EgyptAir 804 disappears from radar Paris-Cairo
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Screen Grab of the PMS Burulla track for the last few hours.
(Courtesy AIS Vessel Tracking)
ScreenShot00252.png
(Courtesy AIS Vessel Tracking)
ScreenShot00252.png
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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.
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.
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I know what the Egyptians said, but wondered if they had the capability?
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)
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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.
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.
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'decoding' digital FDRs
I found a fascinating article 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.
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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.
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.
Last edited by wheelsright; 25th May 2016 at 15:51. Reason: Improve accuracy
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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
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
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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?
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But yes, it would seem to imply that the transmitter remained powered and in a position to be received from for that period.
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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.
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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.
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.
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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.
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.
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PMS BURULLUS
Egypt sends robot submarine to help plane crash search | The Expat's Guide To Cairo
May232016
Egypt sends robot submarine to help plane crash search
Expat CairoNews 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.
May232016Egypt sends robot submarine to help plane crash search
Expat CairoNews 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.
grizzled, Spot on!
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 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/
Quote:
Originally Posted by Contact Approach
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...
Originally Posted by Contact Approach
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...
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 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/
Last edited by PJ2; 26th May 2016 at 00:51.
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/
..
Searching for ACARS af447 in "tech log":
ACARS af447 site:http://www.pprune.org/tech-log/
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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/39510...esume-122.html
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/39510...esume-122.html
Last edited by wheelsright; 26th May 2016 at 07:28. Reason: typo
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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/dat.../ATP/atp10.pdf
http://www.navedu.navy.mi.th/stg/dat.../ATP/atp10.pdf
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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.
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.
