the temperature profile down to, say, 4,000m? Or maybe, past a thousand feet, or so, it doesn't matter that much?
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Old 1st Jun 2016, 23:08
  #945 (permalink)  
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It matters very much indeed.

A device is lowered through the water column, recording temperature, salinity and depth continuously.

The thermoclines and haloclines are then calculable and shadow zones can be identified.

The Med in summer is a bit of a bugger. Cold dense seawater flows in to the Med through the Straights of Gibraltar at depth and stale warm water flow over it in the opposite direction. This is further complicated by evaporation which itself increases salinity and therefore density. The multiple layers are a complication which cannot be ignored and must be allowed for in survey run-line planning on a job such as this.
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Old 2nd Jun 2016, 00:43
  #946 (permalink)  
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Originally Posted by notapilot15 View Post
...Even after 14 days if SAR teams are not sure where it went down, how long it is going to take to recover FDR/CVR. There is near zero possibility of recovering human remains.
OTOH, in the case of Air France Flight 447, they recovered 104 bodies from the wreckage lying at 3980 meters depth some 700 days after the flight was lost. ( https://en.wikipedia.org/wiki/Air_Fr...h_and_recovery )
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Old 2nd Jun 2016, 07:01
  #947 (permalink)  
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Jean-Paul Troadec has done a bit more than x-raying suitcases ...
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Old 2nd Jun 2016, 07:21
  #948 (permalink)  
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Original statement by Troadec:

Grâce aux messages des instruments de bord de l'avion, France 3 a appris ce mercredi soir que cet Airbus A320 d'EgyptAir aurait fait plusieurs fois demi-tour et procédé à trois atterrissages d'urgence 24 heures avant le crash.

"Cette information est encore imprécise, car on ne connaît pas la nature de l'incident qui aurait obligé les pilotes à faire demi-tour et on ne connaît pas non plus le type d'intervention qui a été effectué par la maintenance. Il appartient aux enquêteurs de faire le lien avec l'accident", réagit Jean-Paul Troadec, ancien directeur du Bureau d'enquêtes et d'analyses (BEA).
Source: francetvinfo

"Grâce aux messages des instruments de bord de l'avion" should mean ACARS, or maybe some QAR information may be available from previous flights?

Edit: Troadec quite enjoys seeing himself regularly on french television these days. He was one of the "experts" who favored the terrorist theory even before wreckage was found and called a technical defect "unlikely".
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Old 2nd Jun 2016, 07:26
  #949 (permalink)  
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Originally Posted by llagonne66 View Post
Jean-Paul Troadec has done a bit more than x-raying suitcases ...
Yes, he's actually President of the BEA, France's equivalent of the AAIB/NTSB. Which makes it even more surprising that he would come out with easily disprovable nonsense. Is it possible that these "new findings" have lost something in translation?
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Old 2nd Jun 2016, 07:31
  #950 (permalink)  
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Originally Posted by DaveReidUK View Post
Yes, he's actually President of the BEA, France's equivalent of the AAIB/NTSB.
He was President of BEA. Wikipedia article is outdated.
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Old 2nd Jun 2016, 07:41
  #951 (permalink)  
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To add to what thf has said:

AFAIK Remi Jouty is the current president/director of the BEA and has been for a couple of years...and TBH I can't really argue with thf's opinion that Mr Troadec has become one of French TV's aviation talking heads who pop up on TV in the wake of incidents and accidents..
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Old 2nd Jun 2016, 08:01
  #952 (permalink)  
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Thought: could Troudec have been referring to the A320 in general, even though the article makes it sound like he was talking about the airframe involved in the crash?
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Old 2nd Jun 2016, 08:51
  #953 (permalink)  
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Hi, French SLF here.

Media outlets cite "France 3" (TV station) and "Le Parisien" (newspaper) as the original posters of these new "findings".

Le Parisien's article :
Vol d?Egyptair : l?Airbus A 320 avait émis trois alertes lors des vols précédents

They don't talk about emergency landings, but rather about "alert messages" related to smoke detectors happening each time at take-off from Asmara, Tunis and Cairo, and not triggering any kind of emergency procedure from the crew.
They also state that the relations between French and Egyptian investigators seem to be "bad to say the least".

They phrase everything beginning with "according to our sources", without citing any, so take it as you will.
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Old 2nd Jun 2016, 09:17
  #954 (permalink)  
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@DaveReidUK, no doubt, Troadec was refering to this particular airframe. It looks like just another leak of maintenance data, if that's true (they don't have the specific data and and can't say what emergency caused landings).

