EgyptAir 804 disappears from radar Paris-Cairo

[Feathered]

There is a big difference between releasing your full capabilities and making yourself look incompetent. All they need do is degrade the quality of the proper surveillance photos by 90% and release those. But to release an iPhone video through a frosted window on an official USN website, is a PR blunder of epic proportions. But having watched a recent documentary on Canadian SAR aircraft, where the equipment was three decades old and barely worked, I do wonder.

Incompetent? PR blunder of "epic proportions?" I strongly disagree and your claim has no basis in fact. US Navy does not need or want to fly around the Med just to do a PR patrol or to show off images (and what are you claiming they should show images of?) . The photo you saw merely indicated that USN has a search in effect, it has assets joining the international search effort, and there is no need to say anything else at this time. If they find something relevant, they will report it to the incident command of the search effort.

The Navy aircraft is not a news helicopter. Even if they wished to show off better capabilities, there is a long process to move sensitive details to a public forum and it has nothing to do with simplistic claims like "degrade by 90%" or whatever. Instead of doing this for images of the empty sea, resources are much better spent elsewhere, even if you just want to look at some reconnaissance details.

[D Bru]

http://www.ahram.org.eg/News/181912/25/516639/الأولى/«الأهرام»-تنفرد-بنشر-«وثائق-اللحظات-الأخيرة»-للطائ.aspx

State owned newspaper al-Ahram publishes new docs. Can't somehow make them bigger and with that more legible.



EDIT: this ACFT Technical Log seems for sector CAI-CDG, not CDG-CAI! A more complete pic is here:
http://arabic.cnn.com/world/2016/05/25/pilot-signed-documents-egyptair-ms-804

[andrasz]

al-Ahram publishes new docs


The one on the left is a printout of the ACARS messages, nothing new. The other is the maintenance release log for the CAI-CDG sector, noting NIL defects. Has no bearing on the state of the aircraft on the CDG-CAI leg (though if it were released with any MEL'ed defects, we'd probably know by now).

[MrPeabody]

The one on the left is a printout of the ACARS messages, nothing new. The other is the maintenance release log for the CAI-CDG sector, noting NIL defects. Has no bearing on the state of the aircraft on the CDG-CAI leg (though if it were released with any MEL'ed defects, we'd probably know by now).


I think you're reading it wrong; it's the log entry for CAI-CDG and maintenance release for CDG-CAI sector.

Nil Defects is for CAI-CDG; the info is then noted and transit check accomplished; then the maintenance release is for CDG-CAI. Also you can make out the French 1's in the tyre pressures.

[llagonne66]

Please go back to AF447 Interim Report #1 section 1.6.9.2 to get an explanation on how ACARS messages are managed and time-stamped.
https://www.bea.aero/fileadmin/documents/docspa/2009/f-cp090601e1/pdf/f-cp090601e1.pdf
Sorry, the link is for the French version as I cannot find the English one from the BEA website:ugh:
You can work it out with Google Translate;)

[DaveReidUK]

The one on the left is a printout of the ACARS messages, nothing new.

Clearly it is the ACARS log, but the third-from-right column, headed "Priority" is interesting.

Whereas in the original log from a few days ago it simply had codes "L", "H", and "S" in that column, and it didn't take a genius to deduce that the first two meant "Low" and "High" respectively, it now seems that "S" indicates "Spurious", if my eyes aren't deceiving me.

That's shown against the "SMOKE LAVATORY SMOKE" entry, so I guess the question is, if that can be discounted, how does that alter the putative sequence of events, if at all?

[Coagie]

http://www.ahram.org.eg/News/181912/25/516639/الأولى/«الأهرام»-تنفرد-بنشر-«وثائق-اللحظات-الأخيرة»-للطائ.aspx

State owned newspaper al-Ahram publishes new docs. Can't somehow make them bigger and with that more legible.

rgds,

Dutch

EDIT: this ACFT Technical Log seems for sector CAI-CDG, not CDG-CAI! A more complete pic is here:
???? ???? ??????? ??????? ??????? ?? ??????? ???? ?? ????? ????? ??? ???????"MS804"? - CNNArabic.com (http://arabic.cnn.com/world/2016/05/25/pilot-signed-documents-egyptair-ms-804)

I cropped them, but they're pretty low resolution. The CNN one is more complete, but the newspaper one is a little higher resolution:

[D Bru]

Seems that the Greeks are sticking to their interpretation of the radar data (90° left, 360° right).

"We will start sending the main data from tomorrow, including the radar tracking and the conversation with controllers," one source who requested anonymity told Reuters.
....
The source close to the probe, and a second defense ministry official, said Greece stuck by its account that the plane had lurched violently in mid-air before it disappeared from radar screens. There has already been an exchange of information with Egypt, the sources said.

Egyptian authorities said they did not see the plane swerve and lose altitude before it vanished from their radars.

Greek Defense Minister Panos Kammenos last week said the aircraft took a sudden 90 degree turn, before flipping 360 degrees in the opposite direction and plunging from a cruising altitude of 37,000 feet to 15,000 feet, then vanishing.

"The picture we have off our radars is what the minister announced... we insist on that," the defense official said."

[andrasz]

"The picture we have off our radars is what the minister announced... we insist on that", the defense official said.

Oh dear... As we know from the Rt. Hon. Jim Hacker, one should never believe anything in politics unless it is officially denied. Works in reverse too...

[Volume]

the state of the wreckage (and body parts) as shown on photos released so far and/or described fairly conclusively indicates that the aircraft hit the water in one piece at a very high speed in an aerodynamically clean configuration. Considering the very low amount of parts found yet, they may very well belong to what the first explosion/failure has blown from the aircraft, with the main wreakage still not being discovered. Thinking of the recent Daallo incident, United 811 or the THY DC-10 near Paris in the 70s, such a scenario is also still possible.
Otherwise I do agree, if the items found so far are indeed representative for all debris, this indicates a high speed impact, which only is possible for a largely intact aircraft.

[vmandr]

the interim report no 1 in English - AF447

https://www.bea.aero/docspa/2009/f-cp090601e1.en/pdf/f-cp090601e1.en.pdf

and an excerpt re ACARS p50-51


Interpretation of the messages
Interpretation of the maintenance-related messages is made delicate by the
following factors:
 this type of message is only transmitted once, at the first occurrence. It
can only indicate that a fault has appeared. If the fault has disappeared, no
message is transmitted to indicate this,
 some messages concerning the aircraft’s configuration such as stall or
overspeed warnings are not recorded,
message-timing by the CMC is accurate to within one minute,
 the order in which these messages are transmitted does not necessarily
correspond to the associated sequence of events,
 the limited rate of communication by satellite does not make it possible to
determine directly the time of message reception precisely to the nearest
second,
 in the CFR, a class 1 fault message is not necessarily accompanied by a
cockpit ef-fect, and it is possible that a cockpit effect message is not the
consequence of a fault message.



and the flow...

415

[mross]

Will the Egyptian authorities be able to analyse the FDR and CVR or does this need the expertise of the units' manufacturer? If the French are not given access directly I don't think we will ever learn the truth. Who is the manufacture of the CVR and FDR on the A320?

[Eclectic]

Seems that the Greeks are sticking to their interpretation of the radar data (90° left, 360° right).

"We will start sending the main data from tomorrow, including the radar tracking and the conversation with controllers," one source who requested anonymity told Reuters.
....
The source close to the probe, and a second defense ministry official, said Greece stuck by its account that the plane had lurched violently in mid-air before it disappeared from radar screens. There has already been an exchange of information with Egypt, the sources said.

Egyptian authorities said they did not see the plane swerve and lose altitude before it vanished from their radars.

Greek Defense Minister Panos Kammenos last week said the aircraft took a sudden 90 degree turn, before flipping 360 degrees in the opposite direction and plunging from a cruising altitude of 37,000 feet to 15,000 feet, then vanishing.

"The picture we have off our radars is what the minister announced... we insist on that," the defense official said."
Surely whatever happened could also be seen by the British military radar on Cyprus. The crash site seems to be approximately equidistant between Crete, Cyprus and Egypt.

[llagonne66]

Thanks for retrieving the English version of AF447 Interim 1 report.:ok:
I feel the answer to Ranger One's query is contained in pages 25 to 27 where the BEA explains the one minute "correlation window" principle that regroups alarms upon priority.

[M-ONGO]

Surely whatever happened could also be seen by the British military radar on Cyprus. The crash site seems to be approximately equidistant between Crete, Cyprus and Egypt.

You would think so. Even Nicosia probably had it.

[A0283]

@mross Will the Egyptian authorities be able to analyse the FDR and CVR or does this need the expertise of the units' manufacturer? If the French are not given access directly ...

The Egyptians have stated earlier that the recorders would be read by the Egyptian authorities. Unless the damage would be too severe. Then the recorders would be sent to a 'foreign' specialist/manufacturer. Which is normal practice in cases like these.

Also note that the BEA and other parties are represented in the investigation. These parties will know. But in the case of AirAsia, in spite of explicit requests from the BEA, for instance the CVR data was not published 'en plein publique'. So lessons learned are not shared in full, which of course detracts from the value of a safety investigation.

My impression is that ACARS information would not have been adressed by the parties involved if they had not been 'leaked' earlier. Also, I think that modern day requirements for earlier public disclosure of known (and checked) and unknown facts is something that cannot be ignored by authorities. The case of MH370 has shown what it does to the credibility of authorities if they do not act properly in this respect. If the authorities do not publish these fact, then they run the risk of information being leaked that contains information that should not be leaked, like for instance privacy and such details.

[mross]

I know what the Egyptians said, but wondered if they had the capability? Much of what they say seems ill-informed!

[A0283]

@mross - what an Egyptian spokesman said is that they have the read-out capability. Which is getting more and more common. What they also said suggests that they do not have a large specialist lab. When you have to go there, then you are often close to going or working together with the manufacturers of the recorders anyway. So that is normal too.
I have no inside information on what they actually have. But it is clear that more countries are working on getting more capabilities in this field.

[Dont Hang Up]

Quote:
Surely whatever happened could also be seen by the British military radar on Cyprus. The crash site seems to be approximately equidistant between Crete, Cyprus and Egypt.
You would think so. Even Nicosia probably had it.

Indeed. And it is very re-assuring they are being discrete about it. If they have anything it is reasonable to assume that conversations through the appropriate channels have been had.

No need to add to the feeding frenzy of amateur conjecture on here.

[PDR1]

It depends whether it's actually switched on. My last source was about three years ago, but at that time the cyprus Watchman radar had been switched off for years because interference from egypt (allegedly) created a picture that the SATCO didn't like.

Also looking at the projected location it would have been, what, a couple of hundred miles from Akotiri? Would that be within PSR or SSR range? (I genuinely don't know - hence asking the question!)

[grizzled]

All the bodies have not yet been recovered. It seems equally strange, to me, to suggest a high speed impact was the definitive prime force as opposed to the Egyptians claim of explosive residue, at this juncture.

Why do airline professionals, whose careers have been most negatively affected by terrorism, strive so hard to accept any cause over even the mere suggestion of foul play? It doesn't compute.

With respect...

sitigeltfel did not suggest "a high speed inpact was the definitive prime force" etc. What he, and klintE and myself were pointing out is that the statement by the Egyptian "forensic expert" -- that the condition of the remains proved the existence of an explosion -- was both incorrect and premature. That's all.

Contrary to your assertion, we (aviation professionals), at least those of us with experience in accident investigation, are not accepting any cause at this point. And I certainly have no problem accepting that foul play could be involved. Or not. Time, and the evidence, will tell.

[andrasz]

I know what the Egyptians said, but wondered if they had the capability?
Most airlines these days have quality assurance programs based on QAR readouts and analysis, the data on the FDR-s is identical, if the interfaces are not compromised then with the right software the data readout is as straight forward as looking at pictures on a SD card. It only becomes tricky if the interface or the memory module itself is damaged (which could be the case given the intensity of the impact). Similarly the CVR records digital audio, it can be easily read out by the right software with the appropriate interface.

[vapilot2004]

If the French are not given access directly I don't think we will ever learn the truth.

Are things really that bad in Egypt?

[goeasy]

Exactly Scott. You have answered your own question. The reason your post has likely been removed is this was all discussed much earlier in this thread so your query is a duplication.

Why don't people read THE WHOLE THREAD before posting duplicate BS? Most questions being asked here have been answered more than once already.:{

[AT1]

Looking at the "marinetraffic dot com" web site the vessel "PMS Burullus" is engaged in what has to be a search pattern! About 200 miles NNW of Alexandria. Shows as a pale blue diamond on the web site, but look at its recent track.

[Contact Approach]

goeasy,

People don't generally have all day to read 40 pages worth of nonsense?

[AT1]

According to the marinetraffic web site the vessel "PMS Burullus" has spent the past 10 hours in a rectangular grid pattern searching an area just 1Km by 400 metres. You have to zoom right in to see the pattern. All done with the vessel pointing NE, which means it has been reversing and crabbing its way around most of the time moving very very slowly.

I wonder if they are "on to something"?

Fingers crossed for the sake of all involved.

[wiggy]

goeasy is correct..it was discussed..but as long as chunks of discussion ( no doubt deemed to be off topic) are being deleted there's bound to be an on going game of whack-a-mole....

[Ian W]

It depends whether it's actually switched on. My last source was about three years ago, but at that time the cyprus Watchman radar had been switched off for years because interference from egypt (allegedly) created a picture that the SATCO didn't like.

Also looking at the projected location it would have been, what, a couple of hundred miles from Akotiri? Would that be within PSR or SSR range? (I genuinely don't know - hence asking the question!)

The airport radars may have been switched off but the larger ones higher up on Cyprus almost certainly were not. I would be very surprised if that area of the Mediterranean was not in solid radar cover from several sources other than the normal ATC systems. However, none of them will be eager to publicly declare their coverage.

[grizzled]

goeasy,

People don't have generally have all day to read 40 pages worth of nonsense?

True enough, but what people can do (should do) before posting a question, or media quote, is do a quick word search of the thread. That takes but a minute or two and saves the rest of the readers having to endure multiple repeats, and perhaps saves the poster being embarrassed, or exposed to the slings and arrows of other ppruners...

[DARK MATTER]

Screen Grab of the PMS Burulla track for the last few hours.

(Courtesy AIS Vessel Tracking)

417

[AT1]

Dark Matter

It is worth pointing out that the "grid" you can see is approx 1km in the North South direction and just 450 metres East West. Each sweep is just over 200 metres from the last.

It strikes me that this is too "fine" a grid for a pinger search - and rather more a sonar search. Each pass would have to sweep a 200 metre or so wide path, but I rather hope somone with undersea submerisble/sonar expertise might step forward.

[Methersgate]

Not an expert, but with a little experience, yes, AT1, that's a sonar search pattern.

[Mad (Flt) Scientist]

I know what the Egyptians said, but wondered if they had the capability?

I believe that either during or subsequent to the accident where the Egyptian authorities violently disagreed with the NTSB conclusions (the suicide vs flight controls failure one) that the Egyptians bought a FDR etc lab capability from FlightScape, now CAE-Flightscape, which is the software provider to a number of the "big" accident agencies (if you've seen a recent "official" FDR plot, chances are you've seen a Flightscape plot).

While having the kit doesn't always equate to having the expertise, I think it's safe to say they do have the ability to do what they say, unless, as has been mentioned, the units are so badly damaged only the original manufacturer can read them (which can be the case with the "big boys" as well)

[oldchina]

Mad F S: " While having the kit doesn't always equate to having the expertise."
Agree. Take the example of the A320's FBW flight controls. If an FDR trace shows a given sidestick input and a control surface moving in a certain direction, how to know whether the plane behaved as designed? I'd venture that the way to know is to ask Airbus not the Egyptians.

[mross]

I found a fascinating article (https://www.bea.aero/uploads/tx_scalaetudessecurite/use.of.fdr_01.pdf)on 'decoding' digital FDRs on BEA's website. Even if the Egyptians have the equipment it may not be plain sailing. The CVR is probably much easier. Article is in English.

[wheelsright]

Correct me if I'm wrong but AF447 ACARS was received via Satcom. In Egypt Air 804's case the ACARS was received by a ground station via VHF or VDL mode 2. For this reason it would not be ideal to draw too many comparisons. But there are a few points that are in line with the AF447 report:

ACARS does not transmit all ECAM's it is a subset that is programmed by the operator. This may introduce some differences between operators.

The messages are not real time, the data is processed before transmission and placed in a queue. This may result in a delay before a message is transmitted.

In addition, ACARS in VHF mode only transmits at 2400bps and there is no round trip confirmation in any mode.

If the aircraft was severely damaged (fire, decompression, bomb etc.) one would not expect comprehensive ACARS messaging; only a short burst that is a subset of the faults or cautions that existed. The ACARS transmissions may well be consistent even with a rapid decompression. However, the evidence points to the aircraft colliding with the sea at high speed and largely intact.

Many of the theories proposed in this thread are not consistent with the "evidence" so far (if any of it is true?!). There are quite a few things that can be ruled out as very unlikely already.

[wheelsright]

J. Kitaori, "A performance comparison between VDL mode 2 and VHF ACARS by protocol simulator," 2009 IEEE/AIAA 28th Digital Avionics Systems Conference, Orlando, FL, 2009, pp. 4.B.3-1-4.B.3-8.
doi: 10.1109/DASC.2009.5347498

Abstract: VHF Aircraft Communications Addressing and Reporting System (ACARS) is the most popular VHF aeronautical datalink. It is used for such applications as airline operation and air traffic control. VHF ACARS has only a 2400 bit/s (bps) transmission rate air-ground link. The VHF Digital Link mode 2 (VDL2) system, which has a thirteen times higher transmission rate air-ground link than VHF ACARS, is very similar to VHF ACARS. Both systems can deal with messages in ACARS format. Even though the systems are well used for various operations, their effective link capacities are not so clear. Finding out effective communication performance, including real link capacity and acceptable maximum delay, is useful for the design layout of ground facilities and rebuild datalink operation guidance in the near future. We built both VHF ACARS and VDL2 protocol models on an OPNET protocol simulator to evaluate their effective communication performance. This paper gives an outline of the protocol models and comparison results of these performances by simulation. Statistics such as transmission delay and throughput have been obtained under various load conditions for up to 200 aircraft. Before starting the simulation, we analyzed message data length and the message generation interval of VHF ACARS from real communication logs in Japan. The message data length was mostly distributed randomly, below 660 bytes, and messages exceeding 660 bytes rarely appeared. The message generation interval mostly followed Pareto distribution. We assumed that the message data length and data generation interval followed uniform distribution and Pareto distribution respectively. We found the following by analyzing simulation results. i) When data traffic load generated from an aircraft equaled the load directed to the aircraft, the VDL2 system was able to process 4.6 times more congested load than the VHF ACARS. ii) When data traffic load generated from an aircraft was five times higher than the load directed- to the aircraft, the VDL2 system was able to process 8.8 times more congested load than the VHF ACARS. The load condition approximated real VHF ACARS data generation ratio between forward link and reverse link.

