Malaysian Airlines MH370 contact lost

[threemiles]

Good that there is a factsheet out now.

But I am still surprised about some "facts".
E.g. the Last SSR position is followed by a right turn and then a left turn in the colors of a SSR track (or what do the colors mean?).

The yellow primary track starts after a gap in coverage more westerly.
We know from Flightradar24 ADS-B data, that the airplane made a right turn along the airway, indeed. But we did not know about the left turn, because ADS-B data ended before it started.

It MAY be Vietnam SSR data that helped here, but why is it not indicated as such?

Even if such details may not be too relevant to the public there are so many educated spectators of this event out here, that the investigators should treat any release of facts with utmost care and let outstanding people check it before its release.

Otherwise they may heat conspiracy theories, certainly unwanted.

http://i60.tinypic.com/28bbdao.jpg

[olasek]

Otherwise they may heat conspiracy theories, certainly unwanted. It will happen regardless. Release of the data will do nothing to stop such theories, most likely they will only intensify.

[mm43]

From ATSB Fact Sheet

At the time MH370 reached the 7th arc, the aircraft is considered to have been descending. A study completed after the Air France 447 accident concluded that the majority of aircraft in loss of control accidents were found within 20 nautical miles (32 km) of their last known position. This provides a reasonable limitation for the size of the search area across the arc.
The above differs somewhat from the findings of MAK/IAC, i.e.

The distance of the impact point from the initial point of upset depends mostly on the type of upset and, sometimes (in dives and unclosed spirals), from the duration of coming down. In spins and closed spirals the impact point location has significantly lower correlation with the duration of coming down. In any case the distance is hardly possible to be more than 12 NM.

The average time interval of loss of 1 km of altitude is shortest for dives and longest for spins, but in any case it seems hardly possible to be more than 14-16 seconds. It means that for AF447 flight, with cruise altitude of about 10700 meters, the duration of coming down was less than 3 minutes.

[porterhouse]

I would trust much more the study done by French/Metron, etc in the wake AF447 since they looked at actual historical data. Also, not every upset is the same (even a definition what "upset' is can be far from razor sharp), there could be different degrees of upsets and this could impact how steep or shallow the descent is.

[Propduffer]

The ATSB fact sheet along with some other recently discovered information has given me a clearer picture of the route taken by MH370 just after the turnaround.

The Thais' have said that they tracked (MH370) but that they didn't track it in Thai airspace, so in my earlier plots I had the flight skirting the Thai border; but when I tried to plot estimated groundspeed, the timing got a little tight. The plane would have had to maintain a cruse FL in order to have reached the vicinity of MEKAR at 18:22 UTC.

The ATSB plot shows the flight over Thai airspace, that more direct route west would fit other known facts better but is this a contradiction of the statement by the government of Thailand? Not at all, they did say that their track of the target was intermittent - so the ATSB plot is correct, they just didn't see the flight when it was over their territory.

The location of the Thai radar antenna that tracked MH370 is located at 6°50'38.02"N 100°25'11.64"E (you can see the antenna in Google Earth.) The slice of territory MH370 flew over in Thai airspace is blanketed by the high ground around Ban Panang Bo Ngo (a ridgeline at least 250 meters high at and near 6° 7'0.44"N 101°48'1.29"E.)

The person flying the plane knew about this "dead spot" in Thai radar coverage and crossed Thai airspace at much reduced altitude from cruise. This has been indicated in both early Malaysian radar reports as well as by the civilian sightings of the aircraft near Kota Bharu.

IMO this solidifies one part of a reconstructed flight path for MH370.

[Vinnie Boombatz]

@Shadoko on 26th May 2014, 11:16

The satellite moved slightly over 1 degree in latitude over 6 hours, and far less in longitude.

Farthest North at the 19:41 ping (1.63 N), and then South to 0.58 N at the last ping.

The longitude change was around 0.06 deg over the same time span.

So as others, including you, have noted, not noticeable at the scale of the ATSB Fig. 4.

[oldoberon]

RAW Inmarsat data to be released today.

Raw data tracking last moments of missing flight MH370 that was used to calculate search area to be released tomorrow | Mail Online (http://www.dailymail.co.uk/news/article-2639836/Raw-data-tracking-moments-missing-flight-MH370-used-calculate-search-area-released-tomorrow.html?ITO=1490&ns_mchannel=rss&ns_campaign=1490&utm_medium=twitter&utm_source=twitterfeed)

[RatherBeFlying]

Also having the relative speed to the satellite will help considerably.

Assumptions have to be made on TAS and cruise altitude and how they may change over time with fuel burn.

There are several scenarios, each of which may produce a different search area.

Likely the last several hours were on a constant course. Back driving the various scenarios to a turnpoint NW of Sumatra and LKP from primary may produce a number of solutions consistent with fuel, aircraft performance and Inmarsat data.

I am not in accord with the proposition that MH370 necessarily went into a steep descent after running out of fuel. It may just as well have proceeded on course while descending. The lack of debris is indicative of a ditching under control.

[JakartaDean]

Also having the relative speed to the satellite will help considerably.
I agree, but I can't tell if they have released the necessary data on the satellite position and velocity. If they have, anyone can reproduce the Doppler analysis, which would be reassuring.
In general I accept the concern over crackpot theories, and also understand that Inmarsat has the right to protect its intellectual property, but the more eyeballs looking at the most data possible can only lead to either new interpretations or more confidence in the analysis already done -- either is desirable.

Edt: No satellite position or velocity information in the pdf from Malaysian DCA website. The information can be used to confirm the reasonableness of the analysis, but not confirm it as far as I can tell. It may end up that somebody is needed with knowledge of how "Inmarsat Classic Aero mobile terminals are designed to correct for aircraft Doppler effects on their transmit signals. The terminal type used on
MH370 assumes a stationary satellite at a fixed orbital position."

[Blake777]

The BFO analysis chart would indicate that the turn south probably happened within a few minutes of passing MEKAR.

The ATSB fact sheet mentions timing of last primary radar as 0222. The BFO chart indicates probable turn a few minutes before 0230.

On another issue: does anyone have any comments on the fact that Vietnamese military radar detected the turn back and advised Malaysia in real time? I am unsure from press releases "who" was officially advised. I am asking from the point of view of recent discussions over ATC protocol and whose job it was to attempt to find the missing aircraft. Were there grounds for the aircraft's possible movements to be placed back under either Subang's attention, or Malaysian military attention, in view of the above?

I find it somewhat curious that, whilst in other circumstances an unidentified aircraft on military radar might not attract much attention, in this case knowing that the aircraft had lost all communications, and that Vietnam advised of a turn back, no-one thought it worth connecting the dots.

[MG23]

I agree, but I can't tell if they have released the necessary data on the satellite position and velocity. If they have, anyone can reproduce the Doppler analysis, which would be reassuring.

I doubt there's anything particularly confidential about the satellite position, since anyone with a suitable antenna could track the pilot signal. But that wouldn't give the position as accurately as Inmarsat could measure it.

Edit: BTW, here's the link to the logs on the DCA site, for those who haven't found it yet:

http://www.dca.gov.my/mainpage/MH370%20Data%20Communication%20Logs.pdf

[ATC Watcher]

Pontius : the diagram above shows the exit from the airway to the right followed by a left hand turn back through the airway
There is no " airway" anymore at this altitude , there are only tracks with no width.

Blake 777 : What the Vietnamese military saw in real time we do not know. . Afterwards , looking at the tapes maybe. For Vietnam civil ATC , the last positive ID/position stopped when the transponder stopped. The left turn shown on the map was probably not seen ( or detected ) by them in real time .

Maps shown 2 months after the event can be very precise when dozen of people have been sudying for hours tons of tape recordings from various sources , but what controllers saw in real time , and were expecting is not what we see on those maps.
So saying they should have done this or that based on those maps is irrelevant and futile.. .

[Seabreeze]

The density of sweater changes little with depth (about 1024 at surface to 1050 kg/m3 at 5000m). With pressure increasing at 1 atmosphere every 10m of depth, all air -pockets will be squeezed out or imploded as wreckage sinks. The aeroplane construction materials are pretty well all denser than seawater at any depth, so when filled with water, the entire wreckage will sink (excepting perhaps a few lighter items such as spongy seatbacks, personal effects, garbage etc which might escape prior to sinking).

They are looking at the right depth, but it appears in the wrong place....

I too would like to see the detailed calculations done by Inmarsat. If they had been released much earlier, just maybe the search would not have wasted time in the far southern Indian Ocean; just maybe there would have been a much greater opportunity to locate the FDR pinger.........

[p.j.m]

MH370: Malaysia releases raw satellite data on missing Malaysia Airlines flight - Australia Network News (Australian Broadcasting Corporation) (http://www.abc.net.au/news/2014-05-27/malaysia-releases-satellite-data/5481612)

The Department of Civil Aviation (DCA) said in a statement it had worked with British satellite company Inmarsat to provide 47 pages of data communication logs recorded by the operator as well as explanatory notes for public consumption.

http://www.dca.gov.my/mainpage/MH370%20Data%20Communication%20Logs.pdf

[Volume]

It means that for AF447 flight, with cruise altitude of about 10700 meters, the duration of coming down was less than 3 minutes.The duration of coming down for the wreakage of the midair over lake constance was a little over 2 minutes, so that would be the number for a total desintegration. Stalled/spinning would be a little more, a dive a little less. so we are talking about 1-3 Minutes from cruise to impact.

[mickjoebill]

They have the fuel remaining at time of last ACARS. From this they believe fuel exhaustion would have occurred close to the last handshake.

Why wasn't this piece of information, that indicates the plane flew on for hours, released earlier? It is a significant (fact?) that next of kin should have been made aware of…..

[HeavyMetallist]

@mickjoebill: the last ACARS transmission, with the fuel remaining, was sent over VHF very early in the flight. The INMARSAT satellite handshakes are unrelated to ACARS (on MAS aircraft) and carried no ACARS data. This isn't new information.

[RTD1]

http://i60.tinypic.com/28bbdao.jpg

Do we know when the military primary radar BEGAN picking up MH370?

I'm curious how the v-shaped route from the time of last secondary contact to the time of last primary contact was drawn. Is there actual evidence to support it or is it just based on the Thais saying "we didn't pick it up so it couldn't have flown over Thai airspace"?

[Shadoko]

Is there anybody who understands why the same line of data is repeated? For example, on page 10, there are 26 lines of data, 23 of them identical. Has this a meaning?

Another question: it seems that all the BTO times last digit are 0 and the penultimate are even. Could we state the time is filed with a 20 µs step?

[OleOle]

@Shadoko

I would suspect the identical lines to belong to one data block that was transmitted in sub-blocks which were logged with the time stamp of the time when the block was completed.

I agree on the time resolution being 20µs. Taking into account it's round trip time and 1µs corresponds to 300m at speed of light, the line of sight resolution is 3km. With an elevation angle of ~45° the lateral resolution on the surface would be ~4.5km.

[MG23]

Is there anybody who understands why the same line of data is repeated? For example, on page 10, there are 26 lines of data, 23 of them identical. Has this a meaning?

Long SATCOM messages will presumably be split into the initial signal unit that identifies the type of message, and multiple subsequent signal units containing the rest of the data. Could also be retransmissions, but I'd expect to see some kind of 'NAK' message from the aircraft before anything was retransmitted.

Another question: it seems that all the BTO times last digit are 0 and the penultimate are even. Could we state the time is filed with a 20 µs step?Hadn't noticed that until you mentioned it, but it seems likely. Given the low bit-rates of the channels, I'm not sure you could measure it to microsecond accuracy. That would also be consistent with the 10km accuracy mentioned in the 'considerations on defining the search area' document. Twenty microseconds looks like about 6km to me.

[syscons]

Ian W

Thanks for the clear explanation http://www.pprune.org/rumours-news/535538-malaysian-airlines-mh370-contact-lost-543.html#post8492799

I note you had previously said: "the Malaysian ATC followed the book pretty well. They were not responsible for the aircraft which had been handed off and accepted by Ho Chi Minh center."

I just wonder where the certainly about handover and acceptance comes from. There are some anomalies:

(1) The Malaysian Preliminary Report does not say that the aircraft had been handed over and accepted.

(2) Both the Preliminary Report and the "Action Taken" document specify a lot about what KLATCC did to find the aircraft. For example in the PR "Thereafter KLATCC initiated efforts involving MAS OPS Center, Singapore ACC, Hong Kong ACC and Phnom Penh ACC to establish the location of MH 370. No contact had been established by any ATC units and thus the Rescue Coordination Centre (RCC) was activated at 05:30 MYT". Discussing what KL did is all rather beside the point if it is HCM's task and responsibility to contact the aircraft. Would it not have been HCM's responsibility to activate a search? Is MH370 still with you - he's not talking to me'".]

(3) Vietnam apparently denied responsibility Vietnam requests Flight 370 information after Malaysian claims | DTiNews - Dan Tri International, the news gateway of Vietnam (http://www.dtinews.vn/en/news/024/34589/vietnam-requests-flight-370-information-after-malaysian-claims.html) saying "“In fact, there is no evidence that the aircraft had passed through the “Igari” way-point and entered our country’s airspace,” said Lai Xuan Thanh, Director of CAAV.". [I do understand that handover and entering the countries airspace are not necessarily the same thing].

I'm not trying to construct any conspiracy theory, I agree with you, peacetime, no threats apparent etc. I am just curious to understand. It seems pretty clear that HCM had probably accepted the aircraft, as they were the first to raise a query with KL, but the curious points above remain.

[Shadoko]

OleOle: Yes, 4.5 km. And because they are very cautious (and from data not absolutly steady when the a/c was stationary) they double it to ±10 km.

Another thought: After the handshakes at 19:41, 20:41, 21:41 and 22:41 there was no handshake at 23:41. It was (long time ago!) presumed as a "miss". But it is well explained by the sat call (from ground) of 23:15: this call attempt reset the one hour timer and so the next handshake was at 00:15. But no "ring" because C-channel BTO is not filed.
Seems consistent?

[SLFgeek]

If you compare the PSR track (in the recent ATSB document) to the map on this post ...
http://www.pprune.org/rumours-news/535538-malaysian-airlines-mh370-contact-lost-70.html#post8364326
It seems pretty clear that someone was aware of the PSR track very quickly after the incident. The "E" box being the area where they lost PSR coverage.

I do wonder what altitude the aircraft was at when it passed Butterworth.

[Shadoko]

"Raw data PDF": 18:25 - Log-on Request, initiated from the aircraft terminal. This is the end of the link lost period that began at sometimes between 17:07:48 and 18:03:41.

What it the meaning of that?
- a trick (before turning South) from somebody who handled the a/c knowing it had have to be "viewed" on a west route?
- an automatic sat link after HF was available along the route above Malaysia and lost again?
- some automatic data Tx from a so big change in flight caracteristics it had to be "signaled" for frequency or BFO adjustment between sat and a/c?
- ... ?

It would be interesting to know what were the subsequent "user data".

[oldoberon]

I believe if you make a sharp turn and blank out the aerial, comms with sateliite has to be restablished. presumably from aircraft end.

[MG23]

That's certainly a possible cause, but I would expect the aircraft to try to log on again soon after the turn. In this case, it appears to have been out of comms for at least 22 minutes.

I don't know whether there's any way it could have thought it was still logged on, but not have responded to messages from the ground? If it was still receiving the satellite signal, it should presumably have received those messages and been able to respond.

[roninmission]

I found this from ATSB interesting:
Low frequency hydroacoustic signals present in the Indian Ocean are being examined to determine whether they can provide any information to help define the search area. These signals are recorded by hydrophones as part of the United Nations Comprehensive Nuclear-Test-Ban-Treaty Organisation (CTBTO) or the Integrated Marine Observing System (IMOS).

Way above my pay grade but wouldn't one have expected it to be done long ago?

I assume that as well as the U.N. hydrophones it is entirely possible that there are military arrays as well?

[Propduffer]

Do we know when the military primary radar BEGAN picking up MH370?

I'm curious how the v-shaped route from the time of last secondary contact to the time of last primary contact was drawn. Is there actual evidence to support it or is it just based on the Thais saying "we didn't pick it up so it couldn't have flown over Thai airspace"? The Vietnamese have indicated that they saw the plane turn around but they didn't give any details as to whether this occurred before or after the transponder was turned off, but if we assume that it occurred after the transponder was turned off we will know that Vietnamese primary radar tracked the flight as early as 1:22 local time. The Thai government has stated that they first picked up the flight at 1:28 'flying in the direction opposite from the MH370 plane, 'back toward Kuala Lumpur' (paraphrased.) The Malaysians have remained vague and the Indonesians have left it up to the reader to read between the lines to know that they tracked the flight at all. (see my post above)

As to the Vee shaped flight path in the diagram:

I see no reason to think the flight went near Butterworth; the pilot had brought the plane down to low altitude to avoid (at least) Thai radar, and ground speed was suffering as a result; he (or she) would have wanted to clear Thai/Malaysian airspace as quickly as possible so I predict a turn towards MEKAR somewhere around 5°36'25.08"N 101° 6'29.92"E (or about 45nm ENE of Butterworth.)