I'm watching the interview, JP Troadec was simply questioned during the News about this information revealed by the "News staff of France 3"; he commented that he wasn't aware of that, and cautiously said that the investigators would take that into account for their inquiry but needed much more detail about it. So, Troadec, former head of BEA (the man leading AF447 investigation) is obviously not at the origin of the leak.


Last edited by takata; 2nd Jun 2016 at 09:38.
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Old 2nd Jun 2016, 09:27
  #955 (permalink)  
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More details there :
Vol d'Egyptair : l'Airbus A 320 avait émis trois alertes lors des vols précédents

Three alerts probably with smoke detectors on previous flights on the same day.
The same article reports lot of tension between french and egyptian investigators.
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Old 2nd Jun 2016, 10:08
  #956 (permalink)  
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Troadec quite enjoys seeing himself regularly on french television these days. He was one of the "experts" who favored the terrorist theory even before wreckage was found and called a technical defect "unlikely".
Or French TV like questioning him, considering his background and references. Nonetheless, during this inteview, he told that terrorism thesis has been first to come to mind only based on pure geopolitical considerations, but such thesis was never backed up by any factual information. After ACARS leak and "last week informations" (no specific) this case was more likely oriented toward technical issues.

This new information from "France 3" is also based on ACARS from previous flights they put their hand on (without saying where they came from).
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Old 2nd Jun 2016, 10:12
  #957 (permalink)  
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Originally Posted by phylosocopter View Post
The "range" of an underwater ping can vary from much less than advertised to very much more, this is because the attenuation is actually fairly low ie water is a very efficient conductor of sound. It is the spreading out of the signal that causes it to diminish , sometimes due to differences in density the signal can be refracted on itself and can even become "ducted" beteween different layers of water. In such case the signal may pop up at a greart distance and not give much info on where the pinger is.+
Which is why the ULB should modulate its signal with the last GPS location as was suggested on the AF447 thread. Just think what could be achieved by a ULB that was more intelligently designed and powered by a battery with a longer life.

And for all the 'what is the hurry we will find it' group - the huge expense of a search of 3 weeks with the possibility that the DFDR/CVR may not be found leading to significant assets being deployed, should be compared to a search that takes a few days and a simple SONAR buoy drop followed by recovery.

I still say that the costs of the search should be charged to the airline (insurance) company. That is the only way that funding will become available for a constructive approach to the retrieval of this information in future crashes. With more transoceanic routes being set up we can expect to see more of these searches not less.
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Old 2nd Jun 2016, 10:56
  #958 (permalink)  
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@Ian W - My impression is that the points you mention (GPS mod, batt life, expense, charging, transoceanic routes, ...) all make sense. And should be included in discussions in solving the issues that have become clear with (RedSea), AF447, MH370, AirAsia, and now Egyptair.

One of the issues that has to be solved is what the cost of such a search is. You need that to focus the related solution efforts (engineering, manufacturing, operations, maintenance, training, etc). That would require a very serious effort by itself. The perception of people and parties in this respect varies wildly and is changing. The Australian government for example had the opinion early in the search for MH370 that 'we have these assets anyway, so there is no cost'. They have been forced to change their opinion since. The Fugro contract is an example of part of a possible search cost.

I have collected data during the MH370 and AirAsia searches and used that to make an estimate of the actual cost of such an effort. The numbers get very very big. How big, that depends for instance on how much of the cost of a SAR infrastructure, and shared use of military resources is allocated to a specific search. Such an allocation means that insurers and airlines would never be charged the 'full costs'. In that sense in the end it would probably look more like setting a 'price'. Where the price is lower than the cost.
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Old 2nd Jun 2016, 11:24
  #959 (permalink)  
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The tortuous path taken by this "leak" (from the original, anonymous source via France 3, then the French media reporting Troadec's reaction upon being told of it) makes it even more likely IMHO that it has been misreported.
Having just seen French lunchtime news I suspect you (and Squawk Ident) are right - there does appear to a bit of backtracking going.
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Old 2nd Jun 2016, 11:32
  #960 (permalink)  
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I apologise if this has been discussed previously. It has been commented on that needing the retrieve 'black boxes' from burnout wrecks in inhospitable places, or from the bottom of oceans, in 21st century seems very old tech. This scenario seems a case in point. AF447 was sending ACARS data back to base, as was the QA A380 with its engine blow up. Is there enough satellite data storage for every a/c to send back FDR/CVR data in live time? The data could be overwritten every 60/90/120mins, what ever is decided by the authorities. There would, of course, be confidentiality protocols as per OFDM's. All modern jets have GPS nav systems. Why not install at manufacture a satellite data transmitter; mandatory to counter those cost cutters. I'm sure it would not be expensive with economy of scale. What has been the cost of searching for; Air India in the Atlantic, AF447, MH370, many others & now this Egypt air?
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