URL: IEEE Xplore Abstract - A performance comparison between VDL mode 2 and VHF ACARS by protocol simulator (http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=5347498&isnumber=5347412)

[wes_wall]

Has anyone seen the Greek radar tapes yet. Egypt also was to release what they had.

[klintE]

The messages are not real time, the data is processed before transmission and placed in a queue. This may result in a delay before a message is transmitted.
In addition, ACARS in VHF mode only transmits at 2400bps and there is no round trip confirmation in any mode.

OK, but 3 minutes between received messages means that they were transmitted exactly in that time period.
No matter how slow the messaging is because time travel is always the same. So something bad happend and systems were alive at least 3 minutes later. Correct?

[Kitiara]

OK, but 3 minutes between received messages means that they were transmitted exactly in that time period.
No matter how slow the messaging is because time travel is always the same. So something bad happend and systems were alive at least 3 minutes later. Correct?

Since there is no seconds information in the transmitted data, then the time span could be as low as 2 minutes and 1 second.

But yes, it would seem to imply that the transmitter remained powered and in a position to be received from for that period.

[HeavyMetallist]

Looking at the abstract of that Kitaori paper, the typical ACARS message is going to need less than two seconds to transmit even at 2400 baud. Low data rate isn't going to explain the limited number of messages received over a period of several minutes.

[Filler Dent]

It's likely, as Wheelsright pointed out earlier, not all faults are sent to ACARS for transmission. The CFDS is operator configured, so some messages will be stored, some printed (immediately or after landing) and others sent to ACARS.

As we do not know what filters were applied (if any) we can only assume other fault messages were likely to have been generated as well and were never transmitted on ACARS either because they were filtered or ACARS/VHF 3 failed.

I'm sure the FDR when its found, it will tell us what we need to know and shed some light on this catastrophe.

[normanl]

Dark Matter

It is worth pointing out that the "grid" you can see is approx 1km in the North South direction and just 450 metres East West. Each sweep is just over 200 metres from the last.

It strikes me that this is too "fine" a grid for a pinger search - and rather more a sonar search. Each pass would have to sweep a 200 metre or so wide path, but I rather hope somone with undersea submerisble/sonar expertise might step forward.
Some side scan sonars can produce a image of the sea floor out to 100m on a side. The sonar is usually towed from a long cable with the tow body near the sea floor. The image should show any of the larger parts and structures of the aircraft. One drawback it doesn't image directly below the tow body so you have to make sure the images overlap.

[justamom]

Egypt sends robot submarine to help plane crash search | The Expat's Guide To Cairo (http://expatcairo.com/egypt-sends-robot-submarine-to-help-plane-crash-search/)

http://expatcairo.com/wp-content/uploads/2016/05/PMS-Burullus-IMO-9680750-1.jpg May232016
Egypt sends robot submarine to help plane crash search

Expat Cairo (http://expatcairo.com/author/admin1/)News (http://expatcairo.com/category/news/) Reuters (http://www.egyptindependent.com//staff/reuters)




Egypt has sent a robot submarine on board the PMS BURULLUS to join the hunt for an EgyptAir plane which crashed in some of the deepest waters of the Mediterranean Sea with 66 people on board, President Abdel Fattah al-Sisi said on Sunday.
Ships and planes scouring the sea north of Alexandria have found body parts, personal belongings and debris from the Airbus 320, but are still trying to locate the black box recorders that could shed light on the cause of Thursday’s crash.
Sisi said that underwater equipment from Egypt’s offshore oil industry was being brought in to help the search.
“They have a submarine that can reach 3,000 meters under water,” he said in a televised speech. “It moved today in the direction of the plane crash site because we are working hard to salvage the black boxes.”
An oil ministry source said Sisi was referring to a robot submarine used mostly to maintain offshore oil rigs. It was not clear whether the vessel would be able to help locate the black boxes, or would be used in later stages of the operation.
Air crash investigation experts say the search teams have around 30 days to listen for pings sent out once every second from beacons attached to the two black boxes. At this stage of the search they would typically use acoustic hydrophones, bringing in more advanced robots later to scan the seabed and retrieve any objects once they have been found.
Separately, the US Navy’s Sixth Fleet said one of its patrol aircraft supporting the search had spotted more than 100 pieces of debris positively identified as having come from an aircraft, and passed the data to the Egyptian Navy.
EgyptAir flight 804 from Paris to Cairo vanished off radar screens early on Thursday as it entered Egyptian airspace over the Mediterranean. The 10 crew and 56 passengers included 30 Egyptian and 15 French nationals.
French investigators say that the plane sent a series of warnings indicating that smoke had been detected on board shortly before it disappeared.
The signals did not indicate what caused the smoke or fire, and aviation experts have not ruled out either deliberate sabotage or a technical fault, but they offered early clues as to what unfolded in the moments before the crash.

[PJ2]

grizzled, Spot on! Quote:
Originally Posted by Contact Approach http://www.pprune.org/images/buttons/viewpost.gif (http://www.pprune.org/rumours-news/579183-egyptair-804-disappears-radar-paris-cairo-post9388018.html#post9388018)
goeasy,

People don't have generally have all day to read 40 pages worth of nonsense?

True enough, but what people can do (should do) before posting a question, or media quote, is do a quick word search of the thread. That takes but a minute or two and saves the rest of the readers having to endure multiple repeats, and perhaps saves the poster being embarrassed, or exposed to the slings and arrows of other ppruners... When many were struggling with the very same problem of double, triple, ad-nauseum posts on the same question or topic, John Tullamarine, (Tech Log), provided the following search tool. One can use this to search any thread on PPRuNe. One can search for his/her subject or some key words which are in his/her pending contribution, to see what may have been said/posted regarding same.

The bolded words are the words one is searching for. The rest of the text points to pprune and to the forum one wishes to search in, (tech log, rumours and news, etc.)

Give it a try - it does return all instances of the search words, so be discriminating!

Make sure the entire text of the URL is included: site:http://www.pprune.org/rumours and news (http://www.pprune.org/rumoursandnews) etc., then add your search text to the front of the URL:

Searching for ACARS af447 in "tech log":

ACARS af447 site:http://www.pprune.org/tech-log/

[Nadar]

When many were struggling with the very same problem of double, triple, ad-nauseum posts on the same question or topic, John Tullamarine, (Tech Log), provided the following search tool.

..

Searching for ACARS af447 in "tech log":

ACARS af447 site:http://www.pprune.org/tech-log/

I'm not sure what search tool you are referring to, but you can use that syntax on most search engines, for example on Google (https://www.google.no/?gws_rd=cr,ssl&ei=4IovUpXeA-rx4QSpwIDYBg#q=ACARS+af447+site:http:%2F%2Fwww.pprune.org%2F tech-log%2F) or DuckDuckGo (https://duckduckgo.com/?q=ACARS+af447+site%3Ahttp%3A%2F%2Fwww.pprune.org%2Ftech-log%2F&ia=web). You can also combine that with the normal search operators like +, - etc.

[wheelsright]

Reviewing the AF447 ACARS data received via Satcom shows a possible maximum delay of up to 115 secs between time-stamp and reception. In the event that there are widespread failures to report via ACARS one would would not expect many of them to have had a chance to propagate and transmit within a window of 2+ mins.

As has been mention previously, ACARS is designed as a maintenance aid and transmission is the systems lowest priority. It would be interesting if someone has an example of the last ACARS transmissions via VHF for an aircraft that had widespread electrical failure to see what ACARS managed to transmit.

Of course, the reason for the abrupt end to the ACARS messages could still be explained by loss of reception.

I am not sure whether it has been confirmed that Egypt Air had subscribed to the transmission of ACARS via Satcom? If they did there may be additional Satcom data that has not yet been released.

AF447 ACARS See #2431 http://www.pprune.org/tech-log/395105-af-447-search-resume-122.html

[dipperm0]

For those interrested in Search And Rescue, the bible in the western world is the ATP 10 rev (D) which is a NATO UNCLASSIFIED document which can be easily accessed on the internet.

http://www.navedu.navy.mi.th/stg/databasestory/data/laukniyom/ship-active/big-country-ship/United-States/ATP/atp10.pdf

[vapilot2004]

I am not sure whether it has been confirmed that Egypt Air had subscribed to the transmission of ACARS via Satcom? If they did there may be additional Satcom data that has not yet been released.

If the airline paid for SATCOM service for their ACARS, the VHF link would more than likely not have been active.

FMC's/FMS' can setup transmission to default to VHF when over or near land, then switch to the more expensive SATCOM service (or to a lesser extent, HF) only when out of range of a VHF ground station.

[paulmoscow]

I can't see anything from your link that answers the question.

The correct link is as follows:
http://www.pprune.org/9387723-post759.html

[Cazalet33]

Are there airline crashes at sea where there were no large human remains? Or does the lack of large body parts not indicate anything definitive?

Yes, to both questions.

I was aboard the first specialist responder work vessel which attended the wreckage of the Itavia DC9 in 1980. We had been working in the straights of Messina and as we had two manned submersibles and a crew of hydrographers we were immediately despatched by the Italian Admiralty to investigate the scene. Our gear was limited to 600m and the depth at the locus was much greater than that, so our onscene work was limited to surface recovery only.

At the time, there was no doubt in the minds of the two senior officers who we had on board from the charterer that the aircraft had been shot down accidentally by the usual suspect, mistaking it for a known Libyan MiG intruder. Subsequent investigation of the seabed wreckage cast some reasonable doubt on that and it's a bit of an open verdict as to how the aircraft was brought down.

One's first impression on arrival at the scene was the incredible number of bits of paper were among the more solid flotsam. Thousands of pieces of paper. Of the human remains, there were a hundred or so that we recovered and the local fishing boats who arrived a few hours before we did recovered many more, but mostly very small. The largest were recognisable parts of limbs, but most were really quite small.

From other work on the seabed in other cases, I've found quite intact remains of almost whole bodies within and very close to airframe parts.

When an aircraft comes apart at very high speed and high altitude, eg the shootdown of an Iranian Airbus by the usual suspect, ejected occupants tend to be stripped of clothing by the airstream during the deceleration to terminal velocity.

From personal experience in several such field investigations I expect that the condition of size of the remains on the seabed will be quite different to those found on the initial surface search.

I doubt that the lack of large body parts indicates anything definitive. I also doubt that a bomb is indictated by the skimpy evidence we have so far, but we need more data before we can analyse the three principal postulates.

[cooperplace]

Thank you for this post describing a horrifying and unique experience; our thoughts go out to first responders in such situations. I thought the Itavia DC9 was brought down by a bomb in the rear lavatory?

[Cazalet33]

Cooperplace, you may be right.

At the time, the Rear Admiral and Captain of the Italian Navy who were our client reps were in no doubt that the aircraft had been shot down. They knew that the suspect navy had been trying to engage the Libyan MiG which we later learned had crashed unseen on Italian territory.

The official theory, for public consumption was, as usual, a conspiracy theory of a bomb. That's quite normal in these cases. It exonerates almost everybody in positions of public responsibility and it stops the public from thinking.

I don't know the true story behind the downing of that Itavia jet, but I entirely understand why the USN made the radar record of the salient time 'disappear'. Out of sight, out of mind. You don't need to know. It never happened. Move along. Nothing to see here. Do not discuss, especially publicly. Wait until you are officially told what to think. Most especially, wait until you are told what you can say about what happened.

[Cazalet33]

The AIS plot shown above is very strongly indicative of the search vessel looking at a credible search datum.

They are clearly using Dynamic Positioning (DP) to manoeuvre the vessel on the search pattern and they are clearly using a deep tow sensor. They are not 'towing' the side-scan towfish or deep-tow pinger locator like a trawler tows a net. It's not astern of them, most of the time.

Sidescan sonar seems quite likely, but you would use a very similar pattern to 'box in' a suspected target with a deep tow hydrophone to locate a pinger signal.

A sensible searcher would concentrate his efforts, at this stage in time, to getting best data from the battery-limited pinger.

The way you do that is not by triangulation but by measuring the signal strength as you pass by the source. You plot that out with signal strength in the Y axis and the distance along track on the X axis. You get a parabolic curve, albeit a lumpy bumpy one which can sometimes be a bitch to interpolate. Maximum strength suggests that that is where your line reached closest point of approach (CPA). That gives you an LoP to/from the target, perpendicularly. By repeating that line perpendicularly you get a cross-cut of that LoP. By covering the other two sides you eliminate the baseline side confusion and further refine the position. Voila. You have a good approximation to the actual co-ords of your Dukane (or whatever) pinger.

I do, however, concur with those who have pointed out that the line-spacing is more consonant with a medium frequency sonar run, eg 125kHz, than what you would choose for a broad-brush pinger locator run in anything other than very shallow water. The reason why I think it's more likely to be a pinger locator on the end of the wire than a side-scan is that the speed over the ground is something like half a knot. That's Okay for a hydrophone but would not be enough water speed to keep a side-scan towfish on any kind of of sensible heading and would make sonar trace interpretation impossible.

I therefore conclude that they've got a pinger within earshot and are boxing it in before putting an ROV onto it.

The water depth at that locus, btw, is approx 3106m. The seabed sediment consistency in that area is like baby-poop. ROVs will have to be negatively ballasted, ie positively buoyant at bottom depths, so that they don't stir up the fluffy sediment and blind themselves during recovery of high value items such as the 'box(es)'.

[SysDude]

Per the WSJ an ELT signal was picked up by satellite and that is why they have localized the search area to where they are now.

[SysDude]

Capry -

The article was clear that it was an ELT, which floats, sends a radio frequency beacon, and is detectable by satellite, unlike a ULB.

They are using the ELT to focus the search for the ULB.

There was no indication of when the ELT beacon was detected, but the PMS Burullis made a bee-line to their search location immediately after the crash.

[D Bru]

To note that distance from LKP (33.6757/28.79242) to last night's BURULLUS search location (33.5322/029.1371) is just under 20NM.

And perhaps more important (in view of the Greek Defense statement on their final radar images and the Egyptian denial of that) is that the BURULLUS location is on about a 100° course, East SE from LKP (noting that MS804 while at FL370 at LKP was heading 136°).

If MS804 is found around BURULLUS' location, this implies IMO that the claimed left turn after LKP indeed would have to have taken place, while that in turn gives further credence to the also claimed subsequent 360° right.

[.Scott]

ELT's have changed since my flying days.
There is now a digital 406MHz signal that includes information registered to the aircraft or ELT owner.

[grizzled]

Contact Approach...

I agree. If only it were that simple... The past few posts re ELTs and ULBs are a good example of why your perfectly sound idea doesn't work on these forums.

Somebody posts a quote from a newspaper (WSJ in this case), probably because they assume what is written in that article is "factual". A discussion then ensues based on completely wrong information about ELTs, first from the article itself, then made worse by answering another poster's question erroneously by citing that same article as a source of accurate info about ELTs and ULBs: where they are located on an aircraft, do they float, do ELTs transmit underwater, if so can the signal be received by a satellite, discreet ELT IDs (BTW... yes, one can tell what aircraft it's from) and on and on and on.

Which is why, with the utmost respect to the Mods whose job is so very difficult and frustrating, this should not be considered a "Professional Pilots Rumour Network" when reading this (Rumours and News) forum.

Sigh...

[Lonewolf_50]

@grizzled: for the edification of the casual reader/lurker/ we could point them to the Tech Log forum,
where there's a thread (http://www.pprune.org/tech-log/376584-elt.html)with a discussion of ELT's with at least one good post (http://www.pprune.org/tech-log/376584-elt.html#post4978084). Summary from that (PPruNer avspook)



ELTs transmit on 121.5/243/406 MHz. (406 MHz contacts a satellite monitoring system. It uplinks messages to a Satellite that includes aircraft identifying information. Thanks to David Reid for the specifics in his post a few down from this one)
Some ELT's are tied into the Navigation system to uplink last position.
Many rely on the Satellite system to direction find the signal
An ELT (due to the frequencies involved) is not able to contact the satellite from underwater. It is also not a waterproofed box.
The aircraft hull mounted ELTs are typically set up to transmit when a G-load of a particular magnitude is detected (crash)
Sample product sheet (https://www51.honeywell.com/aero/portal/Common/Documents/myaerospacecatalog-documents/BA_brochures-documents/ELT_For_Web.pdf)(Honeywell; Thales and some other vendors also make products in this class).

FAA Spec TSO-C126A (http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgTSO.nsf/0/0ac772bbed9b95a586257523007629b3/$FILE/TSO-C126a.pdf)(Update: pages 9-16 of this link are TSO-C126b (https://www.faa.gov/about/office_org/headquarters_offices/agi/reports/media/FAA_Report_to_Congress_on_Emergency_Locator_Transmitter_Moun ting_Requirements.pdf).
DO-204A, DO-160F are specs cited on some product sheets (DO-204b is pending based on some ICAO docs posted on line).

[wes_wall]

guara
Agree with you regarding the size of (or lack of) the debris field. Any one familiar with the foot print left by an airplane making contact with the ground, or water, would be thinking it strange that more objects would have been seen, and or, collected. Too many whys creep into the possibility the crew flew the airplane into the ocean. Large things which separate from the airplane after contact will float, and debris will bleed quickly from inside the interior.