[OleOle]

Extract of the explanations in the PDF:

16:41 - Take-Off.Logged-On to Ground Earth Station (GES) 305/301, via the Indian Ocean Region (IOR) Inmarsat I-3 satellite
17:07 - Last Acknowledged Ground to Air DATA-2 ACARS Message. Link lost at sometime between here and 18:03:41.
18:03 - No Response to Ground to Air DATA-2 ACARS Data. Link lost at sometime between 17:07:48 and here.
18:04 - Last of five requests for Acknowledge to the Air DATA-2 ACARS Data at 18:03
18:05:11 - Data-2 Ground to Air transmission, automatic ACARS retransmission after expiry of 90 sec timer. Terminal is not responding.
18:25 - Log-On Request, initiated from the aircraft terminal. This is the end of the link lost period that began at sometime between 17:07:48 and 18:03:41.
18:39 - Ground Initiated to Air Telephony Call - Zero Duration (Not Answered)
19:41 - Handshake Request, with response
20:41 - Handshake Request, with response
21.41 - Handshake Request, with response
22:41 - Handshake Request, with response
23:13 - Ground Initiated to Air Telephony Call - Zero Duration (Not Answered)
00:10:58 - Handshake Request, with response
00:19:29 - Log-On Request (reported as a Partial Handshake), initiated from the aircraft terminal
00:19:37 - Note that the following R-Channel burst at 00:19:37.443 is the last transmission received from the aircraft terminal
01:15:56 - Handshake Request - No Response from Aircraft Terminal
01:16:06 - Handshake Request - No Response from Aircraft Terminal
01:16:15 - Handshake Request - No Response from Aircraft Terminal


- ACARS Messages are Ground to Air.
- link lost period that began at sometime between 17:07:48 and 18:03:41 due to electrical power issues?
- why no more Ground Initiated to Air Telephony Calls ?

Both Ground Initiated to Air Telephony Calls tried 1 minute before the caller gave up. Even though nobody picked up the phone, the terminal itself acknowledged it was there. Was it ringing in the a/c? Was the caller on the ground aware, that the terminal was still alive?

[MG23]

- why no more Ground Initiated to Air Telephony Calls ?

I haven't looked at the precise times, but I would presume either the airline or ATC called when they disappeared and couldn't be contacted by radio, then called again when they were overdue at their destination. Not much point calling every ten minutes if no-one is responding.

[Rev1.5]

23:13 - Ground Initiated to Air Telephony Call - Zero Duration (Not Answered)

Somewhere there will be a record of who made that call.
Has that information been made public?

[rampstriker]

It's infuriating how coy the Malaysians are being about the plane's PSR altitude profile after the transponder datastream stopped. This information is so critical to understanding what may have happened.

[threemiles]

18:25 - Log-On Request, initiated from the aircraft terminal. This is the end of the link lost period that began at sometime between 17:07:48 and 18:03:41.

This is quite exactly 1 hour after the last SSR response.
I bet this is not coincidence and there is some technical explanation behind it.

Also: the 00:19 Log-on request was explained as a system restart after flame-out and subsequent RAT or battery kicks in or whatsoever. How then is the 18:25 Log-on request explained? There would have been no flame-out before that time. Generators failed? APU not started? Low altitude? There must be a technical reason for that, too.

[Ian W]

The Vietnamese have indicated that they saw the plane turn around but they didn't give any details as to whether this occurred before or after the transponder was turned off, but if we assume that it occurred after the transponder was turned off we will know that Vietnamese primary radar tracked the flight as early as 1:22 local time. The Thai government has stated that they first picked up the flight at 1:28 'flying in the direction opposite from the MH370 plane, 'back toward Kuala Lumpur' (paraphrased.) The Malaysians have remained vague and the Indonesians have left it up to the reader to read between the lines to know that they tracked the flight at all. (see my post above)


It is probably this report from Ho Chi Minh that they had seen the aircraft turn back (presumably on PSR) that was why the Malaysians took on the RCC role rather than the Vietnamese who were meant to be the control authority, or the Singaporians whose airspace the loss of contact occurred in. It is another reason that the loss of contact appears too well timed to be coincidental with an in flight emergency. The subsequent track and profile of the aircraft was also not what one would expect from an aircraft with a severe emergency. This is no doubt why the Malaysians seem to think this was a criminal act.

[TOMCAT22]

Quote:
23:13 - Ground Initiated to Air Telephony Call - Zero Duration (Not Answered)
Somewhere there will be a record of who made that call.
Has that information been made public?


I have followed this thread from the very beginning and I believe this call was made by someone from Malaysia airlines. I can't find the exact reference but I remember reading it in a transcript that someone (perhaps maintenance personnel) called the plane when the controllers couldn't see it on radar.

[MrPeabody]

Threemiles,

The 18:25 logon was initiated by the aircraft, if you refer to the Inmarsat BFO graph it mentions possible turn. Had a tight turn been initiated that shadowed the SATCOM beam, this would have been when the aircraft reacquired the satellite (bank reduced to the point of reacquisition).

Cheers

[oldoberon]

Looking at the relative positon of the aircraft and satellite I don't think a left turn wound have screened the aerial but a right hand would, remember the chinese video to the pax, that had a right hand turn??

[threemiles]

I don't think a turn causes a logon. This would generate endless logons when airplanes fly holdings or so.
To me a logon would happen after some kind of system restart. As if you boot your windows computer.
I do not see a difference in the sequences at 18:25 and 00:19, that makes it strange when the latter was very firmly associated to a power up.
I would believe that this system behaviour is essential to the investigation and it should be replayed on board a real life flight. My feeling is that there is more involved than just a manual intervention by someone onboard.

[hamster3null]

Somewhere there will be a record of who made that call.
Has that information been made public?

In all likelihood, someone at Malaysian Airlines trying to figure out where the plane is. This is 45 minutes after its scheduled arrival in Beijing.

[hamster3null]

"Raw data PDF": 18:25 - Log-on Request, initiated from the aircraft terminal. This is the end of the link lost period that began at sometimes between 17:07:48 and 18:03:41.

What it the meaning of that?
- a trick (before turning South) from somebody who handled the a/c knowing it had have to be "viewed" on a west route?
- an automatic sat link after HF was available along the route above Malaysia and lost again?
- some automatic data Tx from a so big change in flight caracteristics it had to be "signaled" for frequency or BFO adjustment between sat and a/c?
- ... ?

It would be interesting to know what were the subsequent "user data".

If the system was not responding to interrogations at 18:03 and it initiated a logon at 18:25, the logical conclusion is that it was physically shut down from the cockpit at some point prior to 18:03 and then (possibly unintentionally) turned back on at 18:25.

The interesting question is what would have caused it to come back on. Perhaps the aircraft was flown manually between 17:21 and 18:25 and the pilot turned on the autopilot to continue the route via waypoints at 18:25.

"User data" may be part of the standard logon procedure for this aircraft, you see the same two packets at 16:01:16.

Side note: It looks like attempts to call the aircraft at 18:39 and at 23:13 had the side effect of resetting the interrogation timer, which is why we see handshakes at 19:40 and 00:11.

[kayej1188]

Why would a turn initiate a log-on? What are some possible causes of the loss of connection from sometimes after 17:07 until 18:25? Lastly, no doubt that at least one of the pax would have made a cell phone call/text when the plane dropped to 5000 ft. This must mean all the passengers were out of commission at that time, no?

[SAMPUBLIUS]

Lastly, no doubt that at least one of the pax would have made a cell phone call/text when the plane dropped to 5000 ft. This must mean all the passengers were out of commission at that time, no?

At night - how many passengers at that time would or could know what the altitude or direction was- absent a violent manuver ? :=

Puuuhleese do not read too much into such events

Its fairly certain the plane is in the Indian Ocean - and until found, and passenger or flight recorder data are found and analyzed- ALL else is just fodder for the next ' tell all speculation book "

[MrPeabody]

hamster3null,


The SATCOM is powered by Left Main AC and comes on with power established.


The system will reacquire if the aircraft to satellite beam is interrupted or power interrupted. Beam interruption could be due to wing masking (large bank angle), blind spots or terrain. This aircraft is the last of the Malaysian aircraft to be fitted with dual side mounted antenna; this in itself raises some food for thought.


Side mounted systems have fore and aft blind spots (key holes). The satellite connection was lost somewhere between 17:07 and 18:03; apparently the period where some severe altitude changes were to have taken place. The course from around 18:03 to 18:22 is straight and toward the satellite; if climbing in this period, could it simply be the SATCOM is in a drop out condition?? Change direction at 18:25 and system reacquires.


Alternatively Left AC was turned off and re-established at 18:25.


My guess is a drop out condition.

[hamster3null]

hamster3null,


The SATCOM is powered by Left Main AC and comes on with power established.


The system will reacquire if the aircraft to satellite beam is interrupted or power interrupted. Beam interruption could be due to wing masking (large bank angle), blind spots or terrain. This aircraft is the last of the Malaysian aircraft to be fitted with dual side mounted antenna; this in itself raises some food for thought.


Side mounted systems have fore and aft blind spots (key holes). The satellite connection was lost somewhere between 17:07 and 18:03; apparently the period where some severe altitude changes were to have taken place. The course from around 18:03 to 18:22 is straight and toward the satellite; if climbing in this period, could it simply be the SATCOM is in a drop out condition?? Change direction at 18:25 and system reacquires.


Alternatively Left AC was turned off and re-established at 18:25.


My guess is a drop out condition.

The course from 18:03 to 18:22 is not exactly toward the satellite. The aircraft was going at heading 285..295 and the satellite was at the heading 262..265 and high in the sky. I just don't see a drop out condition that would result in SATCOM operation being continuously disrupted for 22+ minutes. That's why I speculate about the system being manually powered down.

Left AC being off is an interesting possibility. What other systems are there on the same circuit?

[Propduffer]

When I said that other people had brought up the subject I made a misassumption that what I was referring to was common knowledge.

It comes from a blowup of the graphic given to the families.
http://ogleearth.com/wp-content/uploads/2014/03/mh370-penang.jpeg
If you have very good eyes or if you blow up the picture; it shows a constant track for each sweep of the search radar for the a/c along the upper green airway.

The MH370 track does not present as being so symmetrical.
This picture was released by the Malaysians.

I think the person who believed it hand flown made a good case. I see other supporting evidence. The known altitude excursion after turnaround also required hand flying.

I see much evidence to support the hand flown premise.

[DrPhillipa]

Anyone have an idea what these large amounts of User Data are in the logs if they are not ACARS? (T-Channel RX)

Also would one emergency land a T7 in the dark at Penang without comms from the South West or from the North East?

4.1.1.2.1 P channel. Packet mode time division multiplex(TDM) channel transmitted continuously from the aeronautical ground earth station (GES) in the to-aircraft direction to carry signalling and user data. A P channel being used for system management functions is designated Psmc, while a P channel being used for other functions is designated by Pd. The functional designations Psmc and Pd do not necessarily apply to separate physical channels.

4.1.1.2.2 R channel. Random access (slotted Aloha) channel, used in the from-aircraft direction to carry signalling and user data. An R channel being used for system manage-ment functions is designated Rsmc, while an R channel being used for other functions is designated Rd. The functional designations Rsmc and Rd do not necessarily apply to separate physical channels.

4.1.1.2.3 T channel. Reservation time division multiple access (TDMA) channel, used in the from-aircraft direction only. The receiving GES reserves time slots for transmissions requested by aircraft earth stations (AESs) according to message length. The sending AES transmits the message in the reserved time slots according to priority.

4.1.1.2.4 C channel. Circuit-mode single channel per carrier (SCPC) channel, used in both to-aircraft and from-aircraft directions. This channel is time division multiplexed to provide a primary channel for voice or data traffic and a sub-band channel for signalling, supervision and data messages. The use of the channel is controlled by assignment and release signalling at the start and end of each transaction.
The 4 channel designations in the SATCOM log, FYI.

[OleOle]

Time stamps are for T-Channel assignments.
Number of subsequent signaling units corresponds to amount of data send by A/C?

Downlink Comms:

16:00:23.905 5 Subsequent Signalling Units

16:01:20.405 5 Subsequent Signalling Units

16:09:37.905 8 Subsequent Signalling Units

16:11:04.405 5 Subsequent Signalling Units

16:28:01.905 10 Subsequent Signalling Units

16:29:17.905 30 Subsequent Signalling Units
16:29:42.405 13 Subsequent Signalling Units

16:41:53.405 6 Subsequent Signalling Units
16:41:58.405 12 Subsequent Signalling Units
16:42:17.905 30 Subsequent Signalling Units
16:42:33.405 30 Subsequent Signalling Units
16:42:48.905 29 Subsequent Signalling Units

16:55:24.405 30 Subsequent Signalling Units
16:55:38.905 30 Subsequent Signalling Units
16:55:53.905 30 Subsequent Signalling Units
16:56:08.905 5 Subsequent Signalling Units

17:06:49.906 30 Subsequent Signalling Units
17:07:04.905 30 Subsequent Signalling Units
17:07:19.905 30 Subsequent Signalling Units
17:07:34.905 30 Subsequent Signalling Units

18:28:06.407 5 Subsequent Signalling Units


@DrPhillipa

16:29 could be "Gate Out"
16:41 could be "Wheels Off"
OOOI Data - ASPMHelp (http://aspmhelp.faa.gov/index.php/OOOI_Data)

17:07 was an ACARS message Inmarsat used for calibration:
The engineers at Inmarsat were able to validate their estimates of the plane’s location by matching its position at 1:07 a.m., when it sent a burst of data through its Aircraft Communications and Reporting System, McLaughlin said.
Hunt for Jet Switches to Visual Search as Radar Empty - Bloomberg (http://www.bloomberg.com/news/2014-03-21/missing-plane-flew-steady-speed-over-ocean-inmarsat-estimates.html)

[Ian W]

Why would a turn initiate a log-on? What are some possible causes of the loss of connection from sometimes after 17:07 until 18:25? Lastly, no doubt that at least one of the pax would have made a cell phone call/text when the plane dropped to 5000 ft. This must mean all the passengers were out of commission at that time, no?

The number of phones left on 'inadvertently' in an aircraft is probably in the 5% range. So there could have been up to 10 cell phones active in MH370, they do not need anyone to tell them to connect as soon as they see a signal they do so. If they didn't it says nothing about the state of the pax.

[Propduffer]

My interpretation is that the track plot to the south east of the circle is MH370 at a medium altitude. The circle shows where the plot went dark, most likely as the aircraft dropped below the radar horizon. The continuation plot to the north west was regained as the aircraft resumed a climb.I don't know what the circle represents, but we can see the 'MH370' track before and after the circle on a (gustimated) 295 degree heading. So the circle isn't where the track was lost. If you look closely at the MH370 track you'll see a series of dots that presumably indicate the sweeps of a search radar.

Using the circle for reference, look inside the circle and you will see two solid lines which I take to indicate airways. On the upper of these two airways there can be seen a series of dots which I also take to be representations of radar sweeps. These dots paint a much more symmetrical pattern than does the 'MH370 track.

I will add that these radar tracks provide no altitude information.
And I agree that this is a doctored composite.Now I am not in to conspiracy theory, evasive routing etc, but that loss of contact could also have put the aircraft in the dark to Indonesian radar as well. Having gone out of cover why climb while within range of the PSR? One possibility is that going dark would throw off short range interceptors reliant on close radar control. I do see strong evidence for evasive routing:
There are multiple indications that the flight descended sharply and passed over the Malaysian landmass at lower altitude than cruise. (Radar reports from the Malaysians and sightings of a plane descending on a westerly course near Kota Bharu, 'intermittant' Thai radar contact.) I believe that a blind spot in the Thai radar at Hat Yai was exploited to reduce exposure to Thai radar (this is borne out by Thai statements that their track was "intermittent" which it would not have been the case if the flight was at cruise altitude.)

I believe that subterfuge was used to decieve the Indonesian's monitoring their ATC and primary radar - from an Aceh view, the flight would have appeared along a frequently used airway which is used by flights from Penang to Australia. These airways avoid Indonesian national waters (beyond 12 miles.)

It's quite a coincidence that the flight flew a part that would mimic a skilled military spyflight's intended course to avoid detection from IGARI to the Indian ocean. Too big a coincidence for me to ignore.

[SLFgeek]

I don't know what the circle represents, but we can see the 'MH370' track before and after the circle on a (gustimated) 295 degree heading. So the circle isn't where the track was lost. If you look closely at the MH370 track you'll see a series of dots that presumably indicate the sweeps of a search radar.
If you notice the top of that image, it claims that the radar track is from Pulau Perak. I'm not familiar with that part of the world, so I looked it up on Wikipedia. Pulau Perak is a very small island at 5° 40′ 50″ N, 98° 56′ 27″ E (5.680556, 98.940833). It does not even appear (at least to me) on Google Maps satellite view. I was able to see a rough image of it on Yahoo Maps. Pulau Perak appears to be very close to the flight path that was tracked from Butterworth. In other words, the aircraft transited above the highest beam angle of the military radar there. That is likely why there are no returns. It is possible that the white circle represents an internal limit which the radar there cannot see unless the return is from something quite low in altitude (when that close).

[Pontius Navigator]

I don't know what the circle represents, but we can see the 'MH370' track before and after the circle on a (gustimated) 295 degree heading. So the circle isn't where the track was lost. If you look closely at the MH370 track you'll see a series of dots that presumably indicate the sweeps of a search radar.

