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.

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.

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?

CELLPHONE OR WHATEVER CALLS
 

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 "

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?

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/uplo...70-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.

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?

The 4 channel designations in the SATCOM log, FYI.

Text filtering of the A/C -> Ground down link comms
 

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

Downlink Comms:
@DrPhillipa

16:29 could be "Gate Out"
16:41 could be "Wheels Off"
OOOI Data - ASPMHelp

17:07 was an ACARS message Inmarsat used for calibration:
Hunt for Jet Switches to Visual Search as Radar Empty - Bloomberg

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.

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.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.

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).

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

I see white lines. I still see no dots.

@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.

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?

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

@Shadodo

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

@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.

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?

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...

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