[FE Hoppy]

@grizzled: for the edification of the casual reader/lurker/ we could point them to the Tech Log forum,
where there's a thread (http://www.pprune.org/tech-log/376584-elt.html)with a discussion of ELT's with at least one good post (http://www.pprune.org/tech-log/376584-elt.html#post4978084). Summary from that (PPruNer avspook)



ELTs transmit on 121.5/243/406 MHz. (406 MHz contacts a satellite monitoring system. It uplinks the serial No of the Box which the Satellite authority uses to look up the Regulatory authority, who keep a list of serial no's versus tail nos)
Some ELT's are tied into the Navigation system to uplink last position.
Many rely on the Satellite system to direction find the signal
An ELT (due to the frequencies involved) is not able to contact the satellite from underwater. It is also not a waterproofed box.
The aircraft hull mounted ELTs are typically set up to transmit when a G-load of a particular magnitude is detected (crash)
Sample product sheet (https://www51.honeywell.com/aero/portal/Common/Documents/myaerospacecatalog-documents/BA_brochures-documents/ELT_For_Web.pdf)(Honeywell; Thales and some other vendors also make products in this class).
FAA Spec TSO-C126A (http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgTSO.nsf/0/0ac772bbed9b95a586257523007629b3/$FILE/TSO-C126a.pdf)(not sure if an international spec is also in print) DO-204A, DO-160F are cited on some product sheets.
For the love of god! don't show them the way to tech log it's the last bit bit of sanctuary I have on here.....

[DaveReidUK]

ELTs transmit on 121.5/243/406 MHz. (406 MHz contacts a satellite monitoring system. It uplinks the serial No of the Box which the Satellite authority uses to look up the Regulatory authority, who keep a list of serial no's versus tail nos)

The ELT sends the (programmable) ICAO 24-bit address belonging to the aircraft (same as used for Mode S, TCAS, etc). That's sufficient to identify the aircraft without the need to maintain a separate database of unit serial numbers.

[A320FOX]

In post 808 it is implied that the country that shot down Itavia DC9 in 1980 is the same that shot down the Iranian Airbus which everybody knows who fired the missile. This is misleading because if somebody shot down the DC9 it was not the same suspect. It is a fact that the USN and the Italians and the French hid and destroyed evidence but the usual suspect did not shot the DC9.

[DaveReidUK]

It is a fact that the USN and the Italians and the French hid and destroyed evidence but the usual suspect did not shot the DC9.

It's generally accepted that nobody shot it down.

[Lonewolf_50]

@FE Hoppy: apologies.
@David: Thank for the point on the ICAO 24-bit code.

[guadaMB]

guara
Agree with you regarding the size of (or lack of) the debris field. Any one familiar with the foot print left by an airplane making contact with the ground, or water, would be thinking it strange that more objects would have been seen, and or, collected. Too many whys creep into the possibility the crew flew the airplane into the ocean. Large things which separate from the airplane after contact will float, and debris will bleed quickly from inside the interior.
I'm so sorry if was understood that I claim THE CREW sent the airplane against the Med Sea INTENTIONALLY. Now my post is deleted by mods, buy what I wanted to explain is that the crew INTENDED TO MAKE THINGS RIGHT to control but weren't able to success.
What I suppose (and many in my circle) is that once things came to be really BAD, the PiC or the FO took command of the a/c with the intention of a controlled/smooth splash-down but coudn't (possibly with serious electrical damage/smoke/etc and in full darkness this may be very difficult). The lack of rational debris for an A320 (in quantity) makes me think of a relatively quiet sinking. I don't forget the pieces of bodies and some objects really torn by strong forces, but those maybe cause of a localized break in fuselage, leaving the remaining of the hull in one piece (and possibly passengers caught by belts and in their seats).

[alphasun]

There was a CNN report this evening (26th May) quoting the Egyptians as saying that some sort of beacon has been detected, enabling the search area to be shrunk to a few km2.
According to the reporter, the Egyptians are attributing this information to Airbus, yet the beacon in question only has a transmission life of 2 days, suggesting that the information is a few days old. One set of specs on the Technical forum seems to indicate that these beacons transmit for much longer than two days. I was perplexed by the CNN report -- thanks to the Technical Forum I am at least perplexed at a slightly more informed level.

[bloom]

In the US, ELT being reported located.

[GarageYears]

In the US, ELT being reported located. Er, that's not quite what is being said.

This is what is currently on CNN for example:

Airbus has detected signals from the Mediterranean Sea where EgyptAir Flight 804 crashed last week, Egypt's state-run Al Ahram news agency reported ThursdayI don't know if that is accurate, since I haven't seen anything directly from Al Ahram.

[klintE]

AFAIK, typical ELT is able to broadcast only for 50 hours from the time of activation...

[AT1]

According to the marinetraffic web site the PMS Burullus spent a day moving at a snail's speed in a classic zig zag course coverign an area about 1Km by 1Km. Its position has not been updated for nearly 24 hours - at least on the "free" version of the tracker I have used.

The lack of an update is most likely due to the Burullus being in exactly the same area of poor radio coverage, with the added problem of its antenna for the tracking system it uses, AIS, being just a few metres above sea level. In fact there was a loss of coverage for a hour or so yesterday. Some vessels use a satcom version of AIS, but you have to have a rather expensive subscription to see that data. Anyone have access to the Satcom version? I do not know if the PMS Burullus is using satcom to broadcast its position though.

It could be that the "authorities" do not want the vessel's movements to be tracked of course, and the vessel has simply turned its AIS transmitter off.

There is no suggestion that the vessel is stationary - the last update is time stamped nearly 24 hours ago, so it is simply the data is not available.

It is also notable that there seems to be a big empty space around the Burullus clear of other shipping, though that may just be coincidence, or a consequence of the particular location.

What was interesting is two days ago the Burullus moved on a relatively long "base line" (my interpretation) NE to SW many Km long at quite some speed, before retracing its steps to roughly halfway along that line, then moving very slowly 2Km SW, perpendicular to that line and then starting this 1Km by 200 odd metres zig zag back and forth (see posts 784 & 785).

Could the base line be the "pinger" being heard and triangulated, approximately, and then the fine zig zag be a sonar scan? Post 808 gives some very helpful information about sonar, but makes the point the Burullus was moving rather slowly for a sonar fish. My logic would say the pattern was more closely spaced than you would need to home in on a pinger, which I understand has a range of several Km not the hundred or so metres the pattern suggests. Would you not "just" make one pass in an arbitrary direction, looking for the peak sound level, then pass through that peak point at right angles looking for a peak again, and thus, with a bit of trigonometry, home in on the source?

But the fact that a vessel has swept an area just 1Km by 1Km (2 square Km or so if it has kept going at the same rate for the past 24 hours while its position has not been updated) may suggest they are hunting something down. The press "noise" would seem to support this.

We will know in due course.

[x_navman]

AFAIK, typical ELT is able to broadcast only for 50 hours from the time of activation...
not only that..., but ELT will not transmit through water...

CNN reporter seem to think the ELT was transmitting from the wreckage on the ocean floor.

It's amazing that with all the coverage of AF 447 and MH 370.., reporters still don't understand even the most _basic_ aspects of the technology about which they report.

anyway, this info apparently originated from Egypt and something about it is wrong - ELT signals are not being received from the ocean floor

[takata]

The BEA just issued a communiqué tonight :
Marine Nationale Hydro. "Laplace" (A793) is sailing to the crash site with two BEA officers, in order to join the search for the CVR/FDR. She also boarded three pinger locators.
They are actually planning to send another vessel equiped with deep sea recovery assets.
The Egyptians authorities are still in charge of the search, assisted by the BEA.

A793 Laplace :
Laplace (A 793) (http://www.defense.gouv.fr/marine/equipements/batiments-de-soutien/batiments-specialises/hydro-oceanographique/laplace-a-793)

http://www.defense.gouv.fr/var/dicod/storage/images/base-de-medias/images/marine/batiments/laplace/laplace2/2429401-1-fre-FR/laplace.jpg

BEA :
https://www.bea.aero/fr/les-enquetes/les-evenements-notifies/detail/event/accident-survenu-a-un-airbus-a320-immatricule-su-gcc-et-exploite-par-egyptair-au-large-des-cotes-egyptiennes-survenu-le-190516/
http://takata1940.free.fr/BEA_Laplace.jpg

[takata]

Alseamar DETECTOR 6000 System boarded on Laplace:
Underwater Detection Systems DETECTOR | ALSEAMAR (http://www.alseamar-alcen.com/acoustics-positioning/underwater-detection-systems-detector)
Black Boxes Relocation | ALSEAMAR (http://www.alseamar-alcen.com/acoustics-positioning/black-boxes-relocation)

The other company contracted for next step might be DOS (Deep Ocean Search)
Deep Ocean Search - Home (http://www.deepoceansearch.com/)

The cost of operational search is actually shared by Egypt and France.

[Cazalet33]

AT1's interpretation is pretty good.

The absence of nearby vessels is almost certainly a consequence of a day shape signal which either declares that the vessel is manoeuvring with difficulty or is "not under command". All ships will see that signal either by day, in the form of a ball over a double cone (diamond shape) over a ball, or by red/white/red vertically arranged lights at night and will give her a wide berth. There are variations on that theme, such as "engaged in underwater operations", but the message is pretty much the same: please push off out of my way. Furthermore the ships watchkeepers on the bridge will be watching any traffic within a dozen or more miles on radar and will call them on CH16 marine VHF (similar to 121.5) and request that they stay well away.

If the vessel appears to be almost stationary on AIS then one interpretation might be that she has deployed her ROV.

The way that works is that the ship maintains station on the ROV at a predetermined number of metres laterally and longitudinally from the ROV in "follow sub" mode and the ROV therefore controls the ship. It's quite cumbersome as the ROV is the size and weight of a Ford Transit or Galaxy and the ship weighs several thousand tons. The ROV therefore has to manoeuvre very gingerly and avoid making suddenly turns or accelerations. If the ship has to make very large thruster inputs to try to maintain station you can get aeration of the water under the ship which can cause loss of acoustic contact with the ROV and a massive muddle ensues. Angry words are exchanged on the intercom between the bridge and the ROV control shack. That's another reason why the bridge will want all other vessels to stay well away, preferably at least a mile or two.

It may perhaps interest Prooners unfamiliar with how these things work for me to explain a little about underwater nav.

There are two principal methods. Long baseline and (ultra) short baseline.

USBL works in one of two different modes. The first involves the ship sending out an interrogation pulse from a transducer which extends below the hull telescopically rather like a military submarine's periscope, only in the opposite direction. The ROV has a transponder which waits a known number of milliseconds and transmits a reply pulse. The ship's USBL transducer is a small cruciform affair and by measuring the phase difference at the four transducers you derive the angle at which the pulse arrived. Thus you get a 3-D position with respect to the ship. The other USBL mode involves sending the interrogation pulse electrically down the umbilical and a "flowerpot" responder on the ROV replies with a pulse just like a transponder. Advantage is that the interrogation is almost instant and not prone to raypath anomolies or acoustic noise on the outbound signal.

Long baseline is completely different. It involves setting out an array of seabed transponders and co-ordinating them. The ROV then self-navigates by doing what amounts to a DME/DME fix, using at least three and preferably four or five transponders. It then telemets its self computed position up the umbilical. Much more practical for deep water work like this job than USBL which will be slow and wooly. I'd be adversely surprised if these guys haven't deployed an LBL array around the locus by now.

[Lonewolf_50]

Long baseline is completely different. It involves setting out an array of seabed transponders and co-ordinating them. The ROV then self-navigates by doing what amounts to a DME/DME fix, using at least three and preferably four or five transponders. It then telemets its self computed position up the umbilical. Much more practical for deep water work like this job than USBL which will be slow and wooly. I'd be adversely surprised if these guys haven't deployed an LBL array around the locus by now. Would the quality of the sea bed in this area (which you alluded to in an earlier post as being pretty bad) argue against the long baseline method, or do the transponders have mechanical means to mitigate issues with sea floor conditions? I'd guess that the state of the art has advanced to where you'd have kits optimized for differing conditions, and thus have some "muddy/silty" sea floor models for use in such conditions.

[Phalconphixer]

Bit of verbal diarrhea... but a bit more aint going to make a lot of difference...
During the mid nineties I was involved in bringing 5 ex-RCAF (CC-117) Falcon 20's onto the UK civil register. Three of these aircraft had previously been used for transport work and the other two for Electronic Warfare training. The transport variants were fitted with a detachable panel at the bottom of the fin. This panel carried a 121.5 / 243 /406(?) self powered Crash Locator Beacon; essential equipment given the RCAF operating environment in the wastes of the Arctic.
Deployment of the panel was initiated either by the crew and a switch in the cockpit, or in the event of a crash, by one of 5(?) Vacuum Crash switches, three along the lower fuselage and one in each wing tip. Operation of any one of these switches would deploy the panel and set the CLB to transmit. The boxes involved had been removed when the aircraft were retired but the activation mechanism was still in place...
As the Avionics Lead on the mod program, initially this and other role equipment wiring left me head scratching because the wiring diagrams for the said role equipment were 'not available'... but since we were going to remove all unidentifiable role equipment wiring it didn't matter too much. But the detective work was fun!
To the point however... I have often wondered why aircraft manufacturers don't design in something similar into modern airframes... an automatically deployable floating panel carrying a 406MHz ELT... ELT's are OK but once the aircraft submerges thats it... finito.
I always thought my former employers positioning of the required ELT was a bit stupid... the antenna was located forward of the tailcone at the base of the fin, but the ELT Transmitter was in the tail cone itself, the two connected by a length of RG-400 coax... in the case of a land crash the tailcone tends to separate from the rest of the airframe, thereby removing the Antenna from the transmitter... oops?

[Cazalet33]

Wolf,

Good question.

What you do in soft sediment is deploy the beacon atop a long rope which is is attached to a bloody great big clumpweight and has a floatation collar on itself.

This keeps the beacon above the seabed, hopefully at a similar height above seabed level to that of its brethren in the array so that its depth does not vary much with the others in the array if the seabed current changes direction as a consequence of tidal or other current movements. If the current changes direction, the entire array sways and the resultant fix just goes with the flow, so to speak. They are generally five or so metres above the local seabed, but that depends on the planning of the array vis-a-vis intervisibility acoustically for the calibration of the array. They have to be able to 'talk' to eachother acoustically for them to to be able to self-calibrate trilaterally so that all of the baselines among the array are measurable.


The flot collar is there anyway to recover the beacon at the end of the job. There is an acoustically addressable release device at the base of the beacon. When you want to send the beacon up to the surface you send the command acoustically and the acoustic release releases the physical connection to the clump weight and the buoyancy of the transponder's flot collar sends it upwards. The flot collar is chamfered at its upper end so the the transponder floats nose down in the water at the surface and enables it to give ranging information to the recovering vessel. They cost several tens of thousands of Dollars/Pounds/Euros apiece and are not regarded as being expendable like the sonobouys that the military use with great abandon.

I've had a few rug-munching encounters with bean-counting bosses, without tea and biccies, when having to explain my failures to recover such beacons.

In the North Sea, they usually end up on the beaches of the Fresian islands. Rich rewards to be had by the cattlemen there!

[aterpster]

The cost of operational search is actually shared by Egypt and France.

Probably 10% Egypt and 90% French, if that.

[underfire]

http://i68.tinypic.com/9szeh4.jpg

http://i66.tinypic.com/2r2q79l.jpg

[EW73]

Hey Phalconphixer,

Your post regarding the detachable crash transmitter located in the base of the vertical fin, triggered electronically in the event of a crash, closely describes the system as fitted to the Lockheed P3C Orion, used widely by various navies throughout the world - great airplane!

[Porker1]

Cazelet33

I didn't understand your reference to prop aeration muddling acoustic links between the ship and the ROV. The deep water installation vessels that I work with all have their ROVs powered and controlled via reeled umbilicals, I.e. the ROVs are physically connected to the ships and do not rely on acoustic signals between the two.

Even the AUVs (autonomous underwater vehicles) that I've worked with are pre-programmed, dumped in the water to do their sonar runs, then come back up at end of mission for recovery and data download - no acoustic comms during the scanning run.

[A0283]

@Cazalet33 "engaged in underwater operations",

At the time of my posts on Burullus early in the thread the message linked to the ship was something like "sub sea operations".

Early in the thread I also posted comments from a UK oceanographer who sketched specific sea floor shape and sediment issues which would make detection and search more complex than you might expect. Wonder if you can agree with his comments.

Just checked it - the label was “SUBSEA LOCATION”,

Was Dr Simon Boxall, an oceanographer from the Univ of Southampton ... see my post May 20th of around 10.20hrs

[A0283]

@Cazalet33 I'd be adversely surprised if these guys haven't deployed an LBL array around the locus by now.

Burullus has been in the same spot at least since May 22nd, at the time it was in port, made a short move to Abu Qir (its home port), and then directly sailed to the spot at 9-10 knots. Quite early on there was a bit of an open 'circle' around it, but as i posted, quite a few ships still crossing close at between 10-16 knots. See Note *
As far as i can see B is supplied on station by a big French vessel. I have not detected a screen of navies vessels yet (like there was with AirAsia). But perhaps they have xpdrs off.

*Note: I checked the information that i have from the start of the surface search. Definition of "close" is when you look at it from the viewpoint of multiple ships making surface sweeps. When you look at it from the viewpoint of a single ship sounding around one specific location, then the 'circle' diameter was more than the 2 miles or so that Cazalet indicated.

[.Scott]

Per CBS News:The Reuters news agency quoted anonymous officials "close to the investigation" as saying no new signals from the plane had been detected "since day one."

[wiggy]

FWIW it might be worth bearing in mind that if anybody quotes the likes of Reuters or AFP you can often cut out at least one middle man (in this case CBS) and do what most of the media do - go to the agency's own website. If you do that you often find subtle differences in wording and emphasis between what the relatively "raw" stuff the agencies often put out and what makes it into the more popular media output.

No new signal from EgyptAir jet since day of crash as search intensifies | Reuters (http://www.reuters.com/article/us-egyptair-airplane-search-signal-idUSKCN0YI17M)

[Cazalet33]

I didn't understand your reference to prop aeration muddling acoustic links between the ship and the ROV.

I phrased it badly. I meant that the USBL link, which is used by the ship's DP system when in follow-sub mode, gets corrupted and the ship starts overcontrolling and becomes more and more divergent.

An ROV can easily come to a dead stop, from a cruise speed of two or three knots in a matter of two or three metres. A 4,000 ton ship cannot. The DP system will command more and more thrust in an attempt to maintain station and that's when you get loss of acoustic link between the USBL and the sub. The ship can easily move out many tens of metres and start dragging the umbilical so much that the ROV itself can be jerked around. The tail starts wagging the dog and dogs don't like that. They bark and get quite snappy. The ROV crew blame the bridge crew and the bridge crew blames the ROV crew.