As previously stated, the circle represents the track where no radar returns were received

look inside the circle and you will see two solid lines which I take to indicate airways. On the upper of these two airways there can be seen a series of dots which I also take to be representations of radar sweeps.

I see white lines. I still see no dots.

[Propduffer]

@SFgeek
I plot the center of the circle to be about: 6°16'16.02"N 97°49'29.62"E.

BTW the Malaysian radar antenna that tracked MH370 during this part of the flight is the Polu Pinang Radar at 5°25'28.70"N 100°15'2.89", it is on a peak of at least 800 meters height.

[Shadoko]

About the photo with the radar returns.
Do the green "things" not added for a better viewing, but text lines completly pixelised? It seems (to me) all those green "things" are horizontal on the right of yellow dots.
Just a tought, but perhaps someone has a better picture? Could it be time and altitude?

[hamster3null]

I see no radar sweep dots either.

But I just came to the same realization as Shadoko - most of the greenish-yellow dots in that screenshot are not tracks but pixelized text labels.

http://i59.tinypic.com/5nsrol.png

[Propduffer]

@Shadodo

That picture has more detail that is noticeable at this resolution.
Put it into windows picture viewer and zoom in on it.

@hamster3null (http://www.pprune.org/members/422332-hamster3null)
I have been ignoring the greenish yellow smudges.
You're probably right they are remnants of text.
The dots that mark the track are there in the midst of the smudges.

[susier]

The plotted positions before the white circle appear not to be on a drawn flight path, but those after it are.


Obviously it is only a short section between waypoints so could appear on many different standard routes.


Why would the plane go from flying off the beaten track to flying on it again?

[portmanteau]

propduffer/pontius. the airway passing through the circle is N571 and the airway below it is B466. the dots look to me to be man-made. each one is accompanied by a label and where many labels are close to each other, they overlap and appear to cause the green "track "effect. the labels appear to have 5 characters, and they appear to be different for each dot. the only one I can make out ends in - - - TA. possible that dots represent received aircraft blips and MAF have appended a label to each one... pity label for the long arrow pointing to "track" is obscured by someone's camera...

[susier]

Portmanteau, I thought the small greenish text labels were coordinates.

[sSquares]

These are time labels.

[Shadoko]

On this picture, the white arrow label is visible :
http://tmfassociates.com/blog/wp-content/uploads/2014/03/Beijing-event.jpg

[sSquares]

See http://i.imgur.com/N0MWBCK.jpg

[grity]

http://s7.directupload.net/images/140528/temp/6irryar8.jpg (http://www.directupload.net/file/d/3636/6irryar8_jpg.htm)

IMO the circle is just a circle in the picture to show the holow in the path

[Pontius Navigator]

gritty, back to my explanation, was it below the radar horizon in the circle and then climbed?

[threemiles]

The airplane could have made the distance from IGARI to the last plot at around 500 kts ground speed only. Distance about 494 NM, flying time a little less than 1 hr.
If it flew lower for a longer period it could not fly such a high ground speed value.
Air density and physics do not allow that.

[Pontius Navigator]

I suspect a 15 wind component at 200mb level.

[Propduffer]

@threemiles

That's not how I plot it. You must have the flight passing over Penang, I don't think it went there.

My first leg is from IGARI to Kota Bharu (90nm) at mach .84 (or a tad more)
I place MH370 over Kota Bharu at 1:33 local time.

My second leg is from Kota Bharu to 5°39'12.74"N 101° 7'2.61"E (74nm) at 340kts. I plot it arriving there at 1:46.

My third leg is from 5°39'12.74"N 101° 7'2.61"E, where I believe a turn was made towards MEKAR. From here the A/C regained altitude and I plot the average speed for that leg (290nm) as 470kts which gets the A/C to the area of MEKAR by 2:22 local time.

I would appreciate a review of these plots. I'll post a Google Earth KML file showing this flight scenario as soon as I have it cleaned up and ready for prime time.

@Pontis
I didn't factor in winds. But I believe they were tailwinds during the Malacca leg. Maybe you can help me there.

[Sir Richard]

Also would one emergency land a T7 in the dark at Penang without comms from the South West or from the North East?

R/W 04 has VOR/DME/ILS, R/W 22 has VOR/DME/NDB so an approach from the South West for 04 would be much preferred.

[parabellum]

Now that the USN have made their statement, if it is accurate, the best we can hope for is that eventually some wreckage/baggage/flotsam will appear on a coastline somewhere, (and be found), then the oceanographers will take over and back track the known currents etc. Right now science would appear to be out the door.

[neville_nobody]

Well looks like the Indian Ocean search was a giant waste of time.

A series of pings detected in the southern Indian Ocean and originally believed to have come from missing Malaysia Airlines jet MH370 are now thought to have been emitted from either the searching ship itself or equipment used to detect the pings, a US Navy official says.

Michael Dean, the US Navy's director of ocean engineering, told CNN that authorities now believed the four acoustic pings at the centre of the search off the West Australian coast did not come from the missing passenger jet's black boxes, but from a "man-made source".

"Our best theory at this point is that (the pings were) likely some sound produced by the ship ... or within the electronics of the Towed Pinger Locator," Mr Dean told CNN on Wednesday.

"Always your fear any time you put electronic equipment in the water is that if any water gets in and grounds or shorts something out, that you could start producing sound."

He said other countries involved in the massive search for the jet, which disappeared on March 8 with 239 people on board, had also reached the same conclusion.

When the pings were first detected in early April, retired air chief marshal Angus Houston, the head of the search's Joint Agency Co-ordination Centre (JACC), said experts believed the signals were consistent with those of a flight data recorder.

He said the first two pings - detected on April 5 at 4.45pm and at 9.27pm Perth time - had been analysed by the Australasian Joint Acoustic Analysis Centre, based at HMAS Albatross in Nowra, on the NSW south coast.

"The analysis determined that a very stable, distinct and clear signal was detected at 33.331 kilohertz, and that it consistently pulsed at a 1.106-second interval," Mr Houston said at the time.

''They therefore asses that the transmission was not of natural origin, and was likely sourced from specific electronic equipment. They believe the signals to be consistent with the specification and description of a flight data recorder.''

The final two pings were detected on April 8 - at 4.27pm and 10.17pm, Perth time.

But despite an extensive underwater search, no evidence of the plane has been found in the search area in the southern Indian Ocean.

Fairfax Media has contacted JACC for comment.

Read more: Malaysia Airlines jet MH370 pings 'may have come from searching ship' (http://www.smh.com.au/world/malaysia-airlines-jet-mh370-pings-may-have-come-from-searching-ship-20140529-zrrdr.html#ixzz333hzSMyv)

[MG23]

The amount of $ wasted if this is true is insane.

Why?

Just under three months ago, all we knew was that it was somewhere within a few thousand miles of the airport it took off from. Two months ago, all we knew was that it was probably somewhere around the southern Inmarsat arc. If this is true, all we know is that it's probably still somewhere around the southern Inmarsat arc, but not in the place they were looking.

The only way it would add a significant cost is if the ships which were looking in that area would otherwise have located the real ULB signals before the batteries expired.

And, from a purely financial point of view, the eventual cost of losing an aircraft full of passengers probably won't leave much change from a billion dollars. So it's worth spending at least tens of millions to try to ensure it doesn't happen again.

[aterpster]

MG23:

And, from a purely financial point of view, the eventual cost of losing an aircraft full of passengers probably won't leave much change from a billion dollars. So it's worth spending at least tens of millions to try to ensure it doesn't happen again

"Try" is the operative word.

I suspect some person or persons is/are laughing at the focus on Western values.

[onetrack]

There is now an official refutation from the USN, that Deans comments about the pings not coming from MH370, are wrong.
It appears there's a wide range of interpretation with regard to the signals received by the TPL, and that interpretation is still ongoing.

MH370: US Navy dismisses expert's comments on pings from missing Malaysia Airlines flight - ABC News (Australian Broadcasting Corporation) (http://www.abc.net.au/news/2014-05-29/mh370-us-navy-dismisses-experts-comments-on-search-pings/5485970)

[triton140]

The key sentence in the ABC report is:

"As such, we would defer to the Australians, as the lead in the search effort, to make additional information known at the appropriate time."

They are not denying the report so much as recognising it's up to Australia to break the news, hence terms like "premature".

Diplomatic embarrassment!

[rmiller774]

Yes. Long ago they should have begun throwing out an insane amount of money to buy information in confidence from participating or knowing evil persons who know how this tragic happening was planned and was to be executed. Either it was an aircraft failure or a planned attack. Why not try to find out which it was?

[rh200]

The only real issues, are the speculation, and uninformed opinion by arm chair experts etc.

As has been made clear several times, about several aspects of the search including my self. The search works on probabilities of the information they deem is the most reliable at the time.

The authorities at each step of the way (Australian side) have always said the "best so far" or "most credible". It has also been stated that they are sharing that data with various outside organizations for separate analysis.

This all takes time, hence they will keep searching at the "most probable" site until they have other information to go on. If some of that data is found to be not valid, then they will rejig the search accordingly.

[GlueBall]

Either it was an aircraft failure or a planned attack. Why not try to find out which it was?

It's hard to conceptualize any combination of credible aircraft failures which would produce such a bizarre, deceptive flight profile. :ooh:

[threemiles]

@propduffer
According to the plot in the latest Australian fact sheet, it went VKB VPG VAMPI MEKAR
Clearly passing overhead VPG
MEKAR is about 230 NM from Butterworth, on R285 ( the 200/295R on the "radar" picture is wrong )
If you use skyvector to construct this route it comes up with 460 NM. Together with the right, then wide left turn after IGARI it is about 480 NM in total.
IGARI plus a few miles was at 17:25, short of MEKAR was at 18:22

[500N]

Just released

Media Release
29 May 2014—pm
Yesterday afternoon, Bluefin-21 completed its last mission searching the remaining areas in the vicinity of the acoustic signals detected in early April by the Towed Pinger Locator deployed from ADV Ocean Shield, within its depth operating limits.
The data collected on yesterday's mission has been analysed. As a result, the Joint Agency Coordination Centre can advise that no signs of aircraft debris have been found by the Autonomous Underwater Vehicle since it joined the search effort.
Since Bluefin-21 has been involved in the search, it has scoured over 850 square kilometres of the ocean floor looking for signs of the missing aircraft.
The Australian Transport Safety Bureau (ATSB) has advised that the search in the vicinity of the acoustic detections can now be considered complete and in its professional judgement, the area can now be discounted as the final resting place of MH370.
Ocean Shield departed the search area last night and is expected to arrive at Fleet Base West on Saturday.
As advised by the Australian Deputy Prime Minister on 5 May 2014, the search for MH370 continues and now involves three major stages:


reviewing all existing information and analysis to define a search zone of up to 60,000 square kilometres along the arc in the southern Indian Ocean;
conducting a bathymetric survey to map the sea floor in the defined search area; and
acquiring the specialist services required for a comprehensive search of the sea floor in that area.

The expert satellite working group continues to review and refine complex analyses of radar and satellite data and aircraft performance data to determine where the aircraft most likely entered the water. The findings of the review will be made public in due course.
The Chinese survey ship Zhu Kezhen has already begun conducting the bathymetric survey—or mapping of the ocean floor—of the areas provided by the ATSB. Its operations are being supported by the Chinese ship Haixun 01 and Malaysian vessel Bunga Mas 6 which are assisting with transporting the survey data to Fremantle weekly for further processing by Geoscience Australia. A contracted survey vessel will join the Zhu Kezhen in June.
The bathymetric survey is expected to take about three months. Knowing the seafloor terrain is crucial to enabling the subsequent underwater search.
The underwater search will aim to locate the aircraft and any evidence (such as aircraft debris and flight recorders) to assist with the Malaysian investigation of the disappearance of MH370.
It is anticipated that this component of the search will begin in August and take up to 12 months.
The ATSB will shortly release a formal request for tender to source the capability to undertake the underwater search. A single prime contractor will be chosen to bring together and manage the expertise, equipment and vessels to carry out the search.

[Propduffer]

Threemiles:

This doesn't match other known facts, the low altitude excursion being of prime importance. There are three independent sources that indicate a low level over Malaysia; the first being the earliest Malaysian press releases, the second was the eyewitness at Kota Bharu and third, the Thai radar report which stated that their track was intermittant - this would not be the case had the flight been at cruise altitude. The flight path would have been around 100nm from the Hat Yai radar, not at a range extremity for that radar. It was clear weather and the side profile of a 777 is literally as big as a barn. Any radar that couldn't display an unambigious track of that target (at altitude) would be a broken down radar. There is no reason to think the Thai radar was on the blink that night.

Then there is the question: where did the Australians get the information they used to draw that flight path, and how much critical thought went into plotting the early parts of the flight before the Inmarsat data provided their arcs? I have to assume that they just accepted a Malaysian plot without question.

If we take the 2:22 arrival at MEKAR as bedrock then the known information doesn't support that flightpath, a 777 doesn't go that fast.

(I have some personal doubts about the 2:22 time. Remember that in the first couple of days they gave a time of 2:40 for last radar contact. Then for a time they were using a time of 2:15. But for now we have to accept it.)

Portions of the flight path released makes no sense. They have the plane looping south of Butterworth and even south of Pulau Pinang island. That would just be an attention getting excursion, or diversion, from the intended direction of the flight. The only way one could make a case for that flight path is if they accepted the onboard fire scenario, which I do not. That has been discussed thouroughly here.

I ask you to reconsider.

[slats11]

Based on the evidence available, the balance of probability would surely suggest the following deliberate sequence:
1. At FIR boundary, turn off ACARS / transponder and fail to handover to Vietnam ATC.
2. Low level flight back over the Malaysian peninsula
3. Once over the Indian Ocean and beyond primary radar, climb back to normal cruise levels, and turn south. Ultimately it likely headed towards Perth while hiding in plain sight flying along airways - possibly M641 (India to Perth) or L894 (Middle East to Perth)

This sequence would achieve the following outcomes, which I believe were intended:
1. Maximal confusion with ATC at handover. A catastrophic systems failure exactly at the FIR boundary is sufficiently unlikely to permit the tentative conclusion this was a deliberate act.
2. Minimse the risk of real-time detection crossing Malaysia. The main risk was primary radar, so a low level flight was necessary to make primary radar sporadic. Any layperson accounts of a low flying aircraft (in the middle of the night after moonset) would likely be contradictory, and would not emerge until the next day anyway.
3. Subsequent climb to normal cruise levels to maximise range and allow a long flight away from Malaysia in the wrong direction.
4. A chance sighting by a ship of an early morning flight at high altitude heading in the direction of Perth would not be suspicious.
5. A controlled ditching at first light so as to minimise the risk that debris would eventually wash up somewhere. Possibly turn off airway during descent so that any floating wreckage would be less likely to be seen by aircraft later that day.

If the pinger data is now void, all we really have is the Inmarsat data.

Without the Inmarsat data (perhaps an oversight), all we would have would be a sighting by an oil rig worker in the South China Sea, a suggestion of a turn back by Vietnam ATC, few vague reports of an aircraft crossing Malaysia at low level, and a sporadic primary radar contact.

How does this scenario fit with the last few Inmarsat arcs (assuming by then a constant course and speed)?

If we are now down to a needle in a haystack, it might be worth looking near the last arc along these two airways. Even then the search area would be huge. So far the Bluefin has only searched 850 square km.

The only other way we might get lucky is if someone provides information (e.g. that mystery telephone call prior to departure), or by looking for unlikely patterns of internet searches (this was likely very carefully researched).

[hamster3null]

See http://i.imgur.com/N0MWBCK.jpg

Do you have access to full-resolution image from which this was cut?

The "02:07:06" point is not aligned with the rest of the track and may be an unrelated aircraft (maybe SQ68 or UAE343) or just a false positive.

Lines marked "other a/c's" are waypoint corridors.

[martynemh]

@Sir Richard #10929

Approach to PEN. Given decent cloudbase and surface W/V, a no-radio approach to R/W22 would be preferable. Not sure that they would have any on-board nav receivers remaining, and there are bits of dark forested hills just N of the approach to R/W04. All the lights of George Town are available for a sraight-in app to 22.

Whatever, we do know that they didn't land at PEN.

Any overall explanation of what went on has to include the Inmarsat curved position lines and, I believe, the reports from (several) fishermen at sea and others along the coast to the south of Kota Bharu. No-one has yet explained how the radar traces etc can be positively attached to MH370, except on the basis of 'well, who else can it have been?'

[threemiles]

@propduffer

what you call independant sources is less than inofficial and called rumours. Nowhere has been any confirmation of the data you apply. Nowhere has been a release from Thai radars. Weather is not a factor for modern primary defense radar.

At 5000 ft a plane can go not faster than 330 NM ground speed (very optimistic). For half the way between IGARI and MEKAR it would lose 1/4 of its forward speed, which is 1/8 of the total route progress. This is at least 55 NM from a very conservative route length estimate (neglecting the 15 kts headwind and the lengthy turn after IGARI).

You may doubt the few hints that are published in official reports but believe the rumours from Malaysian newspapers, though.

[RetiredF4]

If the black box pings go down the drain, the conclusion for a south path from the sat pings might follow. After the release of the (incomplete and edited) raw data there is still no evidence, why only a southern path is possible.

There was and is no need to protect this evidence and the methods, how this conclusion for a southern path was reached.

Nobody has come up for a valid motive to choose a southern path, and discussions about a possible northern path have been avoided.

To repeat myself, if it wasn't some kind of a weird accident, the motive will lead to evidence.

edit:
henra
In an investigation it is of utmost importance to keep an open mind.

Wise words. Doesn't that include the option, that not only an accident but also some kind of criminal action may have caused the disapearance of MH370?

[Blake777]

No joy from Curtin's undersea recorders either.

MH370: Curtin University team checks undersea recorders for sounds of plane crash - ABC News (Australian Broadcasting Corporation) (http://www.abc.net.au/news/2014-05-29/curtin-university-team-researches-mh370-sounds/5487054)

[catch21]

It would be helpful if the Curtin underwater acoustics experts had indicated whether they would have expected to hear a ditching aircraft or not. The absence of any sound at about the right time might be quite informative as it may exclude large areas.

[flyball]

What a small world, I used to work alongside these guys. Would be worth knowing the bearing of the signal and if interesects the Inmarsat arcs....

[flyball]

A controlled explosion (of the same energy as MH370 hitting the ocean) slightly below the ocean surface with the Curtin University & Cape Leuwin sensors listening might tell us whether the signal is genuine, by the received amplitude and the arrival time.

[SLFgeek]

@P.J.M., map at http://www.pprune.org/rumours-news/535538-malaysian-airlines-mh370-contact-lost-548.html#post8498024

The times on that map do not match the (positive handshake) times on the most recent factsheet issued by the ATSB. The times on that map appear to be smoothed to provide an even hourly reference.

[slats11]

It doesn't invalidate the greater southern path, which put the possible crash site in a much broader area - about 1,200km long - than the region from which the suspected 'recorder pings' were coming.

Its very bad if we don't have any pinger data and we just have the arcs

The Bluefin searched 850 square km. That search took about a month (there were a few interruptions due to equipment problems, which will also occur in any subsequent search).

Assume the flight ended right on on the final arc, which we believe has a resolution of approx 10km "wide." That is 1200 x 10 = 12000 square km. Thats at least 12 months.

If we assume MH370 could have glided say 100km beyond the final arc, thats 120000 square km or perhaps 10 years.

Then you have to allow for increased technical and logistic difficulties as the search goes further south. The initial search was relatively close to Australia and in relatively calm waters. It will get far harder as you search further south.

Who is going to fund this?

Sure you can use multiple AUVs, but we are still looking at years.

I fear we are going to need another source of information to narrow the area down significantly.

[sSquares]

Nope, I only got the cut from MH Malaysia Airlines B772 Missing Enroute KUL-PEK Part 64 — Civil Aviation Forum | Airliners.net (http://www.airliners.net/aviation-forums/general_aviation/read.main/6087189/)

Post 38 discusses the source.

[BOING]

Since circumstances have changed I will repeat my suggestion that was previously "modded".
In my experience aircraft can only fly TO an FMC fix. Now, as a pilot in an aircraft west of Indonesia who wishes to fly the aircraft on an unlikely track for a long enough period of time to ensure it runs out of fuel what fix position would you enter into the FMC to meet these needs, a fix position that requires no great imagination. Obviously the geographic South Pole.
If anyone is taking bets I would locate the aircraft on a track from its last known position to the geographic South Pole and a distance along track to a little beyond the last Inmarsat ping.

[MG23]

Sure you can use multiple AUVs, but we are still looking at years.

If you read the JACC press release a few posts back, they appear to be planning to search up to 60,000 square kilometres, and expect it to take up to a year. If they start in the most probable areas, hopefully they won't have to search all 60,000 before they find it, but that would appear to cover an area tens of kilometres wide along the entire final arc.

[Lonewolf_50]

In my experience aircraft can only fly TO an FMC fix. Now, as a pilot in an aircraft west of Indonesia who wishes to fly the aircraft on an unlikely track for a long enough period of time to ensure it runs out of fuel what fix position would you enter into the FMC to meet these needs, a fix position that requires no great imagination. Obviously the geographic South Pole.
Or to an airfield near the south pole on the antarctic continent? You'd still flame out before you got there.
If anyone is taking bets I would locate the aircraft on a track from its last known position to the geographic South Pole and a distance along track to a little beyond the last Inmarsat ping. Looks like a decent bet.

[Shadoko]

From the JACC:
Yesterday afternoon, Bluefin-21 completed its last mission searching the remaining areas in the vicinity of the acoustic signals detected in early April by the Towed Pinger Locator deployed from ADV Ocean Shield, within its depth operating limits.

What it means?- that the Bluefin has only searched the areas within its operating limit?
or
- that all the area in the vicinity of pings was within its (upgraded) operating limit?
Sorry to ask something perhaps evident for all but not for me as a French speaking native :O

[porterhouse]

In my experience aircraft can only fly TO an FMC fixNo, it can also fly using hdg-select, no FMC involved.

that requires no great imagination. Obviously the geographic South Pole.Any other number would take 'no great imagination'.

[Sans.Armes]

Shadoko:What it means?- that the Bluefin has only searched the areas within its operating limit?
or
- that all the area in the vicinity of pings was within its (upgraded) operating limit?

It was reported some time ago that the bluefin-21 was unable to scan it's entire assignment despite it's "upgraded" limit.
Consequently there maybe smaller areas that were not scanned, but bluefin-21 had done the majority of the area.

Recall that the AF scanning "missed" the major debris field, it was after WHOI (as a private contractor) was engaged that they located the field close to where it was expected almost a year earlier (and in an area that had been previously scanned)

[DjerbaDevil]

Asking for clarification
From the JACC:
Yesterday afternoon, Bluefin-21 completed its last mission searching the remaining areas in the vicinity of the acoustic signals detected in early April by the Towed Pinger Locator deployed from ADV Ocean Shield, within its depth operating limits.

You are quite right, it could be understood as meaning that Bluefin only searched areas which were within its operating depth BUT if you read on to the 4th paragraph, it states:

The Australian Transport Safety Bureau (ATSB) has advised that the search in the vicinity of the acoustic detections can now be considered complete and in its professional judgement, the area can now be discounted as the final resting place of MH370.

The above leaves no doubt that Bluefin completed the search and did so within its operating limitations.

Well, that's how I understand it but could be corrected.

[BOING]

porterhouse
Yes, heading select could be used but if you wanted to remove all human intervention from subsequent events you would use the FMC.

And something like 90S 90E has a certain attractive simplicity. The man we are working with has demonstrated that he was a planner and he was thinking ahead, he would not choose a random position.

[oldoberon]

within its depth operating limits.

That is a ryder to the statement and to me causes confusion/doubt , why add it?

These pings, what were they? A fault in the ship or TPL electronics that caused a piece of circuitry (probably an amplifier) to go into oscillation not an unusual fault, BUT asking for it to be intermittent at a regular mark to space ratio of 1.1sec and 33.7kc , sorry I find that one difficult.

Be interesting to see where the next search starts, any bets on it being the failed bluefin search area.

[ve7pnl]

The 1.1 second pulse rate and the frequency sound about like a hydrographic sonar system I worked on designing back in the late sixties. At 4800 feet per second in water and a two way path that is appropriate for depths of 2500 feet. The pulse width we used was in the 5 to 25 millisecond range depending in part on the bottom material which has varying reflectance qualities at 33 KHz.

But that range limitation is only if you only have one pulse in the water at a time. For the higher range sonar chart recorders we could have 8 or 10 pulses in the water at a time. The chart and some memory let us focus on the bottom profile so the multiple return echos were easy enough to identify... if you did a few 1 pulse soundings to get the bottom range. Something like the old Omega nav system: you had to know where you were to get started.

Our sonar output used a very large transducer to help focus the signal. But not too narrow a beam because of survey vessel roll. With 500 to 2000 watts into a good transducer the range to a sensitive receiver would be very long. Certainly many miles. The signals heard may have been an echo off the bottom.

The reported frequency of the pings sounded much too low and that deviation from spec was apparently considered a possible consequence of low battery voltage. But maybe the frequency did not go down further. I would be very surprised that the resonator could go more than 2-3 KHz off the centre frequency due to dropping battery voltage.

I would hope someone obtained an identical pinger and measured the output frequency with decreasing battery voltage.

[Lonewolf_50]

I would hope someone obtained an identical pinger and measured the output frequency with decreasing battery voltage. And at a similar depth underwater. ;)

[gonebutnotforgotten]

OK, I give up, if these pings came from the searching ship(s), why did they disappear, roughly at a time when the original locator batteries were expected to die?

[amc890]

Quote:
In my experience aircraft can only fly TO an FMC fix


I think you will find a B777 can fly a bearing away from a waypoint that is in the nav database using LNAV

[mm43]

... if these pings came from the searching ship(s), why did they disappear, roughly at a time when the original locator batteries were expected to die?

The #3 and #4 ping detections were dismissed some time ago as not being related.

#1 ping detection apparently occurred as the TPL was in the process of being lowered, I think around the 250 ~ 300m mark and while the vessel was moving slowly ~0.5 knots. The detection was lost after 2h 40m, and it is possible that if the source was on the Ocean Shield, that could be an explanation if the tow catenary had lengthened to beyond the detection range.

#2 ping detection was 7.16NM by 205°T from the initial #1 ping and about 5 hours later as the vessel was returning on a reciprocal track, but only for a short duration. The timer on the ship's bar door had started! Think of any other explanation?

#2 ping location was the center of the 10km radius on which the Bluefin-21 search grid was based. JACC's reference to the search being centered on the 2nd ping detection of 8 April was not correct.

[RayCee]

#1 ping detection apparently occurred as the TPL was in the process of being lowered, I think around the 250 ~ 300m mark and while the vessel was moving slowly ~0.5 knots. The detection was lost after 2h 40m, and it is possible that if the source was on the Ocean Shield, that could be an explanation if the tow catenary had lengthened to beyond the detection range.

#2 ping detection was 7.16NM by 205°T from the initial #1 ping and about 5 hours later as the vessel was returning on a reciprocal track, but only for a short duration. The timer on the ship's bar door had started! Think of any other explanation?

I always thought the plane was floating at a great depth and drifting south at about 1 kt which accounted for the long first encounter.
Pings 3 and 4 killed that theory.

[slats11]

Given it took a month to search 850 km2 (possibly with some deep areas missed), the proposal to search 60,000 km2 suggests a different methodology. Perhaps using multiple more capable AUVs.

Anyway the dramatic increased size of the proposed area suggests we are really back to the Inmarsat arcs.

I guess a ditching is an advantage here. We will presumably be looking for a large relatively intact fuselage rather than a debris field.

[mm43]

I always thought the plane was floating at a great depth and drifting south

Anything on an aircraft that had the potential to provide some sort of buoyancy, is not designed to withstand the pressure differential it would meet as it sunk. Put into perspective, at a depth of 4500m the pressure imparted is the equivalent of just under 1 atmosphere per 10m - in this case 447.4 atm / 6575 psi.

The aircraft will be on the bottom - wherever that may be.

[twentyyearstoolate]

Yeah the 777 landed perfectly without any damage. Then no doors or evacuation was commenced. It then sank to the bottom perfectly intact and therefore no debris.

What utter nonsense!

[Ian W]

OK, I give up, if these pings came from the searching ship(s), why did they disappear, roughly at a time when the original locator batteries were expected to die?

There seems to be a common thread here.

The ULB, is at a frequency where its range is less than the ocean depths over which aircraft routinely fly
The ULB battery life is insufficient for a search and recovery operation in remote areas - such as over the ocean
The ULB is not encoded so a ping has to be assumed to come from a ULB based on its frequency and recurrence frequency
The CVR with the voice data is shorter than the oceanic flights routinely made and only records sounds not what is happening in the cockpit
The DFDR does not record the output to the pilots on the assumption that both sets of instruments are receiving and displaying the same data
etc etc

This discussion of pings by subject matter experts reminds me of similar discussions by other subject matter experts on 'what that noise was' on CVR recordings. Or the discussion on the data actually shown to the PF rather than the PNF

This is poor systems analysis. These 'black boxes' are literally not fit for their purpose in multiple ways. Not only have recording and data communication capabilities vastly increased but also the type of flying has changed with aircraft commonly flying 'thin routes' over sparsely populated areas including all oceans and the poles. Rather than a piecemeal approach to fixing shortcomings (or demanding that they are not fixed), it is time that the industry started a complete reappraisal of the areas such as recordings, emergency location, aircraft tracking, survivable recording devices; and generated a formal functional requirement that included all of these issues in one overarching specification. This is a job that ICAO, RTCA, EUROCAE and other standards bodies should take on urgently.

[rog747]

Ian W
well said - good study

beggars belief with the latest technology now (and its cheap) that ETOPS is given out for 3 hours or more (5.5 hours max) with major safety recording instruments that record just for 30 mins and batteries that give up in 30 days plus the signal given off is poorly identifiable it seems.
its nonsense now...

considering these ETOPS aircraft now have been given that sanction which no doubt takes them further over very remote seas and land masses that technology has been not applied retrospectively -

[sky9]

Quote:
Originally Posted by BOING View Post
In my experience aircraft can only fly TO an FMC fix. Now, as a pilot in an aircraft west of Indonesia who wishes to fly the aircraft on an unlikely track for a long enough period of time to ensure it runs out of fuel what fix position would you enter into the FMC to meet these needs, a fix position that requires no great imagination. Obviously the geographic South Pole.
Or to an airfield near the south pole on the antarctic continent? You'd still flame out before you got there.
Quote:
Originally Posted by BOING View Post
If anyone is taking bets I would locate the aircraft on a track from its last known position to the geographic South Pole and a distance along track to a little beyond the last Inmarsat ping.
Looks like a decent bet.

See my post 8089 25th March

I do wonder whether the aircraft flew from close to MEKAR to SPOLE (South Pole) or to YWKS (Wilkins Runway) using LNAV thereby independent of further input.

Jeppesen should be able to provide a more accurate calculation of GS for the period rather than the 450kts GS estimate for the whole route south.

[gonebutnotforgotten]

To MM43 @00:59 today,

Thanks for the thoughtful reply, but any explanation of why the false positives occurred surely has to extend to why they stopped, given that the towing operations continued for some time. I remain puzzled. Though if the TPL results are indeed entirely false, it partly solves the problem of how the search area was successfully narrowed down so dramatically... it shouldn't have been.

[IRpilot2006]

Reading between the lines, the govts and other authorities seem convinced this was a criminal act, so IMHO we can definitely expect some changes to the satellite tracking systems so they (a) transmit the position (i.e. the airlines will have to pay up the fairly trivial amounts involved) and (b) cannot be disabled from the cockpit or cabin.

None of that is technically hard. Maybe relocating some circuit breakers.

If this pilot really did what many think he did, it was a clear "go out in style" job, which some may want to copy. Let's face it, it is amazingly easy to do. Either pilot can do it if the other leaves the cockpit.

[imaynotbeperfect]

My understanding, I think was from one of Angus Houston's briefings, is that the ULB is not intended to be detectable at such depths. It is for finding the flight recorders once you have already found the debris field.

Having said that it does lead one to the conclusion that when it was introduced possibly there was no expectation that debris would be recoverable from somewhere as deep and remote as the southern Indian ocean.

[Dont Hang Up]

Reading between the lines, the govts and other authorities seem convinced this was a criminal act, so IMHO we can definitely expect some changes to the satellite tracking systems so they (a) transmit the position (i.e. the airlines will have to pay up the fairly trivial amounts involved) and (b) cannot be disabled from the cockpit or cabin.

None of that is technically hard. Maybe relocating some circuit breakers.

Every electrical system or circuit breaker removed from the control of the flight crew is an added fire risk.

Let's not be in such a rush to quick fixes for one in ten million risks that make more-likely risks worse.

If this pilot really did what many think he did, it was a clear "go out in style" job, which some may want to copy. Let's face it, it is amazingly easy to do. Either pilot can do it if the other leaves the cockpit.

I cling to the the perhaps naive view that there are not that many commercial pilots out there waiting to take out their aircraft and passengers - waiting only for suitable "inspiration".

If there is someone like that up-front who has decided that today is the day then basically we are pretty much stuffed. New tricks for finding the wreckage afterwards are not that much of a comfort.

[Ian W]

My understanding, I think was from one of Angus Houston's briefings, is that the ULB is not intended to be detectable at such depths. It is for finding the flight recorders once you have already found the debris field.

Having said that it does lead one to the conclusion that when it was introduced possibly there was no expectation that debris would be recoverable from somewhere as deep and remote as the southern Indian ocean.

This is absolutely correct the design was for cases such as when the debris was in a river - say the Potomac and the CVR/DFDR needed to be found. So what we have is a failure of systems analysis, what happens if an aircraft goes NORDO on the way to Hawaii and does not arrive? What about LAX - SYD? My suspicion is that the systems analysis was limited at the start by external inputs like funding, weight and the capabilities of the then systems. It is in urgent need of revisiting.

[holdatcharlie]

....do the authorities/countries involved have to report what they know. How much information are they obliged to release?

....if it was a criminal act by a radical group - they would have let us know within hours that they were responsible to bask in their infamy.