It can happen quite easily when, for example, the ROV suddenly encounters a snagged fishing net and has to make an emergency stop. It can also happen when the ROV suddenly finds an orange box on a job like this one!

[A0283]

@.Scott The Reuters news agency quoted anonymous officials "close to the investigation" as saying no new signals from the plane had been detected "since day one."

If true then:
a. surprising what Burullus is doing then ... certainly at this stage of the search ...
b. you would expect the search to 'spiral outward' then, say filling a circle of 25 nm diameter, perhaps Cazalet33 can say something about this,
c. the French research vessel referred to above and its patterns will tell us more later,

It is also not clear what kind of signals they are referring to ... was it a signal from the plane, from the radar, or a ULB (if not a spurious one) ...

Just thinking. Authorities could also decide that in modern times it is better to clearly state the main points of what they know, what they dont know, and what assumptions are the basis for the activities that are ongoing. This could also indicate and educate people on the complexity of these searches and investigations. All this leaking and anonymous stuff ... makes a bad impression on the general public.

An illustration of this could be the find of another probable MH370 fragment today. It was found by a guy who by chance had just seen a few photos of earlier finds. During the MH370 search an Australian SAR official was quoted who said that his experience was that people could not recognize such fragments as being from an aircraft - especially when they had been in the water for (even) a (short) while. After the fact other officials say that this find is a prove of the accuracy of the drift predictions. That also surprises me, if these predictions were so good as claimed, why did they not publish them as soon as possible with a request to the public to report possible finds. And the give the public (and seafarers) a number of examples of what they might expect to find and see.

[notapilot15]

1) Fixed ELTs(Qty 2) - Works only in case of over land crashes.
2) Portable ELT(Qty 1) - Someone has to turn it on and not under water
3) Beacons on rafts(Qty 8) - Need salt water contact to activate, but has to be above water level to transmit.
4) ULBs on CVR/FDR(Qty 2) - Underwater only, limited range, limited life.

Big assumption these are maintained properly.

So sonar sweeps and ROV visual searches have better probability than these.

[Cazalet33]

you would expect the search to 'spiral outward' then, say filling a circle of 25 nm diameter, perhaps Cazalet33 can say something about this,

Yes, an expanding square spiral search pattern is what you would expect for a blue water search around a vague search datum point, but the recorded track pattern as seen on AIS looks to me much more like a contact investigation track.

[AT1]

Looking at the marinetraffic web site, the PMS Burullus has simply vanished without trace. Its position was last reported, what, 48 hours ago.

In the past half hour or so a French Warship described as "9014" (no other details given) has now appeared on the same bit of Mediterranean. As yet there is only one position report so there is no track to see. It is shown as heading just north of west at 10 kts.

[paxrune]

"9014" may be this:

https://en.wikipedia.org/wiki/French_ship_Tonnerre_%28L9014%29

[Flexable]

During the search for AF447 they used a French nuclear submarine...
source
Submarine begins search for Air France jet's black boxes - World - CBC News (http://www.cbc.ca/news/world/submarine-begins-search-for-air-france-jet-s-black-boxes-1.796099)

Are they doing it now secretly ?

[HamishMcBush]

1) Fixed ELTs(Qty 2) - Works only in case of over land crashes.
2) Portable ELT(Qty 1) - Someone has to turn it on and not under water
3) Beacons on rafts(Qty 8) - Need salt water contact to activate, but has to be above water level to transmit.
4) ULBs on CVR/FDR(Qty 2) - Underwater only, limited range, limited life.

Big assumption these are maintained properly.
There is also the "passive" transponder that stays in a very low power-consumption mode until it is interrogated whereupon it "wakes up" and starts to transmit. After all, there is no point in a locator beacon using up all its battery power in the few days immediately after a crash when there may not yet be anyone in the area looking for it.
What you need is a device that is fitted to the plane that uses very little power whilst listening for someone out to locate it, then when it detects a signal of someone or something hunting it down, it responds and uses its battery up when it knows that there is something close by looking, and picking up its transmission signals

[Oldpilot55]

That is what the ULB does.

[DaveReidUK]

HMcB was describing how a ULB should ideally work, not what they currently do.

[underfire]

Looking at the marinetraffic web site, the PMS Burullus has simply vanished without trace. Its position was last reported, what, 48 hours ago.

If they are on station, typically they will turn off the AIS.

This will keep the news helos and other aircraft from interfering...

2 days ago.

http://i.imgur.com/NMGRoxF.jpg

[StormyKnight]

Ideally a beacon should transmit every so often last known position & depth (5,10,30,60 minutes?), but be listening as well. When it detects a trigger signal, it will go into full transmit for 1,3,6 hrs? It would then revert to the previous mode to save battery until triggered again. It would be good if it transmitted the received trigger signal strength too. The trick is that the beacon receiver will be affected similarly as the surface receivers are. Signals can be blocked by terrain as well as thermoclines (temperature layers in the water that can reflect/refract signals), however the surface trigger transmitters can have a lot more power. Of course ideally you don't want to be transmitting whilst trying to listen, so the beacon would need to know to transmit at a set minute of the hour (:00?)

In this scenario you could drop 100's (1000's?) of buoys with the transmitter & receiver over the suspected area, thus covering a much larger area more quickly. Some of the buoys could be designed to sink to a specified depth & the return to the surface (or part of the buoy) to transmit a found beacon.

At the moment it seems a bit old fashioned the way searching is done. Even today 1000 receivers could be made, dropped on the area, slowly sink down to the seabed & then if one of them detects a pinger, release a transmitter back to the surface & transmit its location & depth of detection. Hopefully several will pick-up the signal & a map can be made to narrow the location further.

Can we do better with today's technology than we are at the moment?

[Ancient-Mariner]

Ideally a beacon should transmit every so often last known position & depth (5,10,30,60 minutes?), but be listening as well....
Of course ideally you don't want to be transmitting whilst trying to listen, so the beacon would need to know to transmit at a set minute of the hour (:00?)

That is very similar to the now discontinued radio silence periods of 15 to 18 and 45 to 48 mins past each hour where W/T Morse transmissions on 500 kHz would cease (it was a calling frequency as well as a distress frequency). Similarly, 00 to 03 and 30-33 mins past each hours for R/T Speech transmissions on 2182 kHz.

This method enabled the automatic keying of a low efficiency medium power W/T transmitter powered by batteries for a lot longer than would otherwise be the case.

[thf]

The Wall Street Journal writes about the history of the avionics bay smoke detector:

Smoke Alerts Like That on Flight 804 Have Raised Questions in the Past (http://www.wsj.com/articles/smoke-alerts-like-that-on-flight-804-have-raised-questions-in-the-past-1464390994)
(Paywall, use this Google search to try to circumvent: Google Search for Article (https://www.google.de/search?q=Smoke+Alerts+Raise+Questions+Amid+Flight+804+Invest igation))

[airman1900]

Another link to the WSJ article titled, Smoke Alerts Like That on Flight 804 Have Raised Questions in the Past

http://on.wsj.com/1OSGvk0

NTSB links on this incident:

Current Synopsis, Preliminary:

http://www.ntsb.gov/_layouts/ntsb.aviation/brief.aspx?ev_id=20110404X21934&key=1&queryId=cf4d4fc0-3844-48cf-9c06-27eaf65428f9&pgno=2&pgsize=20

Dockets:

Accident ID DCA11IA040 Mode Aviation occurred on April 04, 2011 in New Orleans, LA United States Last Modified on January 18, 2012 14:01 Public Released on January 18, 2012 14:01 Total 49 document items (http://dms.ntsb.gov/pubdms/search/hitlist.cfm?docketID=50891&CFID=460516&CFTOKEN=d3ebdc1f3c578fee-A81C4550-E5F5-4AA5-2F39E17C6F6DFD78)

I'm wondering why the final report has not been released.

[ArchieBabe]

At 2.36am (Local) NOAA “received two bursts from the beacon, but was unable to make a location”. “They received the beacon ID and were able to correlate that with the beacon that was on MS 804”.




Satellites Captured Doomed EgyptAir Jet?s Distress Signals - Bloomberg (http://www.bloomberg.com/news/articles/2016-05-27/satellites-captured-distress-signals-from-doomed-egyptair-jet)


Business: Washington Post Business Page, Business News (http://washpost.bloomberg.com/Story?docId=1376-O7UM1W6TTDSP01-1FU30JAC0776RHP55EMDTNMN44)

[takata]

Thank you thf, for bringing this up, and airman1900 for linking the NTSB reports. It's a very intersting reading about smoke detection system and related procedure.

Concerning MS 804, beside using optical detectors (see Airbus statement), I would add that the smoke warning(s) were triggered several hours after take off. At this point, such warnings would be very unlikely resulting from prior ground contamination of smoke detectors, which is what happen in most cases.

Also, ACARS of MS 804 are reporting two warnings at 0:26 and 0:27 (Lavatory and Avionics), which make it even less likely that they were related to nearly simultaneous faults of two detectors reporting spurious alarms. They are related to different compartiments and systems.

Moreover, both warnings were possibly triggered by cockpit adjacent areas (Lavatory A door is only a few centimenters away from the cockpit door while the avionics bay is right below the cockpit's floor) ; on top of it, the avionics vent system is using cockpit air to refresh both instrument panel and the whole bay, where the avionics smoke detector check the exhaust ducts for particles.

Finally, the two system faults reported at 0:26 and 0:28 are telling something related to the cockpit right windows heating sensors (sliding first, then fixed one) ; both window sensors faulted... but not the right windshield which is also heated by the same WHC-2. Hence, one could think that it wasn't related to the state of WHC-2 in the bay which was still working on the right windshield and triggered no fault on its own. In case of such a single fault reported, one would suspect the sensor first, the computer next and the wiring last. Now, if the computer is not at fault, we are still left with two faults with different wirings, sensors, and circuit breakers...

So far, and without any further evidence, I would rather suspect that those smoke warnings reported were actually real ones ; also, it seems to be more likely due to an external system cause, probably in cockpit, like a sudden surge of temp close to the right sliding windows ; the original event would have to last for at least 1-3 minutes (0:26 to 0:28) in order to trigger the second sensor fault on the fixed right window.

Considering that the investigation is in possession of the full ACARS content, they would have more details on each time stamping; they would also be able to tell if any probable delay happened during the string of ACARS between 0:26 and 0:29. But based on what we have, it's still possible to make some sense out of the first faults reported.

Of course, it's not the only scenario as one could also suspect a more complicated sequence, like a wiring combustion or electrical issue contaminating one and second right window heating system. It's only less likely because it would alert the crew of something wrong (like smell) in the cockpit, and probably well before this point.

Now, looking at any previous report of incident at cruise involving cockpit windows overheating in A320 might be more interesting than spurious smoke warning events, in order to understand if this could make more sense than an external surge of temp in cockpit.

[silverstrata]

Takata.

Concerning AS 804, beside using optical detectors (see Airbus statement), I would add that the smoke warning(s) were triggered several hours after take off. At this point, such warnings would be very unlikely resulting from prior ground contamination of smoke detectors, which is what happen in most cases.

Who needs ground contamination? Because I would not let them smoke in the flightdeck, my first officers used to smoke in the forward toilet. I won't say how they overcame the detector (mostly). Its like pushing water uphill sometimes.

[Water pilot]

I would suspect the sensor or the wiring well before assuming that there is a computer issue. Of course, sometimes it is wiring to the computer that is the problem.

It might be interesting to consider that the wires for temp probes are usually significantly smaller than any other wires in a wiring bundle and are thus the first to melt through if the bundle overheats for some reason. (Those tiny wires can also be the devil to crimp although I suspect in aircraft standards are a bit higher than for the marine stuff that I deal with.)

Slightly related case in point -- this week the state of charge gauge on our electric utility vehicle (think 'glorified golf cart') failed. It is cheap junk and since the car ran fine and the charger reported no issues I was going to disregard it and replace later. Actually thinking about this thread and the importance of checking out all electrical faults, I opened the battery compartment and found that one battery had been venting acid, eating through the copper connectors. The one that was eaten completely through first was the small one for the state of charge meter. The big ones that carry a lot of amps @ 48V were partially eaten through.

[framer]

As a passenger you are probably not driven mad by all the mis-information dressed up as factual information and delivered by flight simmers who research stuff on the net then pretend they are professional pilots.
To a passenger it comes across as knowledgable and experienced, to actual airline pilots it is obviously rubbish.
Personally I have no problem at all with pax who post here if they preface their posts with that fact, or, if they don't give advice or operational opinions.

[FakePilot]

Another link to the WSJ article titled, Smoke Alerts Like That on Flight 804 Have Raised Questions in the Past

Smoke Alerts Like That on Flight 804 Have Raised Questions in the Past - WSJ (http://on.wsj.com/1OSGvk0)

NTSB links on this incident:

Current Synopsis, Preliminary:

http://www.ntsb.gov/_layouts/ntsb.aviation/brief.aspx?ev_id=20110404X21934&key=1&queryId=cf4d4fc0-3844-48cf-9c06-27eaf65428f9&pgno=2&pgsize=20

Dockets:

Accident ID DCA11IA040 Mode Aviation occurred on April 04, 2011 in New Orleans, LA United States Last Modified on January 18, 2012 14:01 Public Released on January 18, 2012 14:01 Total 49 document items (http://dms.ntsb.gov/pubdms/search/hitlist.cfm?docketID=50891&CFID=460516&CFTOKEN=d3ebdc1f3c578fee-A81C4550-E5F5-4AA5-2F39E17C6F6DFD78)

I'm wondering why the final report has not been released.

From a quick search, sounds like the warning source hasn't been identified and the items that failed had actually been switched off per checklist. Meanwhile other incidents have been prioritized for the investigators.

[takata]

Silver, sorry but my comment about ground contamination wasn't related to your point.

I was refering to NTSB discussion involving spurious smoke detection which is all about the Avionics bay fire detection (see above NTSB report linked) and the following Airbus procedure ; it's not about the toilets that one can avoid being flagged while smoking.

Indeed, most of false AVNCS SMOKE triggered in flight were due to contamination on the ground released after the take-off phase. And it's an old discussion lasting since a while.

My other point was to underline that both Lavatories and Avionics were detected in MS 804 ACARS, almost simultaneously, and several hours after take-off. It's unlikely related with someone trying to smoke in lavatories that get the smoke detector warning in Avionics bay triggered.

TFU 26.15.15.001 in July 1999

*DESCRIPTION: SOME OPERATORS HAVE REPORTED MANY CASES OF SPURIOUS AVIONICS SMOKE WARNINGS, LEADING TO "AVIONICS SMOKE" OR "LAND ASAP" ECAM MESSAGES. THESE WARNINGS HAVE MAINLY BEEN REPORTED ON GROUND, HOWEVER THERE HAVE BEEN A FEW CASES GENERATED IN FLIGHT, SHORTLY AFTER TAKE-OFF AND GEAR RETRACTION.

*CONSEQUENCES: N/A

*INVESTIGATION STATUS: THE AIRCRAFT FLIGHT PHASE CONFIGURATION WHERE AVIONICS SMOKE WARNINGS HAVE BEEN GENERATED FALL INTO TWO MAIN CATEGORIES; ON GROUND AND TAKE-OFF.

- ON GROUND - WITH THE AIRCRAFT ON GROUND THE AVIONICS VENTILATION IS SET TO 'OPEN LOOP', WHEREBY OUTSIDE AIR IS USED TO PROVIDE VENTILATION FOR THE AVIONICS COMPARTMENT. IN ENVIRONMENTS WHERE HIGH HUMIDITY AND/OR CONTAMINATION EXISTS (JET EFFLUX/BLOWN DUST ETC). IT IS POSSIBLE FOR THE SENSITIVITY OF THE AVIONICS SMOKE DETECTOR TO BE AFFECTED CREATING AN ALARM CONDITION.

- TAKE-OFF - THE AVIONICS SMOKE WARNINGS ARE INHIBITED FROM 80KTS TO 1500 FEET. DURING THIS TIME IF THE AVIONICS DETECTOR GOES INTO ALARM THEN A 'LAND ASAP' (IN AMBER) IS GENERATED ON ECAM. THE ONLY WAY TO IDENTIFY THE CAUSE OF THE AMBER WARNING IS BY DEPRESSING THE RECALL BUTTON ON THE ECAM CONTROL PANEL. INVESTIGATIONS HAVE DETERMINED THAT SOME OF THESE 'LAND ASAP' WARNINGS HAVE BEEN GENERATED DUE TO A PREVIOUSLY LATCHED, BUT INHIBITED AVIONICS SMOKE WARNING THAT HAD BEEN GENERATED WHILST THE AIRCRAFT WAS ON GROUND. INVESTIGATIONS HAVE SHOWN THAT THE IONIZATION TYPE SMOKE DETECTORS SENSITIVITY IS SUBJECT TO THE AMBIENT TEMPERATURE, PRESSURE AND AIR CONTAMINATION WITH MOISTURE, DUST OR POLLUTION. THE HIGHEST SENSITIVITY TRANSLATED INTO A VOLTAGE SHIFT BEING ON THE GROUND AND DURING TAKE-OFF.

*INTERIM SOLUTION: N/A

*MAINTENANCE ADVICE: IN CASE OF AN 'AVIONICS SMOKE' WARNING TRIGGERED AND LATCHED ON GROUND, FWC1 AND FWC 2 SHOULD BE RESETED ONE AT A TIME BY MEANS OF THEIR C/B (3WW C/B 49VU FOR FWC1 AND 2WW C/B 121VU FOR FWC2). THIS WILL CLEAR THE LATCHED CONDITION OF THE WARNING IF THE AVIONICS SMOKE CONDITIONS HAVE DISAPPEARED. THEN AN UNDUE 'LAND ASAP' ALARM WILL BE AVOIDED. OPS ADVICE: N/A REPERCUSSION ON A/C DISPATCH: N/A PERMANENT OR FINAL SOLUTION: A NEW GENERATION OF SMOKE DETECTOR PN CGDU2000-00 USING AN OPTICAL TECHNOLOGY HAS BEEN DEVELOPED IN ORDER TO REPLACE THE 'OLD' GENERATION OF IONIZATION TYPE SMOKE DETECTOR. THIS NEW GENERATION TYPE OF SMOKE DETECTOR HAS A DIFFERENT TRIGGERING PRINCIPLE AND IS THEREFORE NOT AFFECTED BY THE TEMPERATURE AND PRESSURE CONDITIONS. IN SERVICE EVALUATION (6 MONTH PERIOD) OF AVIONICS OPTICAL SMOKE DETECTOR PN CGDU2000-00 HAS BEEN PROPOSED TO TWO OPERATORS. DEDICATED SB A320-26-1052 HAS BEEN RELEASED MID JULY 2000. THE IN SERVICE EVALUATION HAS BEEN COMPLETED SUCCESSFULLY. SB A320-26-1052 REVISION HAS BEEN RELEASED THE 30TH OF AUGUST TO INCORPORATE ALL AIRLINES IN THE EFFECTIVITY.