....if it was the sad act of an individual who had the extensive knowledge and cunning to perpetrate this - surely that person would want the world to know that they were that clever/sick! They would have left some note, tweet, Facebook clue. I feel they could not have the self-control to leave no clue at all - unless the authorities have that clue and want to keep it to themselves.

....or it was an insurance job and had to be scrupulously covered up.

[IRpilot2006]

if it was the sad act of an individual who had the extensive knowledge and cunning to perpetrate this - surely that person would want the world to know that they were that clever/sick! They would have left some note, tweet, Facebook clue. I don't think this one is a problem. Two reasons for a start:

1) To protect the dignity of the family (very important in those cultures)

2) To enable them to get the full life insurance payout

I feel they could not have the self-control to leave no clue at all - unless the authorities have that clue and want to keep it to themselves.The "clues" are probably fairly obvious, but until you have proof you have nothing at all in legal terms.

I cling to the the perhaps naive view that there are not that many commercial pilots out there waiting to take out their aircraft and passengers - waiting only for suitable "inspiration".

If there is someone like that up-front who has decided that today is the day then basically we are pretty much stuffed. New tricks for finding the wreckage afterwards are not that much of a comfort.

That's why I think the search will never end.

[Zionstrat2]

Don't Hang Up- I understand your concern-

"Every electrical system or circuit breaker removed from the control of the flight crew is an added fire risk.

Let's not be in such a rush to quick fixes for one in ten million risks that make more-likely risks worse."

But as I understand it, if current technology is mandated and processes are updated, we could almost immediately reduce the risk of entirely lost aircraft where no one is aware of a potential problem and the dragnet isn't thrown out until it is too late.

1. All commercial AC of x size/over water routes should be required to use a satellite based acars system that trickles out a small amount of info every 5 minutes- If it stops reporting for more than x minutes- a minor problem is assumed, however the alert processes is started and escalates over time.

2. All commercial AC of x size/over water routes should be required to use a satellite based communication system like Immersat with a minimum of 5 minute handshakes- If it stops reporting for more than x minutes- a minor problem is assumed, however the alert processes is started and escalates with time.

(Note that I am talking about a potential process-- not specific technologies, ie where ACARS stops and Sat com starts-)

Of course, if this leads to a crash, it doesn't give us the crash coordinates- However,
1. We are altered to a potential problem, we know where the AC was at the time and we can escalate as needed.
2. The search area would be greatly reduced
3. Some type of assistance might be possible (a military AC leading an electrically comprised AC to a suitable runway)
3. No one would imagine they could get away with an intentional MH370 like event.

Forget about the transponder for a moment- there are too many reasons it could be turned off and the alerts described above would be easily automated.

Costs would be limited to current technology, process changes aren't drastic, and it's unlikely to set off false alarms- ie 5 minutes after an alert, an aircraft with minor electrical issues may report in and stop the alert.

Or 10 minutes after an alert, if officials can't make a radio connection, it's likely that something's going on. Maybe just electrical, but we're aware and looking at potential to assist?

Other than fear of change, and possible satellite bandwidth, does anyone see major holes in this thinking?

[Timothy Quinn]

The post of IanW and the reference contained within, is the most important for everybody.We all live in a world which is virtually shrinking,even my present keystrokes are probably being monitored from afar!
Unwilling taxpayers worldwide are paying for defence systems which generally are useless to most of us and I think the time has come for a better use of people's money.Ruling elites have to mandate better regulations covering air travel.
Like any other human activity,if one type of event has happened,there is no earthly reason to state that it has only been an isolated event,the same type of event can again happen.
Just take a quick peep at the nuclear industry and it's massive spend on safety,bad things do happen.

[kayej1188]

http://www.pprune.org/engineers-technicians/472227-boeing-777-acars-aims-user-guide.html#post6913079

^From a guy who lives in Malaysia

[HeavyMetallist]

Every electrical system or circuit breaker removed from the control of the flight crew is an added fire risk.

Let's not be in such a rush to quick fixes for one in ten million risks that make more-likely risks worse.

@Dont Hang Up: I entirely agree. There are far too many people piling in here with apparently quick fixes, without looking at the wider situation and the probabilities of different occurrences. I'm not at all sure I'd want to fly on aircraft where the crew have no control over some systems, just on the off chance that they might have some homicidal intent. The legal profession has a saying, "hard cases make bad laws", which I think applies to a lot of these ideas.

[IRpilot2006]

OTOH, major mishaps are so rare in "1st World operated" big jets that every case you react on is going to be a rare hard case.

This isn't the 1950s when stuff used to crash all the time. When it comes to improving airline safety, one has been scraping out the bottom of the barrel for many years now, reacting to hugely improbable events.

Look at AF447. "Extremely improbable" (though most old timers would say "it was only a matter of time"). Yet probably every airline has changed its training after that.

Even if MH370 is never found, it's obvious that there are gaping holes in the system (the ease with which an airliner can vanish in a remote area) which need to be plugged, and which can be plugged relatively very cheaply.

And that's assuming one assumes this wasn't a criminal act. But if it was, and it happens again, you will have two jets vanishing and you will still be totally clueless.

[Ian W]

IFF another aircraft does a similar disappearing act flying out of a busy airport and vanishing, then I can see many people being reluctant to fly. There will be an extreme drop in the public trust in flight crews and aircraft generally. A second disappearance could be an industry killing event.

This is why the airline industry worldwide must get systems in place to ensure that all aircraft are tracked and remain tracked regardless of flight crew actions.

There are existing on-board systems like ADS-C that could do this, but it will require mandates from ICAO and the ANSPs to stop the beancounters insisting they are switched off.

[Teevee]

Not a pilot but a historian. There were very few real facts known about this event right from the start and those that were known seemed subject to any number of interpretations. Now it is theories about theories based on speculation. The truth behind most historical events only really comes to light with a significant concrete discovery. When other news gets quiet expect more 'theories' to surface as journalists try to earn their salary for that particular week .....

[winsteve]

Apologies for being slow to respond and thank you for your further analysis.

For me, with the official release of the Inmarsat data, the roles of BFO and BTO are a bit clearer. I still think that the inferred location for the first point is somewhat problematic, and I am concerned that this casts doubt on the BFO calibration for the remaining points. The BTO seems a lot clearer, in placing the aircraft on the "ping rings". However, there are a lot of assumptions being made about the aircraft's southerly path that could significantly shift the most likely area along the rings.

On a first principles basis, I am still troubled about the role of probability in the analysis. To be honest, in my opinion, a full "Monte-Carlo" simulation would probably be the best way to go. Since we haven't yet seen the Inmarsat "model", we can't yet tell whether this has been done.

[porterhouse]

To be honest, in my opinion, a full "Monte-Carlo" be the best way to goAgreed. But then we assume the scenario when pilot on purpose flies such a confusing track (frequent heading changes) to maximally confuse investigators. If you think about it - the same 'rings' could be generated by millions of trajectories, some probably quite spread out in directions, if this is the case, if we are dealing with such conniving person in control of that flight - we have no chance finding this aircraft.

[Fubaar]

Ex Prime Minister of Malaysia, Martiar Mohammed, never slow to accuse the a West (usually Australia) for every woe befalling his country, has informed the world via his personal blog that the CIA know what happened to MH370 and that the search in the Indian Ocean is a waste of time and money. On the last point, the man may be right.

[Pontius Navigator]

If you think about it - the same 'rings' could be generated by millions of trajectories, some probably quite spread out in directions.

I did.

If you knew the accurate groundspeed hour by hour you will finish up with a very narrow probable track band.

As you increase the speed range you will get a wider band.

I presume from successive Doppler they have been able to deduce a reasonable accurate speed range hence the track band was determined and the cessation of transmissions determined the track box length.

As there is uncertainty between transmission cessation and aircraft crash they would attempt to refine the box based on estimated fuel exhaustion. Fuel burn is probably the most problematical of the assumptions, next is the descending flight path once transmissions ceased.

The flight path could be near vertical as some have supposed or a shallow glide in any direction.

And lastly there are the pings.

[Propduffer]

I presume from successive Doppler they have been able to deduce a reasonable accurate speed range hence the track band was determined and the cessation of transmissions determined the track box length.
I haven't seen any claims along that line; I think they are delighted just to be able to tell if it was moving towards the satellite or away from it. That's how they knew it went south instead of north.

The speed is calculated from a 777s' performance envelope (they knew how much fuel it had, and when it presumably ran out.)

[threemiles]

... if it flew straight, not circling in between, or zig-zagging a bit here and there.

[Pontius Navigator]

The zigzags would have had to be very consistent otherwise the arc angles would not have been uniformly spaced.

The aircraft vector in relation to the satellite will exhibit a Doppler shift or did I miss something?

[Propduffer]

You've got it right, but I don't think the doppler shift provides enough precision to determine speed. But I don't know that it doesn't either. I just haven't heard any claims of such.

You have a good point about the linear pattern of the later shifts displayed in the burst chart. That does indicate continous cruise with no turns.

[Pontius Navigator]

Propduffer, I suspected you referred to Doppler as a speed indicator; I didn't, I referred to it as a direction indicator - Doppler low to mean opening range.

olasek, in theory. In practice at the precise moment of the ping time the aircraft would have had to present the same Doppler as the previous pings.

[slats11]

I feel it likely that the person flying the plane wasn't aware of the ongoing handshakes between the satellite and the aircraft. Everything else was turned off - transponder, ACARS, no response to ATC. Why leave another form of "communication" alive - unless you were unaware of it.

So I think you have to assume a relatively constant velocity once established on the track south. If you believed you were completely "dark", the most important consideration was distance. The further away you got, the less likely you would ever be found.

Anyway assuming a constant velocity is already a difficult enough task. To try and calculate the effects of random changes during this final leg would appear pointless on the grounds of futility.


The recent comment about the inflight entertainment is intriguing. Things started to happen while passengers would still have been awake and some would have been watching flight path (or whatever moving map package was part of the IFE). So is may have been necessary to disable the IFE so passengers were unaware of the turn back. If so, that implies the turn back was very gradual. If on the other hand the plan was a steep climb with the packs off to disable the passengers, the IFE doesn't really matter. Why worry about the IFE if the passengers were about to be aware there was something wrong but would shortly become incapacitated. So something here doesn't quite fit.

The other thing is the passenger phones. I know some hear are sick of discussions about phones. But after 2 months searching I don't think we are in a position to discount any possible information that could aid understanding. A low level flight across Malaysia would have generated calls from any able passengers. And also handset registration with the phone networks from any phones left (on even if all the passengers were disabled at this point). So that doesn't make sense either. Possibly a phone jammer. Even an accomplice in the cabin could not have ensured that all phones were put in flight mode and / or turned off.

The other thing that would concern me as the pilot would be the chance that one passenger (and it would only take one) might have a sat phone on board.

[Propduffer]

The Inmarsat packets from the A/C contained an identifier code which has been compared to a MAC address. The identity of these packets as being from MH370 has been positivitly confirmed.
As for the radar: the Vietnamese state that they saw it turn around (circa 1:22) Thai radar picked up what could only be the same target approching Kota Bharu at 1:28 and the Malaysians picked up what can only be the same track shortly after that.

There is no doubt that this was MH370.

[BOAC]

Looking at the Inmarsat data, the variation in BFO between the contacts is such that I cannot see how a reliably accurate determination of BFO at each of the handshakes can be determined based only on the one value. Way back we heard about some sort of signal 'elevation' determination at the satellite ("40 degree arcs") - was that a false report or was it in fact simply referring to the BTO?

Do I understand that there is NO 'best fit' northerly route based on the BTO/BFOs?

[oldoberon]

I'll reply again using different wording

there mathematically must be a theoretical best for north, but validation tests against other flights indicated with great certainty it was south.

[billslugg]

The determination of the southern arc was made because of a doppler rate change that occurred when the satellite made a u-turn in the sky. The Inmarsat drifts north of and south of the equator in a 24 hour cycle. It forms a figure 8 against the sky. When it made one of those turns the doppler shift of MH370 changed in such a way as to determine which track it was on.

If the satellite was drifting south and MH370 was flying south, and then the satellite made a u-turn and headed north, it would be expected that MH-370 would be seen as moving away even faster.

Had MH370 been on the northern arc, it would have been seen to move more slowly away from the satellite when the satellite made the northern turn.

[oldoberon]

Pontius can't be very far eastwards otherwise will come up on two satellites.

[sky9]

I think this link has been put up before but it is relevant to the current discussion.
Considerations on defining the search area - MH370 (http://www.atsb.gov.au/publications/2014/considerations-on-defining-the-search-area-mh370.aspx)

[IRpilot2006]

one passenger (and it would only take one) might have a sat phone on board.

A satphone transmits the GPS position only when an outgoing voice or SMS call is made, and a dead person isn't going to be doing either.

Thuraya and Immarsat satphones might reveal their position to within a few hundred nm via the spot beam used, but not Iridium which is probably the most popular network.

[ZAZ]

An article titled "Where in the world is MH-470"
Sunday
Sums up the 9000 opinion here with 10 scenarios.
And in as few words unlike here.

[BOAC]

Can any of the experts here tell us (UTC) when the satellite reached the reversal point of its Lissajous figure and how the BFO data shows this?

[Keef]

... the simplist thing to do would be fly a plane along the assumed track and check the satellite signals

If you read back a few dozen pages, you'll find that Inmarsat used the signals from a number of aircraft crossing the region to "calibrate" their model. More effective, and simpler because no need to borrow a 777 to do it.

[Vinnie Boombatz]

@BOAC at 1st Jun 2014, 23:54 :

I calculate that Inmarsat 3-F1 reached its furthest North latitude at about 19:33 UTC on 7 March.

This site has a table of satellite positions at the "ping" times, and shows the maximum North latitude at 19:41 :

Aqqa on MH370 (http://www.aqqa.org/mh370.htm)

The site also has large files of satellite position and velocity in Excel or CSV formats. I downloaded one of the Excel files, and previously computed very close to the same velocity (about -82 m/s, i.e., South, at the last "ping").

That would give a maximum Doppler of 400 Hz for an aircraft due North or South of the satellite, but less than 40 Hz at the presumed last position, since that position is almost orthogonal to the satellite groundtrack then.

Here's one explanation of how the satellite data could have been processed:

https://www.siam.org/news/news.php?id=2151

It links to this 31 MB set of slides:

http://www.utdallas.edu/~zweck/MH370_UNM.pdf

Slide 47 shows the ground track of the satellite. It's a teardrop shape rather than a figure 8, due to the very slight eccentricity of the orbit. It also links to the aqqa.org site, so all 3 of these sources are probably by the same person (John Zweck).

For any STK users, here's the AGI page on MH370:

AGI Blog (http://blogs.agi.com/agi/2014/04/04/using-stk-for-malaysia-flight-370-search-analysis-2/)

[Shadoko]

Slide 47 shows the ground track of the satellite. It's a teardrop shape rather than a figure 8, due to the very slight eccentricity of the orbit.The teardrop shape comes from a longitude scale ~30 times larger than the latitude one.
The 8 shape is visible from a "lateral" view (exchanging longitude coordinates for altitude ones).

[Wannabe Flyer]

Recorded Noise Might Offer Clues to Missing Plane | NDTV.com (http://www.ndtv.com/article/world/recorded-noise-might-offer-clues-to-missing-plane-535121?pfrom=home-topstories)

[mmurray]

Recorded Noise Might Offer Clues to Missing Plane | NDTV.com


I think those guys at Curtin decided their stuff wasn't related

MH370: Curtin University team checks undersea recorders for sounds of plane crash - ABC News (Australian Broadcasting Corporation) (http://www.abc.net.au/news/2014-05-29/curtin-university-team-researches-mh370-sounds/5487054)

[Backoffice]

My reading of the original report was that the quoted yacht was in the Indian Ocean en route Thailand and never in the Malacca Strait. The report said the aircraft was tracking north to south.

Perhaps she was the only person (so far) to see it heading South.
If only I could get my head around what time setting is on her screenshots.:ugh:

[mixture]

PN - why not look at the reported positon on the charts?
I Think I Saw MH370 - Cruisers & Sailing Forums

I can't help thinking something's a bit fishy about that post (beyond the question of why she waited until the 31st of May !).

She says she's cruising at night, in her own words she says " I wouldn't know." when answering a journalist's question "How far away did the object appear?"... and yet at the same time she says "I could see the outline of the plane with a tail of black smoke coming from behind it".

Really? You can see the outline of a plane in the pitch black in the middle of the sea ? So its close enough for all that detail but too far away for you to be able to give a distance ?

And of course, as with the oil right worker... no other witnesses.

[mixture]

Mixture, before dismissing her claim we should consider ambient lighting at the time. Good night vision adaptation, moon light, star light, cloud cover etc.

Maybe she needs more benefit of the doubt, who knows ? But things like waiting so long doesn't help her cause. She also says the weather was not its best "we were at the tail end of a very, very harsh passage into the weather which was had been mountainous, having been flooded badly from the anchor locker and swamped ".

Parts of the story are possibly plausible, but then the detail seems to be causing a few eyebrows to be raised.

[BOAC]

094:30E 06:20N?

[Chronus]

I followed BOAC`s lead and looked at the enroute charts for crossings of the Indian Ocean. All SW bound routes converge at Plaisance. A327 and B344 may offer suitable routing, particularly if already present in the FMC.

[imaynotbeperfect]

Reports starting to appear in AUS and other press about Curtin University's analysis of data received by underwater microphone arrays off the coast of Western Australia.

MH370: Indian Ocean crash may have been heard by underwater microphones | World news | theguardian.com (http://www.theguardian.com/world/2014/jun/04/mh370-indian-ocean-crash-may-have-been-heard-by-underwater-microphones)

[Blake777]

Actually, a little further information today from the ABC.

Curtin university researchers investigate possible MH370 signal recorded off Perth - ABC News (Australian Broadcasting Corporation) (http://www.abc.net.au/news/2014-06-04/curtin-university-investigates-possible-mh370-signal/5500198)

[AstraMike]

This is getting silly

I have to say that when I signed up I thought this was a forum for Professional Pilots. I wonder where they have gone?

How come all this talk about someone who may, or may not, have seen something although the day/night on which she saw it is uncertain and who knows what it was she thinks she saw? Surely the recent statements of Emirates Chairman, Tim Clark are far more deserving of consideration, after all, he operates one of the largest fleets of B777 and is likely as familiar and likely more familiar with the aircraft than most posting here. His questions and concerns are certainly worthy of consideration and comment and although dismissed here the question "where were the fighters?" has never been properly answered. He is also quoted as saying "I need to know how anybody could interdict our systems,” as well as “this aircraft was disabled in three primary systems. To be able to disable those requires a knowledge of the system which even our pilots don’t know how to do. Somebody got on board and knew exactly what they were up to.”

Seems to me we should be paying attention to what matters!

[Lonewolf_50]

"where were the fighters?"
On the ground.

AstraMike:

Are Tim Clark's comments/concerns posted somewhere that you can link to?
Per your point on his background, a read well worth the time.

That last point you raised "I need to know how anybody could interdict our systems,” as well as “this aircraft was disabled in three primary systems. To be able to disable those requires a knowledge of the system which even our pilots don’t know how to do. Somebody got on board and knew exactly what they were up to.” strikes me as a "nail hit on the head" observation.

[Green-dot]

@Lonewolf 50:

Are Tim Clark's comments/concerns posted somewhere that you can link to?

Link below:
Emirates? Clark Sees MH370 Investigation Deficiencies | Commercial Aviation content from Aviation Week (http://aviationweek.com/commercial-aviation/emirates-clark-sees-mh370-investigation-deficiencies)

[DespairingTraveller]

this aircraft was disabled in three primary systems.

I presume this statement refers to VHF voice, ACARS and the SSR transponder.

I remember hearing a statement by a Malaysian official in an early presser that one or more of these had been disabled. However, I don't recall ever seeing an explanation of how the investigators know that these systems were deliberately disabled by human intervention (which is the interpretation constantly assumed here and elsewhere, not least in what I've seen of Tim Clarke's remarks), as opposed to transmissions from them simply ceasing to be received past a certain time, for reasons unknown.

Could someone enlighten me? Were logoff or shutdown messages received from some source? I haven't seen reference to such in the disclosed ACARS information, and I didn't think that audio transceivers and SSR transponders did such things.

[MG23]

Could someone enlighten me? Were logoff or shutdown messages received from some source? I haven't seen reference to such in the disclosed ACARS information, and I didn't think that audio transceivers and SSR transponders did such things.

I'm not aware of any such evidence. The SATCOM logs, for example, didn't show any kind of logoff message from the aircraft, it just stopped transmitting for a while around the time the transponder went off.

To me, that tends to imply a power failure, but that power failure could be due to human actions.

[Ornis]

Emirates? Clark Sees MH370 Investigation Deficiencies | Commercial Aviation content from Aviation Week (http://aviationweek.com/commercial-aviation/emirates-clark-sees-mh370-investigation-deficiencies)
“We have never lost an aeroplane in 50 years, we have always known where they are. Whoever was clever enough to interdict the system, will be able to interdict this one as well.” To [Tim] Clark, tracking is not the main issue: “the first thing you need to do is do not allow anybody on board to disable ACARS – job done.”

I don't think Clark understands probability and luck. There but for the grace of God ...

So, is the answer pilotless airliners?

You can only go on the information you have, and that's not much. But there's no indication anyone but the PIC had the knowledge or opportunity to deliberately disappear.

[oldoberon]

I don't understand Tim's comment re his pilots not knowing how to turn off vhf,hf, and acars.

Turn of VHF and HF , acar is dead because no sat con acars on MAS.

Many pilots on here say no way to not being able to turn off systems in the case of fire for example, how does thisstack up to Tim's statement.

What am I missing or mis-understanding please.

[Backoffice]

You know, you might deliberately turn off something because there is smoke coming out from behind its panel.
There is deliberate with intent and deliberate with cause.
One may lead you to be suspicious the other is common sense.

[Sans.Armes]

stopped transmitting for a while around the time the transponder went off

more accurately..... "sometime between 17:07 and 18:25"

[oldoberon]

You know, you might deliberately turn off something because there is smoke coming out from behind its panel.
There is deliberate with intent and deliberate with cause.
One may lead you to be suspicious the other is common sense.

I agree but he seemed to say his pilots wouldn't know how to.

[Sheep Guts]

Tim Clark interview was nice. Except for assumptions about MAS ability to track Aircraft and its ACARS subscription service. He seemed to compare it to Emirates which more than likely has a full subscription to these services. MAS didn't subscribe and it Operations Control was using an Internet based free Aircraft Tracking software, which is becoming the norm for Low Cost Operators but is spreading to larger ones to curb costs. The LCC I worked for in Singapore for example didn't use ACARS. We as Pilots were still using VOLMET HF and VHF for our ETOPS flights. Which seemed idiotic but was apparently legal in that state. Our Chief Pilot ( ex Large European LCC)was dead set against ACARS usage, hence all our Aircraft were disabled in that regard. The only connection available was the engineering side. At my current Airline we use ACARS all the time and we see the benefits immensely. This Low Cost disease of saving money by not subscribing to ACARS has caught in Asia. And the usage of these free tracking systems has taken over and honestly its dangerous. The MAS OCC were telling ATC that MH370 was in Cambodian Airspace for hours after ATC lost it at Igari, because there were using this free tracking software. Don't get me wrong this software is great for enthusiasts, but officially something more accurate needs to be used.
The thing about this latest IATA conference in Dubai, did they talk about the Lithium Ion battery carriage rules again? This definitely needs to be attended too.

[bilby_qld]

"I need to know how anybody could interdict our systems,” as well as “this aircraft was disabled in three primary systems. To be able to disable those requires a knowledge of the system which even our pilots don’t know how to do. Somebody got on board and knew exactly what they were up to.” How can anyone assess with such confidence what things his employees don't know?

It is known (or at least it is to be hoped) that the pilots are thoroughly familiar with many, if not most, of the systems on board. Of course, there will be some aspects of the aircraft that pilots are not explicitly trained in; a pilot is not expected to be able to build his aircraft from scratch.

There may be ways to disable certain systems that pilots are not trained to know about, but then, nobody is born with that knowledge; it must be learned somewhere. And surely a trained and qualified 777 pilot is further along that road to knowledge than anyone else?

The implication that a terrorist or terrorists unknown, coming from outside the aviation industry, have the ability to learn such things more readily than persons who start their acquisition of knowledge from the position of type-qualified pilots is, frankly, bizarre.

If it can be done, any intelligent and motivated person can learn to do it. Complex failure modes can be the result of deliberate action - and as Backoffice points out, this may not imply malice, but can arise from a genuine attempt to prevent disaster.

Complex failure modes can also result from damage to systems; while not readily reproducible, it is nevertheless common for fires and other escalating failures to produce patterns of failure that common sense would suggest were hugely implausible.

The evidence presented so far is insufficient to rule out any of the following:

Deliberate malicious act by one or more passengers
Deliberate malicious act by one or more crew
Deliberate crew actions intended to prevent or mitigate disaster (unsuccessful)
Non-deliberate failure of one or more systems leading to fire or structural damage, resulting in an unusually complex series of events

In other words, despite the vast quantity of ink and pixels expended so far, all that is really known is that the aircraft went missing; and that there is some good evidence, including primary radar traces and the INMARSAT pings, that it re-crossed the Malay peninsula, and then headed into the southern Indian Ocean, after it disappeared from secondary radar.

Any hypothesis that fits those facts is possible; none are plausible; one is correct.

[imaynotbeperfect]

ATSB has, this morning, released the tender documents for the MH370 search. You need to be registered to download it but synopsis is available from AUStender at this link:

http://www.tenders.gov.au/?event=public.atm.show&ATMUUID=C1B3888F-F6FA-5874-5FBEB3C04BEB2FB0

The tender itself calls for a complete range of services and specifies the detail to which the search is to be conducted including the requirement to provide raw search data for others to analyse independently of the contractor and daily, weekly and monthly reporting of activities.

[MotCap]

If one would be willing to take Emirates Chairman Tim Clark's statement at face value, then passenger #240 has reared it's ugly head again.

[flyball]

Acoustic signal received at Rottnest at 1:30am UTC. The final ping arc is about 2,000km from Perth. Sound travels 1500m/s in seawater. This means it would have taken 22mins to reach Rottnest from the final ping arc, which would be 1:08am UTC. Final satcom communication at 00:19am, 49mins difference. Is it possible to glide 49mins in a 777?

[4Greens]

Its now all blood under the bridge. Introduce transmission of recorder data asap. Let us work on stopping the next one happening.

[Minimbah]

The 7th Arc (http://www.atsb.gov.au/mh370/search-area-map.aspx)

[Ornis]

flyball. Might the speed be less than 1500m/s?
Velocity of sound in sea-water Calculator - High accuracy calculation (http://keisan.casio.com/exec/system/1258122391)

[slats11]

The PhD who investigated this acoustic data gave a very comprehensive interview on radio 18 hours ago. He is almost certain (90% confidence) the noise was NOT MH370.

He feels more likely it represented a small earthquake or ice breaking off Antarctic shelf.

He did say low frequency sounds (at or below lower limit of human hearing) can be detected many thousands of km away. Main variables are:
1. topography of the bottom (helpful if the ocean bottom at the source sound was sloped towards the listener, as this will "lens" (reflect) noise towards the listener.
2. temperature layers (deep water channel)

He also confirmed frequencies in range of pingers would be limited to just a couple of km regardless of conditions.

Worth a listen if you are interested. Maybe available online (2gb.com). But he didn't leave much room for doubt.

[flyball]

Ornis, you may be correct, its hard to find accurate sea surface temperature measurements for the 8th of March and it also depends on whether the plane hitting the surface caused the signal or the plane imploding under the ocean caused the signal. The acoustic sensor is located at a depth of 400m so this affects the speed as well.

Using the image Minimbar posted the final ping is about 1600km away from Perth, so this would make it 17mins for the travel time of the signal and a further five minutes the plane would need to glide (54mins).

ETH961 glided for 27mins after last engine shut down from 20,000ft, (even with hijacker interference).

[Ian W]

The PhD who investigated this acoustic data gave a very comprehensive interview on radio 18 hours ago. He is almost certain (90% confidence) the noise was NOT MH370.

He feels more likely it represented a small earthquake or ice breaking off Antarctic shelf.

Unfortunately, I cannot access the recording. But I would be interested to know his reasoning. Has he seen recordings of a 777 ditching and imploding at depth or anything similar? If not then he is giving a 90% assumption.

The recordings of an identifiable noise (in fact two) happening at approximately the time that 370 was expected to have 'ditched' is an extreme coincidence.

[Heathrow Harry]

Speed of sound in water is APPROX 1500 mps but it varies with temperature, salinity, surface conditions and half a dozen other things

You use 1500mps as an approximation but it could be +/- 5%

[Ian W]

Bilby, Desparing Traveller et al,

ACARS "was deliberately turned off" was reported early on. Now ACARS 'logs on' and 'logs off' usually on aircraft systems power up and power down. ACARS using VHF often (regularly) loses contact as the aircraft flies out of line-of-sight. There is a difference to the system between just not getting any more transmissions and receiving a log-off. So it would be possible to know if the system was shut down via a pilot input or just 'stopped' as it would if out of line of sight of VHF, fire had burned through the power supply, or the pilot had tripped a circuit breaker.
The repeated statements that someone had "switched ACARS off" rather than we received no more ACARS transmissions after the last one at cruise, implies that there is evidence of a tidy log-off. This evidence is crucial as it would settle several hypotheses - a pilot with a cockpit fire or some other emergency, does not find the correct place to log off from ACARS. SITA/ARINC should have that evidence and it should have been in the initial report.

[slats11]

@IanW

The Curtin University receivers are based off Rottnest Island, pretty much due west of Perth. I gather these receivers serve a scientific purpose (whales etc).

He explained the data had been cross referenced with data obtained from different receivers based quite a way south of Perth (off Cape Leeuwin). The purpose of these receives is to help monitor compliance with the comprehensive test ban treaty. He was a little vague regarding precise details at this point, perhaps deliberately so. But I got the impression differential timing suggested a source well to the south (he did specifically mention Antarctica as a likely source).

[thommo101]

@IanW
The recordings of an identifiable noise (in fact two) happening at approximately the time that 370 was expected to have 'ditched' is an extreme coincidence.

As mentioned, the first acoustic transient, if originating from the final Inmarsat ping ring would have been produced approximately 50 minutes after the time of last Inmarsat ping.

The second acoustic transient was much later and would have originated approximately 4.5 hours after the last Inmarsat ping

Both signals received contain only low frequency energy, suggesting a large propagation range, and have rather different characteristics (frequency and time spread).

[martynemh]

Glide from 35,000ft?

Less than 15 mins.

[Dale C]

Hello, a first-time poster here with a couple of points I would like to contribute:

When Tim Clark talks about 3 systems disabled, he probably refers to the transponder, ACARS and SATCOM. Please note that ACARS and SATCOM are separate systems.

Transponder being disabled (turned off or failed) is self-evident.

Last ACARS transmission from the plane through SATCOM was at 1707 Z and none received after that, thus ACARS disabled.

In the Inmarsat logs, there is a gap of SATCOM transmissions between 1707 Z (after the last ACARS transmission) and 1825 Z (when the SATCOM in the plane initiated a handshake). In particular, the SATCOM modem didn't respond to a satellite query at 1803 Z. We can deduce therefore that SATCOM was disabled at least between 1803 Z and 1825 Z, and enabled at 1825 Z.

[slats11]

Curtin University researchers find possible acoustic trace of MH370 (http://m.watoday.com.au/wa-news/curtin-university-researchers-find-possible-acoustic-trace-of-mh370-20140604-zrxaw.html)

IanW, a brief media presentation by Dr Duncan. The 15 minute interview I heard was much more in depth, but you might be interested in this.

[Ornis]

Dale C. Acars was VHF only. The systems off: VHF (Acars), HF, transponders, satellite phone. This reply will disappear soon along with your comment.

[mm_flynn]

Bilby, Desparing Traveller et al,

ACARS "was deliberately turned off" was reported early on. Now ACARS 'logs on' and 'logs off' ....

The repeated statements that someone had "switched ACARS off" rather than we received no more ACARS transmissions after the last one at cruise, implies that there is evidence of a tidy log-off.
I don't think there is any 'Official' statement that ACARS was switched off or logged off. I believe the position/time of last ACARS on the various plots is that of a complete and normal ACARS transmission and there is no indication of a log off ACARS message.

The log ons at 18:25 (from memory) and the 7th ping, are the satellite communication system itself, not the ACARS communications. Further, I believe it is established fact that MH370 was not configured to have the ACARS system use the satcom link, Satcom was only onboard to provide telecommunications for Business/First class (and potentially available to the flight crew for calls).

I have little technical knowledge of the ACARS system, but it appears to not intrinsically require a log on/log off process. It seems to just be a VHF/HF/Satcom store and forward system where individual data packages are sent to the central service for storage and then periodically polled or pushed until an ACK is received or a retry limit is hit.

It is also not clear to me that the Satcom system itself has any 'logoff' function and therefore if there would be anything to distinguish between the device being turned off/ put into standby/ loosing power/ being destroyed

[Ian W]

I have little technical knowledge of the ACARS system, but it appears to not intrinsically require a log on/log off process. It seems to just be a VHF/HF/Satcom store and forward system where individual data packages are sent to the central service for storage and then periodically polled or pushed until an ACK is received or a retry limit is hit.

It is also not clear to me that the Satcom system itself has any 'logoff' function and therefore if there would be anything to distinguish between the device being turned off/ put into standby/ loosing power/ being destroyed

The logon sets up the store and forward system and checks that you are a subscriber to ARINC or SITA messaging systems. Similarly, the SATCOM sets up a link at the lower protocol layers that also allow check of subscription against the aircraft ID, or you would not be able to start the SATCOM phone or other uses of the SATCOM system. These actions all happen on power on and are 'transparent' to the pilot. This is what was meant by the Earlier statements about 'pilots not knowing how to switch the comms systems off'. From the pilot perspective the comms can be switched off - but they are actually still connected at the network level in case the pilot wants to switch the higher level application on again.

[DespairingTraveller]

@IanW

Thank you for the explanations.