[underfire]

Yes, an expanding square spiral search pattern is what you would expect for a blue water search around a vague search datum point, but the recorded track pattern as seen on AIS looks to me much more like a contact investigation track.

Not sure what you mean, but we dont search the way that was show on AIS. They are spending too much time stopping/slowing down for the turns, and the optimum search is in a straight line, especially at the depths they are working at.
This is a basic towed array search pattern that we use to optimize area:
http://i.imgur.com/DmOW9Am.jpg

The fish is towed, so anything over about 4 kts will cause it to cavitate, (or the harmonics in the umbilical) and degrade the measurements.

[underfire]

DOS hired to search/recover

Deep Ocean Search - Contact & Info (http://www.deepoceansearch.com/Contact_Info.htm)

[AT1]

Underfire

Your explanation of a possible search pattern is interesting. However, when the PMS Burullus was visible on AIS there were several puzzling things whcih do not seem to fit the scenario you have described. She was sailing at variously 0.4 kts and 0.3 kts all the time. She did not seem to be slowing to turn, it was just very, very slow all the time - and there were many observation points along its route where data was available, so this was not a sampling problem. AIS reports show many items of data, including the ships actual heading as well as its course over the ground. The heading showed that at all times when zig zagging the vessel had its head pointing NE, no matter which way it moved. When moving to its search area the heading was different, suggesting this was not just "stuck" data in the AIS stream, but was the actual heading as it moved. I guess that was holding the ship "head into the prevailing wind", but I have not checked the weather. Lastly the scale of the pattern it was sweeping was very "tight", with only 1Km - roughly 0.5 nautical mile - along each "long" leg and with 200 odd metre gaps between passes.

None of these seem to me to fit with a towed anything. Maybe it was a "dangled" something, or perhaps as has been suggested it was tracking a self powered ROV with or without an umbilical.

Any thoughts about what it was using?


Just noticed French Warship 9014 is back in the area and is "moving" in a way that suggests it is looking for something. Moving at 10 or 11 knots most of the time. There is a period where there were no position reports when it moved only a few Km in 4 hours.


And there is a survey ship - the Hugin Explorer just to the NE of the supposed site. It arrived in the area from Cyprus at 11 knots and now seems to be just drifting.

[D Bru]

http://www.civilaviation.gov.eg/News/news%20pages%20ar/messs_28_5_16.html

"CAIRO - 28 May 2016

Investigation Progress Report (4) by the Egyptian Aircraft Accident Investigation Committee

The investigation committee received satellite reports of the electronic emergency signal that came out of the Emergency Locator Transmitter (ELT); which is equipment that sends automatic signals to satellite in the event of a crash or fall into water. Concerned search units were then informed of the updates recorded by the satellite to intensify searching in that area.

Efforts to search for the data recorders of the A320 continues; including the use of the most advanced search equipment of Alseamar company that was brought aboard the French vessel. The Ministry of Civil aviation has also made agreement with DOS (DEEP OCEAN SEARCH) company for other equipment with high capacity to receive signals and conduct sonar scan, in order to diversify research methods and to carry them out in the shortest time possible.

On the other hand, the investigation committee has started studying the information received from the Greek air traffic control about the accident; more information of the records of the radar that had followed the path of the plane before the accident, is expected to be also received."

[Cazalet33]

Looking up French warship 9104 I see her described by Wiki:
Tonnerre (L9014; lit. Thunder) is an amphibious assault helicopter carrier of the Marine Nationale.

Undoubtedly a very capable ship, but not the first type that springs to mind when selecting a vessel of opportunity for what amounts to hydrographic survey work.

I wonder if perhaps they are using her as a base for naval ASW helicopters to cover a large area with numerous dips of their dunking hydrophones to listen for the pinger(s). Half a dozen of those helicopters could join up a lot of dots and do vastly more acoustic searching in a limited time than a full spec hydrographic survey vessel could ever hope to achieve.

As AT1 points out, the limited track info that we have/had from AIS is not at all consistent with towing a hydrophone eel array, nor with towing a towfish. Hence my speculative conjecture, in which I should have used the word 'surmise' instead of 'conclude', that they were doing some kind of contact investigation rather than the boustrophedontical pattern of an area search.

[gmorton]

In Le Monde this afternoon:
EgyptAir : les boîtes noires ne seront pas repêchées avant 12 jours (http://www.lemonde.fr/international/article/2016/05/29/egyptair-les-boites-noires-ne-seront-pas-repechees-avant-12-jours_4928553_3210.html)

[gums]

I am not sure about the ASW frequency capabilities, and the various naval assets around the world may not wish to "advertise" all their capabilities.

At least we know the passive sonar can easily detect very low freq sounds like propellors that are turning. Apparently, they can detect higher freq sounds like whale calls, which seem to be at upper range of human hearing.

Listening for "pings" that are up in the near ultrasonic range sould not be that hard for the ASW sonobouys or maybe subs. You don't need more than one ASW plane like the Orion or the new USN one to drop a dozen sonobouys in a very good pattern. The problem is revealing military capabilities. Up to me I would claim we found the beacon a hundred miles away! OTOH, if you drop a good pattern within a few clicks and don't detect the ping before the French boat does, then.........

[AT1]

Another warship, the "F262 Erfurt" which is described as a UN warship and also as "DE", is now heading for the area at speed from Cyprus. It may be just coincidence.

The track of the French warship is very very odd - with no obvious "pattern". Maybe it is searching the surface to recover floating debris spotted by helicopters or the Orion rather than an undersea search?

The Hugin Explorer has stopped drifting and is now closing at speed on the area where the French warship is.

I would have thought the military world would be OK revealing quite a lot about their ability to detect a distress "pinger" - particulary if they have had time to go to port and pick up suitable hardware. This is not going to reveal much/anything about their ability to detect ships or subs.

[Lonewolf_50]

I wonder if perhaps they are using her as a base for naval ASW helicopters to cover a large area with numerous dips of their dunking hydrophones to listen for the pinger(s). Half a dozen of those helicopters could join up a lot of dots and do vastly more acoustic searching in a limited time than a full spec hydrographic survey vessel could ever hope to achieve.
Not likely that dipping sonar will be the search option of choice for this signal (the cable only goes down so far) but that ship is a great C2 platform and can take on board a variety launchable vehicles that can aid the search. Also good for further search for stuff afloat with the Search capability of its helicopters. (Per AT1's post).

[A320FOX]

Translation from Le Monde: It will not be possible to recover the black boxes of the flight Paris-Cairo EgyptAir before at least 12 days, the time that a specialized vessel arrives on site, reported Agence France Presse (AFP) sources close of the investigation.
The Airbus A320 suddenly disappeared from radar screens at night May 19th before breaking sea between Crete and the northern coast of Egypt for reasons still unknown. Only the analysis of flight recorders, the "black boxes", will allow to know exactly the causes of the accident.
Egypt and France have signed agreements with two French companies specialized in finding shipwrecks in deep water, and Alseamar Deep Ocean Search (DOS). Forty Egyptians, including the crew, and 15 French are among the victims of the crash.
Read: What is known about the plane EgyptAir disappeared between Paris and Cairo
complementary role
"Both companies have a complementary role, the first to locate the" pings "black boxes [echo sonar emitted by their tags] the second to go down and recover" with a robot, explained AFP in Cairo a source close to the investigation who requested anonymity. But "the DOS specialized ship left the Irish Sea Saturday and will reach the presumed area of ​​the crash in about 12 days, after embarking in Alexandria Egyptian and French investigators," she added.
The information has been confirmed by other sources close to the investigation, which evoke a depth of about 3000 meters in the research area, some 290 km north of the Egyptian coast.
Three DETECTOR-6000 Alseamar immersed equipment can detect "pings" up to 4000 to 5000 meters, were loaded aboard a French naval vessel, the Laplace, who left Corsica Thursday . It should arrive in the presumed area of ​​the crash "Sunday or Monday at the latest," according to one source.
Automatic alerts issued
"Pending the DOS ship equipped to detect" ping "deep water but most of robots able to descend to 6000 meters to retrieve the black boxes, there will be no waste of time and since the Laplace attempt to locate the meantime, "says one of these sources, which evokes, even in 12 days," a very good chance to recover the flight recorders through the combination of the two French companies. "
Time is running out as beacons of these flight recorders can emit only "four to five weeks" before exhausting their batteries.
Read also: In Cairo, MS804 flight passengers families EgyptAir angry against the authorities
The hypothesis of the attack, initially put forward by Egypt, has lost ground to that technical incident since it was found that automatic alerts have been issued by the unit two minutes his fall, indicating smoke in the cockpit and a failure of the computer managing orders.

[Coagie]

Another warship, the "F262 Erfurt" which is described as a UN warship and also as "DE", is now heading for the area at speed from Cyprus. It may be just coincidence.

The track of the French warship is very very odd - with no obvious "pattern". Maybe it is searching the surface to recover floating debris spotted by helicopters or the Orion rather than an undersea search?

The Hugin Explorer has stopped drifting and is now closing at speed on the area where the French warship is.

I would have thought the military world would be OK revealing quite a lot about their ability to detect a distress "pinger" - particulary if they have had time to go to port and pick up suitable hardware. This is not going to reveal much/anything about their ability to detect ships or subs.
Don't assume naval submarines are already set up to search for 37.5khz pingers.
The French sub, The E'meraude, wasn't set up for listening for 37.5khz, nor did they know they were supposed to be, in the initial search for AF447. Looking for Black Boxes wasn't a mission they'd had. Only, maybe, after the batteries for the pingers had died, and it was too late, was The E'meraude possibly set up for 37.5khz. The area the airplane was eventually found in, had been crossed off as already searched by The E'meraude, but they were not equipted to detect 37.5khz. It's deep in the BEA report.
A hard lesson learned, so, I hope, maybe, that mistake won't be repeated.
Knock on wood. It's beginning to sound like the searchers have it under control. May not be long yet.

[Cazalet33]

that ship is a great C2 platform and can take on board a variety launchable vehicles that can aid the search

C2 is good. C2 is very good.

But to find sunken ships and aeroplanes you need ships that can find sunken ships and aeroplanes.

[SteveCox]

Don't forget there's also the 'fishing immigrants out of the sea' operations going on in this approximate area. The Tonnerre could well be engaged in that.

[gums]

Coagie has pointed out that most of the naval ASW gear is not optimized for the high freq beacon we are looking for.

One current sonobouy system only goes up to 2400 Hz or so with any good sensitivity. I would imagine the subs to have much larger bandwidth, but just try to get the specs for those!!!!

As Lonewolf said, "dipping" by ASW choppers ain't gonna work. The gear is not real good when passive and needs to "ping". It is not designed for deep work, as most operational subs won't be down there at a thousand meters or more, ya think?

I would place my bets on a sub, but they can't down to the depths we are looking at, but might get a "ping" if the acoustics are right.

[Cazalet33]

Okay, so why would you select an amphibious assault ship with helicopters to find a wreck in three thousand metres of water?

Just askin 'cos I doan unnerstand.

I sort of understood why the RN offered the services of a passing "coalition" RFA, but that was a matter of hours after the aircraft went down.

What, on earth, is an amphibious assault ship with helicopters doing in a hydrographic job?

Don't forget there's also the 'fishing immigrants out of the sea' operations going on in this approximate area.

Okay, I'll give you that, but what, on earth, is an amphibious assault ship with helicopters doing in a hydrographic job?

[takata]

@Cazalet33
Looking up French warship 9104 I see her described by Wiki:
Tonnerre (L9014; lit. Thunder) is an amphibious assault helicopter carrier of the Marine Nationale.Helicopter Carrier Tonnerre was not dispatched for supporting this operation. So this tag "9104" is more likely given to PHM Jacoubet which is, since May 23, only doing surface sweep and visual researches for debris and they deployed two aircraft, a Falcon 50 and Atlantic 2, in addition to Egyptian and US assets deployed.

See official French Navy media, 28 May situation :
Vol Egyptair : Point de situation au 28 mai | colsbleus.fr : le magazine de la Marine Nationale (http://www.colsbleus.fr/articles/8479)

Hydro Vessel Laplace would be on spot by tomorrow with pinger locators. Search for beacon will start then. Next, in about a dozen days, they would be joined by Deep Ocean Search R/V John Lethbridge (sailing from Ireland sea) for the deep sea recovery mission.
Deep Ocean Search - Home (http://www.deepoceansearch.com/Capabilities.htm)

[underfire]

AT!,

Yes, that is correct. The explanation in the post was regarding searching with a towed array. The pattern shown in one of my last posts was not a general search pattern. It is also not indicative of ROV deployment. An ROV is not towed around, it is self powered. The ship must remain relatively stationary, or basically on station, not moving at all, moving perhaps in 5m increments, the DP keeping it as stationary as possible.
The concept is to hold, and let the ROV drive around. One cannot have too much slack in the umbilical, as the current drag on the line would be too difficult for the ROV to overcome, and you dont drag the ROV around.
They may have deployed the towed device that looks for the pinger. It is tough with only one vessel as one cannot triangluate.
Cheers

[gmorton]

From Le Monde 29/05
"Trois DETECTOR-6000 d’Alseamar, engins immergés capables de détecter les « pings » jusqu’à 4 000 à 5 000 mètres, ont été embarqués à bord d’un bâtiment de la Marine française, le Laplace, qui a quitté la Corse jeudi. Il doit arriver dans la zone présumée du crash « dimanche, ou lundi au plus tard », selon une des sources."

English Translation: 3 Alseamar DETECTOR-6000's, devices capapble of detecting the "pings" to a depth of 4000 to 5000 metres, were taken on board a French Marine vessel, the Laplace , which left Corsica on Thursday. It should arrive in the presumed crash area by "Sunday, or Monday at the latest", according to one of the sources.
EgyptAir : les boîtes noires ne seront pas repêchées avant 12 jours (http://www.lemonde.fr/international/article/2016/05/29/egyptair-les-boites-noires-ne-seront-pas-repechees-avant-12-jours_4928553_3210.html#8iC1WSssMW9QUWG4.99)

[Lonewolf_50]

But to find sunken ships and aeroplanes you need ships that can find sunken ships and aeroplanes.
We agree completely, that was part of the point in my post. This is a task for specialized ships and equipment.
Okay, I'll give you that, but what, on earth, is an amphibious assault ship with helicopters doing in a hydrographic job?
Supporting the effort.

[takata]

I just wonder why there is still people talking about BPC Tonnerre and researches for MS804 while she is actually part of the Naval Group Jeanne d'Arc sailing in the Pacific Ocean with FLF Guépratte.

There was US Marines from Okinawa visiting Tonnerre... a few days ago.
Coopération franco-américaine pour le groupe Jeanne d?Arc (http://www.defense.gouv.fr/marine/actu-marine/cooperation-franco-americaine-pour-le-groupe-jeanne-d-arc)

[Cazalet33]

Why would you put three sets of pinger detectors on one ship? Given there is a clock running before the batteries in the pinger run out, would you not put three detectors on three boats and cover as much ground/sea as possible?


I wondered about that too.

My speculative guess is that one of them is to be suspended on a deep tow cable and a second one is to be deployed on an ROV. The third one may be a spare or perhaps is to be redeployed onto another vessel, such as the one which mobilised from Cyprus in a hurry, in the field.

[mickjoebill]

Given there is a clock running before the batteries in the pinger run out, would you not put three detectors on three boats and cover as much ground/sea as possible?

What an archaic process.

We can track, target and precision bomb people in hiding but can't find a bloody airliner transmitting "here I am"!

The public think it's nuts.

[ZFT]

The public couldn't care less and the majority have already forgotten all about it.

[notapilot15]

For the amount of publicity under water search being a highly sophisticated, some of technology and techniques are old and crude.

If I recall correctly, ship with pinger locator actually drops a test ULB, so if multiple vessels does this, they will be chasing each others pings than the actual one. If they have too many pings in very close frequency it makes all the more difficult.

It is also a myth that navies have superior underwater technology. Oil companies and research organizations have latest technology.

30 day life period is based on the assumption ULB has been stored and maintained properly.

[Lonewolf_50]

It is also a myth that navies have superior underwater technology. Oil companies and research organizations have latest technology. A good point on specialized equipment for deep water work suited to this task.
30 day life period is based on the assumption ULB has been stored and maintained properly. Let's hope they work better than ELT's, whose 'it works' rate could use some improvement.

[Maddie]

The public couldn't care less and the majority have already forgotten all about it.

I am a member of the Public, and I DO care. And not just selfishly because of my fear of flying and a quest to know what happened. I care because anybody on that plane could have been my brother or sister, Mother or Father. Behind every person on that plane is a story, as to why they were travelling, what their intended destination was. They leave behind a multitude of inconsolable family and friends also searching for answers and some closure. So many of us do care and remember and empathise.

[Cazalet33]

Pattern is full, sadly MS804 is now at a phase where it is temporarily more of a nautical matter than aeronautical.

[Cazalet33]

If I recall correctly, ship with pinger locator actually drops a test ULB

Yes, but it is good practice to deploy the beacon with a flotation collar and an acoustic release to recover the device when the calibration runs are completed. Else to recover the beacon with an ROV on a test dip.

The Party Chief is under immense and most insistent pressure from the client reps, eg the accident investigators and the interested partners such as the airline and the manufacturers, to get on with producing line kilometres and square kilometres of searched seabed. Those guys tend not to understand the importance of prelim work such as measuring the temperature/salinity profile of the water column and calibrating the signal strength characteristics of the hydrophone in the ambient conditions. They just want you to get on with the search. Therefore it is sometimes necessary, under protest, to skip the preliminaries and start knocking out the mileage to satisfy the men who are paying the dayrate.

[PrivtPilotRadarTech]

LoneWolf50: Let's hope they work better than ELT's, whose 'it works' rate could use some improvement.

It would be simple to modify ELT's in large commercial aircraft so they are triggered any time the descent rate exceeds X fpm for Y time period. It would be a tremendous help to have several minutes of ELT transmissions to alert the authorities and narrow down the search area.

[underfire]

Why would you put three sets of pinger detectors on one ship? Given there is a clock running before the batteries in the pinger run out, would you not put three detectors on three boats and cover as much ground/sea as possible?

You need at least 3 to triangulate the location, and pinpoint the location as quickly as possible. With a unit, you simply get direction. Relative strength is difficult to tell distance with thermoclines, etc.
With only one vessel, or one unit, it is very difficult to pinpoint the location. You have to drive, get a direction, then drive perpendicular to get direction, then parallel wide and combine the three to get a general location, if you have gone wide enough. Then start again to narrow down further...
http://i.imgur.com/lbiZUx4.jpg
You can deploy them from RHB from the mother ship, and these can usually get far enough away to triangulate, and narrow down an area.

This is in a perfect world. In reality, the currents, thermoclines, and salinity cause a signal to wander...

[Ian W]

As much as I sympathise with what you say, comments such as “the public deserves to know” or the public demands to know” or the “public think it’s nuts” are simply not true. Yes, some people genuinely have concerns over flying and accidents unfortunately bring out these (unfounded) fears but the average member of the public has already totally forgotten about this accident and goes about their normal lives.

There seems to be a ghoulish fascination about aircraft accidents when almost every man and his dog on this forum becomes an accident investigator or aircraft designer overnight dissecting every piece of miscommunication and misinformation and comes to totally unfounded conclusions based on 1 minutes Wikipedia research!

Professional pilots actually have not only a professional interest but also a need to know why an apparently serviceable aircraft in cruise with no inclement weather suddenly departed its cruise and crashed. They are in that position themselves and need to know what happened that led to the deaths of 2 of their number so that they can avoid the same fate. This is the major benefit of a forum like this. It is finding the DFDR/CVR of AF447 that has led to an increase in training in handling stalls, possibly preventing future similar accidents.

Unfortunately, bean counters and those not directly involved in aircraft operations do not see the same problem. Most times the DFDR and CVR have been found, so what does it matter? The same reason the ULB was given such a puny battery and a signalling protocol that was designed to be easy to implement rather than to aid recovery in deep sea scenarios. The cost of the last 3 or 4 under-sea searches would have equipped the world wide transoceanic fleet of aircraft with really advanced technology. But it does not come from the beancounters' budgets it comes from the tax payers of the countries involved; so 'shrug' who cares? The charges for searches for aircraft should be levied on the airline - or more specifically on its insurers. This would result almost immediately in retrofit of more suitable DFDR/CVR location systems or streaming of their data in emergency.

[esa-aardvark]

Back in the days when I worked there was a proposed satellite prograrm
'Aerosat', concerned with monitoring and communicating with aircraft
over the water. It got quite a long way before being cancelled around 1978.
No one would pay to use it. Might have helped with the problem of aircraft
falling in the sea.

[Ian W]

Iridium Next satellite constellation will be carrying a system call AIREON which is intended to track all aircraft ADS-B transmissions worldwide including the poles. INMARSAT will handle tracking data 'free' of charge, but of course you have to be carrying the INMARSAT SATCOM equipment.
Neither approach will give any assistance to finding aircraft that switch off their ACARS, transponders and ADS as in MH370, nor give any support to DFDR/CVR data recovery from aircraft that crash in deep ocean waters. As usual the attendees at ICAO are not systems analysts determining the functions that are required, they are more conference attendees trying to get an agreement so that it can be said they 'did something'.

[.Scott]

It is also a myth that navies have superior underwater technology. Oil companies and research organizations have latest technology.
I would say they have different technologies. But the commercial technology may be more useful in this case. US Navy submarines have significant sonar ability - but they probably don't go down far enough to get a good reading on a pinger 10,000 feet below the surface.
Here's the frame of the sonar detector that you'd find in the nose of a US Navy sub:
http://ww1.prweb.com/prfiles/2007/10/27/61329/lukens.sonarsphereinfactory.jpg

[Methersgate]

Quote:
The charges for searches for aircraft should be levied on the airline - or more specifically on its insurers. This would result almost immediately in retrofit of more suitable DFDR/CVR location systems or streaming of their data in emergency. unquote
quote:
Absolutely. It's a shame that when it comes down to the nitty-gritty in these (and most) things, it's the beancounters requirements that come first. unquote

I am not quite sure how that would work. Large airlines would no doubt pay; operators with one or two aircraft would find it hard to do so. If the underwriters are to do the paying, then we must first identify them, then send them the bill, then persuade them to pay it, when they have just paid out for a hull loss.

[.Scott]

For what its worth, news releases from the Egyptian State News Agency can be found at this link:
http://www.sis.gov.eg/en/
Type "egyptair" into the search box and click the magnifying glass.
Here's the most recent one:An equipment shipment arrived on Sunday 29/5/2016 at Cairo International Airport from several European countries to help find the two black boxes of the EgyptAir plane that crashed into the Mediterranean on May 19.

The Civil Aviation Ministry said that it is difficult to find the two black boxes before two weeks as the batteries of the two boxes cannot send or receive any signal.

A specialized ship would be sent to the crash site if the imported equipment failed to find the two black boxes.
Many MS804 news agency articles are based on this source. :sad:

[takata]

Many MS804 news agency articles are based on this source.I would rather use Egypt Ministry of Aviation site here:
http://www.civilaviation.gov.eg/

It's last report was N°4, dated 28 May:
(there is an English translation, scrolling down the page)

http://www.civilaviation.gov.eg/News/news%20pages%20ar/image003.jpg القاهرة في 28 مايو 2016
ورد الى لجنة التحقيق تقارير الاقمار الصناعية والتى تفيد بتلقى إشارة استغاثة إلكترونية صادرة عن جهاز ELT ( وهو جهاز وظيفته إرسال إشارات أتوماتيكية إلى الأقمار الصناعية حال حدوث إصطدام أو سقوط بالماء ) وقد تم ابلاغ جهات البحث المختصة عن الإحداثيات التى رصدتها الأقمار الصناعية لتكثيف البحث بتلك المنطقة .
وفى إطار جهود البحث عن صندوقى المعلومات الخاصين بالطائرة ، تم الاستعانة بأحدث الأجهزة فى هذا المجال كان أولها من شركة السيمار (Alseamar ) وقدم تم استقدامها على متن السفينة الفرنسية ، كما سيتم الاستعانة بأجهزة أخرى ذات قدرة عالية على التقاط الاشارات والمسح السونارى، والتى قامت وزارة الطيران المدنى بالاتفاق عليها مع شوكة DOS (DEEP OCEAN SEARCH) وذلك لتنويع طرق البحث وانجازها فى اقصر وقت ممكن.
ومن ناحية أخرى تلقت لجنة التحقيق المعلومات الخاصة بالمراقبة الجوية اليونانية وبدأت فى دراستها ولازالت اللجنة فى انتظار المزيد من المعلومات المتعلقة بتسجيلات اجهزة الرادار التى تمكنت من متابعة مسار الطائرة قبل الحادث .





CAIRO - 28 May 2016
Investigation Progress Report (4) by the Egyptian Aircraft Accident Investigation Committee

The investigation committee received satellite reports of the electronic emergency signal that came out of the Emergency Locator Transmitter (ELT); which is equipment that sends automatic signals to satellite in the event of a crash or fall into water. Concerned search units were then informed of the updates recorded by the satellite to intensify searching in that area.
Efforts to search for the data recorders of the A320 continues; including the use of the most advanced search equipment of Alseamar company that was brought aboard the French vessel. The Ministry of Civil aviation has also made agreement with DOS (DEEP OCEAN SEARCH) company for other equipment with high capacity to receive signals and conduct sonar scan, in order to diversify research methods and to carry them out in the shortest time possible.
On the other hand, the investigation committee has started studying the information received from the Greek air traffic control about the accident; more information of the records of the radar that had followed the path of the plane before the accident, is expected to be also received.

[GarageYears]

PMS Burullus is back on the AIS map....

AIS Vessel Tracking - AIS Positions Maps | AIS Marine Traffic (http://www.marinetraffic.com/en/ais/home/shipid:748412/zoom:10)

[Out Of Trim]

Unlikely, the fixed ELT is designed to trigger due high G forces of a crash. It doesn't continue to transmit under water!

Other Mobile ELTs can be triggered by someone manually in a controlled ditching scenario, but again unlikely in this case.

So the ELT transmission received must have been during impact and the data captured by satellite at the time.

[Chronus]

How many nanoseconds worth of tx would that be.

[Lonewolf_50]

For a typical ELT, take a look at this Honeywell brochure and (https://www51.honeywell.com/aero/portal/Common/Documents/myaerospacecatalog-documents/BA_brochures-documents/ELT_For_Web.pdf)look at the features for a fixed installation (two of the models). Other manufacturers offer similar capability, as a variety of standards/specs are out there for compliant equipment. (No, I don't work for Honeywell. Thales and Artex make them as well). You could also read back a few pages, within five of this one, and find a variety of posts regarding ELT's. This is one such post (http://www.pprune.org/rumours-news/579183-egyptair-804-disappears-radar-paris-cairo-41.html#post9389331). Within a page either side of it is some more info. You could also take a gander at the ELT threads in Tech Log.

[notapilot15]

If it was from fixed ELT activated on impact, it would transmit until it is destroyed or submerged

If it was a portable ELT activated by cabin crew, it would transmit until it is destroyed or submerged

One thought I have, without any new technology, airlines should instruct cabin crew to turn portable ELT on at the first sign of trouble,ie., don't wait for the crash they can later call airline and give all clear, if everything is a OK. This works only if CC member can reach it, big if.

Bottomline there is no way to estimate the duration of transmission. Like I posted upthread, even though aircraft may have 3xELT,8xRaft Beacons and 2xULB all are useless.

[x_navman]

the portable ELT's will also activate automatically when immersed.

I think a likely scenario is that on impact, the device became immersed enough to cause automatic activation.., but it never floated free of the wreckage. Then, the piece of wreckage to which it was attached popped up to the surface where it remained for a few minutes, broadcasting the 406mhz signal to satellites. Then,as trapped air escaped from that piece of wreckage, it sank, bringing the ELT with it, and the signal was no longer received by the satellites.

more or less the same thing could have happened with a fixed ELT that activated upon impact.

ELT's have unique identifiers that are broadcast with the distress signal, and it's possible that if the transmission was of long enough duration, they know whether it was a fixed or portable ELT that sent the signal.

The portable ELT's are actually designed to operate while floating in the water. So, if you ever find yourself in a life raft with an ELT.., what you are supposed to do is activate the ELT - if it hasn't activated automatically - and tie it with a lanyard to the life raft.., and let it float in the water alongside the liferaft. You are not supposed to keep it with you in the life raft.

[underfire]

Sorry, but salt water to air transmission, especially SAT receiver, would be virtually impossible, especially at the frequencies and power noted. VLF radio waves (3–30 kHz) can penetrate seawater to a depth of approximately 20 meters.

Attenuation of radio signals in sea water is significant. Communication further than just below the surface are not possible unless very low frequencies (10 to 30 kHz) are used. Even if you could use the frequencies in this band, there are other difficulties:

Air to water refraction loss in this band is in the order of 60 to 70 dB.

Antenna dimensions would need to be very large, particularly for the above the surface antenna. (Even at 30 kHz, a wavelength is 10 km). Large transmitter powers are usually required to compensate for the high antenna losses inherent in the shortened low frequency antenna. (remember the Omega system?)

Atmospheric noise peaks to about 160 dB above thermal noise (KTB) at 10 kHz, limiting the minimum discernible receive level.

[sardak]

From Cospas-Sarsat spec C/S-T.001 "Specification for Cospas-Sarsat 406 MHz Distress Beacons." Rev 16, Dec. 2015 (for beacons above the water)

4.5.5.3 - The internal navigation device shall provide valid data within 10 minutes after its activation. Internal navigation device cold start shall be forced at every beacon activation. Cold start refers to the absence of time dependent or position dependent data in memory, which might affect the acquisition of the GNSS position.

4.5.5.4 - The internal navigation device within the beacon shall be activated immediately after the beacon is turned on. (details of this section are based on the spec version in effect at time of beacon manufacture)

4.5.5.5 - For a beacon designed to operate with an external navigation device, if appropriate navigation data input is present, the beacon shall produce a digital message with the properly encoded position data and BCH code(s) within 1 minute after its activation.

4.5.6 After activation, the beacon shall not transmit a 406 MHz distress message until at least one repetition period (as defined in section 2.2.1) has elapsed. [section 2.2.1 defines the 50 second interval].

From experience, many of the first alerts are "unlocated" , i.e. no position data, through the geo sats. Then in the next minute or so, a new solution with location data is provided (for beacons with internal or external GNSS). However, this first position may be the "cold start" position, with minutes in multiples of 15' (0, 15, 30, 45), for a beacon with internal GNSS. In the next minute usually comes a position update with more refined coordinates.

If one is lucky, one of the LEOSAR sats will come over shortly and provide an additional Doppler derived, and maybe GNSS, position.

Mike

[Mesoman]

It looks like the COSPAS-SARSAT rules are not made for this kind of situation - where the ELT may be shortly submerged or destroyed but there is a very large interest in locating the wreckage, survivable or not. I guess they value avoiding false alarms over occasional missed finds, but one would hope there would be a better way of signalling that an activation was false, so the 406 data burst could go out ASAP.

It has been my experience that non-survivable small aircraft accidents usually destroy the ELT or sever the antenna or antenna connection, but this is a different situation. It has also been my experience that ELT's go off way, way too often when there is no emergency, but again, different issue.

[sardak]

Those requirements listed above are for the current 406 MHz beacons. The "second generation beacon" (SGB) design is in work. The limitations of the current system are understoood.
Here are some requirements for the SGB, from C/S G.008, "Operational Requirements for Second Generation 406-MHz Beacons."

3.3.1 Requirements
>The beacon shall have first burst transmission characteristics to allow for independent location computation.
>The operational performance requirement is for first burst 2D independent location accuracy within 5 km, 90% of the time.
>The operational performance requirement is for 2D independent location accuracy of:
- 5 km, 95% of the time, within 30 seconds after beacon activation,
- 1 km, 95% of the time, within 5 minutes after beacon activation, and
- 100 m, 95% of the time, within 30 minutes after beacon activation.

3.4.1 Requirement
The beacon shall transmit a valid message within [3] seconds after activation. The transmission shall meet appropriate signal characteristics.
3.4.3(e) Consideration should be given to the timing of float-free EPIRB automatic activation under water, noting that the EPIRB may not have reached the surface 3 seconds after activation.

3.5.1 [B]The operational performance requirement is for a 99.9% probability of detection of at least one valid beacon message within 30 seconds after activation and independent location accuracy as defined in section 3.3.
3.5.2 Analysis of previous incidents has shown that some beacons fail within the first 30 seconds of a distress situation. It is also important to detect and locate a beacon as soon as possible in all distress cases.

For these and other requirements to be met, the MEOSAR system needs to be fully operational. 20 or so of the 72 receivers are in orbit, all mounted on GNSS satellites (GPS, Glonass, Galileo). A limited early operational capability may be in place this summer.

Mike

[formationdriver]

An AIRBUS vice president says he's in is in favour of jettisonable & floatable CVRs & FDRs that would separate from an aircraft tail section in case of dislocation. Airbus se redit pour des boîtes noires éjectables après Egyptair (http://www.lefigaro.fr/flash-eco/2016/06/01/97002-20160601FILWWW00028-airbus-se-redit-pour-des-boites-noires-ejectables-apres-egyptair.php) "Ces enregistreurs «déployables» se sépareraient de la queue de l'avion lors de la dislocation de l'appareil pour aller flotter à la surface de la mer en émettant un signal de détresse. «Nous y travaillons» a déclaré mardi le vice-président d'Airbus pour l'ingénierie.
Le crash de l'avion de la compagnie aérienne EgyptAir, dont les enregistreurs n'ont toujours pas été retrouvés, milite en faveur de "boîtes noires" capables d'être éjectées avant un accident, estime Charles Champion, vice-président d'Airbus pour l'ingénierie. Des enregistreurs éjectables (ou "déployables") se sépareraient de la queue de l'avion lors de la dislocation de l'appareil pour aller flotter à la surface de la mer en émettant un signal de détresse.
La recherche des enregistreurs de vol de l'Airbus A320 d'Egyptair qui s'est abîmé en Méditerranée le 19 mai dernier avec 66 personnes à bord s'effectuent dans des eaux dont la profondeur peut atteindre 3.000 mètres. Les "boîtes noires" sont conçues pour émettre des signaux acoustiques pendant 30 jours après une catastrophe. Les équipes de recherche ont désormais moins de trois semaines les repérer. "Si nous avons un enregistreur déployable (éjectable), il sera beaucoup plus facile à trouver", a déclaré Charles Champion lors d'une rencontre avec la presse. "Nous y travaillons".
Recommandée par les enquêteurs après le crash d'un A330 d'Air France en 2009, l'idée a ressurgi après la disparition du vol MH370 de Malaysia Airlines en mars 2014. L'Organisation de l'aviation civile internationale (OACI) a demandé à ce que les données clés d'un vol soient récupérables "en temps utile" sur les avions livrés après 2021. Mais la façon d'atteindre cet objectif sera laissée au choix des compagnies aériennes et des constructeurs aéronautiques, qui pourront utiliser des enregistreurs éjectables ou tout autre moyen technique.
Les enregistreurs éjectables sont depuis longtemps utilisés dans l'armée. Mais certains ont exprimé des doutes sur leur utilisation sur les avions civils, faisant valoir qu'ils pourraient se déployer de façon accidentelle et constituer une nouvelle source de risque."

[2dPilot]

In English...