What I've taken away from this very interesting discussion is that possible the ground would know if the system had been tidily shut down because a logoff message would have been received, but that the existence of such a message hasn't been explicitly disclosed publicly. As you quite rightly say, if that evidence exists, it is crucial.

The preliminary report simply states:
It was later established that the transmissions from the Aircraft Communication and Reporting System (ACARS) through satellite communication system occurred at regular intervals starting before MH 370 departed Kuala Lumpur, Malaysia at time 12:56:08 MYT and with the last communication occurred at 01:07:49 MYT.
I was a bit surprised to read that paragraph, as I had been under the impression that ACARS was VHF only on this flight. Like others, I've also been under the impression that the 1:07:49 message was a routine engine report.

[mm_flynn]

I was a bit surprised to read that paragraph, as I had been under the impression that ACARS was VHF only on this flight. Like others, I've also been under the impression that the 1:07:49 message was a routine engine report.
I suspect that the report conflates the Satcom infrastructure (which logged twice in flight, and is the source of the pings), with the ACARS system (which provides store and forward text and data messaging from the flight deck and various aircraft systems). But ultimately, it is irrelevant in that we know when the last ACARS message was transmitted and we know the Satcom infrastructre was connected for many hours after that.

IanW,
Understood - My point was more on the logoff side. It doesn't appear that either system (SatCom or the ACARS store/forward network) have any intrinsic need to have a logoff function. From those with more technical knowledge, is there a logoff message the would or would not be expected in certain circumstances?

I have believed that both are like a transponder in that you know it is not 'on' when it stops responding/sending rather than something like a logout messaging being sent. As such, it is not possible to to deduce the 'Why' from a loss of ACARS or Satcom (or transponder) data. It is intinguishable between the device being shut down in a controlled way (i.e turned off in the normal way), suddenly issolated from power, failed, or destroyed.

[imaynotbeperfect]

I think you will find that the reason for a logon and log off is so that the network knows the aircraft is available to receive traffic in the ground - air direction.

[slats11]

Can't work out how to paste the image here.

I have calculated the solar terminator for 0018 UTC on March 8 2014, and the link below seems to work.

http://www.timeanddate.com/scripts/sunmap.php?iso=20140308T0018


So if plan was to ditch around first light, this would suggest a long way SW along the final (7th) arc. Somewhere close to the initial air search area a long way WSW of Perth.

The further NE along the 7th arc the flight ended, the longer the plane was flying in daylight.

[AstraMike]

The level of presumption here is really quite surprising. Tim Clark, President of the company that operates the largest B-777 fleet, and might just have access that we don't mentions, in an apparent off-the-cuff interview, that there were three things that his qualified crews would not know how to do, THAT WERE DONE and the presumption here is - OH! he must mean VHF com, Transponder(s), and ACARS? So how many 777 qualified pilots don't know how to manage those things? For example, do all aircrew know how to access the flight deck of an aircraft to which they are not assigned?

Isn't it time for a reality check?

Clearly, there is something else and I suspect that as a major operator with the responsibility he has, Mr Clark may know more that he can openly say? So what you, or we, should really be thinking about is what three things could have contributed to the loss of this aircraft that aircrew would not likely know about,but others might? And why is it he assumes that this knowlege boarded the flight and could do so again? Seems to discount all of those fire theories, meteors and structural failure too.

There are far more important issues in play here than LF noise picked up on hydraphones and an anxious lady sailor seeing an aircraft in the early dawn (when it is still dark at sea-level).

It seems that Tim Clark is still asking exactly what was below deck in the hold; amongst other things? That seems to have been brushed aside; as soon as someone found batteries. What else is there that remains unknown about the freight and the people onboard?

Why, then, is it assumed all will be known once the aircraft is found, if it is? Just what do you think the DFDR will reveal about the how and why?

It is time to stop sweating the small stuff and consider the bigger picture.

[Chronus]

Astra Mike makes a good point in closing:

quote "It is time to stop sweating the small stuff and consider the bigger picture"

The big picture now is the 29th May press release by JACC, where we are informed the next steps are as follows:

1. A review of all existing information and analysis to define a search zone of up to 60,000 square kilometres along the arc in the southern Indian Ocean.
2.Conducting a bathymetric survey to map the sea floor in the defined search area.
3. Acquiring the specialist services required for a comprehensive search of the sea floor in that area.

Simply put, this means.
1. Try and decide where to look next, then having made up their minds where to look,
2. have a peep to see where it is flat and where it is not, then
3. get the boys and their equipment on site.

It will take them till end of August to do No1 and at least another 12 months to do the rest.

Could it be that in the interim some debris may wash up on someone`s shores.

[Ornis]

AstraMike writes, "The level of presumption here is really quite surprising." Well, that's the nature of investigation into mysteries, collecting data and trying to fit the bits of the jigsaw together, ideas followed by testing against reality.

You presume that Clark is an authority and hiding stuff, rather than accept what he says at face value. “this aircraft was disabled in three primary systems. To be able to disable those requires a knowledge of the system which even our pilots don’t know how to do. Somebody got on board and knew exactly what they were up to.”

Well, we know it wasn't engine management, control surfaces or undercarriage he is talking about. I put Clark into the same category as many other highly paid executives.

I would suggest no Emirates pilots have disappeared with a B777, not because they can't, but because so far, none of them have wanted to. Professionalism, stability and a stake in the community.

We're not permitted to talk about the different cultures (including their religions), formerly called races, their attitude to life and other individuals ...

[exeng]

Glide from 35,000ft?

Less than 15 mins.

At 320 kts or so you might be correct - however at best glide speed you would be wildly out.

[nick1austin]

This map posted by the witness seems to point to 05:00 (time zone unclear), assuming the section highlighted is where the sighting took place.
The timezone was most likely UTC+8 (the software her husband used to create the plot uses local time), in which case that section of the plot missed MH370 by a couple of hours or so.

However since the yacht only does 3 knots so it would definitely been possible to see the airplane assuming that the ATSB estimated track is correct.

At 02:50 the yacht was on a northern tack so MH370 would have appeared over the bow, then swung around the port side and disappeared off to the stern. Her eyewitness account saw something over the stern and traveling from port to starboard, so that would be West to East, completely wrong for MH370

As for what she saw it was dawn so it may have been a plane catching the red glow of sunrise. The 'other aircraft' she saw could have be low-earth orbit satellites, which would have been clearly visible at that time of day.

[Ornis]

Can't imagine it would be a fighter, Gob, why would anyone send up a fighter on full burn to chase an unidentified primary target brushing up against a sensitive military area?

Well, it clearly didn't catch up with it, did it. I'd file this bright idea with the claim by the lawyer brother of Kiwi Paul Weeks lost on the flight, "It's either incompetency or a cover-up." Wouldn't just be that this caught everybody napping, nobody had a clue what happened or where it went...

[Gysbreght]

18:22 Last primary radar contact, aircraft heading NW
18:25 Log-on request initiated from the aircraft terminal
18:28 First 'handshake' arc, BTO and BFO indicate aircraft heading south

Between 18:25 and 18:28 there were 4 exchanges between the ground terminal and the aircraft terminal. The recorded BTO and BFO values for those exchanges varied considerably, which may be attributed to either the non-stabilized operation of the aircraft terminal or the turning of the aircraft. After 18:28 the BTO and BFO values consistently indicate a southern heading, so there must have been a turn after the last radar contact. Between the first and the sixth arc the BTO and BFO values show a steady progression, then there is another 'jump' to the final arc. The final arc is from a log-on request initiated from the aircraft, probably after a power interruption.

EDIT:
The 'jump' between the sixth and the seventh arc may have been due to the airplane descending at the time of the seventh arc.

[susier]

Katherine states on page 6 of her thread that:


'The GPS (http://www.cruisersforum.com/forums/tags/gps.html) time updates automatically. At no stage did we move beyond Thailand (http://www.cruisersforum.com/forums/tags/thailand.html) time. I don't know when it switched to Thailand (http://www.cruisersforum.com/forums/tags/thailand.html) time.'

[nick1austin]

The GPS track of the yacht was exported almost 3 months after being recorded (when the skipper wrote up the journey for a blog). The track would have been recorded in UTC but the skipper exported it in local time of the location where he wrote the blog. I think he was only interested in the track for the purposes of plotting a map and at the time didn't care about timestamps.

He doesn't seem to be talking online about the incident (in my view probably quite wise) and his wife is so bad at communicating facts that probably only a forensic analysis of the recorded data files would reveal the truth.

But in any case what's the point? She only filed a report after armchair experts elsewhere noticed that the yacht had been close to the estimated aircraft track. Up until then she hadn't connected the two events. It was dawn, she saw strange colours and that time of day always creates unusual lighting effects in the sky).

Had she kept a diary and filed a report sooner it may have helped the ATSB with it's construction of an estimated flight path. As it is her story, even if true, adds absolutely nothing to the investigation.

[martynemh]

From FL350, you'll travel about 85nm. At Vmd (ca 240kt IAS), you'll set off at about 410kt TAS. By FL150, your TAS will have dropped to about 300kt. For tha complete descent your average TAS will decrease from about 7nm per min at TOD, down to 4 nm per min as you reach the Indian Ocean.

You'll do those 85 miles in about 15 mins.

At Vmd.

[Ian W]

From FL350, you'll travel about 85nm. At Vmd (ca 240kt IAS), you'll set off at about 410kt TAS. By FL150, your TAS will have dropped to about 300kt. For tha complete descent your average TAS will decrease from about 7nm per min at TOD, down to 4 nm per min as you reach the Indian Ocean.

You'll do those 85 miles in about 15 mins.

At Vmd.

That is based on a lot of assumptions. Such as a pilot controlling the aircraft descent. Several thousand posts back someone reported testing an uncontrolled engine off descent in the SIM and reported a series of phugoids rather than a controlled descent. If a pilot is assumed then perhaps a dive maintaining speed to provide some controllablility at low level for a minimum wreckage ditching.
Or to put it another way, we are dealing with SWAG, anywhere within maximum glide range of the last 'Ping' position could be the ocean entry point. It could even be under the last ping if 'the pilot' had spiralled down

[martynemh]

I agree. The original discussion centred on how long it would take to glide from FL350 to sea level. Anything other than a controlled descent at or about Vmd would take less time.

I should have said 'not more than' 15 mins or 85nm or so.

[Gysbreght]

Ian W,

Just to be pedantic, and while there is not much else to discuss -

In a phugoid the airplane maintains an approximately constant AoA, i.e. constant L/D. While it is cyclically exchanging potential and kinetic energy, it does not lose total energy more rapidly than in a constant-speed descent, so the total range and time would not be affected.

[exosphere]

I agree. The original discussion centred on how long it would take to glide from FL350 to sea level. Anything other than a controlled descent at or about Vmd would take less time.

I should have said 'not more than' 15 mins or 85nm or so.


Maybe that's the case with the engines failed producing no thrust at all but only drag, but on idle thrust the time to glide from FL350 to sea level would exceed 20 minutes at Vmd at low weights (I know, low weight doesn't really influence gliding distance significantly but it doest influence gliding time).

If it really was an intentional glide I see no reason why the glide would have been conducted with engines failed due to fuel starvation rather than very low fuel remaining.

[aterpster]

exosphere:


If it really was an intentional glide I see no reason why the glide would have been conducted with engines failed due to fuel starvation rather than very low fuel remaining.

Just another "what if."

[GQ2]

With reference to the woman who may have seen the flight from a boat. I've been around aircraft all my life, but back in the 1990's, an odd incident occurred which illustrates a point;-
One summers afternoon, a friend rushed into my house to tell me to 'come and see the plane on fire'. Hastily going outside, my perception was of a light-aircraft at perhaps 500 - 800' agl coming towards me soundlessly. I could see the flames licking around the fuselage. However, after perhaps 15 secs, I realised that something was very wrong with my perception. There was still no sound, and the a/c wasn't any closer.... I then realised that the a/c was MUCH further away and very high. Later, radio and TV reports told of people about 70m away reporting it as 'overhead.....so it was very high. Many thousands of people saw it. (ATC at Birmingham reported no plot. There was much speculation, UFO, SR71, Aurora, you name it, not that it's relevant here.)
What was so amazing was how convincing the a/c was at looking much MUCH closer. It had something to do with the speed of the movement of the flames.
Whilst I'm not supporting her report directly, I am saying that, in clear air, flames, even at a great distance can look MUCH closer. My point is that a seasoned observer can be deceived, then it may explain a 'lay' witness not describing that which we 'expect' them to see, as I can attest.

[tarkay01]

Does anyone know why the USN pinger locator system doesn't use an array of transducers to determine the bearing to the back box acoustic pinger? There are many commercially available systems which use transponders to measure range and bearing to determine positions of underwater targets like ROV's. You can't get range from a free running pinger but you can get bearing. An example Ultra Short Base Line (USBL) system is covered in the link below.

USBL - All Systems (http://sonardyne.com/products/positioning/usbl-all-systems.html)

From the description.

"The second is that the bearing can be determined by knowing the discreet difference in phase between the reception of the signal at the multiple transducers present in the transceiver. This allows the USBL system to determine a time-phase difference for each transducer and therefore calculate the angle of the arriving signal."

All you would need is a compass on the fish along with the derived angle to get the bearing. This would allow the pinger to be found MUCH faster. Using a single transducer seems to be very inefficient.

[Harry O]

$3 million reward offered by families for whistleblower to come forward with information regarding missing flight MH370.
https://uk.news.yahoo.com/malaysia-airlines-plane-mh370-grieving-families-launch-3-101227033.html#CnWhrz1

[Ornis]

Kiwi loses job after MH370 email | Stuff.co.nz (http://www.stuff.co.nz/business/world/10132041/Kiwi-loses-job-after-MH370-email)

NZ oil rig worker who reported seeing burning aircraft, Mike McKay, was sacked for his trouble.

I don't believe he or British sailor Katherine Tee saw MH370 burning, but I would like to see some explanation for this phenomenon.

[oldoberon]

Tarko1

would that be the angle in 2D or 3D. ie bearing or bearing and elevation,and what about all these weird underwater effects we are told about

[p.j.m]

Kiwi loses job after MH370 email | Stuff.co.nz (http://www.stuff.co.nz/business/world/10132041/Kiwi-loses-job-after-MH370-email)

NZ oil rig worker who reported seeing burning aircraft, Mike McKay, was sacked for his trouble.

the article actually says:

McKay said he was paid up until the end of his hitch, or work period, but released from the rig five days early.
McKay was being released early as it had a local-salary engineer to take his place

So we was about to head home anyway, but got a 5 day early mark, and was paid for the 5 days.

[TylerMonkey]

Question... At 250 knots glide speed ( no power) on a 777 what would be the approx sink rate? 30 fps?

[tarkay01]

oldoberon

would that be the angle in 2D or 3D. ie bearing or bearing and elevation,and what about all these weird underwater effects we are told about Normally, it would be the horizontal angle or 2D. The horizontal angle would not be affected too much unless you were tracking a reflection in which case, the angle would be to the reflection point. You could get a 3D solution by having more transducers vertically separated. I would guess the 3D would be affected more by the underwater effects but would still be useful.

The horizontal angle would the get pinger location down to a few meters.

[Ornis]

Kiwi loses job after MH370 email | Stuff.co.nz (http://www.stuff.co.nz/business/world/10132041/Kiwi-loses-job-after-MH370-email) McKay's contractor and rig owner, Songa Offshore, were inundated with inquiries that blocked their communications, McKay said.

"This became intolerable for them and I was removed from the rig and not invited back."

McKay said he was paid up until the end of his hitch, or work period, but released from the rig five days early.

The subcontractor that he was working under, M-I Swaco, said McKay was being released early as it had a local-salary engineer to take his place, he said. "Contracts meant little in the oil field," McKay said. "The oil patch is a rough, unforgiving game."

The drilling fluids consultant has worked mostly in Southeast Asia for the past 35 years and in Vietnam waters almost continuously since 2008. He is now back in New Zealand and is waiting for a new contract.

Sounds like a reliable chap, worked there for 35 years and sent home early complaining contracts mean nothing. But he didn't get the sack. Nudge nudge wink wink.

[billslugg]

Relative to the errors in estimating distance:

I have observed six Space Shuttle launches from my community, Albany, GA, USA which is about 350 miles from the flight path as the Solid Rocket Boosters were completing their burn. If I had not known better I would have said they were ten or fifteen miles away and the flickering flames were a thousand feet long. In reality, they subtended about three degrees of arc, which made them close to 20 miles long.

[susier]

Regarding flames, Katherine Tee said she didn't see any as such. (Page 12, CruisersForum)


'And no, I didn't see any flickering that looked like flames. Just an orange glowing thing that I thought was a plane with orange lights.'

[Ornis]

I Think I Saw MH370 - Cruisers & Sailing Forums (http://www.cruisersforum.com/forums/f108/i-think-i-saw-mh370-127132.html)
Post #1 SaucySailoress I thought I saw a burning plane cross behind our stern from port to starboard;
My questions are:
2 - If it was a plane on fire that I saw,

No mention of flames but I think it's a reasonable inference?