"These recorders" deployable "would separate the tail of the aircraft during the break-up go to float on the sea surface by emitting a distress signal." We are working, "said Tuesday the vice- Airbus President for engineering.
The plane crash airline EgyptAir, the recorders have still not been found, advocates of "black boxes" that can be ejected before an accident, said Charles Champion, Airbus Vice President for engineering. Of deployable recorders (or "deployable") would separate the tail of the aircraft during the break-up go to float on the sea surface by emitting a distress signal.
The search for the flight recorders of the Airbus A320 that crashed Egyptair in the Mediterranean on May 19 with 66 people on board are made into waters whose depth can reach 3,000 meters. The "black boxes" are designed to emit acoustic signals for 30 days after a disaster. Research teams are now less than three weeks locate. "If we have a deployable recorder (ejection), it will be much easier to find," said Charles Champion during a meeting with the press. "We are working on it."
Recommended by investigators after the crash of an Air France A330 in 2009, the idea has resurfaced after the disappearance of flight MH370 Malaysia Airlines in March 2014. The International Civil Aviation Organization (ICAO) asked that a key flight data is recoverable "in good time" on the aircraft delivered after 2021. But how to achieve this objective will be left to the choice of airlines and aircraft manufacturers, who will use deployable recorders or other technical means.
The deployable recorders have long been used in the military. But some expressed doubts about their use in civil aircraft, arguing that they could deploy accidentally and provide a new source of risk. "

[HeavyMetallist]

Probably worth doing, but I would have thought it has to be at least questionable how often it would be beneficial to recover the flight recorders in the absence of the physical evidence to be found in the wreckage - or vice versa. To understand the "why" you still still generally need to find the aircraft, even if the recorders have given you a good idea of "what" happened.

I'd also point out that for all the feverish criticism of the current method of recovering flight recorders from crashes into water, the odds are very much in favour of it working in this case, even if it does take a little longer than some people would like.

[portmanteau]

All the rosy specs listed can't apply when an aircraft goes straight in to the sea and immediately sinks. Egypt says an ELT signal was picked up and that must have been the very brief transmission between the g-force switch activating on impact and the hull submerging. Thats all they have got and it doesnt seem they have been able to derive any position information from it.

[takata]

@ portmanteau
Well it looks like they were able to derivate a very close position of the crash site from 5 satelite pick up of two short beacon bursts at 00:36z. A previous report mentioned that those data were treated by Airbus (or Space Agency in Toulouse) for Egyptian authorities. The Gardian wrote something that is looking accurate yesterday:
Distress signal from EgyptAir flight 804 confirmed by authorities in Cairo and US | World news | The Guardian (http://www.theguardian.com/world/2016/may/31/distress-signal-from-egyptair-flight-804-confirmed-by-authorities-in-cairo-and-us)

[portmanteau]

Takata tks that would seem to end the ELT debate. It worked and it brought the recovery teams to the right spot. Job done. Finis.

[2dPilot]

"Job done. Finis"
I hardly think so ... it isn't the beginning of the end, but it might be the end of the beginning ... comes to mind.

[mm43]

There are now 3 surface vessels located in the area of interest - around 33°30'N 29°10'E; they are the PMS Burullus (Egyptian Offshore Support Vessel), Alnadorah (Tug), and the Laplace (French Navy Hydrographic vessel).

The Laplace arrived on scene over 12 hours ago, and appears to have done a Towed Pinger Locator (TPL) test run; the PMS Burullus is maintaining position nearby, while another vessel a small tug Alnadorah is currently alongside the Laplace.

The search for the ULB's (Underwater Locator Beacons) is about to get underway. The DFDR and the CVR each have an ULB attached to them, and these beacons emit a pulsed Ultrasonic sound wave with a frequency of approximately 37.5kHz. Approximately, because the frequency control parameters are set by resistive/capacitive circuitry, which results in no two beacon's frequency performance being exactly the same as another; handy when identifying multiple beacons in a search area.

With regard to the ELT transmissions received by satellite, there is always the possibility the automated fixed ELT was set to "ON" from the "ARMED" position by actions taken in the cockpit following LOC. This may have given the time needed for the vital positional data to be sent. That being the case, the ULB's will most likely be located relatively quickly [if functioning].

[2dPilot]

Locator signals detected by French Ship: EgyptAir crash: Signals from deep in Mediterranean Sea 'could be flight MS804's black boxes' | Europe | News | The Independent (http://www.independent.co.uk/news/world/europe/egyptair-flight-ms804-crash-latest-black-boxes-found-mediterranean-sea-signals-a7059241.html)
Sky News also reporting

[beamender99]

The BBC is now reporting
"French ship hears signals believed to be from EgyptAir flight that disappeared in Mediterranean, Egypt says"

[notapilot15]

@formationdriver

Airbus has been talking about Deployable Flight Incident Recorder Set (DFIRS) since MH370. If I understand correctly DRS Technologies (a Finmeccanica subsidiary) close ties with EADS puts Airbus in a better position to offer this technology to customers. Hopefully Boeing will come along.

Deployable Flight Incident Recorder Set (DFIRS) 2100 | DRS Technologies, Inc. (http://www.drs.com/products-and-services/deployable-flight-incident-recorder-set-dfirs-2100/)

[Lonewolf_50]

@formationdriver

Airbus has been talking about Deployable Flight Incident Recorder Set (DFIRS) since MH370. If I understand correctly DRS Technologies (a Finmeccanica subsidiary) close ties with EADS puts Airbus in a better position to offer this technology to customers. Hopefully Boeing will come along.

Deployable Flight Incident Recorder Set (DFIRS) 2100 | DRS Technologies, Inc. (http://www.drs.com/products-and-services/deployable-flight-incident-recorder-set-dfirs-2100/) I suggest that further discussion on this particular topic belongs in another thread, or in tech log. If the FAA doesn't make this a requirement, why would Boeing (or Embraer, or anyone) have to "come along" as you put it. (Not saying it's a bad idea, but the flip side is does making this a requirement have a higher importance than something else? ) Is this a solution in search of a problem?

[D Bru]

Investigation Progress Report (4) by the Egyptian Aircraft Accident Investigation Committee (http://www.civilaviation.gov.eg/News/news%20pages%20ar/messs_1_6_16.html)
(actually, this is update 5)

"Cairo, 1st of June 2016

The French vessel “La Place” of the French navy; participating in the search for the two data recorders of the A320 that was downed in the Mediterranean mid of last month; has received through its search equipment signals from the seabed of the wreckage search area; assumed to be from one of the data recorders.
Extensive search efforts are being carried out to locate the two data recorders in preparation for their retrieval by “JOHN LETHBRIDGE” which is a vessel that belongs to DOS "Deep Ocean Search", which will join the search team within a week."

[wiggy]

Life of Leisure...

La Depeche by any chance :ok:


"...Le signal détecté par la Marine française est bien celui d'une des boîtes noires du vol Paris-Le Caire d'EgyptAir qui s'est abîmé le 19 mai en Méditerranée, a annoncé mardi le Bureau d'enquêtes et d'analyses français (BEA).

"Le signal d'une balise d'un enregistreur de vol a pu être détecté par les équipements de la société Alseamar déployés sur le bâtiment de la Marine Nationale Laplace", a indiqué dans un communiqué le directeur du BEA Rémi Jouty, après l'annonce par les autorités égyptiennes de la détection par un navire de la Marine française de "signaux émanant probablement" d'une des deux boîtes noires de l'A320 d'EgyptAir.

And no, I'm not going to do an a full "in English, please", other than emphasise that the BEA boss is saying the signals probably come from from one of the two black boxes...

[notapilot15]

Lonewolf 50

Yes, it is the solution in search of problem on hand. A0283 explained it well.

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.

Arial search happens at 150+ knots, underwater search moves at 3 knots. DFIRS eliminates the FDR/CVR search part, gives exact coordinates where it went down, so SAR teams can work on recovery and aviation accident investigators can start their investigation immediately.

BDS P8-A (a B737 platform) sports DFIRS 2100, so why can't BCA B737/B787 or B777.

Not planning to discuss this technology on this thread, but want to share there are proven solutions for this problem.

[Life of Leisure]

Wiggy,

Yes, La Depeche. You are right in translating "a pu être détecté" as "may have been detected", so not definite, but intereting that he has issued a statement. The newspaper seems to be more definite in its interpretation.

Edited to add: BBC also now reporting the BEA statement.

[pax2908]

my reading is "people have been able to detect the signal"

[Alain67]

pax, you are right, in French we do not have the distinction can/may.
Thus the sentence is quite affirmative.

wiggy, translating La Dépèche : "The signal is definetely coming from one of the recorders..."
in the next sentence the BEA boss says the signal has been detected (like pax has emphazised), recalling that Egypt had, before that, announced it was probable.
Thats is a logical chronology : first probable (source Aegypt), then certain (source BEA)

BTW French people often make mistakes just because they use "can" for "may" or conversely !

[LASJayhawk]

@ portmanteau
Well it looks like they were able to derivate a very close position of the crash site from 5 satelite pick up of two short beacon bursts at 00:36z. A previous report mentioned that those data were treated by Airbus (or Space Agency in Toulouse) for Egyptian authorities. The Gardian wrote something that is looking accurate yesterday:
Distress signal from EgyptAir flight 804 confirmed by authorities in Cairo and US | World news | The Guardian (http://www.theguardian.com/world/2016/may/31/distress-signal-from-egyptair-flight-804-confirmed-by-authorities-in-cairo-and-us)

That would have to be 5 ground stations. The satellites were shut down in 2009...

[airsound]

And thanks to Alain67 for explaining that 'nicety' of translation from French to English!

So, back on track - can we now assume that the BEA is saying that a signal has been identified as definitely from a flight recorder?

[The Ancient Geek]

I think it would be fairer to say that a signal has ben received, the characteristics of which are typical of a flight recorder, and the probability of picking up a false signal in this area is small so it is very probably a flight recorder..

[x_navman]

That would have to be 5 ground stations. The satellites were shut down in 2009...
not sure what satellites you are referring to...

the copas-sarsat satellite system is fully functional

[airsound]

I agree, O Ancient One. But I would like to know if the BEA is actually saying something firmer than 'probability'.

[klintE]

Assuming this is actually it, has anyone idea how long it takes to raise it from the those depths?

[takata]

Alseamar system on H/V Laplace
Not sure how this system work, but it seems different from other trailed beacon locators. They say it's unique, and imerged at 1.000 meters deep, this system can discriminate CVR/FDR signal at a range of +4.000 m. It looks more like sono buoys.

Doté de nombreux moyens d’hydrographie, le Laplace a embarqué des outils spécialisés, dont le système Detector de la société française Alseamar. « Grâce à 20 ans d’expérience dans le domaine de l’acoustique sous-marine, Alseamar a conçu et fabriqué ce système unique au monde. Immergé à environ 1000 mètres sous l’eau, le Detector écoute et discrimine à plus de 4 kilomètres signal émis par les balises fixées aux enregistreurs de vol parmi les bruits ambiants de la mer », explique cette filiale du groupe Alcen, qui dispose à bord du Laplace d’une équipe constituée d’un ingénieur et de deux techniciens. En tout, trois Detector 6000 seront déployés par le bâtiment hydrographique de la Marine nationale pour définir une position la plus précise possible des enregistreurs.


http://www.meretmarine.com/sites/default/files/styles/mem_846_article_content/public/new_objets_drupal/20141021143032_Detector-1000%20Totem.jpg

[Chronus]

Now that we know of u/w signals having been detected by means yet unknown and that such emissions are likely to be from the DFDR could those with knowledge and expertise please of such- sub surface searches inform us of the acoustic/detection range of these signals.

ps whilst typing the above I just read takata`s post which says 4m, but at 1000m depth. Given the wreckage may be lying at greater depth, what then would the range be.

[takata]

That's for their system DETECTOR 1000 but I guess it's the same for greater depth :
http://www.acsa-alcen.com/positioning-acoustics/detector-1000 (http://www.acsa-alcen.com/how-does-system-work)

[India Four Two]

this system can discriminate CVR/FDR signal at a range of +4.000 m.

Chronus,

That's the French way of writing +4,000 m.

[Chronus]

That's for their system DETECTOR 1000 but I guess it's the same for greater depth :
http://www.acsa-alcen.com/positioning-acoustics/detector-1000 (http://www.acsa-alcen.com/how-does-system-work)
In that case they must be well within sniffing distance, even for someone bunged up with a heavy cold, I would have thought.

Is it not therefore time to pop something down there for a quick look see.

[Chronus]

Chronus,

That's the French way of writing +4,000 m.
Ta India4, Gallic things do rather baffle me, give me simple things like feet and inches. By the look of it got excited over nothing. But there again, must say am a bit surprised that these u/w things can detect such small objects at such range. I suppose it is all to do with the Hunt for Red October type of under water going ons.

[Mesoman]

not sure what satellites you are referring to...

the copas-sarsat satellite system is fully functional

The 121.5/243.0 was shut down, at least for the US. All ELT's were supposed to transmit on 406 by 2009, so they stopped listening. Sadly, most ELT's in the US are still not on 406, which means now ELT searches require a lot more work, almost always just to find a false alarm. In the past, COSPAS-SARSAT fixes would give a working area, based on doppler processing of 121.4/243.0, and that would usually resolve to a metropolitan area where a ground team could quickly find it. Now, we get reports from high altitude aircraft who hear it on guard, and have to launch SAR aircraft just to find out the general area of the ELT. :ugh:

[CONSO]

How deep is the seabed there anyway?

not yet reported but the " general " area is claimed to be about 3000 Meters deep

[Coagie]

So, they are using Underwater Autonomous Vehicles!!! Interesting choice. I thought Towed Pinger Locator would be their first choice. But who knows where in the world are those TPLs. I think they are doing the best with they have on hand.

I guess the three UAVs are working in 8 hr shifts.
8 hour survey - Data download few minutes - recharge.

DIRECTOR-6000 goes down 1000 m (DIRECTOR-1000 300 m)

Under perfect conditions ULB can be heard from 4000 m, under normal conditions 2000 m may be.

How deep is the seabed there anyway?
Very deep. 3000m +.

[takata]

@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

Applications

Search and Recovery operations : Underwater Locator Beacons (ULBs), NATO aircraft pingers and distressed submarine signal
Drug enforcement: detection and localization of underwater drugs canisters

[ve7pnl]

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?

https://www.easa.europa.eu/system/files/dfu/NPA%202012-16.pdf

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

http://www.fire.tc.faa.gov/pdf/na68-7.pdf

edited ELB/ULB error, hat tip to Coagie!

[Cazalet33]

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.

[Gilmorrie]

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?

[Cazalet33]

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.

[chromakey]

...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_France_Flight_447#2011_search_and_recovery )

[llagonne66]

Jean-Paul Troadec has done a bit more than x-raying suitcases ...
https://en.wikipedia.org/wiki/Jean-Paul_Troadec

[thf]

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 (http://www.francetvinfo.fr/monde/europe/disparition-du-vol-ms804-d-egyptair/l-avion-d-egyptair-avait-fait-des-atterrissages-d-urgence-la-veille-du-crash_1479713.html)

"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".

[DaveReidUK]

Jean-Paul Troadec has done a bit more than x-raying suitcases ...
https://en.wikipedia.org/wiki/Jean-Paul_TroadecYes, 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?

[thf]

Yes, he's actually President of the BEA, France's equivalent of the AAIB/NTSB.
He was President of BEA. Wikipedia article is outdated.

[wiggy]

Dave

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..

[DaveReidUK]

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?

[Guillaumet]

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 (http://www.leparisien.fr/faits-divers/vol-d-egyptair-l-airbus-a-320-avait-emis-trois-alertes-lors-des-vols-precedents-01-06-2016-5848875.php)

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.

[takata]

@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.

http://www.francetvinfo.fr/monde/europe/disparition-du-vol-ms804-d-egyptair/l-avion-d-egyptair-avait-fait-des-atterrissages-d-urgence-la-veille-du-crash_1479713.html

[dccdz]

More details there :
Vol d'Egyptair : l'Airbus A 320 avait émis trois alertes lors des vols précédents (http://www.leparisien.fr/faits-divers/vol-d-egyptair-l-airbus-a-320-avait-emis-trois-alertes-lors-des-vols-precedents-01-06-2016-5848875.php)

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.

[takata]

@thf
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).

[Ian W]

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.

[A0283]

@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.

[wiggy]

DR

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.

[RAT 5]

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?

[takata]

@DaveReidUK, Squawk_ident, wiggy
I'm sharing all your points : [edit: those "emergency landings" reported are probably plain wrong ; another newspaper is talking now about "spurious smoke detection" during previous flights before CDG, but everything is to be taken with extreme caution].

At least, we know that it's not something endorsed by JP Troadec as his comment was really cautious, if not sceptical, about what they reported. What is pissing me off is that other newspapers are "quoting" Troadec as being behind this story while he simply answered direct questions.

[Squawk_ident]

Takata wrote
I'm sharing all your points : [edit: those "emergency landings" reported are probably plain wrong ; another newspaper is talking now about "spurious smoke detection" during previous flights before CDG, but everything is to be taken with extreme caution].

At least, we know that it's not something endorsed by JP Troadec as his comment was really cautious, if not sceptical, about what they reported. What is pissing me off is that other newspapers are "quoting" Troadec as being behind this story while he simply answered direct questions.

You are absolutely right.
Considering the first "ACARS leaks" that was published and was worldwide spread, it is rather strange and annoying that a media such as FR3 do not publish (a part of) its sources or documents, or at least elaborate more about. For those that are not very familiar with the French media, the "France 3" TV channel is a State-owned media that is supposed to be serious and reliable. Disturbing.

[comcomtech]

Can the remarkable sleuths who tracked down the ACARS report from the incident see if there are any ACARS for the aircraft over the two or three preceding days?

[.Scott]

Can the remarkable sleuths who tracked down the ACARS report from the incident see if there are any ACARS for the aircraft over the two or three preceding days?
I believe that the original screen shots showed more than a day of reports.
This was posted by Takata om May 20:
http://takata1940.free.fr/MS804.jpg

Notice that there the "Occurrence History" shows 7 engine starts and 1 smoke detection before the final flight.
I don't know if other reports, not present in the final flight, would also have been reported.

A post in another blog asserts that the "Occurrence History" shows occurrences in previous flight legs. So it would seem that the units are legs, not a fixed time period.

[vapilot2004]

Is there enough satellite data storage for every a/c to send back FDR/CVR data in live time?

Short answer, No Rat 5.

Accurate answer - satellites have virtually no storage compared to the data they relay. Storage typically occurs at ground stations or data banks networked to the downlink site. On a SATCOM equipped aircraft, the prime limitation is bandwidth which in satellite terms equals dramatically greater cost.

The space bird companies would surely build to accommodate any rea$onable demand.

[takata]

@Scott
Notice that there the "Occurrence History" shows 7 engine starts and 1 smoke detection before the final flight."02-ENG START" labelled ACARS is refering to the flight phase (06 is Cruise) ; those ACARS, like "FWC2: no data... ; QAR Media low..." are triggered only when such circumstance apply, but not each time an engine is started. It looks like the "occurence history" is covering a period of previous flights for each ACARS.

Flight Warning "SMOKE LAVATORY SMOKE" appears to have been previously triggered once, but when was that? If each box, starting from the last one, was for a previous flight, I can count 15 boxes (including the last flight) and going backward, it would have been 8 flights before the last one.

On the other hand, I can't see any occurence history for "AVIONICS SMOKE" during the past 14 flights (if that's how it works). We can't say anything about "CARGO SMOKE" history, because it's not been triggered during the last sequence, neither about "AIR COND SMOKE" which is not triggering any ECAM warning.

Consequently, without any specific ACARS reports from those previous flights, this isn't going to be really helpful. I would only deduct that "SMOKE LAVATORY SMOKE" or "AVIONICS SMOKE" were probably NOT triggered during the previous 24h of operation.

[PersonFromPorlock]

FWIW, it occurs to me that a very low-cost, low-tech step might help to find aircraft downed at sea: a big package of dye rigged to spill on impact. A dye splotch visible from orbit would surely have helped in the case of MH370, for instance. It might even do some good marking a crash on land.

[grizzled]

PersonFromPorlock's suggestion is one of the best ideas I have seen on this issue. The tendency today is for complex technical (read "expensive") solutions, that most often have their own serious drawbacks.

Regardless of what other mitigation or solutions come about in the next decade or so, PFP's idea should be give serious consideration as a relatively simple, relatively cheap mitigator to the problem of figuring out where an aircraft entered the ocean (even considering drift in the first 24 hours). It's not a solution to recovering the aircraft or the data, but it's certainly an idea worth consideration for faster pinpointing of a crash site. And I agree that it might even have helped in several past occurrences of aircraft missing over land.

[takata]

@grizzled, PFP,
if it's a "big-package", meaning heavy or bulky, it's not going to be very "low-cost" in terms of so many aircraft operations.

[grizzled]

takata...

Understood. Which is why I said "relatively' and "worth consideration"

:)

[What Traffic]

A dye pack might be a bit smaller and lighter if it contained a buoyant carrier fluid impregnated with materials which were mildly radioactive. There are numerous airborne and orbital sensors which are extraordinarily proficient at seeing such things. I would worry that the horror and gnashing of teeth from the uninformed about thousands of airliners flying with such materials on board might torpedo the idea before it hit the water, but I believe that there are both safe and detectable materials which could be viable.

[Ian W]

Short answer, No Rat 5.

Accurate answer - satellites have virtually no storage compared to the data they relay. Storage typically occurs at ground stations or data banks networked to the downlink site. On a SATCOM equipped aircraft, the prime limitation is bandwidth which in satellite terms equals dramatically greater cost.

The space bird companies would surely build to accommodate any rea$onable demand.

Answering the wrong question.
As you say, the Satellites have no storage they are part of the virtual 'electric string' from the aircraft to a receiving system. The receiver systems have close to limitless storage in terms of DFDR/CVR. There would be no problem in saving several hours of data for every aircraft in the world. However, that is not the issue. The issue is available bandwidth for the transmissions through the satellites and who would pay for the usage of that bandwidth.

This is where schemes are developed for sending only when the aircraft knows it has a problem. However, that may mean not getting anything as the problem may kill the satellite link especially if the link requires a satellite tracking antenna. So a better scheme may be to record the data onto ejectable ELTs that would be able to transmit their location and also when they are found they contain the DFDR/CVR data that is required - solid state storage being close to indestructible and of significant capacity.

[Lonewolf_50]

This is where schemes are developed for sending only when the aircraft knows it has a problem. However, that may mean not getting anything as the problem may kill the satellite link especially if the link requires a satellite tracking antenna. So a better scheme may be to record the data onto ejectable ELTs that would be able to transmit their location and also when they are found they contain the DFDR/CVR data that is required - solid state storage being close to indestructible and of significant capacity. How often do you need to service the flotation gear to make sure that if it's ever needed, it actually inflates and it floats?

[oldoberon]

oldoberon 17th march 2014 MH370

Saw this idea somewhere, water soluble bags of highly concentrated fluorescent dye in wings and cargo holds,. I liked it because they were passive, ie no batteries or activation needed

not going to happen is it

i also suggest 4 bags, one in each wing one in the nose area and one in the tail area, all different colours so if a break up occurred in the air you would know

[Tinribs]

Thinking back to the start of my military flying (a long time ago) I am sure we had a sachet of yellow dye in our life jackets which would deploy, along with shark repellent, if immersed in water

[RAT 5]

is there enough satellite data storage for every a/c to send back FDR/CVR data in live time?
Short answer, No Rat 5.
My mistake. Not data storage, but data transmission. If every FDR/CVR equipped a/c and its operator was required to have the equipment fitted at manufacture then searching for tiny black boxes might be un-necessary as all the data would already be in the Ops room. If operators couldn't do it then a Google type aviation data collection company could do so. I agree, this 'only on board' data retention method is archaic and expensive when required.

[jugofpropwash]

Perhaps the bean counters out there could compare the cost of carrying large bags of dye (let's say bags equivalent in weight to two passengers?) vs the millions that have been spent looking for just AF447 and MH370. Maybe the numbers don't work - but it seems like they should. Or is it that the airlines would have to pay the cost for the dye, whereas the involved countries are picking up the search costs?

Also - IF it is true that the plane had produced various spurious ACARS messages in the days before it was lost, might that not indicate an intermittent fault in the wiring (perhaps a short) or in the computers?

[Orestes]

@grizzled, PFP,
if it's a "big-package", meaning heavy or bulky, it's not going to be very "low-cost" in terms of so many aircraft operations.





Just dye the fuel.

[Herod]

Orestes. A prime example of thinking outside the box. I like it.

[Tim Hubbard]

Answering the wrong question.


So a better scheme may be to record the data onto ejectable ELTs that would be able to transmit their location and also when they are found they contain the DFDR/CVR data that is required - solid state storage being close to indestructible and of significant capacity.



I published a design for better ELT's last year (see link). With SD cards with a capacity of 0.5 terabytes, it would be very practical to have each ELT carry the full CVR/FDR history, and a great deal more besides.


https://drive.google.com/file/d/0B9xRjb8RW2IhdXo3NlNXLTh4eEk/view?pref=2&pli=1

[HeavyMetallist]

Orestes. A prime example of thinking outside the box. I like it.
Yes, brilliant. So now you not only carry the weight of the dye (it not being fuel it'll just add to the fuel weight), you carry much more of it (since as you need to have enough to still be effective when the tanks are largely empty you'll have far more than needed when they're full), and to top it all off you burn your expensive dye during every flight. This is all assuming the dye would be effective anyway, and wouldn't screw up the engines, of course.

[Sunfish]

Chronus:

Surely the authorities must by now have more information . The question is if they do. then why are they keeping it under wraps. It follows that entertaining such thought will inevitably lead to even more speculation of all manner of skullduggery and mischief.

You cannot base a logical conclusion on "negative evidence".

Despite the best efforts of the fantasists who appear on Pprune after every incident, there is nothing that can yet be deduced from ACARS, the last minute of the flight path or the absence of communication except that the aircraft and/or crew had something happen to it and it went in the water.

Furthermore, the truth, if it is ever discovered, may be quite a bit stranger than the uninformed speculation here.

Furthermore again, the question of positively locating every commercial jet while in flight is not trivial, neither is finding a wreck on land or water.

There are no quick easy cheap solutions despite what some may think.

[underfire]

My mistake. Not data storage, but data transmission. If every FDR/CVR equipped a/c and its operator was required to have the equipment fitted at manufacture then searching for tiny black boxes might be un-necessary as all the data would already be in the Ops room.

Currently, there are several systems, and airlines, that use the IFE system to broadcast ac out/in data real-time.

[Ian W]

How often do you need to service the flotation gear to make sure that if it's ever needed, it actually inflates and it floats?
If I was designing it then I would make the ELT casing of expanded polystyrene or similar it floats without anything active required. Passive is better than active in these types of equipment.

[PersonFromPorlock]

Regarding the dye suggestion, the first thing is to find out how much dye would be needed to make a splotch visible from orbit and go from there. I do like oldoberon's idea of putting different colors at different extremities of the aircraft, for the reasons he gives.

[Feathered]

With the A320 being in Service for almost 30years and more than 7000 of them produced and >6500 of them still flying and >150Million Flight Hours you find the huge bug in the Design that only by pure luck did not down them by the hundreds, previously????
Seriously.... :ugh:


Everytime you think it can't get any crazier...

Maybe, maybe not. Without weighing in on the merits of the specific question currently, consider how many 747s flew perfectly, carrying millions of passengers before TWA 800 in July 1996. And after just that one accident, a design change was required requiring inert gases in the fuel tanks.

Or consider Concorde had a perfect record until one accident in 2000, and suddenly design changes were required after a bad day.

No doubt the A320 series has proven to be a safe aircraft. But lack of accidents does not mean there are no underlying issues, and if any arise in the future they would need to be addressed.

[sevickej1]

In the 60's the JP4 (1mil US gallons a time) we delivered to the Antarctic was dyed bright pink so that it could be seen clearly if it leaked from any pipeline (sometimes up to 7km long) by a helo designated to check-fly the line. Worked well against the white ice/snow. Probably not as effective in the open ocean.

[vapilot2004]

The issue is available bandwidth for the transmissions through the satellites and who would pay for the usage of that bandwidth.


I believe I said that, Ian W. :8

The issue is indeed bandwidth and on SATCOM systems, that equates to cost.

For the most part, the current DFDR and CVR methods work fine in the overwhelming majority of crashes and incidents. Perhaps one way forward would be adding a fare tax that would support the use of SATCOM reporting for long over water flights.

[vapilot2004]

[QUOTE=RAT 5;9396888] If every FDR/CVR equipped a/c and its operator was required to have the equipment fitted at manufacture then searching for tiny black boxes might be un-necessary as all the data would already be in the Ops room. If operators couldn't do it then a Google type aviation data collection company could do so. I agree, this 'only on board' data retention method is archaic and expensive when required.

SATCOM ACARS is getting close to this idea and exists. Perhaps, as suggested in my previous post, a tax on flights over water might support expanded mandatory reporting systems.

[RAT 5]

RYR 350-500a/c. EZ 280-400a/c. Only 2 operators with plans for nearly 1000 a/c and none have Satcom/Acars systems because it is not mandatory. No doubt there are other similar operators worldwide who choose not to fit that equipment. That relates to 1000's of a/c, many flying in, around, over remote areas. If the basic equipment was fitted as standard and mandatory at manufacture what would it add to the cost? Peanuts I would suggest. Less than 1c per pax ticket over the lifetime of the a/c. If there was a satellite link to home base of all FDR/CVR data on a 2 hour rewrite disk then answers to WTF happened might start earlier. I'm sure they would still search for the ac/ and recover what they could of it and the pax, but the delay in finding answers would be less. Black boxes seem so low tech as the ONLY universal method. The techies will know more.

[Evanelpus]

Just dye the fuel.

Probably the best suggestion yet. Adding bags of different coloured dye here, there and everywhere would mean modifications and certifications but coloured dye fuel is too simple for words.:ok:

But the sceptic in me says it won't happen:ugh:

[2dPilot]

Just dye the fuel.
Make some lovely con-trails too - And some discount flights for en-route sign-writing excursions.

[Saga Noren]

Just dye the fuel. Make some lovely con-trails too - And some discount flights for en-route sign-writing excursions.

Choose the right colours and change the Earth's albedo and halt global warming. Result!

[Loose rivets]

Aircraft to aircraft exchange of data packages has always seemed logical to me. There is a limit on range when using VHF, even from cruise altitudes, and also, a fair time to post the data since the carrier frequency is so low, but all so often there are a lot of aircraft to do an exchange with. The time it has to be stored could also be sent.

Surely better than even occasional seabed searches.

[oldoberon]

Adding dye bags, certification would only apply to current fleets then it would come fitted on new supplied frames.

Adding dye to fuel would need tests if not certification to every engine type, fuel tank & internal wiring, pipework and joint seals etc and as already pointed out quantity will diminish during flight, so how effective would be towards the end of a flight.

You are constantly using and renewing it, so cost are increased by mileage, may even be environmental issues.

KISS, passive systems less agro

[PJ2]

Re "mystery" reports on MH370...

It has taken aviation a long time to develop present standards, procedures, formats and fact-checking to which the investigative process and final report must adhere.

While there are clear signs that we are rapidly leaving the age of rationality and enlightenment values, there are some human activities which remain within rationality's purview; - the investigative process is one.

The "mystery" document reads like all other conspiracy-theory publications. It survives on curiosity and pure volume of text and pictures, trying to be what it can never possibly be: the final report.

Sunfish, re the MSR804 ACARS tea-leaves, fully concur with your views. I recall the sometimes-wandering, sometimes quasi-prescient discussions of the AF447 ACARS messages which, until the 3rd Interim Report remained a logical mystery. It was a long time before even just the timing of the messages was understood and that such did not necessarily indicate which occurred first. When all was revealed, it was an interesting exercise to compare the various theories put forth with the actuality after the recorders had been read.

It is not the first time that reference here to various aspects of the remarkable series of threads discussing the loss of AF447 has been made, and with good reason I think.

[grizzled]

PJ2...

As always, a well written and very well thought out post.

As you suggest, some of the (many) lessons learned from AF447 were retrospective with respect to comparing the theories investigators had, versus what actually happened, and then delving into the resulting question: Can we (meaning investigators) use what we learned from AF447 in any valid way in analysing the known events of other so far "unsolved" accidents / disappearances; either to reinforce or to negate or weaken some aspects of a particular theory or postulation (ACARS messages being just one such source of information, albeit a potentially very valuable one).

Thanks also for your segue into logic and investigative procedures by referencing current events and the shadowy descending path so frighteningly evident in world affairs...

[mm_flynn]

A number of posts are suggesting better ways to recover FDR/CVR data or find the crash site. The prime motivations seem to be 1 - reduce cost of search, 2 - improve speed of accident analysis, 3 - provide quick information for headlines and threads ;-).

It is worth considering that in many (probably the majority) of cases, physical examination of the wreckage is necessary to get to actionable corrective actions. That is, the data either says 'this is the pattern of failure, flight path, and crew commentary' (the what); or the data just stops (tells very little). The why, unless it is human motivated, normally needs an analysis of actual components of the wreck. Additionally, there normally is a very strong desire to recover as many bodies as possible to provide proper closure and respect. As such, regardless of how fast the initial location is identified, there is inevitably an extensive effort with a number of ships and expensive recovery equipment to recover the wreck and human remains. I am not an expert, but I would guess that in every case (other than MH370) the cost of locating the wreck is dwarfed by the cost of recovering the wreck. As such, regardless of the technology for locating or transmitting the FDR/CVR data, the main cost of recovery will not be avoided, so the economic balance is going to be against anything expensive.

It appears in this case that, as a matter of luck not design, an ELT did get off a transmission that localised the crash site, that surface debris was found pretty quickly (maybe one day later than a large dye marker) and it appears that the ULB has been localised within 12 hours of the correct gear arriving on station. Additionally, the aircraft was transmitting its location at GPS accuracy to ground stations every second until very likely the power was shut down, so no matter what extra technology was added, it is not likely the undersea location was going to be known to a significantly higher level of accuracy.

Speculating on the little information we have, I would bet the FDR is going to show a cascading set of faults that are consistent with an electrical fire/short circuit 'somewhere', and then the power being shut down. The CVR is likely to indicate the pilots thought there was a fire and took corrective action, and if it remained powered, which I suspect not, then that they lost control in a very difficult set of circumstances. ... But crucially NOT A CLUE as to what actually failed and why; and therefore, no indication of the corrective actions necessary. However, after recovering the wreckage, analysing the damage and context, the investigators, in due course, will provide a pretty clear view of what failed, why, and some recommended corrective actions.

Investing say $4,000 M ($100k per commercial aircraft - not a lot for any change) fitting slicker locator technology to save a thankfully rare and normally small incremental cost of finding the general crash site (even in the extreme MH370 case the cost appears to be budgeted for $130 M) and saving the initial two weeks of searching, in a process that normally takes over a year to reach its conclusions, seems a poor choice.

[Lonewolf_50]

Investing say $4,000 M ($100k per commercial aircraft - not a lot for any change) fitting slicker locator technology to save a thankfully rare and normally small incremental cost of finding the general crash site (even in the extreme MH370 case the cost appears to be budgeted for $130 M) and saving the initial two weeks of searching, in a process that normally takes over a year to reach its conclusions, seems a poor choice. Yeah. If one was going to spend that money industry wide (but really, it isn't spent by the industry but by a combination of companies and countries) that kind of money would be better spent on flying training for pilots -- be it more sim events or whatever -- wherein the pilots fly the aircraft and exercise all of the systems. (Head over to the Mil forum and see the Air Clues article of UK Apache (http://www.pprune.org/military-aviation/579736-ah-64-tail-rotor-loss-article.html) pilot landing an aircraft that had lost tail rotor drive during a combat mission. Flying training pays off when bad things happen).


I apologize if this is thread drift, but the flying proficiency bit strikes me, as I read through PJ2's ref to AF 447, as the critical area of prevention of most accidents. How and whether it applies to this case -- if at all -- will be shown after the investigators dig into any recovered info.

[PersonFromPorlock]

Adding dye bags, certification would only apply to current fleets then it would come fitted on new supplied frames.

Adding dye to fuel would need tests if not certification to every engine type, fuel tank & internal wiring, pipework and joint seals etc and as already pointed out quantity will diminish during flight, so how effective would be towards the end of a flight.

You are constantly using and renewing it, so cost are increased by mileage, may even be environmental issues.

KISS, passive systems less agro

"Fluorescein" would appear to be the dye of choice: a powder, widely available, medically safe and already used as a sea stain. Bags of that could be thrown into cargo holds (or elsewhere) tomorrow. The sort of crashes we've been discussing have disintegrative impacts, so dispersal from inside the airframe shouldn't be a problem.


The extra weight and bulk of the dye pack shouldn't matter since most airline flights are at less than MGTOW, and bags stow anywhere.