[Grommo]

I thought it might be pertinent to point out that fireballs, missile launches, flaming meteors, spaceships reentering, planes on fire trailing smoke etc are quite regularly attributed to normal passenger jets leaving contrails in early morning or late afternoon sun. A classic example was the infamous Los Angeles "Missile" with "flaming tail" which in fact was a ups transport with bright sun reflection and a contrail. Los Angeles Missile Contrail Explained in Pictures - Contrail Science » Contrail Science (http://contrailscience.com/los-angeles-missile-contrail-explained-in-pictures/)
Similarly an airliner flying over Peru misidentified as a fireball. https://www.youtube.com/watch?v=hBKHkWw0oWg

With supposedly expert commentators like ex-airforce commanders claiming such things to be missiles or fireballs when they are in reality just afternoon/morning light effects on normal jets , it would probably be premature to ascribe too much importance to an inexpert observer on a yacht reporting an orange light and a smoky trail on an aircraft in early morning.

[HeyIts007]

It could be anywhere on any radial from where the last ping occurred to where the next ping would have occurred. That's potentially a long distance. We just don't know what happened after the last ping. We don't even know if the satellites data is reliable. If they can stuff up a search by incorrectly identifying false pings, what else can they stuff up? How can we have confidence in anything these so called experts undertaking this search tell us?

[Gysbreght]

It could be anywhere on any radial from where the last ping occurred to where the next ping would have occurred. That's potentially a long distance.That would require another hour of fuel. The time where the next ping would have occurred is irrelevant, only the fact that it did not occur, and that the last handshake was initiated from the airplane and was incomplete.

We don't even know if the satellites data is reliable.I don't see any reason to doubt the reliability of the Inmarsat logs. The real question is how accurate the BFO and BTO values are. The notes that precede the logs in the Inmarsat release discuss the sources of several inaccuracies.

[oldoberon]

Heyits007

Inmarsat data checked by AAIB before handing to malaysians then checked again by them an NTSB sources, it included checks against other malaysian 777 and earlier data from the same airframe.

WHAT ELSE DO YOU WANT THEM TO DO? please tell us what they have missed!

The TPL pings

1) In the area they were expected
2) Died at predicted battery run out date
3) Off frequency

2 out of three seem good, so sensible to try bluefin

I take it if you had been in charge you would have said ok guys forget that crap, lets look somewhere else - anyone got a map and a pin.

[HeyIts007]

What if they had 30 to 45 minutes of fuel rather than an hour? I come back to my original point. If experts can't even get the ping detection reliably, after spending massive resources in the search, it's difficult to have a great deal of faith in other aspects of this search. Perhaps they will get lucky, but eventually there will come a point in time where they will have to question the worth of investing further resources into this.

[oldoberon]

as he is new might worth explaining

a) last ping not on the hr
b) initiated by aircraft
c) probably due to RAT (for a very short period) powering up after both engines stopped

That's what you need to explain

Pontius if A,B or C wrong please correct

[HeyIts007]

Not at all. If the TPL was that easily fooled, especially when they seemed so confident in the pings, it's difficult have a great deal of confidence in the rest of the search operation. Even the partial ping does not seem to have a conclusive published official explanation. It's quite speculative here and elsewhere. They might keep searching, but it seems there will be many unanswered questions. Seems to be much conjecture as to what actually happened.

[Ornis]

HeyIts007. Are you trying to justify an end to the search? If so, argue the point, don't berate the experts. They might get some things wrong along the way but what do you expect of a complex investigation into a complete mystery?

[Chronus]

A number the realtives of missing pax are in the process of launching a reward offer of $5m using the Indiegogo web site. Suspecting a cover up on the part of the authorities, they are hoping this sizeable reward will entice a whistle blower to crawl out of the woodwork.

Similarities to the Aerolinee Itavia 870 crash of 1980 seems to be developing.

[woodpecker]

a) last ping not on the hr
b) initiated by aircraft
c) probably due to RAT (for a very short period) powering up after both engines stopped

That's what you need to explain

Pontius if A,B or C wrong please correct

Once the second engine failed (together with its generator), due to fuel starvation, the only fuel left may well have been in the APU feed line from main tank to the APU in the tail.

The on-board logic within the electrical system, with both generators off line, is automatic APU start so we may well have seen the "aircraft initiated ping" when the APU generator came online, all be it briefly before it also ran out of fuel.

The power from the RAT most certainly would not have powered the satellite system.

[grebllaw123d]

I have just seen an interview with a vice president from INMARSAT - after listening to this I must say that I have regained considerable confidence in the correctness of the data presented by INMARSAT in the case of the missing MH370.
Link:
MH370: Is Inmarsat right? - CNN.com (http://edition.cnn.com/2014/05/27/world/asia/mh370-is-inmarsat-right-quest-analysis/index.html)

[BOAC]

Two queries:

Woodpecker - is the 777 system such that an 'automatic' APU start would automatically bring the APU gen on line?

Anyone - have we seen any estimates of a/c radial groundspeed from the BFO data from Inmarsat? This would give the minimum g/s at any point, and as the a/c travels further from the satellite should approach actual g/s.

[Gysbreght]

Anyone - have we seen any estimates of a/c radial groundspeed from the BFO data from Inmarsat?I'm not sure I understand your question. The aircraft radial groundspeed to the satellite is determined from the BTO (Burst Timing Offset). It is equal to the distance between two successive arcs divided by the time difference between those arcs. The north-south component of the aircraft velocity can be calculated from the BFO (Burst Frequency Offset). The accuracy of both calculations is critically dependent on the precision that the true BFO and BTO values are known (*), and that is the reason for the uncertainty about probable trajectories.

(*) EDIT: That applies in particular to the BFO value. The notes on page 2 of the Inmarsat release explain the factors that may affect the accuracy.

[rh200]

what else can they stuff up?

Pretty well anything, after all they are human. Thats why they share the data with various competent research groups and agencies to get independent analysis. This takes time and they have to have to search on the best evidence they have at the time. It doesn't help they have to report on every little thing on a daily or shorter basis else they get accused of hiding information

How can we have confidence in anything these so called experts undertaking this search tell us?

Thats up to you and your understanding of the process and the challenges involved. As for me I'm more than happy with the effort they have put in considering all the challenges.

[wiggy]

Sink rate therefore would have only been 11 fps . . . does not add up.

So what do you think does "add up?

FWIW a clean 777-200 at light weights descending at say Vref 30 +80 (min clean) possibly needs an ROD of around 1000fpm/16 fps with engines at idle to a maintain min clean IAS. However if you chuck all the rules about buffet margins and min FCOM speeds out of the window due to "Force Majeur"/pilot incapacitation then low RODs become very credible and I think extrapolating "time to splash" from some (alledged ) datalink burst becomes highly speculative.

(777 driver with X thousand hours on type, so no doubt about to be moderated out)

[porterhouse]

. A number the realtives of missing pax are in the process of launching a reward offer of $5m using the Indiegogo web site. Suspecting a cover up on the part of the authorities, they are hoping this sizeable reward
Why so little? They can safely offer $100 mln - the result will be the same.

[Shadoko]

BOAC and Gysbreght.

From the Inmarsat filed data you have for each ping: a time H, a BTO (a length of time), a BFO (a frequency value). Please, reread the first page of the "raw data".

The BTO is only used to know at which distance R is the a/c from the satellite at the time H. From this distance R you can know that the a/c is somewhere on a circle. This circle is the intersection of:
- The sphere centered on the satellite at the time H and with a radius R,
and
- the "sphere" centered at the Earth center and which has the radius of the Earth plus the a/c altitude. This "sphere" is not a true sphere because the Earth is not perfectly spherical, so the circle is not a true circle.

The BFO comes from:
-1- the speed of the a/c relatively to the satellite,
-2- the speed of the satellite relatively to the a/c,
-3- the speed of the satellite relatively to the Earth station,
-4- an "error" from the a/c component which communicate with the satellite,
-5- the position of the satellite relatively to its theoretical fixed position above the equator.
#3 and #5 are perfectly known at whatever time. #4 is deduced from the data of the begining of the flight and from older flights of the a/c. So the global effect of #1 and #2 could be known from the filed BFO.

Theoreticaly, the a/c compensate the BFO from its own speed relatively to the satellite (#1). But this compensation is based on a fixed satellite. So the compensation the a/c mades is wrong when the satellite is not at its theoretical position. Say this value is F1.
The other useful component of the BFO is the one from the satellite speed relatively to the a/c (#2). Say this component value is F2.
Only the sum F1 + F2 is known. It results from the measured BFO after two corrections: 1) for BFO due to the satellite speed relatively to the Earth station and 2) for the "error" from the a/c component deduced from BFOs at times when the a/c position was known before take off.

For a given point on the circle, you can know F2 (because the satellite speed value and direction are perfectly known at the time H). So you can deduce F1.
But, you can't deduce a speed of the a/c from F1, only a "couple" [speed + direction of flight]. There are an infinity of couples which are in accordance with F1, thus with the BFO, but you have a minimum speed (flight direction exactly away from the satellite) and a maximum angle between the direction of flight and the line of sight of the satellite given by the maximum speed of the a/c. This error is also very small, so the incertitude about the "couple" is pretty large.
Fortunately, there are two other constraints:
- you have to reach the next circle at the right time (the time of the next ping),
- the point reached has to be in accordance with the new BFO at this time.

If you knows the first point (from primary radar position extrapolation), it is easy to find a flight path in accordance with all data, after making suppositions about the speed of the a/c (for each one, different headings...).
If you dont't know the first point, you have to compute many hypothesis (about the first point) to find credible flight pathes.

[Communicator]

Shadoko wrote
But, you can't deduce a speed of the a/c from F1, only a "couple" [speed + direction of flight]. There are an infinity of couples which are in accordance with F1, thus with the BFO, but you have a minimum speed (flight direction exactly away from the satellite) and a maximum angle between the direction of flight and the line of sight of the satellite given by the maximum speed of the a/c. This error is also very small, so the incertitude about the "couple" is pretty large.This is an important point. Further comments:

(1) Conceptually, it is tidier to separate out:(a) the velocity component along the axis between the satellite and the aircraft location (i.e. notional point at sea level below aircraft) due to satellite motion relative to earth. This component can be computed precisely for any given time and (assumed) aircraft location.
(b) the total velocity component along the axis between the aircraft and the satellite due to the combination of aircraft and satellite motion. This component is equivalent to the doppler shift between the aircraft and the satellite which contributes to the overall BFO value.
(2) The BFO correction value is apparently derived based on measurement of the frequency deviation of the incoming signal received from the satellite. The idea is that the a/c system pre-compensates for Doppler shift such that the signal received by the satellite appears at the nominal channel frequency.

[HeyIts007]

Doesn't the Power Supply Assembly use a dedicated battery to prevent power interruptions during power source transfers?

[BOAC]

but you have a minimum speed (flight direction exactly away from the satellite) and a maximum angle between the direction of flight and the line of sight of the satellite given by the maximum speed of the a/c. - my point. What prevents detemination of the first from the measured Doppler shift? Obviously if the following is correct, this does......

the a/c system assumes the satellite to be at its nominal position and that error results in the BFO. - if I read you correctly, you are saying that any Doppler shift is PURELY due to satellite motion away from geo-stationary and not aircraft speed? I had understood from all the previous stuff about BFO that it was affected by aircraft ground speed. Now I am told that a/c speed is removed from the equation? Would this not result in a reversal of BFO sign as the satellite 'turned' on its path? Is this apparent in the published BFO data? Can you highlight it?

[Three Wire]

The APU fuel,feed is from the left wing tank. It uses either the FWD wing boost pump or a dedicated AC/DC APU fuel pump.

When Both AC BUS L and R are unpowered the APU is commanded to start. The APU door opens electrically, but the APU will start either electrically or pneumatically.

As an ETOPS airplane, the engines are normally staggered; ie., one of them is a higher time/cycles than the other. On our fleet, the right engine is the higher time engine.

Due to this stagger, the right engine normally consumes slightly more fuel, and would be expected to flameout first. In a fuel flameout situation, there would probably be less than a minutes worth of fuel in the APU fuel lines, probably just sufficient to light off, achieve power generation speed, then flameout. Hence the attempted logon.

[BOAC]

The question was:
"is the 777 system such that an 'automatic' APU start would automatically bring the APU gen on line?"

[SOPS]

The answer is yes.

[oldoberon]

I have just seen an interview with a vice president from INMARSAT - after listening to this I must say that I have regained considerable confidence in the correctness of the data presented by INMARSAT in the case of the missing MH370.
Link:
MH370: Is Inmarsat right? - CNN.com (http://edition.cnn.com/2014/05/27/world/asia/mh370-is-inmarsat-right-quest-analysis/index.html)

thank you for link.

Let's hope this puts the doubters to bed, he clearly stated (twice) the data had been vaidated against other 777 and this frame on previous flights (which rules out any anomolies with this planes satcom system).

The only disappointment was not asking him about the final ping, to have him put that on record.

It does raise the question for me if the TPL pings were not 370,what were they, was the conclusion reached that they weren't because no wreckage was found or for some other technical reason.

I guess we will know that when we see where the next search stage starts.

[roninmission]

Obviously this depends on the efficiency of Bluefin.

TIGHAR - the folks who believe they know where Earhart crashed have been extremely critical of Bluefin. However, I'm not certain of their level of expertise.

[BOAC]

No, BFO depends on the satellite speed and the airplane speed. The BFO sign does not reverse as the satellite moves through its apogee. If the airplane speed is constant in magnitude and direction, the rate-of-change of BFO changes gradually with the changing satellite speed. - this is all very confusing for a simple pilot! As the satellite reverses from its northbound travel to southbound travel I cannot see why the 'error' (the BFO?) caused by the rate of change of displacement from geo-stat does not reverse since the rate has reversed? Looked at another way, why is the BFO not zero as the satellite reaches 'apogee' and the satellite 'speed' wrt geo-stat becomes zero?

Secondly, if I understand correctly (!!), there is a Doppler shift recorded by the ground station for each burst. Presumably this can be translated into an apparent radial 'ground speed' which can then be corrected by the BFO to produce a reasonbly accurate minimum 'ground speed'. Are these values available?

[rans6andrew]

I have been struggling with the various arguments for choosing the southerly arc in preference to the northern one. It seems to me that the doppler/BFO shift is due to the instantaneous rate of change of the path length between the aircraft and the satellite combined with the instantaneous rate of path length between the ground station and the satellite, This same path length rate of change is what has driven the distance between the arcs at the hourly time intervals, ie I can't see how the two bits of information are sufficiently independent of each other to tell whether the southern or northern arc is a better fit.

Also, I have not seen any mention of windspeed or direction. If the aircraft has flown for 6 hours from it's last known positive position would not the speed (and probably the direction) have been influenced by the path passing through different weather patterns thus messing up the "assumed" speed and track constancy?

Lastly, can someone point me to some figures for the actual speed of the satellite relative to it's nominal geostationary position? Is the speed significant relative to the airspeed of a 777 or even relative to the likely winds seen at the assumed altitude of the aircraft in that area of the world?

[BOAC]

Lastly, can someone point me to some figures for the actual speed of the satellite relative to it's nominal geostationary position? Is the speed significant relative to the airspeed of a 777 or even relative to the likely winds seen at the assumed altitude of the aircraft in that area of the world? - I believe I saw somewhere it moves 1.67 degees north and south over 24 hours. If you have the brainpower, you can work out the speed (probably a sinusoidal function) at that radius from the earth. Good luck..........

[Communicator]

Kudos to everyone for finally publishing the Inmarsat "raw data". (BTW - Inmarsat is, of course, bound by its clients' instructions. MAS finally authorized the release of the data.)

Based on a basic understanding of the electronics involved (Inmarsat Classic Aero mobile terminal), the fact that this equipment has been around since the 1990s, and discussions of the "BFO" data (e.g. on Duncan Steel's website), it appears that the BFO values are the amount of Doppler-shift pre-compensation applied by the a/c terminal.

This implies that the BFO value is measured by the a/c terminal and then transmitted as part of the Satcom data to Inmarsat for diagnostic purposes. This makes eminent sense since Doppler shift is a major reason for degradation and failure of the a/c-satellite-earth station links.

Thus, the BFO value is proportional to the relative velocity of the satellite and the a/c along the LOS (line of sight) axis between them.

Still unclear is the precise correlation between the relative LOS velocity and the amount of the BFO change. What LOS velocity (in knots) requires a a Doppler shift pre-correction of 100 Hz? Why are the amounts (apparently) never negative?

It may be that the frequency offset relates to a base frequency equivalent to 600 MHz, rather than the uplink frequency of 1600 MHz. This could make sense depending on exactly how the satellite deals with Doppler shift encountered on uplink and downlink transmissions.

[Rollleft]

Geostationary satellites have typically been station kept in 40 mile boxes since 1972. To save Reaction Control System fuel Inmarsat allowed inclination of the orbit to grow. This resulted in ~700 miles of N-S motion of the satellite during 7 hours of observations. The Burst Frequency Offset value matched in value and sinusoidal rate of change consistent with a 24 hour orbit. The satellite motion was then removed from the observed doppler which generated a vector to resolve the N S ambiguity on the line of position generated by the range measurement. Further Doppler signature analysis bracketed the speed and heading of successive handshakes. Doppler analysis was used for decades by SARSAT albeit with much more orbital inclination but less stable frequency ELT's. Inmarsat deserves credit for figuring it out, and VP Mark Dickinson for explaining it on CNN.:D